India and Australia can support each other’s clean energy journeys

The relationship between India and Australia goes far beyond our nations’ mutual love of cricket. We have deep people-to-people connections that have been formed over generations. At the beginning of the 20^th century, around 7000 people of Indian descent lived in Australia. Now, Indian-born Australians number more than 750,000 – a number that has doubled over the last decade and continues to grow.

It’s natural that our two countries should have a strong relationship across many domains. We have strong strategic and political ties, and our economic engagement opportunities are massive. This will be strengthened even further with the Australia-India Economic Cooperation and Trade Agreement.

In a sign of the deepening India–Australia relationship, in 2023 Australia’s Prime Minister Anthony Albanese and India’s Prime Minister Narendra Modi have shared senior bilateral visits both in India and in Australia. One of the major themes in these meetings has been the potential for the two nations to support each other’s journeys towards a clean energy transition and net zero targets.

Building clean energy connections

I’ve been privileged to be involved in furthering the Australia–India relationship as a member of the Australian Senior Business Delegation to India and a subsequent Roundtable with business leaders in Sydney. During these meetings, I spoke about the potential our nations have, despite our radically different sizes, to work together to overcome challenges in our renewable energy sectors. I put forward the idea of a joint renewable energy council, which was well received. I am now on the Australia India CEO Forum’s Energy, Resources, Net Zero and Critical Minerals Joint Working Group, which had its first meeting this month. And this week, Entura has welcomed a visit from the High Commissioner of India to Australia, Manpreet Vohra, at our Hobart offices.

These opportunities have been realised after forging relationships with government officials across Australia and India over many years – and having maintained an Entura presence in India for more than 17 years with our highly skilled team based in New Delhi. Entura is a leader in the renewable energy industry and at present is the only Australia-based, government-owned business operating in the sector in India.

Entura is an excellent example of how Australia and India can support each other towards our clean energy goals. With India committed to net zero by 2070 and with 60% of its current energy production coming from coal, there are huge decarbonisation moves underway, including plans for 500 GW of renewable energy by 2030. Renewable electricity is growing at a faster rate in India than in any other major economy. Electricity demand is expected to double over the next decade and the share of wind, solar, hydropower, batteries and pumped hydro will lift as a proportion of the mix.

For Entura’s clients in India, we bring deep hydropower and pumped hydro capability and significant expertise in hybrid renewables systems, integrating distributed energy resources, resolving transmission challenges, and delivering bespoke, tailored training and capacity building through the Entura clean energy and water institute, with a particular focus on dam safety. For our projects in Australia, our India team brings a wealth of talent and a boost to capacity. They also have the local knowledge and connections that go a long way towards our success in clean energy and water projects across South Asia and South-east Asia.

Building on Entura’s long engagement with India, and from my involvement with the International Hydropower Association, I see the following areas as particularly important for our nations to focus on for mutual benefit in the energy transition.

1 Diversifying supply chains in critical minerals and renewable energy technologies

As both countries strive to achieve ambitious renewable energy targets, we will need to develop more diverse and resilient supply chains. The extraction and processing of critical minerals will be an essential area for cooperation. Mechanisms such as The India–Australia Critical Minerals Research Partnership and India–Australia Critical Minerals Investment Partnership will integrate Indian scientific, industry and government partners with CSIRO’s developing Critical Energy Metals Mission. This holds great potential to strengthen supply chains, add value to Australian exports, and support the commercialisation of critical minerals technology.

Another crucial factor in the success of Australia’s renewables, green hydrogen and green steel ambitions is the availability of components such as solar PV panels, batteries, electrolysers and electrical componentry. India is a powerhouse of manufacturing capability and could become a major supplier of these essentials to support Australia’s build-out of renewables. The announced joint taskforce on solar and the initiatives underway to collaborate on green hydrogen and green steel are encouraging developments.

2 People power and knowledge-sharing

Developing a skilled workforce, ready to take up the jobs of the future, is a make-or-break factor for the clean energy transition. As Entura has experienced, India has a deep pool of technical talent in renewable energy and a rising skilled workforce. To put it in context, India has over 1000 universities and some estimates suggest that these institutions are producing more than 1 million engineering graduates per year.

Australian businesses such as Entura benefit from having access to this talent – especially facing escalating skills and resources shortages in Australia – and we’ve found that with the right tools, methods and attitudes, our people across Australia and India can work seamlessly together in integrated teams, leveraging each other’s strengths on projects throughout the Indo-Pacific. Our India team adds diversity and capacity to our business – with the added bonus of optimising project delivery across time zones. We also benefit from the ability to build greater understanding of local conditions and regulations in India, and to forge strong networks and partnerships in the region.

Over the years, we’ve identified that despite the size of the potential renewable energy workforce, India still seeks greater skills development and expertise in hydropower, dam safety and the integration of renewable energy technologies. Entura’s clean energy and water institute (ECEWI) is a model of how long-term experience of developing and maintaining renewable energy assets, which we’ve gained through Tasmania’s century-long hydropower journey, can be shared across the world to build skills and capacity that extend far beyond the theoretical or academic.

Through ECEWI, we’ve delivered successful exchange programs, training workshops, and capacity-building initiatives in India, including dam safety training for India’s Central Water Commission as part of its Dam Rehabilitation and Improvement Project (DRIP) – and we’re now supporting the South Asia Regional Infrastructure Connectivity Framework (an initiative of the Australian Department of Foreign Affairs and Trade) by providing capability development on dam safety and cross-border power markets.

3 Innovation and best practice

There is enormous scope for Australia and India to work together to drive innovation in clean energy technologies and to share best practices and solutions. Many initiatives are already underway, drawing on Australia’s advanced technical expertise in solar and wind farms, energy storage solutions, and grid integration projects. For example, Entura is applying experience in India that we’ve gained in world-leading projects in Australia – such as our understanding of offgrid hybrid renewables systems gained from powering the Bass Strait islands, and the work our teams have led to identify and progress the first new pumped hydropower opportunities in Australia for decades in Tasmania and in Queensland.

As developers conduct concept studies and seek to secure licences for renewable projects, sharing international expertise such as ours will be an advantage. We are already applying our pumped hydro screening processes to identify new opportunities in India, and looking at the potential for repurposing disused mine sites for new renewable energy projects, as we are doing at the former Kidston gold mine in Queensland. We’re also applying our knowledge of repowering existing wind and solar farms in the quest for economical and sustainable approaches to boost electricity generation.

This brings me to another key area in which Australia can help to support a ‘fair’ clean energy transition in India. Australia has some of the strongest environmental and social requirements for clean energy projects in the world, and we’ve learned a lot about sustainability along the way. Entura has long been an advocate for sustainable projects conducted with integrity. In fact, I’ve just returned from the International Hydropower Association’s world congress, which reinforced this theme, announcing a new Hydropower Sustainability Alliance and the Bali Statement of Powering Sustainable Growth. Businesses like Entura can foster a fairer clean energy transition in India by promoting high standards of sustainability in all the projects in which we participate and the training we deliver.

Working together on the three factors I’ve discussed here will help build greater success, resilience and sustainability in all areas of the renewable energy transition. Lowering emissions in the global energy sector is an enormous and daunting endeavour that can’t be solved without international collaboration. But we’re at a very exciting point in the journey. We look forward to continuing the close and mutually beneficial relationship between our nations. Accelerating the global clean energy transition is the most important legacy we can leave today’s communities, future generations, and this planet we all share.

About the author

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.

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Who will develop and build our clean energy future – and what will it cost?

I have just ‘returned’ from the World Wind Energy Conference 2023, held just down the road from Entura’s Hobart office. At the conference there was an overwhelming sense that the energy transition from fossil fuels to renewables is well underway and the era of coal-fired power generation is coming to a close.

This has been reflected in the Australian Energy Market Operator’s most recent roadmap (the 2022 Integrated System Plan) which shows the need for a phenomenal increase in energy storage (batteries and pumped hydro), wind and solar generation. AEMO estimates that, by 2050, storage will need to increase by a factor of 30 (from 2 GW now to 61 GW in 2050), and that grid-scale solar and wind will need to increase 9 fold (from 16 GW now to 141 GW in 2050). Take a look at AEMO’s infographic which makes the scale of the energy transition challenge very clear.

This generational change offers many opportunities and challenges for the industry and the wider community. But technical challenges aside, the huge scale of what is needed has me pondering two non-technical questions: who exactly is going to develop and build so many projects, and what will it cost?

Who is going to do the work?

Regarding my first question, I think of the varied background of my colleagues and imagine where the next generation of engineers might come from. At Entura, we have renewable energy experts including an electrician turned civil engineer turned renewable energy engineer who is now pursuing his passion for battery projects and electric vehicles. We have a former manufacturing engineer, now with 15 years of experience as a wind engineer. We have an expert on space tether dynamics, now one of Australia’s most respected solar and battery experts. And we have an electrical engineer from the oil and gas industry who is now helping design and commission hybrid energy systems from outback Australia to Antarctica. The common thread is that we work with people who were willing to change track and pursue what they believe to be the new right course of action.

For renewables to achieve the necessary growth, we are going to need people from diverse technical and cultural backgrounds. Those of us in leadership positions need to be willing to employ new graduates and support people who may initially lack specific experience but will in short time become valuable contributors.

At the conference, Kane Thornton (Chief Executive of the Clean Energy Council) called on leaders in the industry to put aside their own propensity to try to carry the load, and instead focus on developing new leaders as a priority. With such ambitious targets for new renewable energy, this is the right, future-oriented approach. We all have a part to play, and the theme of the conference, ‘Symphony of the Renewables’, points to a collaborative, industry-wide approach rather than a zero-sum project-vs-project approach.

What will it cost?

On the question of cost, CSIRO (in collaboration with AEMO) issues an annual estimate of the cost of different forms of energy generation (GenCost: annual electricity cost estimates for Australia – CSIRO). This study suggests (with evidence) that wind and solar backed by storage technologies will be the cheapest way to replace coal-fired plants and meet new demand as our country grows.

This is worth celebrating, but the industry must also prepare society for the large expenditures needed to rebuild our energy system, and the cost increases that consumers may sometimes see in their energy bills. While wind and solar are comparatively less expensive than new coal, gas or nuclear, it will not be cheap to achieve the necessary build-out of wind, solar and energy storage that will takes us towards 100% renewable energy. By design, this system will have some infrastructure that will be idle during times of plentiful wind or sun but is vital to the security and resilience of the system overall. This will be a challenging feature of the system to communicate to people who might see in any given year an increase in their household electricity bill.

The overall message needs to be communicated, repeated and reinforced – that this is a once-in-a-lifetime rebuilding of our electricity system into something that is more reliable than we currently have, ready for the future, and cleaner and better for our towns and communities and the wider world.

If you would like to find out more about how Entura can help you optimise your wind farm, develop an asset management strategy, or support you with due diligence services for proposed or operational projects, contact Patrick Pease or Silke Schwartz on +61 407 886 872.

About the author

Andrew Wright is Entura’s Senior Principal, Renewables and Energy Storage. He has more than 20 years of experience in the renewable energy sector spanning resource assessment, site identification, equipment selection (wind and solar), development of technical documentation and contractual agreements, operational assessments and owner’s/lender’s engineering services. Andrew has worked closely with Entura’s key clients and wind farm operators on operational projects, including analysing wind turbine performance data to identify reasons for wind farm underperformance and for estimates of long-term energy output. He has an in-depth understanding of the energy industry in Australia, while his international consulting experience includes New Zealand, China, India, Bhutan, Sri Lanka, the Philippines and Micronesia.

