Wave power is the most promising source of ocean energy for South Africa and a "very conservative" estimate is that some 8 000 to 10 000 megawatts (MW) of electricity (Koeberg generates less than 2 000) could be generated from the Cape's West and South Coasts , says eminent marine engineer Professor Deon Retief.

Retief headed the Stellenbosch Wave Energy Converter project, which was established in 1980 following the global oil price crisis of the mid-1970s. They developed a workable prototype, but the project was scrapped in 1989 when the oil price crashed.

Speaking at a Wave Energy Workshop organised by the Centre for Renewable and Sustainable Energy Studies in Stellenbosch last week, Retief - now retired but still doing consultancy work for the marine engineering company he helped found - said there were some "tantalising" opportunities for harnessing other forms of ocean energy such as salinity gradients, thermal (temperature) gradients, tides, bio-conversion and ocean currents off the South African coast.

In his introduction to the workshop, centre director Professor Wikus van Heerden said wave energy had "a long history" in South Africa and was now attracting "huge interest", although there had been "some ups and some downs".

Kevin Nassiep, chief executive officer of the South African National Energy Research Institute, said Germany was leading the way in developing renewable energy options which last year attracted global investment of $66-billion (about R505-billion) - nearly double the 2005 investment of $39-billion and well up on the $55-billion in 2006.

Overall, renewable energy was contributing 17 percent of global primary energy supply, of which hydropower accounted for 15 percent.

There is huge pressure to meet the global goal of stabilising greenhouse gas emissions and the carbon dioxide concentration in the atmosphere by 2050, the "point of no return" of global warming and associated climate change.

Studies have concluded that 50 percent of the primary energy supply could be met by renewable energy by 2050 but this was "highly unlikely" in South Africa, particularly because of current decisions to expand Eskom's electricity-generating capacity through coal-fired power stations.

"If we're serious about these (renewable energy) goals, then policy, regulatory and financial support has to be forthcoming soon," Nassiep said. [capeargus]