What’s the best technology for your pumped hydro project?

For your pumped hydro project to be suited to future energy market conditions, you need to understand the technology options available – because pumped hydro plant is not one-size-fits-all. Let’s go for a deep dive …

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Pumped hydro has been around for more than a century, but in recent years it has leapt into the forefront of the quest for energy storage and firming options as the energy sector embraces increasing levels of renewable energy generation. If you want to get the best from a pumped hydro project, it’s important to come to grips with the implications of the different types and combinations of mechanical and electrical machines that have been developed over the long history of hydropower and pumped hydro.

The choices are among fixed-speed reversible pump turbines, variable-speed reversible units (including doubly-fed inverter arrangement), and ternary sets. Each has its own variations and strengths in terms of the services able to be provided to the energy market. But the technologies also vary in costs, housing requirements and performance.

All pumped hydro projects are likely to offer benefits to the market by contributing to operating reserves, reducing spill or curtailment of variable renewable energy, reducing cycling and ramping of thermal plant, lowering transmission congestion and associated costs, and lowering greenhouse gas and pollutant emissions when used to displace thermal generation. But let’s look at the specific pros and cons of each of the different pumped hydro configurations, and how they compare.

Reversible units

Reversible units comprise a single hydraulic machine (turbine-pump), a single electrical machine (motor-generator) and a single shaft. The unit changes rotational direction to switch between generating and pumping modes.

These reversible units come in two different forms: fixed speed and variable speed. The fixed-speed reversible units can’t optimise the uptake of power from the grid in pumping mode, which is important in a grid with the rapid and frequent fluctuations characteristic of high levels of variable renewable energy. However, with a multi-unit arrangement in a power station, additional flexibility during the pumping cycle could be achieved at a premium.

Variable-speed reversible units provide greater efficiency and flexibility and provide different opportunities for grid support than fixed-speed units in pumping mode. However, should all the thermal plants be retired as the energy market transforms, the lack of synchronous machines could become a major issue where rotating inertia becomes scarce. Asynchronous (variable-speed) machines rely on their power electronic controls to provide inertia. While this can be artificially enhanced relative to synchronous machines, it relies on externally provided system strength which may also be lacking in the absence of thermal units.

Based on recent projects in Australia, the cost of electrical and mechanical equipment for variable-speed reversible units is about 30% greater than for fixed-speed units and the construction cost is approximately 10% more. Yet, while fixed-speed units come at a lower cost, variable-speed machines have the potential under some configurations to provide more valuable services in operation, such as variable load during pumping operation, and as long as there is adequate synchronous generation, inertia distributed around the network.

Ternary sets

Ternary sets comprise two hydraulic machines (a turbine and a pump), coupled on a single shaft, with a single electrical machine (motor-generator). This means that the direction of the turbine is the same in generating and pumping mode. They are often the only solution for projects with very high head but they can be applied for lower head projects too. Without having to change direction, little changeover time is needed between modes, making it possible to respond much faster to the grid. There’s also less stress on the machines, which can be individually optimised. The turbine and pump can even operate simultaneously (in hydraulic short-circuit mode), and the turbine can be used to start the pump (further reducing changeover time).

This description makes it sound as if ternary sets are the way to go … but it isn’t that simple.

Many of the elements of the civil works for a pumped storage project are the same whether fixed-speed reversible units, variable-speed reversible units or ternary sets are used. However, the powerhouse structure for ternary sets needs to be taller or wider (as the units are bigger), penstocks and tailrace branch pipes will require an extra bifurcation, and it is likely that the costs involved in hydro-mechanical equipment such as gates and valves will be significantly greater. 

The extra construction costs can add up to approximately 25 per cent more than for reversible units. And the additional electro-mechanical equipment could come at a 35 to 50 per cent higher price tag compared to the fixed-speed reversible units. However, countering the increased cost of ternary sets is their likely efficiency gain of 2 to 3 per cent and a faster response time than reversible units are capable of.

The increasing need for fast response

Adopting either variable-speed reversible units or ternary sets appears, on the face of it, to be more expensive than fixed-speed reversible units, but there are mitigating circumstances that make them worthy of serious consideration.

With settlement periods in the Australian National Electricity Market reducing from 30 minutes to 5 minutes, fast response is critical. Both ternary sets and variable-speed reversible units have a big advantage over fixed-speed units in this regard, but fixed-speed units can work with the 5-minute settlement if they are utilised appropriately as part of a pumped storage scheme.

Short-circuit mode

Reversible units and ternary units require similar amounts of power from the grid in synchronous condenser mode. For a 125 MW unit, the grid power required is estimated at about 4 MW.

Some projects investigating the idea of hydraulic short-circuit with variable-speed, doubly-fed inverter machines are currently underway. In essence, a waterway is shared between two units with a bifurcation upstream and downstream of the units. In this case one of the units will operate in generating mode and the other in pumping mode.

What’s the answer?

There’s a lot to take in when comparing the different pumped hydro configurations. It’s generally accepted that variable-speed reversible units and ternary sets have certain advantages over fixed-speed reversible units in a changing energy market. Yet, in some cases fixed-speed units will do the job, and at a lower cost, whilst at the same time guaranteeing synchronous generation if rotating inertia is of essence to grid stability. There’s no clear-cut winner when it comes to pitting variable-speed reversible units and ternary sets against each other. As usual, the right choice will depend on the specifics of your project conditions and what changes you anticipate as energy markets continue to evolve.

If you would like to discuss how Entura can help you with your pumped hydro or renewable energy project, please contact please contact Nick West on +61 408 952 315, Mohsen Moeini on +61 421 461 545, or Alan Barrett on +61 437 102 756.

About the authors

Nick West is a civil engineer at Entura with more than 18 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study and is currently involved in feasibility assessments of pumped hydro options as part of Tasmania’s Battery of the Nation initiative.

Mohsen Moeini is the team leader for hydropower and pumped storage at Entura. He has a Masters degree in civil engineering with nearly two decades of experience in design and consultancy of hydropower and dam projects. Mohsen has been involved in more than 20 hydropower and pumped storage projects in the last 10 years in Australia and the Asia-Pacific region, mainly as a design manager, project manager or project director. In 2017, he also led the development of a pumped storage atlas that identified project opportunities in Australia.

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Engineering – by humans, for humans

When engineers think about the future, do we get so engrossed in the complex technical problems that we don’t attend enough to the human angle?

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Engineers have a reputation, whether rightly or wrongly, for being poor communicators, working obsessively and in isolation, and focusing on the immediate goal rather than its impacts on communities. Often, clichés have a basis in truth. If we are going to shift perceptions, we need to start by thinking about the way we work and the leadership we show to the next generation of engineers.

There’s no way we can predict the major developments, challenges or solutions of the next five or six generations of engineering careers. What we should focus on is what we can do right now to lead change in our profession and our communities – and I think the keys are communication, collaboration and community.

Communication

I recently listened to a podcast in which two energy market experts talked with a power system engineer. They discussed all sorts of technical matters relating to frequency and voltage control. I love those topics, but this conversation was limited and uninspiring because the participants simply didn’t have a common language or understanding.

We need to learn to communicate in ways that a variety of people can understand. That will mean better conversations with the people who can help our work have greater impact, and it will help our communities to appreciate the importance of our work in their lives.

It’s too easy for us as a profession to sit at our desks or stand under our hard hats and luxuriate in how clever we are, and then bemoan how so many people have no idea what we do and don’t value our work.

When things that involve engineers go wrong, a flurry of opinions erupts. Failures such as the blackout in South Australia, or the cladding issues at the Grenfell Towers, or issues with airlines or bridges or dams all lead to our communities questioning and debating engineering practice. Engineers tend to try to stay out of this rough and tumble for fear of being misrepresented. Yet maybe it’s better that we do engage where we can, since being misrepresented on a small issue is better than allowing a groundswell of misguided public opinion due to a lack of understanding of engineering principles. 

We need to try to better explain our work and find simple ways to convey the complexities of the decisions that we make. 

Collaboration

The world is far more complex now than it was a century ago – but it is impossible to imagine what level and pace of change future generations will experience. If we want to transform our world or help build a better future, we can’t do it by ourselves. 

Engineering no longer operates in isolation, if it ever did. We must collaborate across the engineering team and across other professional disciplines to achieve truly effective development for our communities. Sometimes we may need to focus a little less on technical delivery as a primary outcome, and increase our recognition of the value gained by engaging successfully with the communities on whom the project relies for success.

Collaboration makes our work more effective, and exposes us to a wider range of inputs and values that we can incorporate into our designs and processes. Engineering can be a leader but it can also be a facilitator for better outcomes when we draw on, listen to and learn from the other experts involved in other aspects of our projects.

Community

Engineering work almost always benefits more people than merely the one who pays the bill. Much of my work is in connecting wind farms and solar farms to the grid. Mostly my work is paid for by the owner of the farm, and while it delivers direct benefits to the owner through return on investment, it also affects everyone connected to the nearby network. It affects the network service provider and market operator, it pays salaries, and it supplies the clean energy that helps the country reduce emissions and meet its international targets. In other words, my work, which may seem intangible, has tangible effects in the real world.

If we agree that our labours produce real impacts, we need to take better care to fully consider the wider consequences of our work, which often has the potential to cause ‘collateral damage’. We can’t build a road or a wind farm without changing the landscape. When we build a machine, it uses energy and may emit pollutants; and it reduces reliance on manual labour, which may put someone out of a job. There may be a risk to lives, livelihoods or the environment if something goes wrong.

Do we always make decisions about these matters with the community front of mind, or do we place our clients on the higher pedestal? This is a tricky area and I’m not espousing a puritanical approach. However, if we knew in 1919 what we know now about lead poisoning, acid rain, greenhouse gases, scarcity and general sustainability principles, what different choices could have been made?

In a time of automation, we need to think about benefits and risks and how they affect our communities. On one occasion early in my career, I designed a controller to turn on and off a couple of compressors at a power station. I wrote some code to balance the run hours. A few months after the new system was commissioned, I asked one of the operators how the system was going, in terms of the run hours management, and he said ‘you’ve done me out of a job’. I hope he was joking. The task he’d been doing wasn’t particularly important, but there was value in having a person who was in tune with the equipment to take care of it, and there was also value in giving that person dignity through work.

My point is that we must keep our communities foremost in our minds as we go about our work. It’s not just about what we produce. It is the way we work and the people we choose to work with and for. Our influence on the development of the next generation of engineers perhaps has more impact on communities than our actual work outputs.

Through communication, collaboration and community, engineering can be both ‘more human’ and ‘for humans’.

About the author

Donald Vaughan is Entura’s Principal Consultant for Primary Electrical Engineering. He has over 20 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

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Becoming the Battery of the Nation

This article appeared first on the International Hydropower Association blog.

How can a small island become a giant battery for a nation? We’re finding the answers in increasing interconnection, developing new pumped hydro and repurposing our existing hydropower assets.
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Tasmania is a small island state, with excellent water and wind resources. We’re powered mostly by an extensive hydropower system developed over the last hundred years – supplemented with newer wind developments. We’re connected to Australia’s National Electricity Market by an interconnector running across Bass Strait to the mainland. This has allowed us to trade in the national market for some time now, but as thermal generation progressively retires and Australia embraces greater proportions of variable renewables, the future national market will be vastly different. It will be characterised by low-cost variable renewable energy sources firmed by dispatchable storage and generation.

With Tasmania’s fantastic natural resources, established hydropower system and expertise, we want to be the ‘Battery of the Nation’, offering the generation and the storage and system support needed to help Australia achieve a clean, reliable, affordable energy future. Our Battery of the Nation vision is shaping up to be one of the most credible, competitive and coordinated solutions, able to be built in stages, aligned to market drivers.

In a nutshell, the Battery of the Nation means generating more renewable energy from our hydropower and wind assets, developing more storage solutions in the form of pumped hydro and building more interconnection to the mainland so that we can get our product to the national market to quickly and reliably support variable generation. 

With the support of funding from the Australian Renewable Energy Agency (ARENA), we’ve been making progress towards this vision on a number of fronts.

Connecting the battery

Batteries aren’t much use if they’re not connected, so we need more interconnection to mainland Australia to get the power to where it’s needed. The initial business case for a new, second interconnector between Tasmania and mainland Australia shows it stacks up, and federal funding has recently been secured to fast track this 1200 MW interconnection project, known as Marinus Link.

Priming the pump

Around the world, significant investment is being made in new technologies such as grid-scale batteries and solar thermal projects, yet pumped hydro remains the most viable technology for longer term storage (greater than eight hours). Our state has significant pumped hydro potential and our existing hydropower assets offer excellent potential to repurpose and create cost-effective pumped hydro. We’re filtering down the possible pumped hydro options to identify around 2500 MW of future potential. The three most promising sites offer between 12 and 31 hours of storage and would cost around AUD 1.5 million / MW to develop. Further feasibility investigations will identify which one of these three will be the preferred option that can be ready to take advantage of more interconnection.

Redeveloping existing assets

We are also focusing on how to get the most out of our existing hydropower assets by repurposing and futureproofing them for a transitioning electricity market. The Tarraleah scheme in Tasmania’s central highlands was commissioned in the 1930s and our studies have been considering whether the scheme should be progressively refurbished or redeveloped. Redevelopment would more than double the scheme’s capacity from 104 MW to up to 220 MW – contributing to Battery of the Nation targets. By converting the station to flexible and fully dispatchable operation, instead of just baseload, it could flexibly boost output at times of high market demand and provide the ancillary services likely to be increasingly valued in the market. It is also expected to have flow-on benefits for the entire cascade of power stations below it.

We are also continuing major refurbishment and upgrades of other existing hydropower assets so that we can get more generation, efficiency and longevity from these assets to support our plan to become the Battery of the Nation.

Benefits for our island and the nation

The Battery of the Nation vision offers economies of scale and diversity by combining flexible, reliable renewable energy resources with cost-competitive, large-scale storage that can be built in stages, aligned to market drivers. 

Battery of the Nation is designed to serve and support our local and national communities. Across the nation it will contribute to achieving lower power prices, reliable and secure energy supply, and meeting sustainability targets. It will also offer specific benefits to Tasmania through energy security and economic stimulus.

Battery of the Nation is a bold and bright vision to unlock our potential to contribute to the nation. It’s an example of how to reimagine hydropower and storage for the new market paradigms of a shifting energy future.

Safer dams are a matter of priority

Examples from around the world demonstrate the devastating consequences of dam failures. Safety must be every dam owner’s key concern, but how should action be prioritised across a large portfolio of dams?