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A fast and fair energy transition demands a skilled, diverse workforce

The clean energy transition is set to create millions of new renewable energy jobs worldwide. It will, however, also bring major change for workers and communities who currently depend on carbon-intensive industries.

This leads to two major challenges:

• how can the clean energy sector find enough skilled workers to enable the mammoth task ahead of us?
• how can we make sure that no one is left behind so that the transition is both fast and fair?

These are enormous questions for the clean energy sector as a whole, not for hydropower alone. All players in the sector need to own our part of the challenge and act urgently to find and implement the solutions that are right for us.

At the recent International Hydropower Association Congress in Bali, I facilitated a panel discussion on these issues. With hydropower globally already experiencing staffing and skills challenges, our panellists agreed that the sector needs to plan and act now on at least five fronts:

1 Retaining organisational knowledge

The sector will need a strong focus on knowledge transfer, especially as talented and deeply experienced professionals retire from the industry. It’s estimated that as much as 25% of the hydropower workforce will reach retirement in the next decade, taking their knowledge and skills with them.

2 Attracting and retaining a skilled workforce

All clean energy technologies will be competing for talent as the energy transition accelerates towards 2050 net zero targets. Hydropower will need to consider how to remain competitive in this tight employment market. The fact that hydropower plants are often located in remote areas can be a barrier to some people. Scholarships, subsidies and payment levels may help to offset some of the barriers, as will creating supportive, flexible and safe workplaces with attractive terms of employment.

There’s also a need to ensure, and promote, hydropower’s environmental and social sustainability, as more and more workers are increasingly motivated by purpose, values, integrity and sustainability. It’s important that we demonstrate how a career in hydropower can be enormously fulfilling, with so many opportunities to make a meaningful difference to society and a sustainable future.

Another important consideration is that we’re not talking about engineers and electricians alone, although priming the pipeline of STEM students and apprentices is particularly urgent in these areas. We’ll also need a vast range of other professionals, with skills in finance, law, project management, people management, IT, environmental science, planning, community engagement and more. Workforce planning needs to take these role into account.

3 Activating a range of options for skills development and training

We will need to ensure that we’ve got the right mix of different training options available – from formal tertiary and vocational training, through to customised and on-the-job training (such as the skills and capacity development that Entura’s clean energy and water institute provides) and less formalised upskilling. The next seven years will be critical here, so that the workforce is ready as we hit the major escalation of clean projects in the race towards 2050.

4 Mapping opportunities in the sector to support a ‘just transition’

What can we do to find mutually beneficial opportunities for workers and communities affected by changes in carbon-intensive industries? The transition to clean energy industries isn’t necessarily a straightforward switch for workers (for example, are the jobs of the right quality, in the right places, and at the right time?) – but could hydropower be an option for some? How can we support displaced workers to adapt to the jobs of the future? To drive policy, countries need to move quickly to analyse their current and future workforce capacity and needs, and their transition challenges and opportunities – as Australia is doing. Take a look at the recent report from Jobs and Skills Australia, The Clean Energy Generation: Workforce needs for a net zero economyand, to see what’s happening in this space around the world, read the International Energy Agency report on Skills Development and Inclusivity for Clean Energy Transitions.

5 Maximising women’s participation in the sector

It’s well recognised that women are still underrepresented in engineering, in the overall clean energy workforce, and in hydropower. The gender gap becomes larger at senior and managerial levels. Women also leave the hydropower sector more often than men (whether that’s changing sectors, changing companies, or leaving the workforce altogether). As I’ve said many times before, our industry simply cannot afford to miss out on the talent of half the population. We need greater action to maximise opportunities for women and other underrepresented groups in the hydropower workforce and access the widest pool of diverse talent.

So what can we do about this? We can:

• address the ‘pipeline problem’ – by raising the profile of STEM as a path for schoolgirls/ university students / apprentices
• create incentives to attract women into the industry (e.g. scholarships)
• ensure unbiased recruitment approaches
• adopt flexible, supportive and equitable workplace strategies to help attract and retain women in the industry, particularly women balancing caring responsibilities
• ensure that hydropower workplaces are secure and safe for women with appropriate facilities
• fix the pay gap
• create opportunities for networking and mentoring to encourage career progression and industry retention
• ensure that women are encouraged to apply for senior positions, and that women in senior roles are visible role models for others
• involve men in understanding and remediating existing gender barriers – a particularly powerful action, as identified in the recent World Bank report on gender equality in the hydropower sector
• think, talk and act on gender issues every day, not only on International Women’s Day!

In short, there’s no lack of action we can take to make the hydropower sector more inclusive and diverse, even if those actions look a little different or take more time in different regions. The most important thing is to move forward.I strongly recommend that you read Power with Full Force: Getting to Gender Equality in the Hydropower Sector, which has just been released by the World Bank. It’s a powerful study of these issues, and, for me particularly, a strong reminder that the conditions we might take for granted in countries like Australia, such as paid parental leave and anti-discrimination laws, are not enjoyed by all women in the global hydropower sector, particularly in developing countries.

Clearly, to secure the next-generation workforce needed to deliver the renaissance in hydropower, we’ll need to work together to tackle the challenges and make the most of the opportunities ahead. None of the five actions I’ve listed in this article are surprising and none are merely a ‘nice to have’ – they are all essential and urgent.

Talking about these issues at global conferences is important, but it’s not enough. Now is the time for meaningful and urgent action to turn observations into actions and intentions into results.

We would like to acknowledge the panel participants: Kate Lazarus, ESG Advisor – IFC, Martin Stottele, Team Leader of RESD (Renewable Energy Skills Development, Indonesia) Programme, and Josef Ullmer, Director Andritz Hydro, Andritz.

Click here for more information about the Entura clean energy and water institute. For more information on our work in sustainability and planning, please get in touch.

About the author

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.

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What is the best way to model complex water structures?

Understanding the behaviour of water as it flows in natural and constructed environments is fundamental to designing and managing many civil assets, and integral to reducing risk and cost in water infrastructure projects.

Water is such an intrinsic part of our lives that we all have a good observational understanding of what water is and what it does in many everyday situations, like falling from a tap or spiralling down a plug hole. But our intuition can only take us so far. When engineers design important infrastructure such as dam spillways, or inlets to pump stations, or need to understand issues such as fish passage for a low weir, they need to turn water into numbers and quantify its behaviour. Being able to quantify complex water flow is one way engineers can better understand the world and make a difference.

Modelling options

When water flow is complex and a deeper understanding of its behaviour is required, the two main options to help improve this understanding are physical scale models and computational fluid dynamic (CFD) models. But when should one be used over the other?

Physical scale models are created and used in a research laboratory, whereas CFD models are created using software and run on fast computers. Here ‘scale’ means the physical models are built at some fraction of the item of interest’s size. Historically, physical scale models have been the gold standard for helping understand complex water flow, but that’s not always the case now. Both methods have a place, and they can complement each other.

It’s generally better to use more advanced modelling techniques early in a project to better guide the design process or understand an existing system.

Has CFD killed the physical scale model star?

Knowledge about the physics of water flow has developed from centuries of physical observation with experiments run in hydraulics laboratories and the field, combined with theoretical calculations. Advances in computing performance in the last few decades have allowed these theoretical calculations to be solved in finer detail and with greater accuracy. But does this mean the end of physical scale modelling testing, in particular as computing power is growing faster than the number of research laboratories? Not for a while.

Even with advanced, powerful computing systems, the outputs of CFD software tools still need to be validated against physical measurements. For the physical scale of the civil engineering problems being solved (e.g. a dam spillway), the CFD models approximate the theoretical calculations, and these approximations need to be validated. Some water flow problems are dominated by well-defined forces, such as gravity, and these problems are easier to validate. But other problems are dominated by turbulence and multiphase flow, and these are harder to validate as the phenomena are more complex.

In the aerospace and car industries, where the fluid of interest is air rather than water, a designer uses a combination of wind tunnel testing and CFD modelling to better understand the performance of a design. Small parts can be simulated in CFD with minimal approximations using direct numerical simulation (DNS) of turbulence. But for a full car and even more so for a large commercial aeroplane, it’s currently cost-prohibitive to only use DNS (e.g. millions of dollars per run), and some level of wind tunnel testing is still required. This is combined with non-DNS modelling CFD methods.

It’s similar in civil engineering. There are different physical sizes, stages of a project timeline, costs, and risks of getting the answer wrong. These drive the balance between CFD and physical scale model testing. Most work, in particular at a concept level, is done with CFD, but physical scale modelling is still recommended for critical infrastructure prior to construction.

A matter of scale

The size of most civil engineering infrastructure – such as spillways, rivers and large stormwater culverts – make it impractical to use DNS of turbulence (based on cost and timing).

Both physical scale models and CFD can be time-consuming tools to use, and for various projects it’s better to use one before the other. For the design of fish passages and recreational water systems (such as whitewater kayaking), doing small-scale, rough physical scale modelling can be efficient for design development of concepts. This is because designers can move 3D-printed shapes around in a hydraulic flume, and see and feel the direct impact on changes to the design. This is a very complex problem with few industry guidelines and without the same body of research as other civil engineering problems, such as dam spillways and energy dissipation.

Where there is a large body of knowledge on a topic, standard designs provide a starting point. Then, it’s often efficient to start with hand calculations or a concept-level CFD model. These calculations may lead to more detailed design, modifications of standard designs with detailed CFD modelling, and then, potentially, physical scale model testing. There are always iterations, and sometimes the CFD modelling can be used to inform the design of a physical scale model testing setup, and vice versa. CFD modelling is also faster and can more easily be used for design optimisation compared to physical modelling.

In some cases, using CFD alone is possible, particularly where there is a solid body of knowledge about a piece of infrastructure. The temptation is to use CFD more and more, as it can often be lower in cost. It is also important to note that physical scale model testing has its limitations. So there are cases where CFD modelling can provide more insight at a lower cost.

With physical scale model testing, the key limitation is in its name. The model is built at a much smaller scale than the feature being modelled – just a fraction of the expected final design or existing system size. Typically a coarse model of a dam or spillway may have a 1 in 200 scale, and a good one may be at a 1 in 50 scale. A 1 in 50 scale model of a spillway that was going to be 100 m high when finally constructed would need to be 2 m high as a model. This is okay for pure water models, but for aerated flow the ideal scale is closer to 1 in 10. So if aerated flow was important in that 100 m high spillway, then the model would be 10 m high. At that size it would not fit in a normal hydraulics laboratory and would be very expensive to build. So, typically, a compromise is made and a 1 in 30 model is constructed. The reason scale is important is that water behaves differently at different scales. For example, surface tension is important in a pipe that’s 5 mm in diameter but is not important in a large river flow.

How do you measure water?

Another limitation of physical scale model testing is measuring the flow during the experiment. There are some limitations on CFD as well but, compared to a physical scale model test, it is generally much easier to get the results from a CFD model accurately, in many more locations, and without disturbing the flow.

Complex multiphase flows for fish passage and smaller whitewater kayak systems can be modelled well with scale models initially, as the system being modelled is relatively small. But when you’re modelling something that is much larger and has complex multiphase flows, scale model testing is harder. Model size is important for CFD models as well, and there is no free kick here. Larger systems where there is complex flow are computationally more expensive to model in detail using CFD. Typically, however, the budget of projects involving larger complex systems are also larger – and so, the modelling costs can be a similar proportion of the total project costs for small and large projects.

At some point in the future, such as when quantum computing becomes mainstream, CFD using direct turbulent simulation (i.e. DNS) of larger objects could completely replace physical scale modelling.

