Huge step in solar energy

SO RENEWABLE energy has a hot new name – Gemasolar.

That’s the news from Europe where the Spanish company Torresol has just won a prestigious award for it’s new concentrated solar power (CSP) plant near Seville in Spain.

Gemasolar, as the plant is called, is using breakthrough technology to produce electricity from the sun, on demand – day and night, bright or cloudy.

Seville’s a long way from Nelson Mandela Bay but a key criteria for the award is the technology can be replicated. In its citation, the pan-European Desertec Foundation called Gemasolar “a pioneer for future power stations”.

At the moment the plant is relatively small, supplying 20MW for 25000 homes and reducing atmospheric CO² by 30000 tons a year. But  indications are Gemasolar or a series of similar plants can be scaled up to supply much larger populations with renewable energy.

As the Climate News Network explains, solar power’s greatest drawback has always been that it is intermittent, and peak electricity demand often hits when the sun has set. Gemasolar’s solar power storage breakthrough solved this problem and that’s the reason it snapped up this award.

The 185ha plant’s  2650 mirrors or “heliostats” train the sun’s rays on a central tower where the heat collects in a tank of molten salt.   The steam generated drives a turbine connected to an electrical power generator and the electricity is distributed by superconducting cables.

Surplus heat is  stored in the molten salt (the temperature rises to more than 500°C) allowing for independent power generation, without any solar feed, for up to 18 hours a day.

In line with Gemasolar’s success, in February this year the Institute for Advanced Sustainability Studies in Potsdam in Germany announced a  milestone in its work on superconducting cables, with much more efficient transmission of much heavier power loads. Their prototype cable is made from the binary compound MgB2 enclosed in a helium gas cryostat to maintain the required temperature for best transmission.

Although Gemasolar is recognised as the most efficient CSP project, there are 105 of them around the world from the US and the Middle East to North Africa and Australia.

And now three CSP plants are due to be established in South Africa, under the government’s Renewable Energy Independent Power Producers’ Procurement Programme. To start with they will only have storage capacity of 2-9 hours but this will allow them to supply power to the national grid at peak times when it is needed most.

The Southern Africa Solar Thermal and Electricity Association says there is much greater potential for CSP in South Africa and has called on government to reconfigure its Integrated Resource Plan in recognition of this.  Presently to supplement its peak time generation Eskom relies on Open Cycle Gas Turbines (like the one proposed for Coega) and the plan allocates 5000 MW to this diesel-driven gas technology and only 1200MW to CSP.

This despite that the power generation costs are much the same for the two technologies and instead of using diesel (a fossil fuel, combustion of which generates CO²) CSP  stations harness the free clean and endless energy of the sun.

For many like myself who support the pressure groups against fracking and the Thyspunt nuclear plant, proper investigation of the potential of renewables is fundamental.

What about geothermal energy where a deep shaft drilled into the Earth releases high-pressure steam that can generate electricity? What about wave energy parks? It is estimated that in Sweden when this technology is fully developed it will deliver a power load equal to 12 nuclear power stations.

What about a combination of these plus solar panels and CSP, landfill methane and waste biodigesters, algae, wind turbines where the bird kill problem is least?

With proper investigation must come transparency and a clear rejection of pressure from powerful interest groups in the fossil fuel industry and government. It must factor in full costs and benefits including to the environment and scarce natural resources and how this plays out over the long term in regard to climate change.

We need to understand finally, as legendary British fund manager Jeremy Grantham says, that even the best energy mix cannot herald a return to the era of high growth.

But the aim is that it will smooth the way towards a new economy that is “less overreaching, less hubristic, a lot humbler about our use of resources and more determined to live in balance with the heat, food and water with which we can sustainably be provided”. - Guy Rogers, The Elephant's Ear