(Photo courtesy of the National Renewable Energy Laboratory)
Whenever solar power is mentioned,
critics are quick to note – when there’s
no sun, there’s no power. Lester Graham
talked with the author of a report who
says one type of solar power can store
energy:
Transcript
Whenever solar power is mentioned,
critics are quick to note – when there’s
no sun, there’s no power. Lester Graham
talked with the author of a report who
says one type of solar power can store
energy:
Lester Graham: Concentrating solar thermal, or CST, can store power. Basically, mirrors are used to concentrate solar rays, heat up water, generate power. The heated water can be stored as heat in tanks – like coffee in a thermos – and produce electricity when needed. Britt Staley is with the World Resources Institute. She’s the lead author of a new report on concentrating solar thermal. So, you found, if it’s done right, CST could be built instead of coal-burning power plants. How practical is that?
Britt Childs Staley: We think that concentrating solar thermal is a very exciting renewable energy technology precisely because of this potential for storage. If you incorporate thermal energy storage, or fossil fuel backup, with your concentrating solar thermal, you can actually use the power of the sun around the clock.
Graham: Now, the CST plants are expensive – they’re more expensive than building a coal-burning power plant. So, why build them if that’s the case?
Staley: With climate change as a major concern in the US and around the world, we are going to need to reduce our dependency on coal in the power sector. And currently, as you said, concentrating solar thermal power is more expensive than coal, but in this report we’ve identified several policy interventions that could help reduce costs. For example, a price on carbon such as the cap-and-trade mechanism in the current Waxman-Markey Bill, and then some solar-specific policy interventions would help as well.
Graham: Now, when you say ‘policy interventions’, really you’re talking about government subsidies, right?
Staley: Yes. Support for R-and-D, for deployment such as the investment tax credit that’s currently in place.
Graham: Obviously, the most sunny places would be the best location for a concentrating solar thermal plant.
Staley: Mm-hmm.
Graham: And the most sunny places are often in arid places, such as the US Southwest. So, they’re the driest places, and CST relies heavily on water. So, in the long term, what’s the solution?
Staley: There are several alternative cooling technologies that are available and that can cut water by up to 95% to 98% in places where that is a concern.
Graham: Is this completely experimental, or have we seen this done anywhere in the world successfully?
Staley: It’s absolutely been done successfully. Here in the US, we have some of the longest operating CST plants. And Spain is another good example of where CST deployment has been particularly successful to date.
Graham: How long would it take to build one of these, and how soon could they contribute, and how likely is it to happen, given the cost?
Staley: A lot of the plants that we see on the drawing board right now are expected to be in operation in the next 2 to 5 years. With climate change concerns, with climate change legislation working its way through the House and Senate, coal plant investments are not particularly attractive right now. And investors are very wary of putting their money into something that’s going to be significantly more expensive in the coming years. Concentrating solar thermal, on the other hand, is a zero-emissions power resource. Also, it has zero fuel costs.
Graham: Britt Staley is the lead author of a report on concentrating solar thermal power plants. She’s an associate researcher with the World Resources Institute’s Climate Policy Team. Thanks very much for talking with us.
Staley: Thank you.
Graham: I’m Lester Graham.