Reliable, renewable energy now powering South Africa
March 21, 2015
In many developing nations, governments and utilities are scrambling to bring much-needed power to their people and industries to improve quality of life and drive economic growth.
Small hydro (around 40 MW or under) from run-of-river schemes is an ideal solution to contribute to growing and greening the energy mix in developing countries, providing clean and reliable power from a country’s rivers without the significant environmental or social impacts of large dams or the economic and environmental costs of fossil fuels.
The Neusberg hydropower project – a run-of-river small hydropower project near Kakamas in the Northern Cape of South Africa – is one small but effective step towards South Africa’s ambitious goals of raising the living standards of its growing population and supporting vital economic activity through encouraging the development of renewable energy by independent power producers.
What is the Neusberg hydropower project?
Using the power of the mighty Orange River, the Neusberg hydropower project creates electricity by diverting some water for a short distance as it runs downstream from the existing Neusberg Weir, returning the water back to the river after it runs through the hydroelectric plant’s three 4010 kW turbines.
The Neusberg project is highly efficient, producing 10 MW of reliable and sustainable baseload power for the equivalent of up to 5000 homes with no adverse impacts on irrigation, fish or environmental flows.
Success through collaboration, innovation and expertise
The Neusberg project needed a particularly innovative design solution and effective planning and collaboration for it to meet the needs of the region, satisfy the requirements of all major authorities and stakeholders, and still achieve the objectives of the developer.
And that’s where specialist power and water consulting firm Entura drew on its extensive experience in hydropower development to find the right answers to move the project towards successful completion.
For example, developing all the necessary tender and contractual documentation and negotiating and achieving regulatory approvals are critical administrative steps but can prove challenging. Entura’s owner’s engineer services helped the Neusberg project overcome these development-stage hurdles – such as helping to achieve the vital water use licence by proposing suitable designs for the project and then working through a collaborative process to modify the designs to meet the authority’s requirements while still achieving the developer’s objectives.
Tailored solutions for tricky challenges
A major challenge for the Neusberg project was to produce economical and reliable power to relieve pressure on the electricity network at the same time as ensuring adequate water supply for irrigation by local fruit-growers throughout the construction and operation of the project. Other specific local requirements also needed to be met, such as maintaining the ability of the Neusberg Weir to meaningfully measure river flow, maintaining the aquatic environment and minimising the impacts from construction activities.
- To guarantee an uninterrupted supply of water to the local irrigation scheme, construction of the hydro project called for clever planning. Since an existing irrigation canal ran through the powerhouse site and needed to remain in operation, a temporary diversion canal was created to allow the powerhouse and forebay to be constructed in two stages without interrupting irrigation supply.
- To ensure that the flows into both the hydroelectric project and the irrigation canals are sufficient, a weir was placed at the offtake for the hydro project providing passive protection against the water level in the reservoir being drawn down. The level of the top of the weir was carefully designed so that the length of the weir was reduced – lowering construction costs while providing the protection required for the irrigation canal and allowing sufficient flow into the headrace canal.
- The Neusberg Weir is a very important flow measuring structure as it provides accurate information on the flow in the Orange River to both South Africa and Namibia. The hydro project takes water away from the weir, so to restore the ability to measure flows, two devices were installed – an instrument in the canal upstream of the powerhouse, and the weir in the tailrace. The measuring weir in the tailrace provided an extra benefit for the aquatic environment, by acting as a barrier to fish movement and enabling fish to find their way to the existing fish ladder to travel upstream.
- To minimise costs and impacts of construction, the design of the Neusberg project dispensed with the typical aboveground powerhouse structure. Instead, the concrete roof of the powerhouse has a removable hatch allowing equipment to be lowered through the roof by crane into the turbine chamber.
Community benefits both now and into the future
The Neusberg project has brought an ongoing social and economic boost to the local community that goes well beyond providing an important source of electricity. During the construction phase, it created much-needed local employment in a region in which opportunities are scarce, and supported local and national businesses through spending on goods and services.
But the benefits keep flowing long after construction is finished, as the local community has a
15 per cent ownership stake in the hydropower scheme and an 8 per cent stake in operation and maintenance contractors, ensuring that the community trust will share in the project’s success for many years to come.
Entura’s role in the Neusberg project
Entura has played a vital role in the successful civil design and was also responsible for the electrical and mechanical construction of the Neusberg project by drawing on our day-to-day experience of owning, operating and maintaining hydropower assets for more than 100 years as part of Hydro Tasmania, Australia’s largest renewable energy producer and water manager, and an equity stakeholder in the Neusberg project.
If you would like to discuss how Entura can help you develop a hydropower scheme that can meet your power needs in a cost-effective and sustainable way, please contact Christoff LeGrange on +27 21 202 2231 or Shekhar Prince on +61 412 402 110.