The Department of Energy (DOE) SunShot Program has a specific goal: to move the cost of solar-energy-generated electricity to be competitive, without subsidies, with the cost of fossil-fuel-generated electricity by 2020. In service to that, it supports research in every dimension of both photovoltaic (PV) solar and concentrating solar power (CSP) along the entire gamut from basic to applied science. DOE calls SunShot “the Apollo Mission of our time.”
Because things in Washington, D.C. go down more easily when there are numbers attached, DOE Solar Technology Development Manager Joseph Stekli noted that the SunShot program designated an unsubsidized cost of six cents per kilowatt-hour as its target for solar power plants. That translates, according to the DOE, to $3.60 per watt for CSP systems with up to 14 hours of thermal energy storage (TES).
The specific goals for TES are a cost below $15 per kilowatt-hour, a round trip efficiency of 93 percent, and a heat-retaining efficiency of greater than 95 percent.
DOE is also targeting a heat transfer fluid, Stekli added, with a thermal stability of as high as 1,300 degrees C, a freezing below-zero degrees C, a heat capacity twice that of current solar cells and other characteristics similar to currently used molten salts.
Stekli and DOE SunShot PV Team Lead Lidija Sekaric talked about the SunShot program during the Smithers APEX solar summit in San Diego.