Solar thermal: the energy of the future?

By Benedict De Meulemeester

By Benedict De Meulemeester on 12/06/2009

I've read an article in last week's Economist on solar thermal power production. This is not the same as photovoltaics. With PV-cells you use electrochemical processes to produce electricity. Solar thermal uses the sun's heating power to produce steam that drives a turbine. You need to concentrate the sun heat for that of course, so you need mirrors.

This makes me think of my childhood days. Together with my cousin, I used a looking glass to let small pieces of wood burn. In the heat of a summer's day we would sit behind my grandfathers shed and then we took a piece of wood and kept the looking glass over it. After a few minutes some smoke came out of the wood, it started to color black and the air started to smell burned. Unfortunately, my grandfather caught the smell and severely scolded us for playing with fire. I should have answered, 'we are experimenting with the energy supply of the future'.

Large-scale solar thermal plants were constructed in Spain and California right after the first oil crisis. Isn't one of them the background of a scene in a James Bond movie? Anyway, as energy prices sank, investment in solar thermal was abandoned for two decades. With recent new oil price spikes and the climate change policies, interest in this renewable way of producing energy has reignited (yes, I know it is a word game). New plants are up for construction.

What strikes me about these plants is their size. A company called Brightsource Energy, based in California, plans to build 14 solar thermal power plants with a joint capacity of 2.600 MW. It takes a lot of PV-panels or windmills to achieve such a capacity! Another interesting feature of this technology is that you can create hybrids. You can link them to gas-fired power plants, using gas only when the sun isn't shining. This brings us to a first downside of the technology. It only works when the sun shines. Therefore, it will mainly be implemented in sunny, warm countries. But the idea of desserts that produce electricity that is transported to industrialized areas is getting a bit closer again.

With such potential, and taking into account the simplicity of the basic technological idea, it is surprising that this technology hasn't been implemented on a larger scale. The article says nothing about it, but I guess investment costs have something to do with it. But with current prices and politicians' willingness to subsidize renewable energy, this should be a less important obstacle. So if you live in Spain or New Mexico, I guess it is more than probable that you will soon tap electricity from the sun's heat. Isn't it beautiful that we are returning to such simple and old energy producing technologies as using the power from the wind or the heat of the sun?

Nevada Solar One

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