 
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To prioritise effort and resources to achieve the best safety result across a whole portfolio of dams, you need a portfolio risk assessment (PRA). A PRA determines the risk position of the dams based on known information, identifies any information gaps, develops a strategy to close these gaps, and then determines the most effective actions to decrease any risks.

APPLYING PRA TO A LARGE AND COMPLEX PORTFOLIO

Entura has supported dam owners and water managers across the Indo-Pacific region with PRAs, but our most extensive application of the PRA process has involved the 54 large dams of our parent company, Hydro Tasmania.

Hydro Tasmania is Australia’s largest water manager and is committed to ensuring that the risk of a dam failure is very, very low across the entire portfolio. Across so many dams, clear priorities are needed to focus dam safety efforts and human and financial resources.

It has now been 20 years since Hydro Tasmania’s PRA journey began in 1999, so it’s timely to reflect on its outcomes.

With so many dams of greatly varying types, ages and heights, the PRA across Hydro Tasmania’s dams was always going to be complex, and needed to be staged. The first step was a small pilot study on five selected dams that represented the range of potential risks within the broader portfolio.

During the pilot study, the five steps of Entura’s PRA process were defined: 
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This methodology was applied across Hydro Tasmania’s dams portfolio, and an average of eight dams were added to the review each year.

By 2005, the initial ‘baseline’ assessment of the full portfolio was complete. The focus of the dam safety program has now moved to investigation and implementation of upgrades, and the communication of outcomes to senior management.

The PRA process has increased the focus on potential failure modes and risk as drivers of the dam safety program and as the basis for deciding priorities for allocating operational and capital resources.

DETERMINING PRIORITIES THROUGH A RISK FRAMEWORK

Entura’s PRA process reviews the consequences of failure of a dam by looking at the impact that it may have on downstream populations and infrastructure. The engineering assessment considers the effects on dams of extreme events such as floods and earthquakes, taking into account the specific site conditions. Combining the chance of failure and the resulting consequence determines the level of risk.

Hydro Tasmania assesses, prioritises and mitigates risks across the business using an integrated business risk management program, and the dam PRA feeds into this overall risk management approach. A dam’s assessed risk rating across common tolerance criteria drives the risk management response. The assessed dam risks are plotted together on a chart to provide a risk profile for the whole portfolio. This allows dam safety risks to be compared, understood and communicated readily throughout the business in a similar way to all other business risks.

The initial objective of the dam safety program is to reduce all the risks categorised as ‘high’ or ‘extreme’ as soon as practical , and then to continue with a program of investigations and capital works to diminish risks even further. Actions for dams lying in the higher risk zones did not wait for completion of the PRA, but were initiated as soon as risks were identified.

Some cost-effective and expedient risk-mitigation was achieved by identifying and implementing ‘quick wins’. These early actions reduced the overall portfolio risk while more complex mitigation plans were being developed. In some cases the ‘quick win’ actions have even provided the ultimate solution. In other cases, more major works have been required.

PROGRESSING THE DAM SAFETY JOURNEY

The PRA process has substantially benefited Hydro Tasmania’s dam safety program, by improving understanding of the dam portfolio, underpinning a strong strategic plan for addressing risks, improving surveillance and monitoring, and considerably strengthening dam safety emergency planning and warning.

However, this isn’t the end of the dam safety journey. Knowledge of any dam is never complete, and it is critical for dam owners to remain aware that not every failure mode may necessarily have been identified in a baseline study that relies on existing information. There may still be a level of uncertainty about the ‘unknowns’.

For Hydro Tasmania’s PRA, identifying these uncertainties enabled development of a prioritised list of investigations necessary across the portfolio. These detailed investigations have been critical to the development of the dam safety program, by confirming any potential failure modes identified in the PRA.

The list of potential failure modes of a dam portfolio must be rigorously and regularly reviewed, and investigations to reduce uncertainty about the portfolio should be ongoing. New methods and techniques for analysis are being developed all the time, and it is important to understand how these may change existing risk assessments. As well, the safety and risk-level of a dam can change as dams age, or when there are changes to the way the dam is managed.

It is also important to realise that the capital works program for dam safety risk reduction across a portfolio must remain flexible and be actively managed to respond to new or changed risks, new developments in the field of dam engineering, shifts in business priorities, delays to projects, and new developments in risk management.

The sheer number and variety of types, ages and consequence categories of Hydro Tasmania’s dams made Hydro Tasmania’s PRA a challenging process, but the benefits are substantial. The baseline study completed in 2005 is not the end of this journey, which continues to prioritise actions, reduce risks and enhance safety across the portfolio. 

If you would like to discuss how we can assist you with assessing your dam risks, developing a resource-effective and comprehensive dam safety program, or applying the same PRA process to other key assets, please contact Paul Southcott, Richard Herweynen or Alan Barrett.

About the author

Paul Southcott is a specialist civil engineer at Entura. He has more than 32 years of professional expertise in civil and dam engineering, as well as expertise in geotechnical, foundation, structural, hydraulic and hydropower engineering. Paul’s dam engineering experience spans geotechnical and hydrological investigation; feasibility and options studies; concept, preliminary and detailed design; engineering assessment, consequence assessment and risk assessment; safety reviews; monitoring and surveillance; and emergency planning. He has extensive experience in dam risk assessment including as project manager for Hydro Tasmania’s, Taswater’s and SAWater’s portfolio risk assessment projects.  He was a member of the ANCOLD committee that issued the Guideline on Consequence Categories for Dams in 2012 and is currently a member of the ANCOLD committee drafting the new Guideline on Geotechnical Investigations for Dams.

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Are you an asset manager or an ‘asset guesser’?

In the hydropower sector, we’re all trying to do more with less. And as hydropower assets age, there’s always more to be done.

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Gut feelings and guesswork won’t be enough if you want to make the best use of your asset management budget and keep your assets safe, reliable and profitable.

Today, ‘asset management’ is a much more sophisticated practice than twenty to thirty years ago. Back then, we’d refurbish or replace components at fixed time intervals (whether the work was needed or not), hoping that this would prevent or reduce breakdowns and forced outages. In most cases, this sort of scheduled maintenance was based on original equipment manufacturers (OEM) recommendations, best guesses or a mixture of both with very little evidence of root causes of actual or potential failures identified.

This maintenance attitude led to repeated failures. It also resulted in short-term planning. And, because of a lack of good evidence that current maintenance approaches were achieving direct positive business returns either in plant or financial performance, it increased the pressure to reduce maintenance budgets.

Asset management today

Hydropower assets are increasing globally, both in number and in size. So too, our knowledge of hydro assets continues to strengthen.  We have much better understanding and insights now into how and why these assets wear out, how they behave, why they fail, and the ways in which they respond to various operating conditions and environments.

Operating conditions are constantly changing due to variables in the energy market, power purchase agreements, increasing expectations of customers, changing technologies and regulatory requirements, and more. So asset management needs to be flexible and to respond to the evolving context.

Today, ‘asset management’ is a trendy term – but there’s a very broad spectrum of practice across the hydropower industry, and it is a long path from basic approaches through to achievement of superior methods and strategies.

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Click to download infographic

To achieve the lowest lifecycle costs for assets, as well as to minimise forced outages and breakdowns, power and water businesses need to see asset management as a crucial component of risk management and business strategy. It also needs to be viewed as an incremental journey of improvement, supported by processes and structures based on standards.

Ideally, your asset management policy, strategy, plans and activities should be based on the ISO/AS 55000 series of standards. The ISO 55000 standard series encourages aligning asset management with your broader organisational objectives, context and plans – and recommends that you regularly revisit this to be sure that alignment is maintained. This can now filter through your asset management policy and strategic asset management plan (SAMP), and be embedded in the reality of implementing your asset management plans.

In other words, your asset management policy provides direction which is aligned to your organisational context; your SAMP translates this; and your asset management plans act as the catalyst to create and sustain change in leadership, culture and asset management practice.

People, plant and process

Alignment with the principles of the ISO/AS 55000 standard series are fundamental to achieving the lowest lifecycle costs for hydropower assets. For success in your business you need to consider not only the physical asset but the entire delivery process, you need to understand what is required in each of three ‘P’s – people, plant and process – and you need an implementation plan to get you there.

Without people, we don’t have plant. Having the right people involved, right from conception, can make the difference between successful projects with years of profitability and projects that face years of increased expenditure and issues to manage. Ensuring that the right people have the right skills, training and competencies to carry out the right maintenance at the right time is paramount to achieving the plant performance you desire.

When it comes to plant, we recognise that, ultimately, all assets have a finite life – but our increasing knowledge of asset behaviour can help us to design components better for longer life and for greater cost-effectiveness and efficiency. By developing and implementing the right asset management techniques, you will increase the likelihood of your assets being profitable, reliable, available and safely operated – and staying that way. A strategic investment in asset management will more than pay for itself through increased benefits and decreased risks.

Turning to the ‘process’ element, we should recognise the importance of assessing, organising, planning, budgeting and reporting on the work effort – but there’s a need to ‘keep the processes real’. In other words, don’t implement processes for the sake of it, nor to try to address or mask problems in other areas that would be better to rectify than to over-manage. Processes should support the integration of the broader organisational context into operations and maintenance and then help to assess and report on effectiveness and performance.

By bringing people, plant and process together, and aligning asset management with your business vision and decision-making, you are far more likely to be able to get the best out of your valuable assets. And you’ll achieve a culture of continuous improvement and proactive, prioritised action – leaving no more room for reactivity and guesswork.

If you would like to discuss how Entura can assist you with assessing and managing your hydropower plants or other power or water assets to minimise risk and maximise efficiency and useful life, please contact Leigh Smith on +61 419 884 318 or or Mathieu Chatenet on +856 2022 214 214.

About the author

Leigh Smith is a specialist consultant with extensive experience and proven ability in asset management, condition assessment, risk management and project management in the power sector, particularly hydropower. He has over three decades of practical experience with hydropower assets and has successfully delivered and project managed many major projects in Australia and internationally. Leigh has produced numerous asset management plans to support financial modelling and feasibility of major hydropower projects, as well as detailed 30-year asset management and maintenance plans that have been critical to the progression of projects around the world.

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Rethinking the role of hydropower in Australia

Although hydropower is older than wind and solar generation and battery storage, its role in Australia and around the world has never been more important.

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Hydropower is still by far the largest contributor to the world’s total generation of renewable energy. The fact that this old technology is still very much alive today shows that hydropower can stand the test of time and help us meet the challenges of the future.

As the proportions of solar and wind generation rapidly rise, and as we see a gradual retirement of existing thermal generation and reduced construction of new thermal generation, the role for hydropower – both in Australia and internationally – continues to broaden and build.

New opportunities for hydropower

There’s no need to see rapidly emerging and increasing new technologies as a threat to hydropower. This isn’t a winner-takes-all environment. Rather, new opportunities are emerging for hydropower as an enabler of integrated renewable developments by providing the storage needed to smooth the intermittency of weather-dependent renewables – creating ‘dispatchable’ renewable energy.

In the last couple of years, particularly since blackouts in South Australia in 2016 and nationwide rises in electricity costs, debate about energy affordability, sustainability and reliability has become both mainstream and continuous. The pressure has never been greater to find the cheapest, cleanest power that is available whenever and wherever it is needed.

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It is well known that traditional hydro schemes can provide baseload power or peaking power, grid stability services, and availability to fill in the gaps when intermittent renewables aren’t generating. However, the recent resurgence in interest in pumped hydro offers something extra: the ability to use excess available generation from wind and solar to pump water uphill into storage so that it can be used for electricity generation later – and this is why it can be described as a ‘battery’.

But how does pumped hydro compare with ‘actual’ batteries? Will rapid improvements in battery technology displace pumped hydro as a preferred storage solution? Technology is advancing very quickly in batteries, but I’m convinced that there are still some major differentiators that create space for pumped hydro.

One advantage is that we have a greater understanding of pumped hydro’s lifecycle costs and sustainability, whereas there are still a number of uncertainties in this respect for newer technologies such as batteries.

Also, critically, while batteries may be a good solution for low-power, short-term storage, they are not yet capable of providing the frequency and voltage regulation required by a grid with a high proportion of intermittent renewables. Batteries also typically cannot supply the significant level of output over a longer duration that pumped hydro energy storage or traditional hydropower can make possible.

Pumped hydro and modified traditional hydropower solutions will be needed for smoothing daily variability as wind and solar plants expand in number and size. And it is really only traditional hydropower with large reservoirs that will be able to provide the multi-day storage needed in extreme events of both low wind and low solar.

Achieving full dispatchability of combined wind and solar PV power will depend on utilising pumped hydro storage and existing hydropower storages to their full potential.

If the future of both traditional hydropower and pumped hydro is strong, why have no new pumped hydro projects been built in Australia in thirty years? What is needed to not only get it going in Australia, but also to make sure we get it right?

I believe that three crucial elements to realising hydropower’s future and ‘getting pumped hydro right’ will be identifying the most viable sites, developing a sound business case, and ensuring that we invest in the skills and capacity we’re going to urgently need in the future.

Identifying the most viable sites

A critical element for pumped hydro success is identifying a viable project – where the right site and the best design can come together into an optimal mix of capacity and cost. Entura has done a lot of work in this area, and we have developed a methodology to filter the many hundreds of potential pumped hydro sites across Australia down to the most ideal.

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This methodology has enabled us to develop a real-world, relevant and practical pumped hydro atlas of Australia identifying project opportunities from many thousands of theoretical possibilities.

Our atlas has already been used to shortlist potential pumped hydro sites for the Battery of the Nation initiative in Tasmania, and it identifies many more promising sites and opportunities for developers in states such as South Australia, New South Wales and Queensland. And the nation has room for many more batteries.

Building a robust business case

We’ve often said that a project won’t get over the line on the base of technical viability and environmental benefits – in the current market, the dollar wins. So pumped hydro needs some level of predictability in its revenue streams. As the dynamics of arbitrage change, we need to explore a range of other revenue opportunities. And that’s a complex forecasting challenge.

Part of the solution may be price insurance and a value placed on providing network support services and firming. Another part is behind-the-meter generation and integration – such as in the Kidston project, in which pumped hydro is coupled with a large-scale solar farm, and potentially wind generation, to form a renewable energy hub.

Investing in capacity development

To me, a third critical component is investing in talent, skills and capacity. This is a global issue as much as an Australian one. To prepare our industry to adapt to change as well as to drive further change in the sector we will need to harness talent and upskill and transition workforces.