Room for both in pushing the knowledge envelope

Both physical scale modelling and CFD modelling require specialised facilities and experienced modellers. With the advent of lower cost computing services and increased CFD training in many engineering courses, CFD modelling has become the lower cost option for many civil engineering water modelling problems. But both physical scale modelling and CFD will continue to remain important for many years yet, and both approaches should be encouraged.

In general, what’s easy or difficult in physical scale modelling is often of a relatively similar level of difficulty for CFD modelling. Often the approach will come down to a modeller’s preference and access to either option, but in some cases it’s prescribed by standards. CFD is often cheaper and faster to set up for most civil engineering scale problems and, once set up, can be run on multiple computers at once and address more questions at once. Viewing the results of the CFD model is more flexible, but some prefer the touch and look of a physical scale model.

For novel phenomena at the edge of our understanding, there is still no substitute for a physical scale model. Over time, this will leave physical scale modelling mainly as a research tool and to aid community consultation and education, with CFD used for operational modelling in industry. Most projects will still use a combination of the two.

Like all good engineering projects, solving complex water modelling problems requires having adequate time and budget to provide a suitable quality result. When approaching a complex water flow problem, inform yourself of the solution options. The best model for your stage of understanding is the one that reduces uncertainty and improves knowledge to aid better decision-making.

If you’d like to talk with Entura about your water or dam project, contact Phillip Ellerton (Australia) or Shekhar Prince (international).

About the author

Dr Colin Terry is a civil engineer at Entura with three decades of experience in Australia and New Zealand. His experience includes modelling, planning, design and construction support. He has worked on multidisciplinary projects across various parts of the water cycle including catchment management, water supply, hydropower, land development, transport, and water quality in natural systems – with a focus on surface and piped water.

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De-risking renewable energy projects is in everyone’s interests

The rapid transformation of the energy sector is exciting and ripe with opportunities. Inevitably, it also involves a level of complexity and a range of uncertainties. Phrases such as ‘decarbonising the future’, ‘net zero emissions’ and ‘energy security’ feature in almost every energy transition seminar, but what do they really mean when it comes to constructing and operating the projects necessary to support a cleaner and greener future? How can developers design and develop for sustainability across the whole project lifecycle?

With over 6 GW of committed large-scale wind and solar projects in the development pipeline, many of which need external finance, it is crucial that projects are developed in a way that will qualify for financing and will align with contemporary sustainability standards. Many financial institutions are applying risk management frameworks such as the Equator Principles to determine, assess and manage environmental and social risks. Over 100 financial institutions globally, including key Australian banks such as Commonwealth Bank, ANZ and Westpac, have adopted the principles. The Equator Principles provide a framework for due diligence into whether the project has been or is being developed in an environmentally and socially robust manner including respecting human rights. Similarly, regulators require evidence of sound avoidance and minimisation strategies to reduce the footprint of disturbance, particularly through construction.

Environmental, social and governance (ESG) considerations throughout the whole project lifecycle, including supply chain considerations, are more carefully scrutinised than ever before. Poor management of ESG can lead to reputational, financial and legal consequences. Investors will want a thorough review of approval documentation and evidence of systems and processes to assess project risk regardless of whether projects are already approved or are still under assessment. The investor needs reassurance that the project will be, or has been, developed in a manner that aligns with their own ESG objectives.

To help your project progress smoothly through the approvals process, consider these points:

Each project’s risks, and their relationships, are unique

No two projects are the same. There are myriad ESG risks for any project, and the work to understand and quantify these risks is also project-specific. The interrelationship of the risks influences the risk profile of each project, which is pivotal to investment and acquisition decisions. Some examples of risks include changes in regulation between the time of construction and approval; changes in the conservation status of threatened species that alter operational monitoring requirements; community resistance post-approval; or lack of transparency throughout the supply chain amidst the risks of modern slavery.

Start early with thorough studies and engagement

From an approvals perspective, there is significant benefit in investing early and proportionately in environmental and social studies. It’s also important to invest in well-documented planning assessments that include building a relationship with the regulator as well as robust community and stakeholder processes. Meaningful and genuine engagement with First Nations communities is crucial, as projects are often developed on Country not previously subject to development. In terms of environmental and social risks, some projects may simply be too difficult or inappropriate to develop at the largest possible scale. As the number of projects being developed in a region increases, cumulative impacts are increasingly at the centre of communities’ and assessing agencies’ concerns, particularly in terms of noise, visual impacts and ecology.

Getting on the ‘front foot’ delivers results

It is important for developers and proponents to understand that the quality of work at this early stage is likely to impact on the due diligence process – for example, whether studies have been prepared to best practice or industry standards, and whether risks have been identified early and managed appropriately. Good early studies, actions and decisions can make a difference even before the project is approved – providing regulators with confidence that you’re being proactive when it comes to ESG risks, whether that be through design iterations or measures to manage construction and operation.

Investing early to de-risk may reduce the potential for disproportionate costs later in the project, such as re-work or offsets, and may increase the project’s likelihood of achieving finance. Due diligence throughout the approval process is likely to reassure a potential investor or buyer that the project has been de-risked as early and as thoroughly as possible. With the energy transition such an urgent priority in Australia and across the globe, it’s vital that generation, storage and transmission projects progress both rapidly and sustainably. A focus on early de-risking is undoubtably a key enabler of this goal.

Entura has led a number of supply/vendor and lender technical due diligence assessments nationally and internationally, assisting in the investment, acquisition and transaction for large portfolios of renewable energy projects, including solar, wind and battery energy storage systems. Reach out to Patrick Pease (Australia) or Shekhar Prince (international) to find out more about how we can support you with due diligence assessments.

About the authors

Cynthia Nixon

Cynthia’s experience and qualifications in environmental engineering, environmental law and communications provide an integrated perspective on sustainability risks for Entura’s clients. She has over 15 years experience implementing systems and managing compliance and risk, including auditing, risk assessment, training and reporting. She currently manages Entura’s Integrity Framework and supports clients to improve their sustainability performance. She has conducted due diligence assessments across hydropower, solar and wind farm projects and assessed performance against the Equator Principles and International Finance Corporate Performance Standards (IFC PS). She is a certified user of the Hydropower Sustainability Standard and Tools.

Bunfu Yu

Bunfu is a Senior Environmental Planner at Entura with diverse experience in strategic and statutory planning, environmental approvals and management, and engagement and consultation streams for small to large-scale projects across Australia and the Indo-Pacific. Working with public and private clients across the water, energy and infrastructure industries, she designs and leads fit-for-purpose approval strategies that consider the community, landscape and regulatory regime, and advises on acquisition, joint venture and/or purchase of portfolios in due diligence roles nationally and internationally. She was awarded the 2023 National Young Planner of the Year by the Planning Institute of Australia.

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What is the value of conventional and pumped hydro storage in a transitioning energy market?

Entura’s Technical Director Power, Donald Vaughan, presented a paper at the global CIGRE Symposium in Cairns, Queensland in September 2023. This is a short summary of the outcomes of the analysis presented in his paper, regarding the value and roles of conventional hydropower, pumped hydro and battery energy storage as the power system transitions to a greater proportion of variable renewable energy in the form of wind and solar PV.

There is a growing need for firming and/or storage in our power systems as we move from predominantly dispatchable sources of power to variable renewable energy (VRE). In the Australian context in the National Electricity Market (NEM), the volume of storage required is expected to be around 46 GW (640 GWh) by 2050 (AEMO 2022). Multiple sources, technologies and methods are being considered but it may be that conventional hydro as well as the more obvious pumped hydro and battery energy storage (PHES and BESS) can play a role.

How do we value storage?

Storage can be valued in many ways. For pure storage, like BESS and PHES, value in a market sense can be measured based on the arbitrage between charging and discharging. Similarly, we can place value on a firming function for VRE. It is more difficult to value the restraint of generation at one time so that stored or withheld energy can be used later. This is the kind of storage offered by conventional hydro sources.

One way of thinking about value is through a measure of realised value vs average value in the market for a particular generator or group of generators. This ‘value factor’ approach is an appropriate measure for storage if we are measuring storage as a contributor to meeting market demand (either local or via interconnections).

One of the problems with the value factor approach is that it is difficult to apply properly without considering market price changes. Introducing plant that can effectively change demand profiles (such as PHES or BESS) will also change the market price, making it difficult to calculate value factors without complex market modelling.

We can instead measure the value of storage by assessing its ability to firm VRE. The measure is based on the ratio of smoothed to unsmoothed VRE with and without the storages applied.

Where there are large amounts of VRE, flexibility from market participants can be valuable. In terms of hydropower generation, conventional hydro plant (storage, Run of the River and head waters) has sufficient flexibility to provide significant market value for modest levels of VRE.

The scale of the transition to VRE will, however, exceed the capacity of conventional hydro to manage variability. Other forms of firming and actual energy shifting, rather than just energy withdrawal (as conventional hydro provides), will be required once the energy balance tips towards energy coming predominantly from VRE sources, with the associated need to manage large diurnal variability as well as longer, weather-based variability. Pumped hydro and battery energy storage will play an important role in providing this more flexible storage.

The role of PHES and BESS in firming

The BESS high power-to-storage ratio allows it to respond to a series of short-lived surpluses or deficits. The PHES deep storage allows it to manage longer duration surpluses or deficits.

The ultimate mix between PHES and BESS in the market is likely to be driven by several factors including the rate of VRE development relative to the level of inter-connection, load growth and VRE mix.

The nature of the VRE will also play a role in determining the storage mix. A predominance of solar will lead to a diurnal pattern that will allow all storage forms to recharge more regularly than would be the case with wind alone. This may allow shallower storage to manage evening peaks with deeper storage reserved for baseload operation overnight. 

The economics of BESS and PHES will also play a role in determining the right balance. The market demand for batteries for other purposes and the high market demand for power electronics may yet lead the price/MW of these two storage forms to begin to converge and to limit the depth of storage that will be possible using BESS. PHES on the other hand requires long-term planning, complex approvals processes and less certainty in terms of capturing value from the market. The Integrated System Plan (ISP) of the Australian Energy Market Operator (AEMO) forecasts a large requirement for PHES as deep storage and some very large projects are beginning to be planned.

As these factors play out, the appropriate mix of BESS and PHES will become clearer – but both will certainly play a role in Australia’s clean energy transition.

For more information about the analysis behind his paper, or to discuss how conventional hydropower, pumped hydro and battery storage can be valuable to your situation, contact Donald Vaughan.

A shift in asset management mindset brings new opportunities for hydropower

Compared with other clean energy technologies, hydropower is a long-distance runner. Many hydropower facilities have an expected lifespan of up to a century. An increasing challenge, however, is that many of these facilities are already well progressed on their life journey. With much of the world’s hydropower fleet already at or beyond mid-life, effective asset management is key to enabling these plants to perform successfully into the future.

But times change – so the way these plants operated decades ago may not be the way they can best serve us now or into the future. Changing energy markets will present different demands and new opportunities that extend beyond the operational states for which some hydropower facilities were originally designed.

In this context, asset management can do more than maintain the functional status quo; it can become a strategic enabler of change, breathing new life into old assets in a rapidly changing landscape.

New roles for hydropower

Energy markets are in transition. The pursuit of clean energy targets, the declining costs of wind and solar power, retirements of coal-fired power stations, and volatility in supply and pricing of gas are driving rapid change. With large amounts of wind and solar, the market needs storage to smooth supply. It also needs ancillary services that maintain a stable, reliable and resilient electricity grid. Hydropower can provide both.

