Solar could supply SA energy - expert

Cape Town - Solar energy could deliver 15 times the current electrical demand in SA if there was sufficient investment in new technology, a researcher has said.

"One of the funny things about solar is that South Africans just don't know it. And it does provide an extremely large potential - much bigger for instance - than wind," Paul Gauché senior researcher and director of the Solar Thermal Energy Research Group (Sterg) in the Department of Mechanical and Mechatronic Engineering at Stellenbosch University told News24.

Gauché conceded that wind power was a maturing technology and even photovoltaic (PV) solar energy was viable with accelerated investment into the sector.

"The potential for PV is immense: If we put PV farms up everywhere we could easily get more than enough power generated in the country, but the problem with both PV and wind is their intermittence," he said.

Gauché is proposing investment into concentrated solar power (CSP) where a set of mirrors concentrate sunlight onto a collector which then acts like a traditional electrical generating plant.

Expensive

"You use mirrors to concentrate the sunlight and basically what you do is you can then generate steam. The back half of a CSP plant is just like an Eskom [coal-powered] plant in that it's got a steam turbine and a cooling system.

"The front half: What you're basically doing is replacing coal with concentrated sunlight," he said.

CSP is an expensive technology at around R2 per kWh (Kilowatt hour) but in the long term costs would be reduced, especially as supplies of fossil fuels decline.

The technology is a direct competitor to gas turbines that burn diesel fuel which typically cost between R3 and R5 per kWh.

Like wind and solar power, CSP is an intermittent source of energy, but Gauché said that new technological innovations meant that it was more viable.

"The most successful developments are these concentrating solar plants where they actually store the heat energy in salt tanks. The top of the tower actually heats salt and keeps salt molten - these are special salts - and they remain in the molten state all the time," he said.

The additional of the molten salt has seen countries like the US exploring CSP plants and over 400MW of capacity was installed in Spain in 2010.

Renewable energy


SA has been talking about renewable energy alternatives for electricity generation, and Eskom said that during winter electricity supply will be tight as the utility races to complete maintenance programmes.

The government has been lobbied to accelerate the development of independent power producers to generate electricity as opposed to a single entity.

"Over the last 30 years or so, virtually all countries have abandoned that model and now have independent generating and an independent grid, and generating itself has been unbundled into different types.

"We actually happen to think that whether it's private or government isn't the big deal - it's unbundling that's the big deal," said Leon Louw, executive director of the Free Market Foundation.

Eskom has received an African Development Bank loan of $365m that will be used to build a solar plant in the Northern Cape province and the utility is also building coal-fired power stations Medupi and Kusile to meet future demand, despite objections from environmental organisations.

"Medupi may be about to start delivering electricity into the South African grid, but this will come at a huge social, economic and environmental cost, which leaves little to celebrate," Greenpeace said after Eskom successfully conducted a boiler test at the facility.

Serious

The utility said that its CSP project in the Northern Cape was serious power station.

"So it's not an experimental project, it will be a real power station. A 100MW is a lot of power - it is scale - it's significant," Eskom spokesperson Hilary Joffe told News24 in 2011.

Gauché said that CSP should be an important part of energy policy over a long-term time horizon.

"It's a very young technology and they [Eskom] are justifiably very uncomfortable with suggesting that they should rely on CSP. I would not rely on CSP today. However, there are nations in the world... where they realise that concentrating solar power is going to be an extremely important part of the mix."

A study done by organisations including Greenpeace, the European Solar Thermal Electricity Association, and the International Energy Agency found that increased investment of €2bn to €92bn into CSP until 2050 would see the technology being able to supply 25% of the world's energy needs.


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