This is the kind of strategic whole-of-business workforce planning that we encourage our clients to adopt, and it will be crucial over coming years and decades.

I am excited about the future of both traditional hydropower and pumped hydro. I firmly believe that if we value hydropower as a key player in the future mix of technologies in our energy markets, we can solve the energy trilemma at home and around the world.

About the author

Tammy Chu is Entura’s Managing Director. She leads Entura’s business strategy, performance and services to clients, and is part of Hydro Tasmania’s Leadership Group. Tammy joined the business in 2000 and has held a range of positions at Entura, from Technical Professional to Project Manager, Business Development Manager and Water and Environment Group Manager.

As a civil engineer, Tammy specialised in the design and construction of mini-hydro and hydropower systems, project management, hydropower investigations, prefeasibility and feasibility studies, environmental assessments and approvals, resource investigations and resource water management.

Tammy is a member of the Board of the International Hydropower Association. She was the first female and now past president of the Tasmanian Division of Engineers Australia, and was an Engineers Australia National Congress representative.    

Tammy holds a Master of Business and Administration from Chifley Business School, is a Fellow of Engineers Australia, and a graduate of the Australian Institute of Company Directors.

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Can the sedimentation problem be solved?

Sedimentation is a problem for water storages, particularly in Asia. It is a major concern for all communities and industries that depend on water storages for water, food and energy security.

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As sediment builds up over time, the storage capacity of a water reservoir will reduce. If we can effectively prevent, manage and reduce sedimentation, more water can be stored, which is critical for a sustainable future in a world experiencing increasing population, industry and climate pressures.

Loss of storage is certainly damaging to the performance of hydropower schemes, but it’s not the only sedimentation-related problem for hydropower developers and operators. High levels of sediment, whether in storages or flowing through run-of-river hydropower schemes, can seriously damage expensive hydro-mechanical equipment, causing significant operations and maintenance issues and costly outages.

It is clear, then, that planners, developers and operators need to consider how to minimise and mitigate sedimentation in all water storage projects, but particularly if the project is in a region that yields a large amount of sediment.

As with any problem, prevention is better than cure. Although, in some cases, prevention isn’t possible, or the problem already exists, so ‘curative’ options need to be explored.

Prevention

The best prevention of sedimentation problems begins at the source – in other words, the catchment area of the river. If we can reduce the sediment yield from the watershed, we can reduce the sedimentation issues in our reservoirs, increasing the life of the available storages. Most of the sediment that reaches a water resource project site is due to rainfall and run-off erosion and transportation of material by the river’s flow. When the sediment reaches a reservoir, it becomes trapped and builds up over time, reducing the amount of water that can be stored.

The quantity of sediment will be heavily influenced by the rate of erosion within the catchment, which depends on interactions among factors such as climate, soil, geology, topography, ground cover, land use and human activity. Some of these factors and interactions cannot be controlled, but human-related aspects affecting erosion and sediment yield can be predicted and managed through an integrated catchment management plan. Such a plan would require significant efforts to counter factors such as agriculture, mining, construction and deforestation, and include attention to revegetation and erosion prevention. Identifying and mitigating impacts in areas susceptible to the geological risk of landslides is another important part of the plan, whether this is around the reservoir rim or within the main catchment of the reservoir, as these areas of instability will affect sediment inflows.

Beyond this catchment-level reduction of sediment yield, planners and designers need to consider how to reduce the inflow of sediment into the particular reservoir, therefore maintaining the storage. Local or project-specific preventative approaches require accurately estimating the sedimentation rate during planning and design – through careful attention to measuring sediment concentration and the capacity inflow ratio – and, based on this estimate, considering building structures upstream of the main reservoir to either trap sediment or encourage sediment to bypass the reservoir. Sediment can be trapped before reaching the main reservoir with a series of weirs or ‘check dams’ upstream of the reservoir, yet these will only be effective until such time as they fill with sediment.

Intervention

The next option is to keep the sediment moving, either through the reservoir or past the reservoir, so the amount that is deposited in the reservoir is minimised. In many cases, the main transport of sediment is in flood water; thus, flood waters can be channelled past the reservoir using bypass structures, or can be allowed to pass through the dam at high velocity (known as sluicing). An important disadvantage of bypassing and sluicing of flood waters is the loss of a significant amount of water that otherwise could have been captured in the storage. As a result, it is most applicable in reservoirs with a smaller capacity in comparison to the total inflow.

Due to the very high cost of creating bypass conduits, bypassing the full length of a reservoir is rare, and would only be considered in special circumstances or where other methods are not effective. If the reservoir is located on a horseshoe bend of the river, a sediment bypass structure may be cost-effective due to its reduced length. Therefore the unique characteristics of the site need to be taken into account when developing the initial concept for the project, looking for opportunities created by the topography.

Sluicing involves discharging high flows through the dam structure during periods of high inflow to the reservoir, to allow sediment to be transported through the reservoir as rapidly as possible while minimising sedimentation. Sluicing is performed by lowering the reservoir storage prior to high-discharge sediment-laden floods. This approach requires relatively large capacity outlets to be incorporated into the dam design to enable the discharge of appropriately large flows at low reservoir levels to maintain the required velocities to transport sediment. This is achieved through low-level under-sluice gates, or tall crest gates, or both.

To understand how a reservoir will behave, appropriate investigations are needed in the planning stage to accurately determine the sediment characteristics, inflow and distribution in the reservoir. This data can then be used to model the flow and deposition of sediment within the reservoir, using sophisticated hydraulic modelling software. These models can be used to fully understand the problem, and to test solutions – helping to determine the appropriate location and capacity of low-level outlets, develop operating rules that will work for the particular reservoir, set the intake invert to avoid future problems, and develop an overall concept for the dam that works – all of which will contribute to avoiding future problems.

The sediment problem becomes particularly worrisome for run-of-river hydropower plants located in rivers which typically carry a high level of sediment, such as rivers flowing from the Himalayas. To protect against damage to equipment, desilting arrangements such as desilting tanks and chambers are generally provided, normally immediately downstream of the intake structure to the water conveyance system, whether a canal or a tunnel, along with modifications to equipment, such as coatings to better resist abrasion.

Remediation

The aim of remediation is to recover the original storage volume of the reservoir. If sediment has built up in a reservoir in the absence of, or despite, preventative measures, the options are now limited to reducing sediment levels through hydraulic methods (flushing through reservoir drawdown) or mechanical methods (excavation or dredging). The advantages of hydraulic methods are that they tend to be cheaper and easier, using water currents or flows to force sediments through gates and outlets close to the reservoir bed. Nevertheless, these methods may release large amounts of valuable water through the emptying of the reservoir, which may not be desirable during either dry conditions, or where the storage volume is very large in comparison to the annual inflow.

Mechanical methods, such as dredging and excavation, are typically very expensive and only practical on certain reservoirs, and therefore seen as a last resort. Dredging can either be via hydraulic pumps (for finer sediment) or mechanical grabs (for coarser sediment) on barges. Due to its expense, it is often only used to remove sediment from specific areas near the intake structure of a dam. If a reservoir can be completely drawn down, which is not practical for many reservoirs, accumulated sediment can be removed through scrapers or excavators and dump trucks.

Finally, there may be the potential to add new storage to the existing reservoir by raising the dam. The practicalities of this will need to be evaluated through a feasibility study process, as is normally adopted for a new dam.

The right solution depends on good information

In many cases, managing sedimentation will require a combination of strategies and technologies, such as reducing the sediment yield at the catchment level, reducing inflows of sediments into storages using appropriate structures and technologies, operating storages effectively during flood conditions, and actively managing storage levels and operating rules to allow sluicing and flushing.

Many of the sedimentation problems experienced around the world were either not predicted or significantly underestimated during design. To avoid this situation, continuous, adequate and accurate monitoring data is needed, as well as appropriate modelling and projections that take current and potential future conditions into account. Solutions that have been tested via appropriate modelling are much more likely to meet performance requirements and to avoid future risks.

The rate of sediment deposition is heavily influenced by the sediment concentration and the capacity inflow ratio, so careful estimation of these two parameters is very important in identifying the seriousness of a sedimentation problem. In existing large reservoirs, sediment management will benefit from supplementing conventional hydrographic surveys with the adoption of improved survey methods and remote-sensing techniques. The resulting data will enable more reliable estimation of sedimentation rates.

Better measurement, modelling and estimation of sediment – for existing storages as well as future reservoirs – will provide the insights we need to improve sediment planning and management. The right combination of sedimentation estimation, prevention, intervention and remediation will be critical for the long-term health of our water storages and a sustainable future.

If you would like to find out more about how Entura can help you develop a sustainable water storage solution or respond to sedimentation challenges, contact  Mathieu Chatenet on +856 2022 214 214 or James Mason on +61 400 603 650.

About the authors

Pradeep Tiwari is a Senior Hydrologist at Entura. Pradeep has nearly 11 years of experience in water resources projects after completing his M.Tech (Civil) from IIT Kanpur, India. He has worked in hydropower engineering and irrigation projects comprised mainly of project hydrology covering water availability, reservoir simulation, Flood Peak Estimation and recommendation for design flood, reservoir and channel routing, diversion flood estimation and sedimentation study for planning and design of dams. Apart from projects in India, he has also been involved in projects in Nepal, Lao PDR and Ethiopia.

Richard Herweynen is Entura’s Principal Consultant in Civil Engineering. Richard has nearly 30 years of experience in dam and hydropower engineering, and has worked throughout the Asia-Pacific region on both dam and hydropower projects. Richard was part of the ANCOLD working group which updated the guidelines for concrete gravity dams, and is the Chairman of the ICOLD Technical Committee on Engineering Activities in the Planning Process for Water Resources Projects. Richard has won a number of engineering excellence and innovation awards, and has published over 30 technical papers on dam engineering.

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Identifying Australia’s best sites for pumped hydro development

There are many thousands of potential sites for pumped hydro energy storage developments across Australia, but how can a developer filter these down to the best few?

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As Australia’s energy market progressively transitions from ageing thermal generation to increasing amounts of wind and solar, there are ample chances to explore and develop the energy storage solutions needed to mitigate the challenges that may come with the introduction of more renewables into the energy market.

With increased intermittent renewables, we will require more storage to smooth out the variability of weather-dependent generation so that energy is available on demand. As well, we will need storage that provides the inertia, voltage and frequency control required for a stable, reliable grid.

The key to successfully embracing these energy storage opportunities will lie in identifying the right mix of technology, capacity and site; however, pinpointing potentially viable projects is complex. A theoretical or academic approach won’t be enough to ensure a future project’s success in the real world.

Pumped hydro is a highly efficient, longer-duration solution with a proven track record, and its future is bright as Australia seeks cost-effective, reliable options to make intermittent renewables ‘dispatchable’.

There are thousands of potential pumped hydro sites across Australia. This means that developers and investors need smart methods of filtering to reduce the many possibilities to just a few ideal sites.

A pumped hydro project is a major capital investment. Getting site selection right is the foundation for success, as it will determine the likelihood of achieving a design that is both technically and commercially feasible with the right mix of capacity and costs.

Pumped Hydro Atlas of Australia offers a head start in site selection

Entura has produced a practical atlas of pumped hydro energy storage opportunities to support development of dispatchable renewable energy generation across Australia’s National Electricity Market (NEM).

Through an exhaustive process, the atlas filtered many thousands of potential sites down to the best 20 around Australia. It is already being used by leading renewable energy company Hydro Tasmania to shortlist potential pumped hydro sites for the ‘Battery of the Nation’ initiative (a major Tasmanian initiative looking at how Tasmania could deliver more clean, reliable and cost competitive energy to Australia’s NEM). Identification of promising pumped hydro sites through the atlas also offers opportunities for developers in states such as South Australia and Queensland, which have set ambitious renewables targets and must maintain energy security.

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Entura’s Pumped Hydro Atlas of Australia takes into account far more than the basics of identifying ideal topography and a source of water. It also accounts for other practical factors that can make or break a project: such as proximity to and location within the transmission network, land-use constraints and environmental risks, and the practicalities and costs of construction and ongoing operation. This makes it a real-world, relevant resource identifying the best sites for pumped storage projects across the NEM.

Developing the Pumped Hydro Atlas of Australia

Originally commissioned by Hydro Tasmania, the Pumped Hydro Atlas of Australia was completed in October 2017. The journey began with a literature review, appraising previous studies. This informed the development of a set of rules, assumptions and algorithms for a GIS-based study of different reservoir types and pairing mechanisms, which were tested on pilot sites.

Using these algorithms, more than 200 000 pairing reservoirs were identified across the NEM states (Queensland, New South Wales, Victoria, Tasmania, South Australia and the Australian Capital Territory). State-based heat maps of potential sites for pumped hydro development were prepared, along with a summary of all key characteristics for each pairing reservoir set, such as installed capacity, energy storage, distance from the nearest substation, gross head, approximate headloss in the waterways, and active reservoir volume.

A subsequent stage of refinement prioritised high-potential sites in some states. This process took into account greater practical detail, such as costings, practical engineering aspects, environmental approvals and risks, realistic high-level arrangements, proximity to other generators, and characteristics of hydrology and energy storage. This stage identified more than 5000 unique potential sites, which were then further refined with a set of rules to select the best pairing reservoir at each site. The approximately 5000 sites were reduced to approximately 500 of the most attractive options: those with an average head of more than 300 m with relatively short distances between the reservoirs.

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This exhaustive refining process ultimately resulted in a shortlist of twenty promising sites across different states, with a desktop review of geology, high-level engineering arrangements, and approvals requirements. For each site a map was prepared including locality, land use, planning zones, and key characteristics of the potential pumped hydro project.

The Pumped Hydro Atlas of Australia is an example of how applied hydropower engineering can be used to create practical outputs, which are ready to be applied in the real world. Overlaying the outputs of this atlas with any new wind and solar development across the NEM could result in opportunities to invest in dispatchable renewable energy generation hubs capable of replacing thermal generation assets as they retire.

Pumped hydro energy storage will no doubt play a major role in the development and expansion of networks powered by renewable energy – in Australia and around the world. As Australia’s electricity mix evolves, so will the economics of storage. While forecasting revenue for storage projects in the Australian electricity market is still somewhat uncertain, there are many opportunities in both the existing and emerging markets to guarantee project revenues to a level sufficient to satisfy a lender’s requirements. The opportunity for investors seeking a head start in this emerging market is now.

If you would like to discuss how Entura can help you with your pumped hydro or renewable energy project, please contact Mohsen Moeini on +61 421 461 545 or Alan Barrett on +61 437 102 756.