To meet these market needs and to take advantage of emerging opportunities, the way we operate some hydropower plants will need to change. This calls for a rethink about how we want our assets to perform. The focus of asset management should now be shaped around maximising market opportunities as well as maintaining reliability while also optimising performance and dispatchability. This focus can be applied to designing new hydropower developments as well as overhauling aging assets.

Getting the strategy right

Over time, asset management has become a catalyst for continuous improvement regarding asset stewardship, evolving beyond reactive and fixed-interval maintenance, through to far more proactive, preventative and risk-based approaches guided by international standards (ISO 55000). However, even advanced asset management approaches tend still to be geared towards replacing ‘like for like’ to maintain desired levels of reliability, capacity and performance.

We believe that what’s needed now is a new chapter for asset management; one in which we employ all the sophistication of existing asset management approaches but add a new focus on ‘designing for dispatch’ to meet the market need whenever opportunities arise.

Here’s how that might look:

The starting point for the asset management strategy must be the organisational context. In other words, the asset management approach needs to enable the organisation’s vision, mission and business plans. But the organisational context cannot be a ‘set and forget’. It may shift due to changes in the broader operating environment, or it may change if there is a transfer of ownership of the organisation.

The next step is to understand the current and potential portfolio capability within the context of the organisational strategy. This means understanding how each particular machine and/or station is currently operating and performing, as well as how it would need to in future to deliver the desired outcome. Part of this process will be identifying any limitingfactors. These could be elements of the operational environment, such as weather patterns, rainfall events, or the relationship between one station and others in the cascade.

With a clear understanding of each asset’s performance and reliability requirements, asset management plans can be reviewed and adjusted to suit – or, in some cases, the asset may even need to be redesigned. The driving question behind the asset management strategy will be what each machine needs to be able to do in the market. Within the market opportunity, what are its strengths and weaknesses, and how will it interact with what the trading floor needs?

A market focus in practice

Let’s look at this in some real-world scenarios.

For an asset that largely performs as a baseload station, the asset management strategy may be to minimise the requirement for minor maintenance outages by designing in redundancy – such as having extra machines available in case of a failure.

Whereas, where an asset needs to operate mainly to meet peaks in the market, the components that suffer stress and wear from stop-start activities could be bolstered in their design, with failure modes addressed or eliminated. This may mean trialling new technologies in advance of the changed operation pattern, to be sure that the solution is robust. A change in style of operation from continuous generation to intermittent generation is also likely to call for changes in the monitoring and inspection regime.

It may also be worth changing the maintenance approach to better suit market dynamics. Rather than taking a machine out of service every 12 weeks to replace some relatively inexpensive components in a set, for example, it may be more cost effective to replace whole set at once and only take the machine down every 24 weeks to do so. The cost of the components may be outweighed by the extra revenue earned through less downtime.

We also have the opportunity to identify what part of the asset lets us down, and how we can engineer that in or out to be able to maximise the value of the market opportunity.

This is the approach that Hydro Tasmania is applying to the aging Tarraleah hydropower station, which previously operated inflexibly, based on the constant water volume that flowed slowly to it. A potential new design for Tarraleah may provide greater control of the outputs of the station, with controllable water flow and machines that are able to turn off and on rapidly as needed when the market requires.

The driver for design and asset management in this context becomes primarily dispatchability. Assets are designed and managed to meet the organisation’s vision and consequent dispatch strategy.

Asset owners that are thinking about dispatch are likely to want to take a lead role in the design phase, working together with original equipment manufacturers (OEMs) to design and customise machines to best meet the dispatch strategy and take advantage of market opportunities.

The outcome of the process we’ve outlined here should be an asset management program that optimises assets for the market and maximises their value for current and future operations. By optimising both asset management and dispatchability, hydropower assets can continue to operate efficiently and reliably, and to make very significant contributions to the stability and sustainability of the grid.

If you would like support to understand your dispatch opportunity, iron out barriers, and set up your operations and maintenance strategies to be dispatch-ready, contact Richard Herweynen or Phillip Ellerton.

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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How to avoid analysis paralysis

Modelling has a very important role in every sphere of engineering. Complex mathematic models help us better predict and understand behaviours and performance so that we can solve technical problems, push the boundaries of applied science, and optimise construction and manufacturing.

We use finite element models (FEM) to determine the forces, stresses and deflections of a complex structure. We use computational fluid dynamics (CFD) to analyse complex three-dimensional hydraulic problems and determine flow vectors, velocities, water depths and pressure fluctuations. A complex finite difference model (such as FLAC) helps us model complex geotechnical problems. A rainfall–runoff model supports our understanding of potential flooding along a river channel.

In the 30+ years that I have worked in civil engineering, computing power has increased dramatically. As a result, modelling tools have become more powerful, enabling engineers to model increasingly complex principles and problems. For example, we can model non-linear stress–strain properties of materials, rather than simply assuming that they are linear. We can model the turbulent nature of water hydraulics, rather than assuming that the flow is laminar.

The advantage of having more powerful and more extensive modelling tools available to engineers is a significant improvement in our understanding and therefore, in many cases, a corresponding improvement in the engineering. But there is a potential downside: the risk of ‘analysis paralysis’, which is when our ability to make timely decisions is impeded by over-analysing or over-thinking scenarios or alternatives.

I am not a psychologist, but some say the root cause of analysis paralysis is the fear of making the wrong decision, choosing the wrong option or missing out on a potentially superior solution. This fear drives ongoing analysis, and the result is a loss of the expected or potential value of a timely, successful decision. Rather than making a decision, we try to preserve all existing options, continuing to analyse and refine.

This might look like a lower risk strategy, but it is actually a losing strategy. Complex modelling with an overload of scenarios, alternatives, sensitivity analyses or options can overwhelm the situation, making it very difficult to reach conclusions and make the decisions that are inevitably needed to move the project forward. This can potentially cause a bigger issue than if a decision had been made earlier. Prolonging the modelling and analysis phase will merely postpone, not eradicate, the risks associated with implementation. At some point, implementation will be expected.

It is very important to always remember the purpose of modelling, which is to help us understand a problem in order to make decisions – in many cases, engineering decisions. Engineering should drive the process. Although we may be able to refine a model further, perhaps we already have sufficient understanding to make the necessary engineering decisions, so the extra refinement is superfluous. Just because you can refine a model, or add complexity to a model to better reflect reality, doesn’t mean you should. The more refined and complex a model becomes, the more time is required to develop, analyse and interpret the results. It also becomes harder to validate the results, which is critical; blind faith in any complex numerical model is dangerous.

Early in my career, in relation to finite element modelling of dams, a mentor advised me to start simple with the model, validating the results against real data and known engineering behaviours to develop confidence in the model before adding further complexity. A big driver for this process was the extensive run times of these models three decades ago. Despite the progress in modelling over the decades, I believe that there is still a lot of merit in this gradual process of building complexity into a model. However, due to the software and computing power available today, a high degree of complexity is often built into a model right from the start. When this occurs, the modelling can become less of an engineering tool and more like a dark art.

The computing power available today certainly offers engineers access to some amazing inputs for our design processes. But numerical modelling does not replace the engineering. No matter how much modelling we do, we must still eventually make some important engineering decisions. If further refinement of the model won’t change the engineering decision, it’s time to stop. Don’t fall into the trap of analysis paralysis!

In summary, my tips for avoiding modelling paralysis are:

1. Keep the purpose of your model in focus.
2. Start simple and add complexity to your model only as required.
3. Validate your models and ensure confidence in the results.
4. Before refining the model, consider whether it will help your decision-making or if you already have sufficient understanding to make your decision.
5. Remember that modelling does not replace good engineering practice and decision-making.
6. Know when to stop modelling. Come back to the problem you are trying to solve or the decision you are trying to make.

To talk further with an Entura specialist about your modelling challenges, contact Richard Herweynen.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group 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 (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.

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Is there still a role for run-of-river hydropower projects?

In 2000, a major report by the World Commission on Dams shone a spotlight on large dams. At that time, some people argued that smaller, run-of-river hydropower could be a more sustainable solution than large dams with large reservoirs. Is this true? And is it still relevant more than twenty years on?

Run-of-river hydropower projects have little or no storage, which means that they don’t require the construction of a large dam, and don’t need to inundate a significant area with a large reservoir storage. Run-of-river hydropower may therefore have lower social and environmental impacts. A diversion weir is less likely to be a barrier to sediment transport, fish passage, or navigation; however, because run-of-river hydropower still involves constructing a structure in the river, these schemes are unlikely to have zero environmental impact. It is interesting to note that run-of-river hydropower projects and other small projects that do not involve the construction of large dams account for more than half of the hydropower projects supported by the World Bank.

Despite potentially having a lower environmental and social impact, run-of-river projects do have a significant disadvantage compared to large reservoir hydropower. For run-of-river projects, not all of the energy is ‘firm’, as the ability to generate depends on the availability of flow in the river. If a river catchment is highly responsive to rainfall, the daily variation of generation from a run-of-river hydropower scheme could be highly variable (similar to wind and solar).

If annual rainfall is highly seasonal, with a dramatic wet season and dry season, then a run-of-river hydropower scheme will generate much more power when seasonal river flows are high, and significantly less during drier months. So a run-of-river scheme will not necessarily be able to play the increasingly important role of firming variable renewables, and is more likely to be considered an additional source of variable renewable energy.

Run-of-river may not offer storage, but it can still have a place

But this doesn’t mean there’s no longer a place for run-of-river hydropower, as it is still a valuable and clean form of energy. In some situations, the lack of firming capacity doesn’t necessarily matter too much due to the existing diversity within the generation portfolio, or the type of generation that is being displaced. Run-of-river hydropower can still be a viable option in these circumstances:

• where the run-of-river hydro scheme is part of a larger portfolio of hydropower assets, which already has storage within the overall system – in this situation, the various hydropower generation assets can be operated together as a dynamic, integrated system, using the various assets to deliver an optimum output
• where the run-of-river hydro scheme is part of a diverse portfolio of variable renewables, including solar, wind and run-of-river hydro – in this case, it is unlikely that the mix of variable renewables will be highly correlated (i.e. it is unlikely that when there is no water in the river, there is also no wind or sun), and therefore less energy storage will be required to firm the variable generation
• where the run-of-river hydro is displacing expensive thermal generation – such as the displacement of diesel-powered generation on an island or a remote off-grid site.

Achieving sustainable storage

If there is potential to add storage to a hydropower scheme in a sustainable manner, then this is likely to create more long-term value, especially in an escalating clean energy transition. Storage will make the hydropower more flexible, agile and responsive, and able to ‘firm’ more variable renewable energy sources. With storage, hydropower can match generation with the demand for electricity. Essentially, storage can ‘unlock’ more renewables, and underpin a faster energy transition.

But the key is to make sure that any larger-scale hydropower projects with storage are developed right. In a previous article, we argued that a successful hydropower project requires:

1. understanding the current water resource and how it might change – and building in climate resilience
2. thoroughly investigating the geological and geotechnical conditions
3. projecting future demand in the context of industrial development and population change
4. getting the power to where it is needed through appropriate transmission and distribution infrastructure
5. carefully considering the project’s stakeholders, community and environment
6. securing project finance.

All of these aspects contribute to minimising risks throughout the project lifecycle and increasing the sustainability of the project in the long term, so that it can deliver social, environmental and economic benefits.

The best way to ensure that your hydropower project is developed in a sustainable manner, from the earliest stages of consideration through to operation and end-of-life, is by applying the international Hydropower Sustainability Standard.

