However, there is a solution that is often overlooked, which is to retrofit irrigation dams that could then be used as a source of water for power without using up the water that is vital for agriculture, says Barta. He says that there are 4 500 dams in South Africa, of which at least 1 100 can be retrofitted to become mini and small generators.

In 20 years, a 1MW plant can replace about 6 000 tonnes of fossil fuels while supplying some 1 000 sub-urban households with electricity, says Barta. Small-scale hydroelectric installations are seen as "exemplary" renewable energy converters because they produce minimal emissions and do not use up the water, he notes.

Adding 75MW to South Africa`s power grid through hydro would cost the country around R2-billion, while on average it would cost between R15-million and R25-million a megawatt to retrofit a dam, which is cheaper or equivalent to wind or solar capital spend, says Barta. Hydropower has the potential to expand Eskom`s margin, the difference between electricity demand and supply, by adding a sustainable amount of around 7 200MW in the next ten years from all types of hydropower schemes, especially in high-potential Eastern Cape and KwaZulu- Natal sites, says Barta.

He says that smaller stations could also aid communities that have yet to be plugged into the grid, with the potential to create jobs.

Barta notes that although not currently in favour, small-scale plants were a significant component of the yester-year electricity production in several parts of South Africa, with a plant installed as far back as 1885 at the foothill of the Table Mountain in Cape Town, along with a few small and defunct plants scattered along the feet of the Drakensberg range. There are a few small-scale plants being upgraded and refurbished, including Belvedere (2MW), Ceres (0.8MW), Clanwilliam (1MW), Kouga (5.3MW), Ncora (2.4MW), Piet Retief (1MW), Pongolapoort (2.7MW) and a few other smaller privately owned installations.

However, the biggest project on the cards is the much-delayed Grand Inga scheme in the Democratic Republic of Congo (DRC). Stage three is set to supply South Africa with about 2 500MW, of a phase output of 4 800MW once complete, says Barta.

The imported power will traverse some 2 800km via several countries, but the project, with a total output of 40 000MW, is likely to cost more than R25-million a megawatt and will escalate, he adds.

Lead-time to commissioning is around 10 years, estimates Barta, noting that this depends on many political and socioeconomic factors in countries such as the DRC, Angola, Namibia, Botswana and Zimbabwe.

However, the risk with imported hydropower is if there are civil wars, supply will be disrupted. Barta says South Africa should rather focus on local capacity, which gives more long-term advantages such as skills transfer. In addition, there is a potential to use the ocean for hydropower, which can be done in harbours without any disruption, he says.

"The potential of ocean-generated energy is completely neglected in South Africa, although there is good potential waiting for the coastally-located communities and urban areas."

Barta says, globally, interest is increasing in the technology and South Africa`s IRP to balance coal-fired power generation with renewable and alternative sources to increase the output from hydro.

He says several countries are looking into the possibility combining hydropower with other types of renewable energy technologies, mostly wind and solar photovoltaic (PV). "In South Africa, hydro and solar PV is the future, particularly for small pumped storage schemes." Hydropower is "undeniably" renewable and robust, says Barta. He notes, however, that South Africa only aims to add another 75MW from hydro, when the country has the capacity to add 10 times as much. Currently, says Barta, hydropower accounts for about five percent of Eskom`s theoretical output capacity of 45 000MW, although this varies depending on whether coal stations are off line for maintenance.

This percentage could grow if the IPP programme capacity is allowed to develop fully to 75MW, but there is a need for a more serious approach in developing both large and small plants, especially in rural areas and within existing urban water supply schemes, says Barta.

* Numerous requests to Eskom and government departments for comment were unanswered by the time of going to print.

This feature has been made possible by advertisers but content sourced independently by Mail & Guardian`s supplement editorial team.

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