Solar Power After Sunset

Intermittency is one of the biggest problems with solar and wind power. When the sun doesn’t shine or the wind doesn’t blow, there’s no power.  For this reason power storage technologies are essential if wind and solar power are to replace base load capacity and become more than bit players in energy markets.  The WSJ reports on plans to build a utility-scale solar plant with substantial storage capacity in the Arizona desert.

Abengoa Solar Inc. expects to start construction in mid-2011 on a plant in Arizona that will store sun-generated heat to provide six extra hours a day of electric-generating capacity. The heat creates steam that is used to turn power turbines.

Abengoa’s $2 billion Solana plant is expected to be the first major stored-heat plant in the U.S. when it enters service in 2013. Some already exist in Spain and a few more are on the drawing board for Nevada and California. . . .

The Solana plant will be able to meet winter heating and lighting needs by putting electricity on the grid early in the morning—before the sun is shining—and help satisfy summer cooling demand by producing power after sundown. The plant, which can power up to 70,000 houses, has signed a 30-year agreement to sell electricity to utility company Arizona Public Service.

The deployment of stored-heat technology like that proposed for the Abengoa facility is a significant development, but it comes at a price.  Solar power is already more expensive than wind power and carbon-based alternatives, including natural gas.  The WSJ reports that adding heat storage increases plant construction costs by approximately 20 percent.