Talk to us about achieving the right mix of renewables for your needs, and getting hydropower projects right.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group 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 (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.

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‘No dams’ or ‘right dams’? – that is the question

The construction of large dams may be controversial, particularly if the social and environmental impacts appear to outweigh the benefits. How can we create the right kind of dams in the right places to deliver maximum benefit with minimal impact?

I recently watched Franklin, a documentary in which eighth-generation Tasmanian and environmentalist Oliver Cassidy retraces his late father’s 14-day expedition to attend the Franklin River blockade in Tasmania in the early 1980s. The blockade aimed to stop the damming of the ‘Gordon below Franklin’. This was a divisive time, when many cars on the roads displayed a ‘No Dams’ sticker.

Indeed, some rivers have such high environmental and cultural heritage value that they should not be developed. However, given that water storage is a critical global issue, especially in a changing climate, is ‘No Dams’ a realistic stance?

Dams play an important role within communities by providing much-needed storage for water supply, irrigation and power generation. With greater hydrological variability due to climate change, more water storage will be vital to provide the same level of security for water, food and energy. The security of water, food and energy are inextricably linked, and all three are critical. For example, approximately 50 per cent of all large dams are used for irrigation. Without sufficient water storage, irrigated agriculture, which supplies 40 per cent of the world’s food, is at the mercy of changing patterns of rainfall and runoff. In our view, more water storage is needed for a sustainable future.

However, there are good dam sites and there are bad dam sites. In 2003, the World Bank, through its Latin America and Caribbean region, prepared a sustainable development working paper. This paper, titled Good Dams and Bad Dams, recognised that not all large dams are alike, particularly in terms of environmental and social impacts. It concluded that the level of environmental impact is largely determined by siting. It argued that while dams at good sites may be defensible, dams proposed at inappropriate sites are likely to remain problematic, even with proper implementation of all feasible mitigation measures, and are best left undammed.

Deciding on a site is not simple, and that is because sustainability challenges are complex. To help with decision-making about dams, the World Bank prepared environmental criteria for selecting sites for hydroelectric projects, building on its earlier work towards greater sustainability of dams throughout the 1980s and 1990s. In addition, the World Commission on Dams had been born out of a meeting in 1997 jointly sponsored by the World Bank and the World Conservation Union, and released its framework for dam decision-making in 2000.

International good practice has continued to evolve – and some principles are encapsulated in the Hydropower Sustainability Standard and assurance framework governed by the Hydropower Sustainability Council (drawing on the International Hydropower Association’s own tools and other sustainability principles) and underpinned by the San José Declaration on Sustainable Hydropower. Although these frameworks were created for the hydropower industry, they can be applied to any dam project.

So now, guided by these sustainability frameworks and motivated by the urgency of the clean energy transition and the multiple benefits of dams and hydropower, the challenge is to find the ‘good’, least-impactful dam sites, to enable more water storages to be developed sustainably. The need for more storage is particularly pressing in many developing countries – where there are critical needs for electrification, drinking water and flood mitigation, and where numerous and varied dam sites are available.

How do we do this? Clearly, site selection cannot simply be about cost-effectiveness alone, given that so much of what we value in life cannot be measured in dollars. At the recent Australian National Committee on Large Dams (ANCOLD) Conference, one of the keynote addresses was delivered by Gigi Foster. As an economist, she argued the importance of choosing the right ‘currency’ when making key decisions for society. She argued that we should judge a society by the extent to which it enables people to experience lives that are both long and of quality and wellbeing. A term used for wellbeing over one year is a ‘wellbeing year’ or WELLBY. Ideally, we should seek to maximise the number of future WELLBYs for people in the present generation, but also for future generations.

Arguably, the best dam sites may be those that maximise future WELLBYs – but this might be difficult to calculate. They may also be the dam sites which are the best based on a multicriteria assessment in which environmental and social risks are fully considered. There will be some potential dam sites where the environmental or social impacts are too great, and a dam cannot be justified. Good site selection is the most effective environmental mitigation measure.

Given that we need more water storage, we can:

1. Explore opportunities to increase the storage capacity of existing reservoirs by raising dams or by improving interconnection between storages to enable them to work together in a flexible and effective manner. Often, this can be more cost-effective and have lower environmental impacts than a new dam project. Where the benefits are high and the impacts are low, the WELLBYs are likely to be high.
2. Identify dam sites, either on-stream or off-stream, that will minimise environmental and social impacts. The simple quantitative indicators proposed in the 2003 World Bank Good Dams and Bad Dams paper could be used for an early preliminary rating and ranking of potential dam projects in terms of their possible adverse environmental or social impacts until more information is generated through detailed environmental and social impact assessments. The environmental and social considerations must be given appropriate weighting in the site selection multicriteria assessment, along with the financial, technical and other criteria typically included. If the assessment is well balanced, it is more likely to reach a positive outcome.

After many decades of controversy about dam development, and with increasing understanding of impacts and far greater sophistication of internally accepted sustainability protocols, it is now up to developers and planners to heed the lessons of the past and find the right dam sites for nature and communities.

If you’d like to discuss how we can assist you with planning, designing and constructing safer dams, please contact Richard Herweynen, Paul Southcott or Phillip Ellerton.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group 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 (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.

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What are some of the challenges of hydropower in South East and East Asia?

Entura’s Rajeev Raina, Resident Director India, discusses the challenges of hydropower developments in South East and East Asia, as well as how these are being overcome. This video is part of a broader discussion about the role of hydropower in a changing renewables landscape, lifted from an Entura webinar to celebrate Global Hydropower Day on October 11, 2022.

If you would like to discuss how Entura can help you with your hydropower project, please contact us.

About the author

Rajeev Raina is Entura’s Resident Director India, managing the team there and overseeing our work in the region. He has over 20 years of experience in civil engineering, specifically in detailed design for various power plant projects. Rajeev has in-depth knowledge of structural analysis and has worked on numerous hydropower developments throughout Asia, the Pacific and Australia.

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Why is hydropower important for deep storage?

Entura’s Donald Vaughan, Technical Director, Power, discusses the role of hydropower in deep storage, and how this will become increasingly important in a future renewables landscape. This clip is lifted from an Entura webinar to celebrate Global Hydropower Day on October 11, 2022, where our Technical Leaders and Executive Team came together to discuss the future of hydropower.

If you would like to discuss how Entura can help you with your hydropower project, please contact us.

About the author

Donald Vaughan is Entura’s Technical Director, Power. He has more than 25 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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What role does hydropower play in the race to net zero?

Dr Amanda Ashworth, Entura’s Director of Strategy, Sales and Commercial, discusses the role that hydropower plays in the race to net zero. This discussion took place during the webinar held by Entura to celebrate Global Hydropower Day on 11 October 2022, where our Executive Team and Technical Leaders came together to explore the future of hydropower in the renewable energy landscape.

If you would like to discuss how Entura can help you with your hydropower project, please contact us.

About the author

Dr Amanda Ashworth holds a PhD, Graduate Diploma in Environmental Studies and Bachelor of Arts. She brings together Entura’s corporate marketing, sales and commercial functions, providing direction to these teams and areas of the business, and leads strategy development and achievement. She is also the manager of the Entura clean energy and water institute. Amanda has 25 years’ experience in multi-disciplinary research and practice on a wide range of environmental, social and economic topics. She has spoken at numerous international conferences and is the author of several peer-reviewed papers.

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How can an Owner’s Engineer smooth the progress of a renewable energy project?

Throughout the renewable energy sector, there are plenty of examples where decisions made during the planning and procurement phases have caused difficulty during construction and affected future operations. A smoother construction process is to everyone’s advantage – avoiding cost blow-outs and time over-runs, and a lot of unnecessary stress and sweat.

An experienced Owner’s Engineer can provide an extra level of continuity and foresight to help reduce risk and minimise surprises. Having independent eyes focused on ‘doing it right’ from the earliest stages is an investment in keeping a project on the path to success.

Here we discuss a few simple and practical opportunities where an Owner’s Engineer can make a meaningful difference to progress.

Providing critical continuity

Continuity during the development lifecycle of a renewable energy project can sometimes be difficult to maintain. Transitions occur when project ownership changes, people come and go, government policy shifts, and when the project transitions from one development phase to the next. An Owner’s Engineer who is part of the project through all the phases of development can add a valuable perspective and source of knowledge to the project team through these transitions.

The Owner’s Engineer can apply industry-wide learnings and experience to identify risks and detect opportunities to maximise value in both the immediate detail of the project as well as later stages of the development’s lifecycle. This increases the likelihood that the transition between lifecycle phases – such as when a project advances to construction, or the handover of a newly constructed asset to an operations team – will be smooth and successful.

Maintaining order and good process

In a project where schedule risk is a big concern to all involved, sometimes good process falls to the wayside. The appropriate order of studies, design validation and construction can be impeded by a desire to get construction underway as soon as possible. Good forethought, data, modelling, discussion and design validation take time, but they are essential inputs for a successful outcome. A rush to get construction underway before this process is concluded increases the chances of re-work being required – a risk that’s always best avoided.

Identifying knowledge gaps

Having an independent Owner’s Engineer involved in a project from the beginning of the development and design process means that there is an independent expert who can review early technical studies, and identify where there may be gaps in the analysis. These early technical studies ― such as geotechnical studies for foundation and road design, and soil thermal resistivity testing to inform the right choices for cable sizing and trenching ― can have major impacts on the cost and effort expended during the design process, and the type of design that is required for a successful project. If these studies aren’t completed early enough, or thoroughly enough, there will be higher risks for the EPC contractor bidding on a project, hence higher cost. There may also be delays in the design process and at critical construction stages, with costly ramifications.

Thinking through logistical constraints at planning application stage

Construction of a wind farm, solar farm or hybrid renewable project is always a logistical challenge. For example, wind turbine components are massive, and getting bigger all the time. Rural roads are rarely of the width, camber and capacity to handle the large vehicles needed to carry materials, components or machinery. They may also not cope well with the volume of truck movements required. Community preferences and planning constraints can also limit the number of truck movements to and from sites per day.

Another important consideration in the construction of large renewable energy projects is how to move cranes around the site. In the case of a wind farm, will it be more effective to choose a crane that can be disassembled after erecting each turbine, moved in sections, and reassembled at the next turbine site? Or will it be quicker and cheaper to drive a crane between turbines? Given the potential for the width of the crane to overflow the width of the local roads, such a decision needs to take into account the potential for additional environmental approvals for a wider area of disturbance.

These challenges need to be carefully considered as early as possible in the planning application stage. Time and effort spent on the planning application can make a big difference to the ultimate project outcome. As the project progresses, clear sequencing and communication is vital for keeping things moving smoothly while also adhering to the constraints of construction and transport conditions.

Writing and enforcing clear specifications

A project’s technical specifications and the contractor’s response to them ultimately determine the end quality of the project. For both the owner and the contractor, it is vital that specifications are unambiguous and reflect the owner’s technical requirements and desired quality for the project. The Owner’s Engineer can help improve specifications based on their experience, for example specifying what sort of fixings can be used to hang cables below the solar panels, thus impacting long-term lifetime and maintenance costs.

When it comes to following specifications during the design and construction process, strict is good from the owner’s perspective. If the Owner’s Engineer rigorously enforces the specifications from the start, it sets the tone and expectations for the rest of the construction process and is likely to result in better project outcomes and fewer issues arising down the track.