About the author

Mohsen Moeini is a Specialist Dams and Hydropower Engineer at Entura. He has 18 years of experience in dam and hydropower engineering, and has worked throughout the Asia-Pacific region. Mohsen was the Project Manager of the Kidston Pumped Storage Project Technical Feasibility Study. He also led the development of the Pumped Storage Atlas of Australia, which identified project opportunities across the NEM.

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Dispatchable renewables: a contradiction in terms?

As Australia replaces retiring coal generation with renewables, can we achieve an energy future that is affordable and sustainable as well as reliable?

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The role of renewable energy in achieving affordability and sustainability is clear. As coal-fired power stations approach retirement in Australia, renewable generation from wind and solar PV appear to be the most cost-effective options for new energy generation. Wind and solar power now offer the lowest cost of energy, have low ongoing operational costs, and emit the least greenhouse gases across their lifecycle – and therefore hold the greatest potential for rapid decarbonisation of the energy sector.

But what about achieving the third element in what has been termed the ‘energy trilemma’: reliability?

Replacing coal-fired power stations with wind and solar PV is not a like-for-like swap in terms of availability of power when it is needed by consumers. Coal-fired power stations produce firm baseload power, but generation from renewable resources varies due to the availability of the natural resource. Wind and solar PV power vary according to the weather and the time of day, and even if we consider new hydropower opportunities, most of these are small ‘run-of-river’ systems, the output of which varies with rainfall and the inflows to rivers.

Yes, these renewables certainly produce energy, but is the power produced when it is needed?

The variability in power from renewables makes matching supply and demand a challenge. This challenge increases as more renewables enter the market. With moderate amounts of renewables, it is still possible to maintain system reliability through clever solutions – in particular, targeted grid support designed through careful planning and study of generation profiles, and supported by solid communications, control, power systems studies and forecasting. However, there is a limit to such approaches, and ultimately Australia will need ‘dispatchable renewables’ in the energy mix to achieve all the elements of the energy trilemma – in other words, renewable generation that is available whenever consumers require it. The time to start planning for this transition is now.

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For generation to be dispatchable it needs to be available at the request of power grid operators or the plant owner according to the needs of the market. Dispatchable generators can be turned on or off, or can adjust their power output according to market need. If a generator is dispatchable it can be used to match load, meet peak demands, or fill the gap if another generator suddenly goes offline. Dispatchable generation is very valuable to the market because it can be used to match the profile of energy demand.

Effectively, baseload fossil fuel generation can be replaced by the combination of variable renewables, dispatchable renewables, smart high-voltage network support and planning to ensure sufficient transmission capacity, and change in use of existing hydropower.

How can we make variable renewables ‘dispatchable’?

The concept of dispatchable renewables seems almost contradictory: how can something generated from an inherently variable resource be dispatchable? There are two parts to this: the first is to look at how well different wind and solar PV sites naturally work together to firm supply (i.e. how likely it is that dips in one source are filled by peaks in another). Once this is understood, we need to consider how much storage is required to manage residual variability. Storage is critical here as it provides flexibility to store excess or low-value energy for times when it is really in demand.

When patterns of renewable generation are highly correlated (in other words, the timing of generation is very similar), more storage is required. For example, if the east coast of Australia develops a very high proportion of solar PV generation capacity, then all of these will be generating within about two hours of each other during the day (because of similar sunrise and sunset times across this region), and not at night. To fully utilise this energy, much of it would need to be made ‘dispatchable’ by adding substantial storage for the night-time hours, or we would need to firm the supply using another generation source, such as a gas turbine. But with a suitable proportion of wind in the mix (and stronger interconnectors to solar generation from other regions), the same dispatchability can be achieved with a more moderate amount of storage. This example demonstrates the importance of achieving a mix of renewable generators to meet the goal of dispatchability. 

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Various studies of generation in the NEM over time have demonstrated that wind and solar generation are not highly correlated. These studies have shown that even with low to moderate correlation, when considered over a large geographical area, a combination of such generators reduces variability and increases reliability of supply. Understanding this effect enables appropriate sizing of storage to create a dispatchable renewable portfolio with maximum value. There will always be some times when multiple generators produce near maximums, as well as some times when both wind and solar produce near minimums; these occasions are not common, but could have significant consequences. This is a risk that needs to be managed by the system.

The amount of firm capacity can be increased by over-installing generation, and curtailing its output when there is too much generation. However, there are still those infrequent periods when multiple generators are at their minimum and parts of the grid need extra support. Having this support available during these rare occasions will be critical to managing risk and maintaining reliable supply.

This indicates that the mixture of different renewables won’t take us all the way to the goal of achieving ‘dispatchable renewables’; storage remains a critical ingredient.

What’s the future for energy storage?

The media is awash with reports of new energy storage options. It is important to recognise, though, that different types of storage solutions vary widely in their ability to discharge power over different time frames. Therefore one type of storage will not necessarily deliver the same solution as another type of storage. Understanding this is critical to the concept of dispatchable renewables.

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The power and duration of the storage are the two key variables in determining the most suitable solution. Low-power, short-term storage is currently more cost-effective using batteries, but longer periods and larger power requirements are likely to rely on bigger storage options, such as pumped hydro energy storage and traditional hydropower.

With individual wind and solar plants pushing 1 GW, pumped hydro and modified traditional hydropower solutions need to be considered. Smoothing out the daily variability in renewables can be achieved effectively through pumped hydro, but multi-day storage to supplement periods of extreme events of both low wind and low solar will require traditional hydropower with very large reservoirs.

In the long run, short-term storage will not be sufficient alone to achieve the aim of ‘dispatchable renewables’. Achieving full dispatchability of combined wind and solar PV power will depend on utilising pumped hydro storage and existing hydropower storages to their full potential.

When will we need dispatchable renewables?

The question of when we’ll need dispatchable renewables is complex. It’s driven by a combination of commercial, regulatory and technical considerations as well as changing customer behaviour (all of which are in motion).

The short answer is now.

There are already isolated opportunities in which dispatchable renewables offer distinct advantages, and where the business case may stack up. With increasing wind and solar PV developments in the network without dispatchable capability, such opportunities will only expand. However, the lead time required to include large-scale storage in these ‘dispatchable renewables’ projects means that planning must begin well in advance.    

If you would like to discuss how Entura can help you explore potential opportunities for dispatchable renewables, please contact  Alan Barrett on +61 437 102 756, Richard Herweynen on +61 3 6245 4130 or Chris Blanksby on +61 408 536 625.

About the authors

Richard Herweynen is Entura’s Principal Consultant in Civil Engineering. Richard has 28 years of experience in dam and hydropower engineering, and has worked throughout the Asia-Pacific region on both dam and hydropower projects. Richard was the Project Director of the Kidston Pumped Storage Project Technical Feasibility Study and, in recent years, Richard has led the design of three roller-compacted-concrete dams within Australia and a number of significant dam upgrades. Richard was part of the ANCOLD working group which updated the guidelines for concrete gravity dams, and is the Chairman of the ICOLD Technical Committee on Engineering Activities in the Planning Process for Water Resources Projects. Richard has won many engineering excellence and innovation awards, and has published over 30 technical papers on dam engineering.

Dr Chris Blanksby is a Specialist Renewable Energy Engineer at Entura, and Entura’s lead solar energy specialist. He has undertaken and published research on the solar resource in Australia, and has led several due diligence and owner’s engineer projects for wind, solar and microgrid projects in Australia, the Pacific and Asia.  

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Maximising the benefits of GIS for better business decisions

‘Location, location, location!’ It’s a familiar catch-phrase in the real estate industry, but it’s just as relevant in the power and water sector. Wherever there’s location-related data, a geographic information system will guide better business decisions.

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Mobile devices and apps are increasingly using location-based data collected via satellites, drones, LIDAR and other rapidly developing sensing and data capture technologies. With these advances, we are able to find relevant information more quickly and draw on that information to make informed decisions. We’re seeing this proliferate in everyday life through apps that help us navigate, find services and products, and make decisions ranging from the trivial to the profound.

Developers and managers of power and water infrastructure projects who embrace GIS (geographic information systems) stand to gain benefits on an even greater scale. Gathering high-quality spatial information and analysing it to guide business decisions will certainly improve productivity and the bottom line.

Better decisions are the necessary foundation for increased revenue, lower costs, greater efficiency and productivity, and reduced risks. So, if the technology is available and there’s so much to gain, why isn’t GIS being as widely used in the power and water sector as it could be? What may be holding businesses back from fully embracing this powerful and dynamic technology?

Do we really need to use GIS for this project?

All power and water projects involve location – from finding an optimum site for your project, to analysing combinations of spatial data to make the best management decisions or to predict events. Whenever you ask a ‘where?’ question, GIS can help. Where is the asset best located? Where are the constraints or hazards? Where are the reports of previous work done in this area? Where are the customers or opportunities?

In other words, rather than asking whether GIS is needed on a project, consider making GIS a default for every project. The real question should be “how can we maximise the benefits of using spatial data and GIS on this project?” GIS can offer business benefits far beyond the most commonly understood use: making a map.

Data capture in the field can now be streamlined – gone are the days of capturing field data with pen and paper. Users can now collect data on mobile devices, sync to databases while in the field, share data, and generate their own maps, queries and reports. Embracing these advances will save time and enable faster and better decisions.

As well as providing valuable business insights, spatial analysis and location intelligence can greatly improve communication and knowledge sharing – within project teams, with the broader business, and with the community and stakeholders – via tools such as web maps and apps, visual analysis and 3D modelling.

One of the most important applications is the simultaneous analysis of different spatial datasets to provide the best solutions or choices between alternative options, locations, objects and so on. This process is better known as multi-criteria analysis (MCA) and it can be used for many applications.

For example, MCA can be used to find the optimum site for your project taking into account a range of values such as local geology, threatened species, resource availability, land use and terrain, planning restrictions, communities and demographics. Using MCA, you can establish areas of best fit for your project based on thematic overviews of areas of constraint, cost of construction, access and transportation routes.

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Risks such as bushfire, weeds, threatened species, pollution sources, landslides and erosion can also be more easily and fully understood, supporting your ongoing site management of such issues.

GIS also links with document management, asset management, business intelligence and enterprise resource planning (ERP) systems. It can act as a portal, creating a central point of easy access, pulling together information and making it available on one of the simplest forms to interpret – a map.

Of course GIS is not the answer to everything, and it is not a standalone platform. However, there’s much it can offer across many different business activities, working together with other business systems.

What about the costs?

The return on investment of using GIS should be positive if it is used appropriately. For site selection of power and water projects, using GIS is a no-brainer. For example, using GIS to find the best site for a wind farm – locating the best winds, minimal constraints, good proximity to existing infrastructure and appropriate land use – will obviously result in vastly greater returns than siting the wind farm in an inferior location.

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Some examples may be less immediately apparent, but equally valuable – for example, using GIS to increase efficiencies in everyday workflows. If your workers are taking an extra half hour every time they need to find previous work completed in an area, this time can add up quickly. Or perhaps they can’t find previous information, so work is re-done unnecessarily. These costs will keep adding up. Instead you could use a GIS web map to locate all your previous reports and projects, so that a simple click on a map finds the files and saves hours (if not days) of time.

Do we need specialist software or skillsets?

With most things, you do need specialised skillsets and software to get good results, and of course bad data in equals bad data out. Users of GIS do need to understand and assess the spatial data needs in each application.

You could undertake some GIS work yourself using free or open-source software. However, be aware of the risks of using data or tools that aren’t fit for purpose. Just because you know how to use Microsoft Word, doesn’t mean you could write a detailed report outside your area of expertise!

We have seen cases where coarse-resolution data has been used to infer finer project details and costs, resulting in poor decisions. We have also seen inexperienced operators make invalid assumptions. To get the best results, you need to be sure that you’re using the technology wisely.

If you are engaging a power, water or environmental consultant on a project, they are likely to have access to GIS capability; however, GIS is still often underutilised. When deciding who to engage on your project, ask your consultant how they will maximise the benefits of GIS to produce better outcomes for your project.

To discuss how Entura can help you harness the potential of GIS to improve your power and water project decisions and outcomes, contact Stephen Thomas on +61 3 6245 4511, Jim Moore on +61 3 8628 9731, Akhil Pai on +61 406 874 101 or Alan Barrett on +61 437 102 756

About the authors

Stephen Thomas is a Senior Technical Officer with Entura, specialising in geographic information systems, 3D visualisation and CAD software. Steve has over twenty-six years of technical experience and specialises in environmental assessments and approvals for engineering surveys and property. He has created 3D models and animations of proposed developments including wind farms, urban landscapes and city frameworks. Steve’s work on the Hobart Waterfront 3D model won an international award in geospatial modelling.

Jim Moore is a Geomatics Consultant with Entura and has a range of experience in spatial analysis, data management and cartography. He has a particular interest in online and mobile GIS technology for collecting, sharing and presenting field data. Jim has applied his geospatial expertise to projects in various sectors including public land management, mineral exploration, software and renewable energy.

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Is there an economic case for pumped hydro?

As the proportion of renewable energy in the grid continues to grow, pumped hydro energy storage offers a solution for greater reliability. But can the business case for storage stack up?

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The future is bright for pumped hydro in Australia, and for storage in general. However, no energy solution can exist outside of the real and competitive pressures of the market. Technical viability and environmental benefits won’t be enough to get projects over the line if they can’t demonstrate their financial soundness.  

So how can pumped hydro generate sufficient revenue to be attractive to investors? And will that revenue continue to be predictable enough over the longer term?  

No doubt there are opportunities, but developers may need to explore a range of different revenue sources in both existing and emerging markets since the arbitrage opportunities of the past may not be present in the future.

Where to for energy arbitrage?

The traditional revenue source for pumped hydro is arbitrage – in other words, making the most of generating when the spot price is high, and pumping when the spot price is low. But this relies on a certain level of predictable variability in the electricity market, and for that variability to continue into the future.

The upcoming retirement of several coal-fired power stations and the continued investment in renewables are likely to cement a market in which variability in power generation and the consequent volatility in energy prices are the norm.

Forecasting revenue – no easy task

Financing an energy project requires a firm revenue forecast. Lenders may consider ‘firm’ to be a 90% confidence limit, which means the developer must demonstrate that the project can generate a certain amount of revenue 90% of the time, or, say, in 9 out of 10 years. This means that a robust and reliable forecast of project utilisation must be made.

