• Crest of a wave

    With so much untapped potential at the disposal of African nations, hydropower is attracting huge investment.

    Crest of a wave

    At full capacity, the Grand Ethiopian Renaissance dam will hold 74 billion m3 of water in total. To put this into perspective, that’s 13 times more water than Ethiopia’s entire 100 million-strong population uses in a year. The dam wall will be 155m high (by comparison, Victoria Falls is 108m) and nearly 1.8 km in length. At a price tag of nearly US$5 billion, the dam (which is about 65% complete) will be the biggest on the continent and eventually produce about 6 000 MW of hydropower from its 16 turbines.

    The GERD, to use its ungainly acronym,is just one of the dams being built in Ethiopia that will produce hydropower. The 1 870 MW Gilgel Gibe III project, on the Omo river, brought its first units online in 2015. It’s the third such project, following the existing Gibe I (184 MW) and Gibe II (420 MW). Two others are planned – Gibe IV (1 472 MW) and Gibe V (560 MW). The Ethiopian plants are among several large hydro facilities on the continent expected to be in production by 2020.

    There’s much to like about hydropower. The energy is clean and long-lasting (facilities can operate for at least 50 years). Unlike renewables such as solar or wind, which are intermittent, hydro produces continuous power – as long as there’s water. The downside, however, can be significant.

    Firstly, the huge costs of designing and building dams and the infrastructure to transport the electricity can cripple many emerging countries’ budgets if funding is not provided mostly by external sources. Secondly, the long lead-in time needed to build and fill them (in the GERD’s case, more than 10 years from when construction first began). Thirdly, the environmental impact these dams – especially ones the size of the GERD – have on rivers and nature in general. By damming rivers, water courses are changed with a knock-on effect on biodiversity and agricultural activities.

    There are geopolitical considerations too. The GERD has heightened tensions between Ethiopia, Egypt and Sudan, as each of the three countries rely heavily on the Nile for their agricultural economies. Egypt in particular is concerned that the GERD’s damming of the Nile will restrict the amount of water available to its own farming activities, with dire consequences. Although Ethiopia and the other two countries have signed agreements concerning water availability and use, the issue has not been completely resolved.

    Despite the complex challenges, Africa has massive potential for hydropower. Apart from the Nile, large rivers such as the Niger, Zambezi and Congo are relatively untapped at present and several countries have a large capacity to generate electricity from hydro.

    There’s Ethiopia’s 45 GW and the DRC’s 45 GW – both huge – down to Uganda’s 3 GW and South Sudan’s 3 GW, according to estimates by the International Hydropower Association. Even though these are much smaller, they are still substantial compared to other methods of power generation.

    Many nations currently rely heavily on hydropower. Sudan receives around 75% of its electricity from the source, Kenya nearly 50% and Tanzania about 30%. Even semi-desert Namibia receives around 60% of its electricity now from the 332 MW Ruacana site on the Angolan border. It has been projected that,by 2020, Ethiopia will produce 95% of its electricity from hydro.

    Even smaller countries are investing heavily. Take Uganda for example. So far it has three big hydro facilities – Owen Falls, Nalubaale and Bujagali – all located near Jinja on the Nile. These generate more than 600 MW in installed capacity combined. And plans for more are under way.

    Stortemelk, on the Ash river in South Africa, began operations in 2016 and is an example of the small hydroplants developed in the country recently

    ‘Our strategy is to develop half a dozen hydropower stations on the Nile,’ Ibrahim Kasita, Ugandan communication director in the Ministry of Energy and Mineral Development, told African Business Magazine in 2017.

    Meanwhile, in tiny Guinea, China’s Exim Bank approved US$1.3 billion in financing for a 450 MW hydro plant on Souapiti dam, about 50 km from the capital Conakry in mid-March this year, according to Reuters. The government reportedly wants to export electricity to neighbouring countries and use the sales to help repay the loan.

    In contrast to many other countries, the continent’s most sophisticated economy, South Africa, has a relatively small hydropower output and potential. A lack of suitable rivers is the primary reason, but the country’s water- stressed climate and propensity for drought have also been factors that have precluded investment in hydropower plants.

    That said, two plants were developedmore than 40 years ago by energy parastatal Eskom. Located on the Orange (the Gariep and Vanderkloof dams), they’re still capable of contributing around 660 MW combined towards the country’s entire energy mix (approximately 45 GW of installed capacity).

    For many years, South Africa has bought power from the 2 075 MW Cahora Bassa hydro project in Mozambique but this has at times been plagued by maintenance issues. The Baseline Study on Hydropower, an assessment carried out by the (then) Department of Minerals and Energy in 2002, pointed to specific areas that could show ‘significant potential for the development of all categories of hydropower in the short and medium term’.

    ‘The Eastern Cape and KwaZulu-Natal are endowed with the best potential for the development of small, i.e. less than 10 MW hydropower plants,’ according to the report. ‘The advantages and attractiveness of these plants are that they can either be standalone or in a hybrid combination with other renewable energy sources.’

    In 2011, South Africa began implementing the highly successful Renewable Energy Independent Power Producer Procurement (REIPPP) programme. It concentrates predominantly on wind and solar, but some small hydro projects have been constructed – most recently, the Stortemelk plant, which started operations in mid-2016. The 4.5 MW, ZAR190 million project is located on the Ash river in Clarens, Free State province, and utilises flow from the Lesotho Highlands Water Project.

    According to Anton Louis Olivier, MD of Renewable Energy Holdings (REH), the developers, there are opportunities for smaller plants to contribute to the country’s renewable energy plans. ‘Unlike big hydro plants, these small-scale plants can be built in three to four years from inception,’ he says.

    Stortemelk is the third in a series ofhydro plants developed by REH. The firm has also been involved in the Merino (4 MW) and Sol Plaatje (3 MW) hydropower stations developed under the Bethlehem hydro project. Another plant, Boston (4.5 MW), is currently in development.

    Olivier adds that retrofitting existing dams and reservoirs to generate energy is also an option. Stortemelk, as with the other plants, has won plaudits for its innovative design.

    ‘We wanted to create a project that would last, that worked really well and could do so for a long time,’ says Olivier.

    Also notable is Stortemelk’s ownership structure. Through the course of its 20-year power purchase agreement term, 1% ofits gross revenue will contribute towards supporting socio-economic development in Clarens’ disadvantaged communities. This, according to Olivier, makes Stortemelk an example of how multidisciplinary engineering and design thinking can create future-proofed solutions.

    By Rachel McGregor
    Image: Gallo/Getty Images