Identifying safety issues and opportunities for improvement

An Owner’s Engineer brings a breadth of experience to a project as well as a clear pair of eyes and the ability to see the details as well as the bigger picture. The Owner’s Engineer is therefore well placed to identify potential safety issues and suggest improvements throughout design and construction. The Owner’s Engineer is involved in all stages of design, so is able to suggest safety improvements during safety-in-design and hazardous operations workshops. This can improve the chances of having issues of construction sequencing, construction safety or operational safety issues raised early in the design stages.

Construction inspections are often undertaken by a regular team member as well as a range of specialists. The regular team member creates continuity and the ability to compare practices on site over time. The targeted inspections by specialists focus fresh eyes on any potential issues arising during key milestones of construction.

Bringing a unique perspective

In our experience, the Owner’s Engineer can play a very valuable role in any project: helping to minimise risks such as construction delays and difficulties and maximise opportunities to achieve ‘best for project’ outcomes. The Owner’s Engineer brings a unique perspective: the ability to see a project from all angles, to maintain an independent view, and to filter everything through the lens of experience.

At Entura, we’re privileged to work with specialists who have been involved in both the design and operation of many power and water assets across their careers. They have worked with assets over the full lifecycle, so their insights stem from deep real-world experience. This ‘owner-operator’ perspective is not common among consultants, and we’re proud to apply it to help our clients get the best from their projects.

If you would like to discuss how Entura can help you with your renewable energy project, please contact us.

About the authors

Kate Hammerton is a Renewable Energy Engineer with a passion for hybrid energy systems and isolated micro-grids. She is involved in managing multi-disciplinary teams as the Owner’s Engineer on utility-scale renewable energy construction projects across Australia and the Indo-Pacific region, including the Agnew Hybrid Renewable Project, the Rottnest Island Water and Renewable Energy Nexus Project (WREN), Antarctica New Zealand’s Scott Base redevelopment at Ross Island, Tasmania’s Cattle Hill and Granville Harbour wind farms, and implementation of 14 MW of battery systems in Tonga.

Andrew Wright is a Specialist Renewable Energy Engineer at Entura. He has more than 15 years of experience in the renewable energy sector spanning resource assessment, site identification, equipment selection (wind and solar), development of technical documentation and contractual agreements, operational assessments and owner’s/lender’s engineering services. He has an in-depth understanding of the energy industry in Australia, while his international consulting experience includes New Zealand, Antarctica, China, India, Bhutan, Sri Lanka, the Philippines and Micronesia.

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Getting your renewable energy project through planning and approvals

The planning and approvals system is complex, and its potential impact on the cost, timeframe and overall success of your renewable energy or storage project should never be underestimated.

Investing time and energy in planning for project approvals makes it more likely that your project will get off the drawing board and into reality. The following principles can help you smooth the process and avoid common pitfalls.

Understand constraints and impacts

The planning system tends not to differentiate between various forms of renewable energy generation, constraining all forms due to the perception and experience of those forms with greater perceived impacts (such as wind farms). Yet each project is unique, as is every piece of land – so each development will bring different values, impacts and benefits into play.

Getting the earliest possible understanding of the environmental and approval constraints over the development site will help reduce risk and avoid a later re-design.

All developments have potential impacts. Communities may be concerned about potential impacts on human health, biodiversity, heritage impacts, visual amenity, noise, changes in land use, construction impacts, just to name a few. However, it is generally ecology and heritage that make or break a project because there may be underlying regulatory requirements associated with existing overlays that prohibit or limit development.

Particularly in the Commonwealth jurisdiction, but increasingly across all state jurisdictions, developers must clearly demonstrate how the project has avoided and reduced impacts, rather than merely offsetting them by purchasing parcels of land elsewhere. Some states actually require the developer’s option analysis process to be documented. Only when the authorities are satisfied that the project has actively avoided and reduced impacts, will they negotiate what mitigation methods are preferable.

Communities are often concerned about visual amenity, so this analysis should be done early as part of identifying ‘red flags’ or constraints. When used properly, visual impact assessment can be a powerful way to design sensitively and responsibly, reducing impacts on views.

The overall impact assessment often takes into account the context of the new development, such as whether it is in pristine environment or existing built-up or industrial areas. An increasing trend is to redevelop brownfield sites for renewable energy or storage projects, instead of focusing solely on greenfield prospects. There is enormous potential to re-use existing infrastructure, former industrial sites or degraded sites, such as mine sites which are no longer viable or operational or former thermal power station sites. This can complement the existing management and rehabilitation regime for these sites which often have very poor environmental conditions, making projects rewarding for the developer and the community.

Get to grips with the regulatory landscape

Depending on the scale, location and potential impacts of the project, approvals may be required at the Commonwealth level (through the operation of the Environment Protection and Biodiversity Conservation Act 1999), the state level (through the implementation of state environmental protection legislation), and the local level (through the implementation of a local development control plan or planning scheme).

These three levels interact differently in each state and for different processes. Some states have very streamlined and integrated approvals processes for large-scale projects which can coordinate Commonwealth requirements and facilitate local government discussions, making the process easier for the proponent or consultant. In other states, consultants often coordinate the different levels of processes, navigating the greater potential for conflicting or onerous requirements across the Commonwealth, state and local level.

Don’t launch into writing the approvals document without first conducting a mapping exercise and developing an approvals strategy. The approvals strategy helps map out all Commonwealth, state and local government requirements across each project component (e.g. a transmission line on a road reserve will often have different environmental values and require different approvals than a transmission line across a farm paddock). This will help you understand what approvals will likely be required and where dependencies exist. Your approvals strategy should be a live document, reviewed whenever there are changes to the project or legislation.

Building a transparent and honest relationship with the regulator/s is a worthy investment, and a consultant can lead this relationship for you. By listening to the regulator/s, paying attention to their advice, and changing the project’s design accordingly, a developer may be able to pre-empt or avoid conditions being applied to the project.

Develop a solid submission

Once the approval requirements are confirmed, detailed technical studies are essential for clearly demonstrating that the issues are understood and that the development (and any mitigation or management measures) is appropriate.

Target the application documentation to match and address the requirements of the relevant development control document, drawing on the conclusion of the technical studies. Include a summary of the proposal that identifies the key issues and mitigation measures, as well as the detailed technical studies underpinning the planning assessment.

Manage conditions

When permits are issued, it is common for there to be a number of conditions requiring further actions or additional documentation. Once you have a permit, create a conditions management plan to lay out clearly what all parties involved in the project need to do. Determine when the conditions apply (e.g. pre-construction, construction, post-construction or during operations) and who should be responsible. This will reduce the risk of not complying, which may be an oversight but could result in action by the responsible authority or, in some cases, lapsing of the permit.

Take the community with you, right from the start

It is important to differentiate between planning for and planning with communities. Those who will be impacted – whether positively or negatively, and over the short or long term – need to be involved in the process. A developer, owner or operator should identify and meet as many different stakeholders in the community as possible to get to know their individual interests and needs.

Engaging with the host community early in the development stages is key to a successful project and developers may be required to demonstrate that they have done so, even before submitting a permit application. This will help assure authorities (and potential buyers) that the project has a ‘social licence’ to operate.

By engaging early, the developer will have time to explain how the technology works, outline the construction process, and conduct a social risk assessment. Engagement should preferably be face-to-face and consistent. People are far more likely to accept projects when they feel that they have been included, heard and respected.

A particular consideration for large-scale developments is that sites are often located in areas outside of council jurisdiction, some of which are state-owned and can be subject to existing leasing arrangements. More remote areas also have greater potential to involve existing Native Title rights. Planning with genuine respect and acknowledgement of Indigenous communities is crucial, but often undervalued. First Nations/traditional owner groups should not be treated like any other stakeholder but as a land-owner (because they are, and governments are increasingly recognising this).

The task of building the community’s confidence in a project is sometimes difficult. The best approach is to communicate any foreseeable short-term and long-term impacts as early as possible and in an open and non-defensive manner. Listening to the community and working together to identify social and environmental risks will help build trust between the project team and stakeholders, and result in a development the community are proud of.

Give your project the beginning it deserves

Ultimately, there’s nothing to be gained by cutting corners or rushing these processes. Your best chance of planning success is through exploring and understanding – at the very earliest opportunity– the development control provisions, permits, consents and the levels of assessment that are required, obtaining high-quality and comprehensive specialist studies, and getting off on the right foot with the project’s stakeholder and community. Your project and your reputation will benefit from doing at least what is required and, preferably, even more. What you put into your ‘once upon a time’ will dictate whether you can reach a ‘happily ever after’.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

About the author

Bunfu Yu is an Environmental Planner with experience across multiple Australian jurisdictions, including Commonwealth, Victoria, New South Wales, Tasmania and Queensland. She advises on a variety of land use and development issues, and scopes environmental and planning projects with a focus on water, energy and electricity infrastructure for a range of clients, including private developers, state utility providers and government agencies. She has qualifications in planning and science, is a sessional lecturer at the University of Tasmania, and serves as a committee member for the Planning Institute of Australia Tasmanian Division and a member of the National Policy and Advocacy Committee of the Planning Institute of Australia.

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Keeping close tabs on your dams

Access to quality long-term records is crucial for dam safety. Read what our specialists have to say about keeping your records under control.

The ANCOLD (Australian National Committee on Large Dams) guideline on dam safety management recommends regular reviews on different timescales – including routine inspections undertaken by the operator (daily to monthly), intermediate inspections by a dams engineer (annually), comprehensive inspections undertaken every five years by a dams engineer and other specialists (e.g. mechanical engineers specialising in gates and valves), and dam safety reviews at least every 20 years. For these less frequent dam safety reviews, the ability to access quality long-term records is crucial.

Because dams are such large structures with a very long service life, they need to be reviewed regularly to ensure that any community risks are mitigated appropriately. Dam safety reviews assess the current condition and performance of the dam in depth, and reassess the design and construction of the dam against modern standards.

When the time comes to conduct a dam safety review, dam owners need good records at their fingertips. Poor recordkeeping can lead to significant extra costs and time to conduct the review, but can also compromise a dam owner’s duty of care.

To properly analyse the performance of a dam and assess it against modern design and construction criteria, the dam engineer needs a thorough understanding of the original design and construction, any modifications to the dam since its original build, and a complete set of surveillance and monitoring data.

For some dam owners, when the time comes to complete a dam safety review, all or some of the records are missing – they may have been lost or destroyed through corporate restructures or a failure to understand the importance of the historical records, or the records may never have been created at all.

Which records are important?

In our work as dam safety consultants, we’ve encountered numerous cases in which poor recordkeeping – across many areas and disciplines – has resulted in costs for our clients. The following are critical records to keep in good order and close to hand.

Hydrological records

Records from stream flow and rainfall gauges in the dam catchment provide key hydrological information for dam safety reviews. The streamflow data can be used directly to statistically analyse the probability of the more frequent floods. It can also be used to calibrate rainfall runoff models used to estimate extreme floods for which dam spillways need to be designed. Without this data, flood studies are more difficult because data needs to be extrapolated from nearby catchments. This not only adds cost, but also reduces the reliability of the data, which may potentially lead to oversizing or undersizing the spillway.

Dam break and consequence assessment records

In Australia, dams are classified according to the consequences of failure – from very low (minimal impact on the community, environment and dam owner’s business) to extreme (catastrophic impact on the community, environment and dam owner’s business). The consequence categories are used to define the level of design (e.g. spillway capacity), the surveillance and monitoring requirements and, in some states of Australia, the regulatory requirements. Where these studies are not available, ‘rule of thumb’ methods may be used to estimate the inundation extent as an interim step, but much more confidence can be obtained by using a flood hydraulic modelling package with good survey data. These studies should be reviewed regularly for currency, especially when development is occurring in the downstream catchment.