Forecasting revenue for an asset with a lifecycle of up to 100 years requires detailed modelling of a wide range of factors influencing the electricity market, including supply (factoring in new entrants, storage, retirements and developments in the thermal sector, etc.), demand (including changes in industrial load, impacts of electric vehicles, etc.), fuel prices, government policies, and bidding strategies for large-scale wind and solar projects.

A business case for pumped hydro relies on all the assumptions that go into regular power plant financial modelling and adds the complexity of arbitrage. 

A further complication is the impact on market prices of the presence of the developer’s own project. In other words, how will the proposed project influence the market in which it participates?

For a storage project, the influence is likely to be both an increase in low prices and a decrease in high prices. If the market is robust enough and the proposed project is relatively small, the influence could be minor. However, a very large project is likely to influence the market to such an extent that the utilisation of the project may significantly reduce, which would reduce project returns.

Building a bankable business case

How can the confidence in a forecast be increased enough for a lender to commit funding to a project, given that variance of any one of these assumptions could disrupt the revenue streams for the project?  While the transition to a renewables-dominated market continues, it may be that lenders need assurance that other revenue streams exist to reduce the project risk.

Price insurance

High price events in the electricity market will certainly continue to occur, but it’s impossible to predict their timing. Energy storage projects can provide insurance to exposed customers (such as retailers and major industrial customers) through a cap contract in a similar way to gas turbines and other peaking plant.  In practice, this may mean that the storage project rarely operates unless the price regularly exceeds the cap.

Network support services

Storage projects have the ability to provide network support services such as frequency control, inertia and fault level control. These services have increasing value in a grid with significant amounts of non-synchronous generation. At this stage, the markets for these network support services are very shallow and competition is increasing. However, the need for such services is likely to increase to the point where more significant markets are required.

Renewable firming

Government energy policy continues to be fluid, yet under the proposed National Energy Guarantee it is possible that there will be value in providing firming services – in other words, pairing ‘dispatchable’ generators (such as storage projects or open-cycle gas turbines) with ‘intermittent’ renewable sources of energy to improve reliability.

‘Behind the meter’ generation

Storage projects are exposed to market prices during both modes of operation (pumping/charging and generating).  If, however, there was an option to pump/charge for ‘free’, wouldn’t that reduce the risk?

Genex Power’s world-first Kidston ‘K2 Project’ will pair a 250 MW pumped hydro project with a 270 MW solar PV farm. During the day, solar energy can be used to power the pumps in the pumped storage project. The pumped hydro project will then generate into the evening (and morning) peak. If the upper storage is ‘charged’ during the day, the K2 solar project can generate into the Queensland market and realise the benefits of large-scale generation certificates (LGCs). Of course, this arrangement relies on sufficiently high prices during peaks to recover the additional cost of the solar farm, transmission losses and any LGC liability.

As our electricity mix evolves, so will the economics of storage. While forecasting revenue for storage projects in the Australian electricity market is still an uncertain business, there are many opportunities in both the existing and emerging markets to guarantee project revenues to a level sufficient to satisfy a lender’s requirements.

If you would like to discuss how Entura* can help you with your pumped hydro project, please contact Nick West on +61 408 952 315 or Donald Vaughan on +61 3 6245 4279.

 

*Entura provides technical advisory services to prospective investors and developers. Financial advisory is not part of our suite of services, however, we partner with financial advisory firms supporting our clients. Entura is the consulting arm of Hydro Tasmania. Hydro Tasmania is licensed (AFSL 279796) to provide general financial product advice.  Hydro Tasmania is not licensed to provide nor will it provide advice which considers a person’s objectives, financial situation and needs and you must therefore rely on your own assessment or seek your own independent advice in respect of decisions in relation to any financial product offered.

About the authors

Nick West is a civil engineer at Entura with more than 16 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study.

Donald Vaughan is Entura’s Principal Consultant for Primary Electrical Engineering. He has over 20 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

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‘Nexus thinking’ for a secure and sustainable future

As the global population continues to grow, how can utilities and water managers balance the increasing and interrelated pressures on water, energy and food?

The complex triangular relationship among these three pillars of life is known as the ‘water-energy-food nexus’. It’s an intricate puzzle, in which the increased demand for each limited resource can significantly affect the security of all three.

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According to the International Renewable Energy Agency, over the next few decades, global growth in population, economic development and urbanisation are expected to raise demands for water and food by 50% and to double the demand for energy. Water, energy and food are all fundamental to growing economies, alleviating poverty, and improving health and educational opportunities worldwide. To create a sustainable future, we must seek holistic and integrated solutions for water, energy and food challenges , as well as the appropriate balances amongst them.

With water being so central to food security and energy security, the potential impacts of climate change on water resources are of increasing concern. Climate change is likely to raise average temperatures in many locations, change the patterns of rainfall and inflows, and affect the frequency and severity of extreme weather events such as drought or floods – all of which increase vulnerabilities for water, food and energy resources already under strain.

A nexus approach

Our experiences throughout Australia and the Asia-Pacific region demonstrate that there is no single solution to the challenges of this nexus. It is really about a way of thinking and approaching decisions rather than a fixed solution or response.

Click on the image to download infographic.

Click on the image to download infographic.

These five broad considerations are likely to contribute to improved nexus outcomes.

Promoting and adopting ‘nexus thinking’

‘Nexus thinking’ means considering and understanding water, food and energy and their interrelationships, rather than viewing any in isolation. It is a strategic and holistic style of thinking that considers long-term implications across the nexus, weighing up and balancing social, economic and environmental goals.

Nexus thinking looks at the big picture: considering the whole catchment or river basin, trans-boundary issues, multiple uses (existing and future) and cumulative effects. It also involves thinking across agencies and organisations where responsibilities for water, food and energy lie.

Gathering the best information to understand nexus challenges

Responses to nexus challenges are more likely to be effective and sustainable if they are based on an informed and risk-based understanding of present conditions and possible future scenarios (taking into account interrelationships across sectors and regions). 

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This means that decision-makers need to understand the resource availability, current demand, known impacts, development opportunities and potential climate change implications in a given situation. They also need to understand what stakeholders and communities need, and explore opportunities for additional benefits to be realised.

Fostering collaboration among government, regulators, industry and communities

All stakeholders can benefit from collaborative and cooperative responses to the nexus and to stewardship of resources. The potential wins include better economic outcomes, improved reputation, reduced risks, avoided conflict, and opportunities for greater synergies. Reaping the benefits will require partnerships and cooperation among food-producing industries, the energy sector and other water-dependent industries, as well as local communities.

It’s also essential that governments, regulators and communities are closely involved in all decisions and developments affecting water, energy and food resources so that different priorities and opportunities can be considered. At a policy and regulatory level, cohesive and stable governance, policy and strategies are needed to facilitate and encourage the right collaboration that brings benefits to all stakeholders.

Assessing risks and building climate resilience

The water-energy-food nexus brings risks as well as opportunities . Interrelationships between water, energy and food, and the threats posed by climate change, should be built into risk assessments in each sector. State-of-the-art data collection, modelling and forecasting can assist businesses, governments and communities to better understand and mitigate their specific climate-related vulnerabilities and take action towards building greater resilience to future climate change impacts.

Innovating

In the water, energy and food sectors, technological and other innovations continue to expand the opportunities for improving productivity and resource efficiency for long-term sustainability of pressured resources.

Nexus challenges may also bring opportunities

The nexus is not only a dynamic of ongoing resource competition. Integrated planning offers opportunities for potential synergies and benefits among sectors.

For example, in the hydropower sector, electricity generation is intrinsically linked with water availability. The need for water for irrigation to produce food and to drive agricultural productivity may compete with water requirements for hydropower generation. Hydropower’s water needs may also compete with the requirements of urban water supply, other industries and environmental and social needs.

However, renewable energy resources such as hydropower can also offer benefits to the water and food sectors through improving water resource management, providing multipurpose storages, contributing to the development of water supply infrastructure and, of course, generating the electricity critical to food-producing industries.

Many existing hydropower storages, both in Australia and internationally, were developed solely to supply water for energy generation. However, over time and with increasing competition for water and food, the storages have become multipurpose, often providing water for domestic supply, irrigation, and commercial and recreational fisheries.

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In South-East Asia, some hydropower storages are now more important as a source of irrigation water for downstream communities than for the energy they generate. By providing water to the downstream communities, irrigation and food production has increased significantly since development of the schemes, lifting the economic development of the region and providing benefits across the community.

Integrating other renewable energies into water supply, irrigation and food production can also provide mutual benefits, such as utilising renewable energy for pumping on farms or for water desalination. Incorporating small hydropower into existing water infrastructure can improve efficiencies and create new low-carbon income streams to support effective water supply delivery. Another innovation of attaching solar PV to covers on water storages provides electricity for pumping while minimising evaporation and maximising water availability.

Whether at small-scale single utility or local geographic area or at a national or multinational scale, nexus thinking can bring about mutual benefits for energy, water and food outcomes .

If you would like to find out more about how Entura can help you develop a sustainable water or energy solution or respond to the challenges of the water-energy-food nexus, contact Dr Eleni Taylor-Wood on +61 3 6245 4582 or David Fuller on +61 438 559 763 

About the authors

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has more than 20 years’ experience successfully managing large-scale, complex projects that run over several years, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, Mekong, Solomon Islands, Fiji and Papua New Guinea. Her experience covers a vast gamut of studies including: environmental and social impact assessment and management; strategic management of wetlands and waterway; feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven Accredited Assessors under the Hydropower Sustainability Assessment Protocol worldwide.

David Fuller is Entura’s Principal Consultant, Water Management and Technology. David has more than 30 years’ experience working on water management projects across Australia and overseas. He has successfully delivered projects for local, regional, state and national government agencies; and for private sector clients in the irrigation, coal seam gas, mining and energy generation sectors. David specialises in engineering and environmental hydrology, and water management. He also has expertise in data management systems, statistics, hydraulics, water quality, ecological risk assessment and natural resource economics.

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Batteries vs pumped hydro – are they sustainable?

A sustainable grid needs sustainable energy sources. While there’s no doubt that it makes sense to store renewable energy, whether in batteries or in a pumped hydro scheme, just how sustainable are these technologies?

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As we move rapidly towards ever-greater levels of wind and solar power in the network, increasing quantities of storage are needed to smooth intermittency and ensure secure supply. Pumped hydro energy storage and batteries are likely to do much of the heavy lifting in storing renewable energy and dispatching it when power demand exceeds availability or when the price is right.

We’ve previously compared the two technologies in terms of their costs, the speed with which they can be deployed, and their ability to support the grid. Here we compare their sustainability in terms of storage efficiency and capacity, safety, use of scarce resources, and impacts through all stages of their lifecycle.

Storage efficiency and capacity

For both batteries and pumped hydro, some electricity is lost when charging and discharging the stored energy. The round-trip efficiency of both technologies is usually around 75% to 80%. This level of efficiency for either technology represents a significant displacement of non-renewable generation if we assume that the stored generation would not otherwise occur.

A particular consideration for batteries is degradation. Batteries degrade as they age, which decreases the amount they can store. The expected life of the batteries that will be used for the recently announced battery storage project in South Australia is about 15 years (depending on how the batteries are operated). By the end of that time, the capacity of the batteries is expected to have dropped to less than 70% of their original capacity.

To maintain a reliable and steady capacity for storage as batteries age and degrade, large-scale battery plants will require ongoing staged installation and replacement of batteries. In comparison, the degradation of pumped storage is close to zero. With appropriate maintenance, peak output can be sustained indefinitely.

Safety

No storage solution can be considered sustainable unless it is safe. The greatest risk relating to pumped storage is dam safety. If it occurs, dam failure can affect downstream communities and the environment, with its impact potential likely to be far greater than a battery safety incident. Nevertheless, pumped hydro technology is mature, dam risks are generally well understood and managed, and the frequency of dam safety events is low.

The main safety concern for batteries is thermal runaway leading to explosions and fires. The severity of this risk will depend on how a battery project is implemented. In a modular arrangement, thermal runaway would be localised, not affecting the whole bank. However, because of the very rapid deployment of evolving battery technologies, safety standards may not be rigorously enforced.

Impacts on land and water

Pumped hydro and grid-scale battery plants may have environmental and land-use impacts. These impacts would vary depending on the sensitivity of the site selected.

A grid-scale battery facility needs a relatively small parcel of land and is likely to be able to be created very close to the energy demand or where generation occurs. Land in these areas has often already been disturbed and the new operations may have little extra environmental impact. Land and water impacts of batteries relate more to their disposal at the end of their effective life, and to the extraction of the resources to produce new batteries.  

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Pumped hydro requires a relatively larger parcel of land with a very particular topography, and may be far from the location of the demand. Any potential environmental impacts associated with construction and operation need to be considered and mitigated, including those immediately associated with the site, as well as downstream.

In most construction of new pumped hydro, sites are selected where impacts can be mitigated to acceptable levels, for example by using existing reservoirs, or locating ‘closed loop’ systems away from rivers. Although these arrangements will have lower overall impacts, some environmental challenges may still occur during construction when existing water is removed from the site as well as finding a source of water without impacting the environment and other users.

Environmental impacts during operation of pumped hydro are minimal.  However, the ecology within the reservoirs will need to adapt to frequently changing water levels, reducing diversity in the system especially within fringing communities.

In all pumped hydro systems, water is re-used over and over again, extracting maximum value from the resource. Nevertheless, depending on the configuration of the pumped hydro project, there may be an ongoing demand for water to top up the storages to counter evaporation.

Minerals and materials

Batteries and pumped hydro require a range of different resources and materials. Lithium-ion batteries use common materials such as plastic and steel as well as chemicals and minerals such as lithium, graphite, nickel and cobalt. Although pumped hydro mainly relies on common building materials such as concrete and steel, the quantities of these materials and the construction impacts can be significant.

Image courtesy of Greensmith, a Wärtsilä Energy Solutions company.

Image courtesy of Greensmith, a Wärtsilä Energy Solutions company.

Determining the ultimate sustainability of the required resources and materials for both technologies needs to take account of the full lifecycle and supply chain (mining, processing, refining and manufacturing) as well as end-of-life issues such as recycling, disposal or decommissioning.

Currently, the environmental and health impacts of mining are a significant sustainability concern for the battery industry, and impacts are likely to intensify as worldwide demand for the necessary minerals rapidly increases. Short-term availability of many of the necessary minerals for battery development, such as lithium, appears sufficient, yet security of supply could be compromised by geo-political factors, and long-term availability will depend on levels of demand.

Ultimately, the minerals used in lithium-ion batteries are finite resources, so limiting or reducing their extraction (for example, through greater recycling or substitution for another battery technology) would increase longer term sustainability.

