June 2, 2010 - Integrated Solar Combined Cycle: piggybacking of solar thermal onto combustion

Yesterday I wrote about FPL's Martin Next Generation Solar Energy Center, which uses "Integrated Solar Combined Cycle" technology. FPL describes the Martin plant as the "first hybrid solar facility in the world to connect to an existing combined-cycle power plant". The idea is to use parabolic trough reflectors to concentrate sunlight to help heat a special heat-transfer fluid that will be used to make steam -- steam that will be mixed with the steam produced by gas- and oil-fired boilers, and used to power generators.

Through discussions, I learned that others are experimenting with integrated solar combined cycle technology. In August 2009, Abengoa Solar announced its plans to build the first CSP installation integrated with a coal-fired plant. The Abengoa modification to Xcel Energy's existing Cameo plant, located near Grand Junction, Colorado, could add up to 4 MW equivalent (MWe) to the installed capacity.

The ISCC plant that is farthest along appears to be a 470 MW plant located at Ain Beni Mathar, Morocco. To be operated by nationalized utility Office National de l'Electricité (ONE), the Ain Beni Mathar plant combines parabolic trough solar technology and a conventional gas-fired power plant. Projections suggest that the solar component will supply 20 MWe, with the remaining 450 MW coming from the conventional thermal plant. On a production basis, the solar output is projected to be about 40 GWh, or just over 1% of the project's annual net production of 3538 GWh per year. Ain Beni Mathar is just one part of an ambitious 2000 MW solar program underway in sunny Morocco.

Here's a link to the Ain Beni Mathar project page on the African Development Bank Group site. The site lists a project cost of 179,073,180 Euro -- or about $218 million in US dollars at today's exchange rates.

Yesterday, we looked at the price tag of FPL's Martin plant: $420 million for 75 MW of solar. Dividing this linearly, we get a cost of $5.6 million per MW installed solar capacity. By comparison, Ain Beni Mathar offers about 20 MW of solar equivalent, or $10.9 million per MW.

Can these numbers be right? From the technology perspective, this is really neat stuff -- but are these prices reasonable?