The Benefits of Solar Thermal Energy

Abstract

The article “Is it time to shoot for the sun?” (R. F. Service, News Focus, 22 July, p. [548][1]) on solar energy overlooked a proven and affordable energy source that is already available, solar thermal energy with storage via heat transfer fluid. A recent National Research Council report ([1][2]) put the cost of a large plant at $0.08/kWh, not competitive with conventional coal ($0.04/kWh), but cheaper than electricity from clean coal power plants equipped for CO2 sequestration [$0.07/kWh plus the cost of CO2 sequestration ([2][3])]. Solar thermal energy has an unacknowledged, unique feature ([3][4]). A solar-concentrating collector and its associated heat storage can be regarded as a fuel plant, which feeds a conventional steam power plant. As the investment for the power plant is less than 14% of the total, it can be overdesigned by a factor of three. This gives the system control capabilities not affordable or available in any clean power plant technology. For intermediate loads (8:00 AM to 9:00 PM), 50% of our electricity requirements, the cost remains $0.08/kWh, cheaper than nuclear energy or clean coal ($0.11/kWh and $0.10/kWh, respectively). All solar thermal power plants need to be competitive is a government subsidy for a few large demonstration plants, as were available for the development of nuclear and clean coal plants. The cost of generating power with solar cells is now three to six times more expensive than with a solar thermal plant. Should solar cells ever become really cheap, instantaneously dispatchable solar thermal energy could compensate for their lack of storage capacity and they could become attractive for large-scale use and merit a large research effort. 1. 1.[↵][5] National Research Council, “Critique of the Sargent and Lundy Assessment of Cost and Performance. Forecasts for Concentrating Solar Power” (National Academies Press, Washington, DC, Dec. 2002). 2. 2.[↵][6] 1. N. Holt , paper presented at the Gasification Technologies Conference, Washington, DC, 4 to 6 Oct. 2004. 3. 3.[↵][7] 1. R. Shinnar, 2. F. Citro , in preparation (available at ). [1]: /lookup/doi/10.1126/science.309.5734.548 [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: #xref-ref-1-1 View reference 1. in text [6]: #xref-ref-2-1 View reference 2. in text [7]: #xref-ref-3-1 View reference 3. in text