End of life

A battery’s life depends on the technology and on frequency of charging and discharging. Once their effective life is up, the batteries must be disposed of and replaced. Disposal of batteries is a problem we’re yet to face, but as large-scale battery storage proliferates, increasing numbers of batteries will enter the global waste stream. Without careful management of disposal, what cannot be recycled may end up in landfill and may be corrosive, flammable, or could leach toxins into soil and water.

The development of cost-effective and efficient battery recycling methods is still in its infancy.

Although most of the components of batteries can be recycled to some extent, recycling is currently expensive and there is insufficient volume to encourage commercial enterprises to take on recycling the new generation of batteries. In time, improved recovery and re-use of materials will certainly increase the sustainability of battery storage, preserving virgin resources and reducing the impacts of extraction and processing.

End-of-life considerations for pumped hydro seem very distant right now due to hydropower’s longevity, but sustainable decommissioning still needs to be planned for, including managing the impacts on the downstream environment if a dam is removed and rehabilitating the reservoir area.

Lifecycle analysis

At this early stage of development of large-scale battery technology, comprehensive lifecycle analysis is limited by the diversity of battery materials and widely different scenarios of charging, battery life and recycling.

In contrast, the full lifecycle of pumped hydro is better understood due to the maturity of the technology. Pumped hydro is not without impacts, but the risks are known and generally manageable. A major advantage of pumped hydro over batteries is that the expected life of pumped hydro is more than 100 years, or effectively unlimited with appropriate maintenance.

Batteries may have a lower upfront cost than pumped hydro and be easier to approve and install; however, they are likely to require greater management over time. If a projection is made based on current information, the full lifecycle cost and impact of batteries may be greater than hydro across the long term, particularly when mining, recycling and disposal are taken into account. Yet, battery technology is likely to improve very rapidly, which would tighten the gap on pumped hydro’s current lifecycle advantage.

A greener grid

Worldwide, increased levels of renewable energy will lead to a greener grid. It is easy to recognise the sustainability benefits of using a storage solution such as pumped hydro or batteries to further enable the decarbonisation of the network through greater uptake of renewable energy. However, the storage solutions that enable more renewables must also be sustainable – not only in the use phase, but also upstream and downstream.

It is difficult to make a straightforward comparison of the sustainability credentials of pumped hydro and battery storage technologies at their very different stages of maturity. As battery technology is still evolving, its overall sustainability is still somewhat uncertain, but this will change with experience and improvements in battery life and recycling. Meanwhile, pumped hydro projects can last up to a century and associated risks are known and can be mitigated.

Either way, as we redevelop the electricity grid, we will also need a mature approach to lifecycle analysis of our storage solutions.

About the authors

Donald Vaughan is Entura’s Principal Consultant for Primary Electrical Engineering. He has over 20 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

Nick West is a civil engineer at Entura with 16 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study.  

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Building climate resilience into operations: Hydro Tasmania’s journey

Climate change presents major risks for power and water businesses. To best prepare for the impacts of extreme or changing weather conditions, asset managers need to act now to build climate resilience into operations and ongoing risk management.

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Around the world, businesses and communities face the many risks of climate change such as higher temperatures, changes in water availability and rainfall, more frequent and severe weather events. For power and water businesses, these may lead to major infrastructure damage and financial and environmental consequences.

In 2015 to 2016, these hypothetical risks became a challenging reality for Hydro Tasmania, Australia’s largest renewable energy producer and water manager. Hydro Tasmania faced unprecedented extreme weather conditions from September 2015 to June 2016 – and managed to come through the crisis while still safeguarding Tasmania’s ongoing access to high-quality, reliable water and power, and limiting environmental consequences and asset damage.

Entura supported Hydro Tasmania’s response to this major climate-related challenge through a range of earlier best-practice resilience-building measures, and significant interventions across a range of areas during the crisis itself.

What happened in 2015-2016?

Although Hydro Tasmania had experienced some variability in the past in Tasmania’s climate patterns, and despite understanding the risk of increasing future climate variability, the extreme dry conditions of September 2015 to April 2016 were unseasonal, unexpected and unprecedented. In Tasmania, summer inflows are traditionally low, but in this case, the usually dry summer was preceded by record-low spring inflows. Below-average rainfall across both spring and summer was the lowest recorded in 50 years.

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In normal operating conditions, low inflows could have been mitigated by importing power from mainland Australia across the undersea interconnector cable, Basslink, so that storages could be maintained. Yet, in another unprecedented scenario, in December 2015 the Basslink interconnector became inoperable just as summer arrived. Hydro Tasmania was now no longer connected to Australia’s national electricity market and many months remained before expected autumn/winter rains.

By late April 2016, Hydro Tasmania was experiencing its lowest storage levels ever, down to 12.5% total energy in storage, and serious environmental risks were emerging in some of its sites.

To compound the challenges, in January and February 2016 at least 70 separate fires were listed in Tasmania’s north-west, west, south-west and central highlands.

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These extraordinary circumstances combined to present Hydro Tasmania with a major operational challenge. How could it keep the lights on and keep businesses operating in Tasmania while also protecting the environmental values associated with water storages and preserving the condition of its assets?

When the drought broke, conditions shifted from one extreme to another. Floods in June 2016 in northern Tasmania hit historic highs, exceeding all previous flood records in many locations. Several river-level measurement stations experienced the highest water levels on record.

How was the crisis managed?

Hydro Tasmania’s climate resilience and risk management strategies were called into action. Entura actively supported Hydro Tasmania through the energy supply challenge across a range of measures.

Generation planning and supply

To maintain adequate power supply, Hydro Tasmania drew on generation modelling and planning based on rainfall forecasts, climate model outlooks, and known and predicted electricity demand.

Voluntary reductions in major industrial loads were negotiated, and actions were taken to assess and instigate alternative generation options, such as restoring gas generation and implementing 200 MW of temporary diesel generation to bolster power generation. Entura assisted Hydro Tasmania to identify and assess feasible generation options and sites, and to progress these options through approvals and into operation.

Through these integrated and rapidly executed measures, Hydro Tasmania was able to maintain electricity supply for Tasmania without any outages for domestic users.

Environmental management and multiple water use

Another critical aspect of the successful result drew on Entura’s expertise in environmental management. Environmental impacts were monitored throughout the crisis. Lake-level risk bands were reassessed to better protect water quality and threatened species and to limit the long-term impacts on environmental values.

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Water management also considered and mitigated impacts on other water users, such as boating, recreational fishing and water supply.

Bushfire management

The bushfires experienced across the state during the summer period did not adversely affect Tasmania’s energy security, as Bushfire Preparedness Fire Management Plans were already in place, and were activated to protect individual power stations and key assets through fuel reduction and other measures.

Dam safety and monitoring

Despite the extreme flood conditions, dams and spillways operated well within their design parameters, indicating that Hydro Tasmania’s ongoing dam monitoring and dam safety systems were robust.  Safety inspections after the floods found only minor damage to non-critical elements of some dams.

During the high rainfall conditions, monitoring of dams and waterways provided alerts to downstream communities.

Road and asset management

Another consequence of the flooding was damage to some of Hydro Tasmania’s secondary assets (roads, canals) due to landslips, and the loss of some river-flow monitoring sites. Entura assisted with assessment and rectification of this damage.

Success drew on prior climate-resilience preparation

Ultimately, the example of Hydro Tasmania demonstrates climate resilience in practice. It shows how an investment in climate resilience enables a power and water business to be better prepared, more flexible and more robust in the face of a climate ‘shock’.

Hydro Tasmania’s management of the crisis required a comprehensive understanding of Tasmania’s climate and catchments. Entura’s involvement in 2007 in developing a Climate Change Response Strategy had provided a basis for this understanding, and a crucial input into identifying the risks and opportunities stemming from climate change.

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Further inputs for climate resilience came through the collaboration in 2008 to 2010 between Entura and the CSIRO (Australia’s national scientific research organisation) on the first fine-scale climate and river system modelling for Tasmania, through the Climate Futures for Tasmania and the Tasmania Sustainable Yields projects.

The results of that research were state-of-the-art regional climate modelling and hydrological models to project future catchment yields for Tasmania. The modelling indicated that under climate change Tasmania could expect gradual temperature rises, changes in rainfall patterns over coastal regions, reduced rainfall over central Tasmania, changes to run-off patterns, and changes to the frequency and severity of extreme weather events including increased rainfall intensity and floods.

This modelling was critical in enabling Hydro Tasmania to plan and balance generation and storage levels over a range of demand and inflow scenarios and to assess environmental impacts during the extended period of drought.

Another key aspect of managing the energy supply challenges through the drought involved setting up supplementary diesel generation. This drew on Entura’s expertise and extensive involvement in developing hybrid off-grid renewable energy systems.

Hydro Tasmania’s climate resilience also involved being prepared for the drought to break. Key contributions from Entura included flood forecasting and flood support systems, ongoing support of Hydro Tasmania’s dam safety and emergency planning programs, and prior involvement in upgrading dams and designing spillways to withstand predicted increases in the frequency and magnitude of floods.

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Entura also supported Hydro Tasmania’s procedures and ongoing activities to manage the secondary impacts of the fires and floods (such as damage to infrastructure), as well as the risks posed by low lake levels to social and environmental values. Entura’s environmental scientists monitored threats to aquatic flora and fauna through the 2015/16 crisis. To ensure the least likelihood of long-term or irreversible environmental damage, Hydro Tasmania’s environmental risk bands were revised.

Investing in your climate resilience

Any proactive and sustainable power or water business needs to invest in understanding the range, likelihood and consequences of the potential impacts of climate change for their current and planned systems and operations – whether for hydropower, transmission, dams, irrigation or water supply – and how to avoid or mitigate the impacts.

The more businesses understand the potential impacts of climate change and risks to their projects and operations, the better they can prepare, adapt, and build resilience to climate change impacts.

If you would like to learn more about building greater climate resilience into your project or operations, please contact Dr Eleni Taylor-Wood on +61 3 6245 4582,  Alan Barrett on +61 437 102 756 or James Mason on +61 400 603 650.

About the authors

Tammy Chu is the Managing Director of Entura, one of the world’s most experienced specialist power and water consulting firms. She is responsible for Entura’s business strategy, performance and services to clients, and is part of Hydro Tasmania’s Leadership Group. As a civil engineer, Tammy specialised in the design and construction of mini-hydro and hydropower systems, project management, hydropower investigations, prefeasibility and feasibility studies, environmental assessments and approvals, resource investigations and resource water management. Tammy is a member of the Board of the International Hydropower Association. She was the first female and now past president of the Tasmanian Division of Engineers Australia, and was an Engineers Australia National Congress representative.

Dr Eleni Taylor-Wood is Entura’s Principal Consultant, Environmental and Social Science. Eleni has more than 20 years’ experience successfully managing large-scale, complex projects that run over several years, as well as providing expert advice and independent review for a range of infrastructure and planning projects. She has worked on projects around the world including in Australia, Mozambique, South Africa, Iceland, Colombia, India, Malaysia, Mekong, Solomon Islands, Fiji and Papua New Guinea. Her experience covers a vast gamut of studies including: environmental and social impact assessment and management; strategic management of wetlands and waterway; feasibility and approvals for new hydropower projects, environmental flow determination and assessment, and sustainability assessments. Eleni is currently one of eleven Accredited Assessors under the Hydropower Sustainability Assessment Protocol worldwide.

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Batteries vs pumped hydro – a place for both?

Two very different storage technologies – one old, one new; one that takes years to build, one that can be built ‘within 100 days (or it’s free)’. How else do they differ, and is there a place for both?

The rapid growth of renewable energy generation has been driven by two concurrent factors: the falling levelised cost of the energy produced by wind and solar, and the retirement of a number of coal-fired power stations. The recently released Finkel Review notes that by 2035, approximately 68 per cent of the current fleet of Australian coal generating plants will have reached 50 years of age.

The Clean Energy Target proposed by Dr Finkel is not yet confirmed but it recommends incentives for technologies with low or zero carbon emissions. More renewable energy generation brings new challenges in an increasingly complex grid. Dr Finkel therefore also proposes that energy storage be mandated for solar and wind farms.

Renewables can’t, on their own, meet the fluctuations in demand that occur throughout the day without some regulation as to when power reaches the grid. Power needs to be dispatchable. Dispatchable means that energy can be provided upon request. If the sun is not shining or the wind is not blowing, renewable energy cannot be dispatched unless it has been stored in some way.

There are a number of different types of storage but the two being discussed most widely right now are batteries and pumped hydro energy storage. These two technologies are very different and there are some limitations involved in comparing a well-known and established technology with one that is new and developing rapidly.

How do they support the network?

Pumped hydro is based on well-established synchronous generation, providing critical ancillary services to the grid, through the provision of inertia, frequency and voltage support and sufficient fault level support.

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Battery inverter technologies are still catching up on most of these fronts. The potential for batteries to provide ‘synthetic inertia’ or fast frequency response is high but this is balanced by their reliance on system strength to be able to deliver this support. They offer minimal support with fault levels but can still provide some support to system frequency and voltage regulation.

How fast can they happen?

There’s no doubt that battery storage is quicker to implement than pumped hydro. South Australia has provided an example of just how quickly battery storage can be deployed.

In March 2017, the South Australian Government called for expressions of interest for the supply of grid-connected battery storage to be connected by the end of 2017. The overwhelming response from 90 interested parties tells us that this speed of deployment is within the realms of possibility.

Battery image courtesy of Greensmith, a Wärtsilä Energy Solutions company.

Battery image courtesy of Greensmith, a Wärtsilä Energy Solutions company.

Pumped hydro, by comparison, is a technology that takes much longer to implement. Typically, development activities (including optimising the technical solution, environmental and social assessments, arranging finance and finalising design) take two years or more to complete, and construction takes another two to three years.

How do the capital costs compare?

Pumped hydro boasts a very low price per megawatt hour, ranging from about $200/MWh to $260/MWh. Currently, battery costs range from $350/MWh to nearly $1000/MWh, with this cost reducing rapidly (costs reduced by about 25% during 2016).

According to the Lazard’s Levelized Cost Of Storage report, capital costs for pumped storage projects around the world range from about $1.5 million to $2.5 million per MW installed. The report also reveals that the cost of installing a grid-scale battery solution ranges from about $3.5 million to $7.5 million. This wide range of pricing for batteries is typical of a developing technology that is implemented in a variety of applications.

