South Africa’s blessed with some of the highest solar irradiation levels in the world, so it makes sense for us to capitalise on one of our most popular national assets – sunshine. Happily we are. Already, numerous solar photovoltaic (PV) plants dotted around the Northern Cape are either already feeding power into our national grid or are about to start. That said, a breakthrough at CSIRO, Australia’s national science agency, looks set to boost large-scale solar power generation up to that of traditional fossil fuel plants in the not-too-distant future – which could mean great news for us.
For the first time ever, a team of solar thermal engineers and scientists at CSIRO’s Energy Centre – using an array of 600 heliostats (or mirrors) to concentrate sunlight on to a centralised receiver point – managed to generate supercritical steam from solar to drive a turbine. What makes their breakthrough so impressive is that, until now, this feat has only been achieved by the world’s most advanced fossil fuel power stations.
Their world record, set in May this year, achieved temperatures up to 570 degrees Celsius at a pressure of 23,5 megapascals (a measure of force per unit area). Simply put, the temperature of the ultra-hot steam they generated is high enough to start melting aluminium alloy. And the accompanying pressure is roughly what you’d experience if you were hanging out 2 km beneath the ocean surface.
Dr Alex Wonhas, CSIRO’s energy director elaborates: “It’s like breaking the sound barrier; this step change proves solar has the potential to compete with the peak performance capabilities of fossil fuel sources. Instead of relying on burning fossil fuels to produce supercritical steam, this breakthrough demonstrates that powerplants of the future could instead be using the free, zero emission energy of the sun to achieve the same result.”
Seeing as most of our electricity is derived from coal, this is promising news indeed.
To find out more, visit www.csiro.au