Geological and geotechnical records

A detailed understanding of the geology of the dam foundations is essential for assessing the risk of excessive leakage (piping), the presence of any low-strength zones that could cause instability, and the potential for landslides around the reservoir that could cause a wave able to overtop the dam. Investigations undertaken before construction as well as mapping and recording of the foundation during construction provide the best possible information for assessing these potential failure modes.

When these records aren’t available, it is often necessary to undertake extensive and expensive geological investigations into the foundation of the dam, usually while the dam is operational. Such investigations need to be carefully planned to preserve the safety of the dam.

The starting point is review of existing geological records of the site, including geological maps, aerial photographs/satellite images and geological/geotechnical reports from nearby locations. This should be followed by geological mapping to confirm the information obtained from the desktop search, including the rock types and joint and defect orientation spacing. From this, a preliminary geological model of the site can be developed. To reduce the uncertainty of the model, intrusive test pitting and drilling investigations can be conducted. Careful consideration of the dam safety risks of undertaking these investigations is needed, including contingency plans to deal with unexpected conditions (e.g. high-pressure water intersected in boreholes or instability of ground around test pits). ANCOLD has produced a very good guideline on geotechnical investigations of dams, their foundations and appurtenant structures, which should be considered an essential guide for dam owners.

Design records

If records of original design information are unavailable, the dam safety reviewer won’t be able to fully understand the designer’s intent and assumptions. The information required includes the design drawings showing the overall arrangement and key dimensions, as well as the specifications and the design report. If drawings aren’t available or are illegible due to poor quality scans, detailed surveys of the structure may be required to determine the actual constructed geometry. To assess the stability of the dam, the material properties of the dam will be required; but if no data is available, sampling and laboratory testing may be needed.

Construction records

To understand the types of defects that may be present in the dam, it’s important to know how the dam was constructed, whether it was actually constructed to the design, and what issues were encountered during construction. Key construction records include construction reports detailing progress, changes to the design and issues; results of quality testing; as-constructed drawings or mark-ups on the design drawings; and photographs of the construction process. If these records are not available, it may be necessary to confirm as-constructed details through survey, sampling and laboratory testing.

Surveillance and monitoring records

Time-series data – such as regular inspection reports, photographs and instrumentation readings – are invaluable in establishing if there are trends or changes over time that may indicate deterioration of the dam. Without these long term records, it can be difficult to assess whether observed features are longstanding (e.g. present since construction) and what recent developments may indicate about the condition of the dam. Without the full time-series of monitoring data, it can be difficult to observe trends and to understand the relationship between various performance parameters (e.g. leakage versus reservoir level).

Keeping your records under control

If adequate records can’t be located, a dams engineer will need to spend a great deal of time searching archives or undertaking investigations to build a historical picture of the design and construction of the dam in order to assess its safety. When records are well managed, dam owners can save time, money and frustration. To keep your records under control, make sure that they are:

• as complete as practical – which may require extensive archive searches and investigations to fill in the gaps
• securely stored (electronically as well as the original paper records) and retained for the long term (so investigations don’t have to be repeated)
• readily retrievable through efficient indexing and archiving systems.

A good dam may outlast generations of engineers, operators and owners. This makes recordkeeping a fundamental part of maintaining the safety and performance of the dam over its long service life and a key responsibility of every dam owner as part of your duty of care.

About the author

Paul Southcott has more than 34 years of experience 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 and was a member of the ANCOLD committees that issued the Guideline on Consequence Categories for Dams in 2012 and drafted the Guideline on Geotechnical Investigations for Dams. Paul pioneered the development of a dam risk assessment methodology for concrete-faced rockfill dams (CFRD). He was the Engineers Australia (Tasmania Division) Engineer of the Year in 2021.

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Multipurpose dams: maximum value for money?

When a dam is being considered, there’s usually a primary purpose. But are there also secondary purposes that can benefit the local and wider community? Have you thought about the potential additional economic development that can stem from a multipurpose dam? 

A simulation of Alaoa Dam in Samoa

Multipurpose dams combine two or more functions of traditional single-purpose dams into one dam infrastructure project. A multipurpose dam may combine storing and supplying water for irrigation, industry or human consumption; flood control; power generation and power storage; navigation; water regulation; environmental releases; climate change resilience; and recreational purposes.

The dam structure will be similar to a single-purpose dam, but the design will incorporate features into the dam and water infrastructure facility to accommodate different purposes. These may take the form of irrigation channels, power generation facilities or navigation facilities. Including various gates or valves can provide greater operational flexibility for floods or environmental releases for downstream community and environmental needs. A single-purpose project can become multipurpose during its planning stage, during operation, or in the long term when re-engineering becomes necessary.

Why consider multiple purposes?

Multipurpose dams are not a new concept; in fact, almost half of all dams are used for more than one purpose. There is a growing trend to consider multiple purposes when developing a dam, for several reasons:

1. Dam sites, particularly storage sites, are scarce national resources (i.e. they are not unlimited), so it makes sense to consider how to extract maximum benefit from them when constructed.
2. Dam infrastructure may commonly last for up to 100 years or more (i.e. they are considered a long-term asset). A dam represents a genuine long-term investment for the future, and so ideally should be viewed as such and incorporate the potential for flexible use over time.
3. Multipurpose dams are very beneficial in developing countries, as the multi-functionality of the dam operations can contribute to a number of development goals simultaneously, such as energy, water and food security, economic development, and climate resilience. In 2016, the International Commission of Large Dams (ICOLD) recognised the importance of multipurpose dams in the release of the ICOLD Bulletin ‘Multipurpose Water Storage – Essential Elements and Emerging Trends’, which rightly links the common global needs of water, food and energy. The sporadic, spatial and temporal distribution of precipitation rarely coincides with demand, making storage essential for food supply, energy production, potable water supply and other water delivery services that depend on sizable, reliable, continuous and efficient supply of water.
4. Climate change scenarios predict increasing variability in rainfall, impacting both yields and flood peaks. Droughts will affect agricultural production, and flooding is expected to increase due to more extreme weather events. With many regions of the world experiencing significant water stress, which is expected to be exacerbated by global warming, storage will play an increasingly critical role in bolstering a water system’s hydrological resilience. Dam projects should be designed with this necessity and value of storage in mind. Even in developed countries, we need our dam infrastructure to be ready to adapt to future changes as required. Taking change into account and considering multipurpose approaches will benefit new dam projects as well as projects that modify existing reservoirs.

Click image to view infographic.

Looking into the future

Multipurpose water storage projects pose additional engineering challenges when compared to single-purpose projects. Given the longevity of the infrastructure of large storage projects, planning professionals need to develop and implement solutions that will provide adequate flexibility to adapt to changes or to the diverse needs of multipurpose schemes. Scale, site selection and operational characteristics should be assessed through a long-term perspective, incorporating anticipated trends and emphasising adaptability so that future generations will inherit infrastructure that can evolve as the world continues to change.

There is no doubt that this sustainability principle is valid; however, determining how best to implement it in practice is not always easy. It is hard to anticipate and predict what will happen in a century (which is the expected life of many dams), yet this should not stop us during the early stages of the project from trying to assess long-term performance based on potential long-term scenarios (i.e. scenario testing).

Multiple perspectives for multiple purposes

Achieving the best outcome for a multipurpose dam is more likely when planners and engineers work together and closely consider the local community’s needs and the potential benefits to be gained. Both social and environmental needs should be considered, with detailed social and environmental impact assessments conducted.

Applying the principles of Integrated Water Resource Management (IWRM) in the planning process will help promote coordinated development and optimal management of water resources – furthering progress towards goals of social equity, economic efficiency and environmental sustainability. It is important to establish criteria by which to monitor the achievement of the multipurpose objectives and the post-construction impacts on the community and environment. Another important consideration is the manner of operation of the multipurpose reservoir, which will also be critical to achieving the range of its objectives.

What is a multipurpose dam worth? 

A key planning challenge in multipurpose dam infrastructure is fully appraising the economic costs and benefits of the project. In many projects there’s a tendency to focus the analysis on the components that provide revenue streams (such as energy and water supply and irrigation tariffs) as these are most easily valued. However, this can underrepresent the project’s value across all of its multipurpose objectives, potentially resulting in suboptimal decision making or difficulty justifying the long-term investment. For example, a fundamental purpose of storage projects is flood mitigation – but flood mitigation does not generate a revenue stream. However, the economic value of flood control to a country (through avoidance of direct and indirect flood damages) often justifies the allocation of funds from the public sector.

Putting this into practice in Samoa 

The Alaoa Multi-Purpose Dam in Samoa is a fitting example of the considerations presented above.

Samoa is a small tropical island country in the Pacific, and has been heavily affected by severe tropical storms. In 2012, Cyclone Evan caused extensive flooding and damage to the Apia region, the capital, where most of the population and economic activity is located. With such storms predicted to increase in frequency and severity as the climate changes, the Government of Samoa has adopted a programmatic approach to address climate-change-induced flooding. This includes the new Alaoa Multi-Purpose Dam, sized and designed with long-term climate scenarios in mind and to provide multiple functions. It aims to increase flood protection, improve the current water supply system’s seasonal reliability, and provide additional hydropower via installation of a small hydro facility.

The dam’s design considered multipurpose functions and climate change risks, and included small modifications to provide better outcomes. Climate resilience was ‘designed in’ by incorporating ‘dead storage’, providing sediment flushing capability, increasing the flood capacity, and including a number of gates and valves – all contributing to future flexibility of operation.

The intake to the small hydro station incorporated a station bypass valve for water supply. As well, a low-level outlet and a mid-level outlet were added to increase the operational flexibility of the dam to meet its three purposes. This also enabled both low-flow and high-flow environmental releases, and improved dam safety management. How the reservoir is operated will be significant in achieving the multipurpose functions. The dam’s flexibility will allow future adaptive modification of the operation to align with the changing demands of the reservoir.

The main purpose of the Alaoa Multi-Purpose Dam was flood retention and mitigation. Consequently, as we discussed above, a limited financial analysis could not justify the multipurpose project, yet the broader economic analysis could. However, the financial analysis indicated that the regular revenue stream from the small hydro’s energy production could increase the project’s sustainability once constructed. This revenue stream would contribute to the ongoing operation, maintenance and dam safety activities associated with the multipurpose project’s long-term operation.

Could multiple purposes be incorporated into your dam project? 

Whether you are in the planning process or the early design phase for a new dam, consider whether your project could be modified to:

• achieve multiple purposes and increase the benefits of your dam project
• increase operational flexibility to allow your dam to adapt to future changes and demands
• improve the use of water resources for all needs, including the environment
• increase the climate resilience of your dam and the impact of climate change on its multiple objectives.

If you would like to discuss how we can assist you with planning and designing a multipurpose dam, please contact  Richard Herweynen, Paul Southcott or Phillip Ellerton.

About the author

Richard Herweynen is Entura’s Technical Director, Water. Richard has three decades of experience in dam and hydropower engineering, and has worked throughout the Indo-Pacific region on both dam and hydropower projects, covering all aspects including investigations, feasibility studies, detailed design, construction liaison, operation and maintenance and risk assessment for both new and existing projects. Richard has been part of a number of recent expert review panels for major water projects. He participated in the ANCOLD working group 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 (including Engineers Australia’s Professional Engineer of the Year 2012 – Tasmanian Division), and has published more than 30 technical papers on dam engineering.