Ultimately, it’s difficult to predict how low the cost of batteries may go, but reports predict costs of lithium-ion batteries at somewhere around $120/MWh by 2025.

Considering that batteries need to be replaced once or twice a decade, with the currently available technologies, a battery facility will need to be replaced a number of times during the potential 100-year life of a pumped storage project. For batteries, assuming an economic life of 40 years, the initial cost plus replacements may mean whole-of-life costs fall in the range of $200/MWh to $330/MWh.

So, what does the future hold?

The rise of renewables will inevitably lead to a diversity of storage and supply solutions. The range of these solutions will depend on the resources of particular regions and locations. It is highly likely that the future for both batteries and pumped storage technologies will be extremely bright.

Batteries are here to stay and will undoubtedly play a significant role in future power systems as the technology develops and costs fall. However, while batteries can provide fast response times, they are yet to demonstrate their ability to provide the full range of ancillary services needed to support the grid. Pumped hydro remains a landmark, proven and reliable technology, able to meet the needs of the grid and provide sustained output for up to a century.

Ultimately, there is room for both batteries and pumped storage hydro, and they may even complement each other. Batteries are more cost-effective at delivering small amounts of stored energy over a short time at high power levels. Pumped storage is more cost-effective at storing and releasing larger amounts of stored energy. Achieving the optimum storage solution will depend on careful planning and finding the best fit for the particular circumstances.

What is certain is that both technologies will play important roles in the development and expansion of a network powered by renewable energy.

If you would like to discuss how Entura can help you with your next utility-scale battery or pumped hydro project, please contact Donald Vaughan on +61 3 6245 4279 or  Nick West on +61 408 952 315.

A version of this article was first published in RenewEconomy.

About the authors

Donald Vaughan is Entura’s Principal Consultant for Primary Electrical Engineering. He has over 20 years of experience providing advice on regulatory and technical requirements for generators, substations and transmission systems. Donald specialises in the performance of power systems. His experience with generating units, governors and excitation systems provides a helpful perspective on how the physical electrical network behaves and how it can support the transition to a high renewables environment.

Nick West is a civil engineer at Entura with 16 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study.  

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Shifting directions for hydropower in Asia-Pacific

The issues and trends we’re seeing playing out right now relating to hydropower and the clean energy sector are not unique to our region.

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Having recently returned from a meeting of the Board of the International Hydropower Association, I’ve been reflecting on the challenges and opportunities facing the global hydropower sector.

It seems that there’s a global shift occurring in hydropower. Traditionally, hydropower has been viewed as a stand-alone, established renewable technology. Now we’re seeing a much greater sense of integration with other renewable technologies as part of broader ‘clean energy’ systems. With the rapid global increase of wind and solar power developments,  hydropower needs to review its place, and its opportunities, within the wider energy sector.

Wind and solar tend to have shorter construction and implementation periods than hydropower projects. When the wind is blowing and the sun is shining, the power flows. But, as we know, the intermittency of these sources of power creates the need for some sort of storage to firm up the system.

Hydropower has traditionally provided both baseload and peaking capacity, but now we also have the opportunity to provide much-needed storage and the firming capacity urgently required to help stabilise grids as they integrate increasing levels of intermittent renewable technologies. Pumped storage hydropower may be particularly useful in this context.

In recent weeks the Australian federal government has expressed new interest in pumped storage options to help alleviate grid pressures, such as those experienced recently in South Australia. But it’s not only in Australia that we’re seeing increased discussion and enthusiasm about opportunities for pumped storage hydropower to integrate with other intermittent renewable technologies by offer firming power and assistance with stabilising the grid. It’s a global trend.

Also under discussion at a policy level in Australia right now is the energy ‘trilemma’ of security, equity (accessibility and affordability) and environmental sustainability. These three factors need to be in balance to ensure a secure power sector that meets the present and future needs of energy consumers while moving towards a lower carbon future. These three big issues that are so relevant right now in the Australian context are just as urgent in the global setting too, and need careful long-term planning, and the right mechanisms in place to support appropriate development.

It is interesting to review the World Energy Council Energy Trilemma Index, noting country rankings through the lens of hydropower and pumped storage integration. Not surprisingly, most countries ranked at the top of the list have been using these technologies for decades, which perhaps signals a direction for others to consider.

Another worldwide trend is the ongoing shift towards development of small to medium hydropower systems because many of the larger opportunities have already been exploited. For example, in China, many of the large hydropower schemes (10 000 MW, plus) have already been identified or developed, so new hydro developments are more likely to fall within the small to medium range, with the added advantage of shorter construction and implementation times. In Australia, smaller pumped hydro systems, or hydropower systems built into irrigation systems or water supplies, also have a significant role to play in the ongoing development of the hydropower sector.

Renewable energy and hydropower is a specialised field, so it’s critical that we also focus on the human resources and the capacity development needed to ensure a healthy future for the global hydropower sector. This is particularly so in regions which are new to hydropower and renewables, as the world shifts towards stronger support for renewables and replacing carbon-intensive power generation.

Hydropower is a mature, established technology, but that doesn’t mean we can’t be flexible and responsive to shifts in the global energy sector. As we strive towards the goal of affordable, reliable and sustainable power for all, hydropower has much yet to offer as a stabilising element of an integrated clean energy vision.

About the author

Tammy Chu is Entura’s Managing Director. She is responsible for Entura’s business strategy, performance and services to clients, and is part of Hydro Tasmania’s Leadership Group. Tammy joined the business in 2000 and has held a range of positions at Entura, from Technical Professional to Project Manager, Business Development Manager and Water and Environment Group Manager.

She has extensive managerial and business development experience in the consulting engineering industry within Australia and internationally, focusing on business strategy, change and transformation, international sales, culture, and profit and revenue growth.

As a civil engineer, Tammy specialised in the design and construction of mini-hydro and hydropower systems, project management, hydropower investigations, prefeasibility and feasibility studies, environmental assessments and approvals, resource investigations and resource water management.

Tammy is a member of the Board of the International Hydropower Association. She was the first female and now past president of the Tasmanian Division of Engineers Australia, and was an Engineers Australia National Congress representative.    

Tammy holds a Master of Business and Administration from Chifley Business School, is a Fellow of Engineers Australia, and a graduate of the Australian Institute of Company Directors.

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Overcoming the barriers to pumped storage hydropower

With energy reliability a hot topic in Australia, eyes are now turning to pumped storage hydropower… but what has been holding it back?

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There are only three pumped storage hydropower projects in Australia, with the most recent completed more than thirty years ago. This is despite the ability of pumped storage hydropower projects to provide the large-scale storage that would complement increasing levels of renewable energy. Why is this, and what are the barriers to developing more Australian pumped storage hydropower projects?

Around the world, pumped storage hydropower projects make up the vast majority of grid energy storage and have traditionally been used by energy utilities to supply additional power to a grid during times of highest demand.

As part of a portfolio of power stations, a utility might operate a pumped storage project infrequently only, if the cost of pumping the water back to the upper storage exceeds the revenue that can be generated from its release.

The main issue facing developers trying to prove the viability of a new pumped storage project is that a sufficient price differential is required to pay for the pumping and to account for the efficiency losses in transmission, pumping and generation. The generation price needs to be sufficiently higher than the pumping price just to repay the variable pumping costs. To repay the heavy capital investment, a margin is required over and above the break-even cost of pumping. This is particularly true where proposed developments are ‘stand-alone’ and cannot be optimised as part of a corporate generation portfolio.

In recent years, electricity price spikes have been irregular with few occurrences each year. Due to the significant capital costs, a pumped storage scheme would require a certain number of pumping/generation cycles at high or maximum pricing to pay a return on investment. These price spikes are unpredictable, so building a business case around these events is risky.

Historically, the daily fluctuation of power prices has not been sufficient or regular enough to attract pumped storage developers. This is beginning to change with increasing penetration of renewable energy leading to an increase in both low and high price periods. More frequent, sustained periods of hot weather (as predicted by climate change models) will also drive up demand for power and therefore the market price.

In the last few months, volatility has greatly increased, creating a greater differential between baseload and peak pricing. This will increase the viability of pumped storage schemes, although the unpredictability and challenges of financing capital intensive assets will remain.

But, even when the economics are right, there are still some other barriers that proponents of pumped storage projects need to overcome:

Finding the right site

Pumped storage projects require significant capital for development. Minimising the cost of construction and operation is key to the successful development of a project. Choosing the right location is a matter of identifying a site with ideal topography, a source of water and good proximity to and location within the transmission network.

A wealth of information is available that is relevant to identifying potential pumped storage hydropower sites. Concept studies for pumped storage hydropower sites can screen potential sites quickly and offer developers greater insight into possible opportunities.

Negotiating access to appropriate sites for pumped storage

While a pumped storage project generally has a significantly smaller footprint than a traditional hydropower project, the features of natural topography that are ideal for pumped storage – high, steep hillsides or cliffs – tend also to be places of great natural beauty and are often designated as reserves, are expensive private land, or have high environmental or social value.

State governments can assist here through streamlined planning and approvals processes for infrastructure developments. This can make sure that the challenges of developing sites do not become insurmountable for developers.

Perceived environmental impacts

Pumped storage projects can occupy many square kilometres and also require transmission lines to connect to the electricity market. Like traditional hydropower projects, pumped storage projects need to attend to environmental issues associated with the project. Environmental impacts for pumped storage projects are assessed in the same manner as for all infrastructure developments.

If the impacts of a project can be mitigated to the satisfaction of the relevant regulatory body and international Standards (such as the International Hydropower Association and International Finance Corporation), a pumped storage hydropower project should face no greater hurdle than any other infrastructure project in this respect.

A pumped storage project may also have to deal with the perception that it uses carbon-intensive thermal power to pump water during the pumping cycle. This may be true unless there is a surplus of renewable energy available, in which case the pumped storage project could be seen to be using this excess renewable energy for pumping. As renewable energy penetration grows, the opportunities for storing surplus renewable energy will increase.

An unfavourable regulatory framework

Inconsistent and uncertain policy positions of the major political parties at both federal and state levels reduce confidence in the energy industry, which deters investment. With debate raging over energy security, a bipartisan view on energy policy, which transcends party politics and the electoral cycle, is urgently needed.

Existing mechanisms are in place to support the renewable energy industry. The Renewable Energy Target (RET) promotes investment in renewable energy projects; however, pumped storage is specifically excluded from the RET where the energy used for pumping exceeds the energy generated. Current policy would have to be amended or complementary legislation enacted in order to reward large-scale storage for the service it provides.

Such changes could include market mechanisms for large-scale storage that could offer incentives for providing inertia and ancillary services from storage at times of peak demand as well as power. Another possible change could be to ensure that large-scale storage asset owners are not penalised under the RET for energy used in the pumping process. This would encourage the development of energy storage as a complement to the growth of renewable energy.

High cost of development activities

The long lead times and high development costs of pumped storage projects are major deterrents to developers. Projects generally take more than 4 to 5 years from the point of conception to ‘power on’, and require millions of dollars of capital for development and hundreds of millions for construction. In other words, when funding is first committed, it may not see a return for five years or more.

In an effort to overcome this barrier, the Australian Renewable Energy Agency (ARENA) has indicated it will allocate at least $20 million to finance the accelerated development of flexible capacity and large-scale storage projects. The Clean Energy Finance Corporation (CEFC) has also committed to provide successful ARENA funding recipients with the opportunity to secure long-term debt finance to support their projects.

With an increasing interest and emphasis on storage in a power system that is becoming increasingly unreliable (e.g. load shedding in South Australia and lack of reserve events in New South Wales), and with finance from ARENA and CEFC for large-scale storage, the barriers to pumped storage development are gradually diminishing. This action can’t come soon enough for residents suffering through blackouts on days over 40°C.

If you would like to discuss how Entura can help you overcome the barriers for a pumped storage hydropower project, please contact Akhil Pai on +61 406 874 101, Nick West on +61 408 952 315, or Richard Herweynen on +61 3 6245 4130.

A version of this article has been previously published as an op-ed in the Adelaide Advertiser.

About the authors

Nick West is a civil engineer at Entura with 16 years of experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study and was involved throughout the development and construction of the Neusberg Hydroelectric Project in South Africa. Nick has successfully completed projects ranging from hydraulic design for small residential developments to the feasibility study of a cascade of four large hydroelectric projects in Malaysia.

Richard Herweynen is Entura’s Principal Consultant in Civil Engineering. Richard has 27 years of experience in dam and hydropower engineering, and has worked throughout the Asia-Pacific region on both dam and hydropower projects. Richard was the Project Director of the Kidston Pumped Storage Project Technical Feasibility Study and, in recent years, Richard has led the design of three roller-compacted-concrete dams within Australia and a number of significant dam upgrades. Richard was part of the ANCOLD working group which updated the guidelines for concrete gravity dams, and is the Chairman of the ICOLD Technical Committee on Engineering Activities in the Planning Process for Water Resources Projects. Richard has won many engineering excellence and innovation awards, and has published over 30 technical papers on dam engineering.

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Is pumped storage hydro the key to increasing renewables in Australia?

Recent electricity price spikes and a state-wide blackout in South Australia have highlighted the need for reliable power to balance the potential volatility of some renewable power sources.

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Pumped storage hydropower projects are a natural fit in an energy market with high penetration of renewable energy as they help to maximise the use of the renewables that are subject to the vagaries of the weather. Pumped storage provides a load when the wind is blowing and the sun is shining, and it also provides a reliable and immediate source of energy when the sun has set and the wind has dropped.

The recent completion of the feasibility study for Genex Power’s Kidston Pumped Storage Hydro Project in North Queensland shows this approach is now technically and commercially feasible.

Pumped storage hydro offers utility-scale storage and system stability

As the proportion of renewable energy in an energy market increases, the need grows for the stability and consistency provided by utility-scale energy storage. For example, South Australia needs system-wide storage of 500 MW for a period of 10 hours to improve the flexibility of wind farm operators, according to the Melbourne Energy Institute.

At the smaller scale of energy storage, the buzz about various types of batteries continues – but the only storage option with a proven track record at the utility scale is pumped storage hydropower.

Pumped storage hydropower works by pumping the water stored in a lower reservoir into a more elevated reservoir. The water stored at height can be passed through a turbine on its path back to the lower reservoir, creating electricity as and when needed, and making the best use of the water resource without waste.

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Click image to view infographic.

In a recent article, my colleague Donald Vaughan stated that a functioning AC power system needs inertia, fault level, frequency and voltage control as well as energy sources to function to an acceptable standard. Pumped-storage assets can provide all of these important contributions to a stable and successful power system, levelling out the fluctuations in availability of wind and solar energy, and helping to regulate voltage and frequency.

