North by Northwest

Solar thermal plants are being viewed as a renewable power source with huge potential. Matthew Wald takes us on a tour of the technology and its potential in this New York Times article.

According to the story there are plans to build several new solar thermal plant in the deserts of the southwestern US.

Today, natural gas prices are much higher [than the 90s when natural gas plants were being built across the nation], and political opposition is rising to construction of new coal-burning power plants. Many states, including California, are imposing mandates for renewable energy. All of that is reviving interest in solar thermal plants.

The power they produce is still relatively expensive. Industry experts say the plant here produces power at a cost per kilowatt- hour of 15 to 20 cents. With a little more experience and some economies of scale, that could fall to about 10 cents, according to a recent report by Emerging Energy Research, a consulting firm in Cambridge, Mass. Newly built coal-fired plants are expected to produce power at about 7 cents per kilowatt-hour or more if carbon is taxed.

How it works:

Nevada Solar One, built by a Spanish company, Acciona, is of a proven design. It uses a mirror in the shape of a parabola to focus light onto a black pipe with a heat-transfer fluid inside. The fluid is used to boil water into steam, which turns a generator that can produce 64 megawatts.

That is small compared with a plant running on coal or natural gas, but far bigger than a typical installation involving solar photovoltaic panels, the type of solar power most people are familiar with. That technology, while good for some uses, is far more expensive than solar thermal power.

…

The newest solar-thermal technology involves building a “power tower,” a tall structure flanked by thousands of mirrors, each of which pivots to focus light on the tower, heating fluid. That design can work even in places with weaker sunlight than a desert.

One of the big advantages of these plants is that they can be built with the capacity to store heat in what amounts to a giant Thermos. Experts say that will smooth production and make it easier to integrate the plants into the electrical grid.

Obligatory environmental considerations:

They could take up immense amounts of land and damage the environment.

Already, building a plant in California requires hiring a licensed tortoise wrangler to capture and relocate endangered desert tortoises.

I’m amazed that the state of California has an office that licenses “tortoise wranglers.” Thank God someone’s watching out for the tortoises!

Also see this 5 min NYT video summarizing the technology.