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Making progress in the field, despite pandemic challenges

While some aspects of fieldwork can be modified through technological innovation, there are other things that simply can’t be done without getting out on the ground or in the water. How can we make fieldwork not only efficient and effective, but also COVID-safe?

photo by Grace Uziallo

For our Environment and Planning team, interstate and intra-state travel restrictions and work-from-home orders rolled in at the height of the field season when most summer and autumn seasonal surveys were being completed and when many in the team would usually spend multiple days each week in the field. We’ve managed the fieldwork challenges through practical modifications for greater safety, taking confounding factors into account when analysing our results, using technology to support fieldwork, and collaborating with our clients, partners and local businesses to find solutions together.

Practical modifications for safety and wellbeing

Despite the restrictions and changed conditions brought about by COVID-19, we have been keen to find safe solutions to continue working seamlessly with our clients. Our teams have adapted their fieldwork patterns and adopted stringent methods, including fieldwork procedure reviews, undertaking day trips rather than longer trips where possible, reducing the number of people per field trip to the practical minimum, maintaining social distancing, and practising good hygiene, such as wiping down equipment and common touchpoints, from car gear sticks to the helms of our boats.

For example, our aquatic scientists are braving the Tasmanian winter chill to ensure that water quality and monitoring datasets for Hydro Tasmania continue to be logged. This data is critical to understanding impacts on aquatic fauna, and forms part of a multi-year monitoring regime for many of the state’s water bodies. The team would normally be undertaking week-long field trips; however, in response to the pandemic and due to the temporary closure of many accommodation options, the trips are shorter and efforts have been made to avoid the virus hotspots within the state wherever possible.

Managing fatigue is always important when undertaking field work, and especially so during COVID-19. For most field work, physical distancing requirements have ruled out travelling in a single vehicle. However, travelling in separate cars means that the driving can’t be shared. To manage fatigue associated with driving, we have made field days shorter, or, if more practical, we’ve stayed overnight in local self-contained accommodation to avoid travelling after long working days. 

Mental wellbeing has also been a crucial consideration while living and working through the pandemic. Our teams have stayed connected, whether working at home or in the field, through more virtual team catch-ups, quiz nights and virtual Friday post-work-week banters. Picking up on cues that indicate someone may be struggling is more difficult over email or a phone or video call than when working together in the office, so it’s more important than ever to actively check in on each others’ and our own wellbeing. At Entura, ensuring staff mental and physical wellbeing is always a high priority – and, particularly during the pandemic, taking time out to breathe and declutter the mind has helped us avoid mental burnouts and kept us as motivated as ever to deliver outcomes for our clients.

Taking confounding factors into account

Our ecologists have continued to undertake their monitoring programs, including night-time roadkill surveys along lengthy stretches of winding wilderness roads to look for threatened fauna such as quolls, Tasmanian devils and wombats. One of the challenges of undertaking this work during the pandemic has been the potential that the data collected may be confounded by reduced traffic volumes, making it questionable as to whether the data collected can be applied to a post-COVID world. In addition, reduced traffic volumes may also be influencing wildlife habits – for example, making them less wary of roads.

When interpreting the data, we took these potential implications into consideration, and some monitoring regimes were extended to compensate for potential changes to usual patterns. This will help ensure that the monitoring program provides a realistic representation of trends from which ongoing management decisions can be made.

Minimising fieldwork through technology

Entura has been actively assisting with Hydro Tasmania’s Battery of the Nation initiative. This initiative, jointly supported by the federal government (through the Australian Renewable Energy Agency) and state government, is investigating and developing a pathway of future development opportunities in hydropower system expansion including pumped hydro. For our Environment and Planning team and our Spatial and Data Services team, fieldwork for their involvement in Battery of the Nation has been able to continue, albeit with some innovative adaptations.

The spatial team has developed robust methods for visual impact analysis that can be applied to multiple project locations and types. To meet COVID-19 fieldwork guidelines, minimal staff have ventured into the field. These smaller teams have used technology to send real-time information (such as geo-tagged photos) to a pre-arranged server, allowing others at the ‘office’ to access the information almost immediately. The data has included light detection and ranging data, 3D models of project elements and real-life photography, which has been processed to generate 3D walkthroughs and web-scenes. These provide an important output for the project, but are also a useful tool for other team members to understand the site context without needing to go into the field themselves.

Solving problems through local collaborations

In some cases, overcoming the fieldwork limitations of COVID-19 has required a higher than usual level of collaboration with clients, partners and other organisations. For example, when the pandemic travel restrictions prevented the original interstate consultant from travelling to Tasmania as planned, our surveyors and ecologists were called in to assist our local partner TasNetworks with an important project on Bruny Island in Southern Tasmania. The submarine cable from mainland Tasmania that ensures security of electricity supply for the Bruny community is currently being replaced after the existing cable was damaged beyond repair late last year. Our proximity made it possible to step in to help. In a display of local collaboration, Entura assisted with the bathymetric and cable trenching clearance surveys, passing the data on to TasNetworks’ cable design engineers so that planning for replacement of the cable could continue.

Anticipating the ‘next normal’

In Tasmania, we are fortunate to be gradually emerging from COVID-19 isolation and we are eagerly awaiting the return of our ability to undertake the works and visits we have had to delay, yet we’re well aware that some changes or restrictions may be with us for quite some time yet. For now, we will keep working closely with our clients to be agile and resilient, so that together we can find safe and innovative COVID-friendly ways to move our projects forward.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

For more articles from our Environmental and Planning team, visit our Thought Leadership collection, where you’ll find their articles about maintaining the progress of international projects and the challenges of starting new projects during the pandemic and the changes it has brought to planning regimes around Australia – amongst many more articles of interest to anyone involved in the power and water sector.

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New circumstances, new projects, new regulations

It’s a major challenge to keep an existing local project running during these tricky times (let alone an interstate or international project!), but how can we start new projects as the ground shifts around us and as regulations around Australia change?

In this third article from Entura’s environment and planning team, we feature a recent win in the national water infrastructure space – the detailed design, and planning and environmental approvals for a new off-creek storage in the Northern Tablelands of New South Wales. And we take a look at how regulatory changes are playing out around Australia to provide greater flexibility to respond to current constraints.

Starting a new project during a pandemic

Entura, working together with Hunter H2O, is now assisting Walcha Council with a regionally significant project despite COVID-19. The township of Walcha is currently serviced by one small off-creek water storage, which means that stringent water restrictions are needed during periods of drought. The regional council, supported by federal government funding, is investing in improving Walcha’s water reliability and security, which will also deliver social benefits to the community.

Our team tendered successfully when COVID-19 was yet to hit our shores, but in a mere few weeks we found ourselves loading up our office gear to set up from home. The same week that our engineering, planning and environmental specialists were scheduled to fly to Walcha to meet with Council on site, travel restrictions intensified and flying out of Tasmania was no longer an option. We adapted by taking to virtual platforms to communicate with our client about the challenges imposed by COVID-19 and how we could still keep the project moving, albeit with some deviations from the original schedule.

As a multidisciplinary firm capable of working across many jurisdictions, we pride ourselves on the relationships we have established with local contractors. In these times we are even more aware of the benefit of these associations to help keep the work flowing. For this project, collaboration with local contractors and swift adaptation has allowed the team to keep the project moving forward. Local geotechnical contractors have begun their investigations to feed information to our teams. Meanwhile, our environmental and planning experts have studied databases and existing literature to determine potential terrestrial, aquatic and regulatory constraints that may affect the design of the new off-creek storage.

Lockdown restrictions are starting to ease across the nation, but for now we are sitting tight and waiting until it is safe to visit the site. We need to ensure that storage design works are undertaken only when our technical specialists have stepped foot on the site themselves and have a thorough understanding of the site context. In the meantime, we continue to provide value through virtual meetings and workshops with our client. Hunter H2O and Walcha Council share our view regarding both the safety of our people and the quality of design required for the project.

On this constantly shifting ground, we are keeping the regulators up to date with the progress of the project, and we are also ensuring we keep up to date with any regulatory changes which may affect the project and that these are well-communicated with our client.

Regulatory changes for flexible responses

Across the country, state governments are establishing new measures to accelerate projects to shovel-readiness to help buffer the social and economic impacts of the pandemic. They’re also making temporary orders to existing legislation to provide flexible planning and environmental responses.

New South Wales

In New South Wales, the Planning System Acceleration Program has been introduced to fast-track State Significant Developments, rezonings and development applications, as well as provide support to decision-makers to speed up local and regionally significant projects to approval. Temporary orders have been implemented to allow some infrastructure construction work to be carried out on weekends to maintain productivity and employment in the sector. In NSW, temporary changes to the Environmental Protection and Assessment Act 1979 (EP&A Act) allows the Minister for Planning and Public Spaces to authorise development to be carried out on land without any approval under the EP&A Act where that development is required to protect the health, safety and welfare of the public during the COVID-19 pandemic.

Other recent legislative change in NSW is the long-awaited amendment of the NSW Bilateral Agreement under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (Cmwth), which was required after the introduction of the new Biodiversity Conservation Act 2016 (NSW). This updated bilateral agreement has allowed environmental assessments and offsets to be streamlined, including endorsement of the NSW Biodiversity Offsets Scheme for the purposes of offsetting for a Commonwealth approval.

Queensland and Western Australia

In Queensland, COVID-19 has been declared an applicable event under planning legislation, thus allowing the Planning Minister more flexibility to suspend or extend any statutory timeframe across the planning framework if required. Similarly, in Western Australia, the Minister for Planning has issued a two-year extension for all current development approvals to assist job-creating projects during the recovery stage, along with other exemptions from planning approval for essential local community services.

Victoria

The Victorian Government has announced temporary measures to make sure that planning and approval processes can continue to function despite remote working arrangements, including allowing local government planning authorities to make decisions under delegation to facilitate efficient application turnaround times. The Victorian Government has also established the Building Victoria’s Recovery Taskforce to explore planning and investment opportunities to boost the development industry. Additionally, the new Victorian Environment Protection Amendment Act 2018 (EPA Act), which is relevant to many infrastructure projects, was to take effect from 1 July 2020 but has been deferred until July 2021 to ensure developers, consultants and regulators have time to adapt to changes in workload and workflow as a result of the pandemic.

Tasmania

Tasmanian planning reform continues with the exhibition and assessment of local planning schedules as part of the transition to a statewide planning scheme. Consultation has also concluded on the proposed process for major projects, which, if enacted, will be the state’s first multi-permit approval process.

Nationwide

The Commonwealth Environment Protection and Biodiversity Conservation Act 1999 is also currently being reviewed, and our planning and environmental consultants are ensuring that they keep pace with the impending changes and implications for ongoing and new projects.

Managing change

For the Walcha project, the approval process is comparatively simple and the changes to approval processes are not likely to impact the project. However, for some of our other projects, these changes create challenges. Most notably, physical distancing requirements have meant temporary shutting of council offices and town information centres where application documents and technical studies are usually displayed. Instead, full suites of application documentation are being published online or, when specifically required, hardcopies are being mailed out. With postal services already under pressure, one way to ensure the community has a fair opportunity to provide feedback is to lengthen comment and consultation timeframes.

Although the global pandemic may have been disruptive to our work arrangements, smart and innovative ways to juggle project commitments and changed circumstances have fostered strong relationships which will persist beyond COVID-19. Elevated levels of trust and virtual teamwork with clients will surely present more opportunities to collaborate once the ground settles and we reach a new equilibrium.

If you would like to discuss how Entura can help you with your environmental or planning project, please contact us.

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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 …

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 Nick West on +61 408 952 315, Richard Herweynen on +61 429 705 127 or Phillip Ellerton on +61 439 010 172.

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.

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