New opportunities for pumped storage hydro in Australia

Despite the significant potential and benefits of pumped storage hydro projects, only three projects currently exist in Australia (two in New South Wales and one in Queensland). These schemes were built in markets in which generation was mainly thermal, where the pumped storage could supplement supply at times of peak demand.

A number of possible sites have been identified for new opportunities for pumped storage hydro, but so far very few have been developed beyond concept level. This means that opportunities exist for developers in states such as South Australia and Queensland that have set ambitious renewables targets and must maintain energy security.

Three factors for pumped storage hydro success

For successful pumped storage hydro projects, developers need to identify a viable site, achieve a technically and commercially feasible design, and make the most of the economics of the energy market.

1 – Identifying a viable site

For a pumped storage project, what’s needed is a source of water, and two reservoirs separated by a significant change in elevation. The water could come from a nearby river, an existing reservoir, or the sea. With many thousands of potential sites across the country, a developer needs smart methods of filtering to reduce the many possibilities to just a few ideal sites.  

An important consideration is the effect on the viability of pumped storage projects of the relative remoteness of sites, through both the efficiency of the power’s round trip and the marginal loss factors (factors applied to a generator or a load, and calculated based on the size and distance of the generator or load from a central point).  

As for any development, the process of identifying sites must also consider topography, land use and environmental constraints. Pumped storage projects generally present similar but reduced environmental risks as conventional hydropower projects as they tend to have smaller footprints.

2 – Achieving a technically and commercially feasible design

Entura’s experience on Genex Power’s Kidston pumped storage hydro project has shown that it is possible to construct low-cost pumped storage projects in Australia through careful site identification and clever project design. Where a pair of suitable reservoirs don’t already exist, constructing a turkey’s nest dam may offer a solution.

A turkey’s nest dam is a reservoir built by excavating earth from the centre of the reservoir and moving it to the edge to help form a continuous embankment. Turkey’s nest dams have been used successfully around the world in pumped storage hydropower projects, providing opportunities to build projects where elevation changes significantly over a short distance.

Additionally, turkey’s nest dams can help to minimise capital costs by reducing conduit lengths and maximising head (the difference in elevation between the upper and lower reservoirs).

3 – Making the most of the economics of the energy market

Understanding the opportunities and constraints in the energy market is critical to a pumped storage project’s financial viability.

When you can store energy, you can dispatch electricity at peak times, gaining the highest price point in the market. Conversely, water is pumped to the upper reservoir in off-peak periods or when supply from renewable sources is high and market prices are low. This ‘energy arbitrage’ makes the most of the price difference in the electricity market.

Selecting the optimum installed capacity of a pumped storage project also requires detailed understanding of energy markets. It is possible that a pumped storage project can act to flatten peak prices to the point where the returns on a project are insufficient to meet financiers’ hurdles, so detailed revenue modelling is essential to determine the tipping point between enough and too much installed capacity.

With careful selection of sites, clever design, and the right mix of capacity and costs, pumped storage hydro holds an important key to unlocking the full potential of renewables in Australia’s electricity market.

If you would like to discuss how Entura can help you explore potential opportunities for pumped storage hydropower projects, please contact Akhil Pai on +61 406 874 101, Nick West on +61 408 952 315, or Richard Herweynen on +61 3 6245 4130.

About the author

Nick West is a civil engineer at Entura with 15 years’ experience, primarily in hydraulics and hydropower. Nick’s skills range from the technical analysis of the layout of hydropower projects to the preparation of contractual project documents and computational hydraulic modelling. Nick was a key team member of the Kidston Pumped Storage Project Technical Feasibility Study and was involved throughout the recently completed Neusberg Hydroelectric Project in South Africa. Nick has successfully completed projects ranging from hydraulic design for small residential developments to the feasibility study of a cascade of four large hydroelectric projects in Malaysia.

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Five steps to better understanding geological risks in hydropower projects

Not fully understanding the geological conditions is one of the biggest risks in a hydropower project, and can lead to large cost blow-outs, major repairs and even public safety issues.

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Understanding the geological conditions enables engineers to design safe and stable structures, and to minimise project and financial risk. The geological risks don’t stop at the dam site, but also extend to the spillway, powerhouse, tunnels and other structures.

Hydropower developers often ask: ‘how much should I spend on geological investigations for my hydropower project?’ and ‘how many drill holes do you normally need for a dam site?’

The answer depends on what is already known and what risks have been identified through the available regional geology and the geological mapping of the site. Geological investigations aim to understand the risks at the site by progressively developing a geological model.

Five steps to achieving a good geological model

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It is important to have a clear, systematic process to achieve a good geological model and, therefore, ensure that the subsurface geological risks are well defined.

Entura has developed and adopted the following five-step process:

Step 1 – Develop preliminary geological model

The first step is to develop a preliminary geological model of the site based on available geological information, aerial photos, topographic data and geological surface mapping. Spending the necessary time to source and collate all the available information is valuable.

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The model should include not only the geological units but also the main defects such as bedding, joints, shears and faults. Understanding the main defects helps to determine whether there are any potential failure mechanisms within the foundations underlying the project structures.

Step 2 – Develop scope of phase 1 investigation campaign

Based on this preliminary geological model, we can determine what needs to be confirmed or known, and then plan the phase 1 investigation campaign. The investigations must relate strongly to what you are trying to confirm or determine with the geological model. Without this strong relationship, the developer may be wasting money.

The investigation techniques planned depend on many factors including known geological conditions, information gaps, environmental constraints, site access, available skills and equipment, time and cost. There should be a clear objective for every test pit excavated, geological hole drilled, geophysical survey performed and laboratory test undertaken.

The outcome of Step 2 is the scope of works for the phase 1 investigation campaign. The development of the scope of works is a task in itself and should be performed by a suitably qualified engineering geologist. The preparation of a scope of works ensures that the developer can call for quotations from prospective consultants and contractors with confidence that the campaign will be targeted at improving the understanding of the identified geological risks.

Step 3 – Undertake phase 1 investigation campaign

The third step in developing a good geological model is to undertake the phase 1 investigation campaign.

The investigation campaign should be supervised by an appropriately qualified engineering geologist who is empowered to direct the investigations contractor and who has the flexibility to adjust the investigations as necessary based on the site observations.

For example, the core is not the only result of a drilling excavation: drilling rates, water loss, the colour of drill cuttings, hole collapse and groundwater levels all provide important information that is not visible in a core tray.

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Local contractors are commonly engaged for geological investigations due to the need for heavy excavators and drill rigs. The contractors must be experienced with well-maintained equipment that is appropriate for the task (hole size, hole depths and geological conditions). Appropriate drilling techniques are required to maximise core recovery in the areas of interest, even if they take some time.

Developers must not underestimate the challenges of site access. A significant amount of time can be lost repairing broken plant in remote locations, so the proposed plant should be inspected and tested before site mobilisation.

Laboratory testing should only be performed at reputable laboratories, otherwise there is a risk of destroying samples and wasting time and money for little benefit. Typically, we use local laboratories for common tests, such as those used for concrete manufacture or road construction, and we may use specialised laboratories for more complex or unusual testing.

The outcome of Step 3 in our five-step process is significantly more factual geological and geotechnical information.

Step 4 – Update geological model

Step 4 is to interpret this additional factual information, and to update the preliminary geological model (developed in Step 1). This will improve understanding of the geological risks at the site, which is the key return on the investment made in the investigation program.

Step 5 – Undertake phase 2 investigation campaign

Step 5, the final step in the process, is a phase 2 investigation campaign. It is very common for hydropower projects to undertake more than one geological investigation campaign. This is because the geological model may change due to the information discovered in the first campaign, which may raise further questions or unknowns.

The second campaign, if required, is likely to be very focused, as it will be addressing a specific question, and will help to finalise the geological model.

Asking the right questions

Rather than asking how many holes are normally drilled for a dam project or how much money is normally spent on geological investigations, hydropower developers should ask: ‘is the money being spent wisely and for a clear purpose?’

Geological investigations do not reduce geological risks; they merely improve the understanding of the risks. A good understanding of the geological conditions reduces the uncertainty of capital cost, and therefore enables developers to make well-informed and less risky investment decisions.

To discuss how Entura can assist you to better understand the geological risks to your hydropower project, please contact Mathieu Chatenet on +856 2022 214 214, Gregg Barker on +61 3 6245 4139 or Richard Herweynen on +61 3 6245 4130.

About the authors

Gregg Barker is a Senior dams and geotechnical engineer at Entura. Gregg has 17 years of experience in dam and hydropower engineering and has worked on projects across Australia and in Oceania, South-East Asia and Africa. His experience spans the whole asset lifecycle from site selection, site investigations, detailed design, operation, upgrades and decommissioning. He has a Masters of Engineering Science in Geotechnical Engineering and Engineering Geology from the University of New South Wales and is a Member of the Australian Geomechanics Society. Gregg regularly provides training through the Entura clean energy and water institute and has published seven technical papers on a range of topics.

Richard Herweynen is Entura’s Principal Consultant in Civil Engineering. Richard has 26 years of experience in dam and hydropower engineering, and has worked throughout the Asia-Pacific region on both dam and hydropower projects. In recent years, Richard has led the design of three roller-compacted-concrete (RCC) dams within Australia and a number of significant dam upgrades. Richard was part of the ANCOLD working group which updated the guidelines for concrete gravity dams, and is the Chairman of the ICOLD Technical Committee on Engineering Activities in the Planning Process for Water Resources Projects. Richard has won many engineering excellence and innovation awards, and has published over 30 technical papers on dam engineering including dam safety and risk assessment, RCC dam design and the unique challenges of older style post-tensioned anchors.

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Hydropower generates opportunities for businesses in India

In recent years, India has emerged as a world leader in renewable energy and this growth is presenting opportunities for businesses looking to diversify their activities.

A range of renewable energy developments such as wind and solar, from the smallest to the largest scale, are planned and getting underway all around India. There’s also still plenty of untapped potential for hydropower, particularly in the rugged north and north-west of the country.

Estimates suggest that less than a third of the country’s potential for hydropower has so far been exploited – and that presents an opportunity for organisations seeking to embrace renewable developments as part of their commitment to sustainable social and industrial development, quality of life, and a clean energy future for the nation.

The time is ripe for private investment in hydropower in India. Significant government incentives and subsidies are available to encourage increased hydropower development. Hydropower also offers added value to the power network in the form of immediately dispatchable power to balance any variability of solar and wind output.

Enthusiasm and opportunities are two important factors leading to hydropower success, but another critical factor is reliable expertise, and this may be less available to many potential proponents of hydropower projects if they are new to the hydropower sector.

Progressing through all the necessary steps of any power development process is difficult at the best of times, let alone for a developer who has little or no prior experience.

Hydropower, like all power developments, has its challenges: land acquisition, resettlement, rehabilitation, geology, technical challenges in dam and scheme design and construction, financing, and so on. These challenges can be considerable, but can also be overcome with the right expertise on hand.

Chanju-I hydropower project: a success story

When Indo Arya, a large conglomerate with interests in steel, thermal power and logistics, decided to make its first foray into hydropower, it recognised the need to engage an experienced hydropower consultant and it turned to Entura to provide the long-term support to ensure the hydropower project’s success, from the earliest feasibility study right through to operation.

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I A Energy, a special purpose vehicle, was formed for implementation of the Chanju-I run-of-river hydropower project in the Indian province of Himachal Pradesh. I A Energy provided all the financial and management capabilities, while Entura provided the technical expertise and project development knowledge.

Entura’s ongoing role in this project, supporting the client across all project stages as a trusted advisor, went beyond what might be described as ‘owner’s engineer’, achieving a considerable level of collaboration between developer and consultant that enabled the project’s success.

Now, nine years since the earliest site visits, the Chanju-I run-of-river hydropower project is set to deliver its 36 MW of renewable electricity, thanks to the power of the water flowing downstream from the confluence of the Bhararu and Chanju rivers. The project will generate attractive financial returns for its owner and the State Government, but will also directly benefit the local community, with power, tuition and health services.

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Entura’s involvement over the full cycle of the project helped I A Energy ensure the right location, access and water availability for a viable project. We recommended the site, and then worked closely with the client to progress the project through its various stages, including site investigations, exploration of hydropower potential, environmental impact assessment, feasibility assessment, project approval, tender design, detailed design and construction advice and support.

Entura also assisted I A Energy to set up the organisation of the project and quality procedures on site, and our engineers regularly attended the site to provide ongoing advice and support during construction.

The project involved constructing a 16m-high barrage, a 5km-long headrace tunnel, two underground desilting chambers, pressure shafts, and a surface powerhouse. Entura provided technical expertise in optimising the design and construction, costing, contract packaging, selection of equipment, scheduling and project management. Our involvement delivered valuable outcomes such as increasing the asset capacity from 25 MW to 36 MW.

Overcoming project challenges

During the development phase, the Chanju-I project faced many issues and challenges with the potential to stop or significantly delay the project. These issues included approval delays, environmental issues, stakeholder management, and disagreements with upstream developers with respect to the location and height of the barrage, river basin development plans and infrastructural development.

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Entura’s continuous involvement, timely advice and support during critical situations helped the project team stay on top of these challenges, ensuring ultimate project success. In spite of the hurdles, the collaborative approach provided an efficient mechanism to address the issues and move the project forward at all times, even enabling early commencement of construction. By fast-tracking the construction of the project, the developer maximised its returns, and the project has been noted for its speed and efficiency in construction.

The way Entura serviced the project was praised by the project authority and strengthened our relationship with I A Energy. The longevity of Entura’s engagement with I A Energy on the Chanju-I project demonstrates the importance we place on delivering well for our clients, whether the project is small or large, and our ability to work as a valued and reliable partner of the client throughout the full project lifecycle.

To find out more about making the most of the opportunities available in the global renewable energy sector, please contact Ajay Sharma on +91 99 1038 6409.

About the author

Ajay Sharma is Entura’s Director International Business Development and Managing Director, Entura India. He joined Entura and the Hydro Tasmania group in in 2005 and has held range of positions in the business, from senior engineer to specialist and business development manager. As a hydropower engineer, he has undertaken a range of project design, feasibility study and project management work. He led Hydro Tasmania’s project development activities in India and Nepal and developed greenfield hydropower projects. Prior to joining Entura, Ajay worked with a number of consulting firms including Halcrow and Mott MacDonald. He holds a Master’s degree in Management and is also a graduate of the Australian Institute of Company Directors.

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