Solar thermal power: From the US to Spain and Back

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Cynthia Graber reports on a kind of renewable energy technology known as “solar thermal” and why most companies that specialize in “solar thermal” are located in Spain.

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CYNTHIA GRABER: Solar power was a niche technology at the time.  Early photovoltaic panels, which used the sun’s energy to move electrons and create electricity, were expensive and not very efficient. Passive solar panels, meanwhile, captured the sun’s warmth to heat water.  They were cheaper, but of limited utility. But Goldman had heard about a third way.  It was called solar thermal, or concentrated solar power, and it was sort of a hybrid of the other two. It used mirrors to magnify the sun’s heat, generate steam, and create electricity.  It was a fairly simple idea with ancient roots.

ARNOLD GOLDMAN: Some of its first recorded beginnings with Archimedes, the time of Greece, getting people shining mirrors onto ships to burn ships invading.

CYNTHIA GRABER: Still, no one had yet figured out a commercially viable way to use the sun and mirrors to create electricity. Arnold Goldman and his engineers cracked the code. They used miles of what are called parabolic troughs to concentrate the sun’s heat on tubes of oil.  The hot oil was then used to boil water, and the resulting steam was used to spin turbines.  By the end of the 1980s, with the help of government tax breaks, Goldman’s company Luz International had built nine such power plants in the California desert. But then, the energy crisis ended. Governments lost interest in renewables. The company went under. Now, fast-forward a generation.

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CYNTHIA GRABER: That was the sound of a heliostat, or a huge giant square of mirror shifting just slightly to catch the sun. I’m standing at the Solucar Solar Platform in Seville, Spain, surrounded by a vast array of special mirrors called heliostats. It’s the first commercial solar thermal plant to be built anywhere in the world since those early American ones. Like those first plants, the Solucar facility uses its mirrors to concentrate the sun’s heat to boil water, create steam, and run a turbine, just like in a conventional power plant. But the Solucar site uses a slightly different technology.  Instead of heating oil, its array of mirrors acts sort of like a field of ray guns.  They focus the sun’s heat and aim it at a receiver, a blindingly bright circle of white atop a tower. Valerio Fernandez is the site’s director.

VALERIO FERNANDEZ: The tower is a concrete tower, and receiver is an innovative boiler, that is fed by solar radiation instead of coal or some other fossil fuels. So, I think, [INDISCERNIBLE] are one of the most promising technologies for making a change in the energetic model in the world.

CYNTHIA GRABER: There are two of these towers on the Solucar site, which together produce enough electricity for about 15 thousand homes. And there are dozens more solar thermal power plants being built in Spain. That’s because the Spanish government has subsidized research in the field, and promised a good financial return for solar companies.  And now, a generation after it hit the skids in the US, Spanish companies are using their newfound expertise to bring solar thermal technology back to the place where it was born.

[SOUND CLIP]

CYNTHIA GRABER: Nevada Solar One is first new solar thermal plant in the US in nearly two decades. It came on line in 2007, built by the Spanish company Acciona. The company’s North American CEO Peter Duprey spoke at the plant’s opening.

PETER DUPREY: You know, with this plant we’re spearheading a new revolution in renewable energy Nevada, in the southwestern United States, and really truly around the globe.

CYNTHIA GRABER: The US southwest has some of the world’s most abundant sunshine.  And there are once again growing incentives to develop solar and other renewable energy sources in the US.  Both of which are drawing other Spanish companies across the ocean as well. Abengoa, for instance, the company that built the solar tower outside Seville, is finishing plans for a plant in Arizona. And after watching for years as others fostered the technology that they first developed, Americans are getting back in the solar thermal game, including Arnold Goldman.  A few years ago Goldman decided the time was right to reassemble his old team, under a new name, Brightsource Energy. Goldman’s company recently signed agreements in California for more than two and a half gigawatts of solar thermal electricity.  Other American companies have signed agreements for more than three gigawatts of solar thermal power.  That’s enough solar electricity to power closet to two million American homes, and counting. You might say it’s a dream come true. For The World, I’m Cynthia Graber.

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