The project combines Areva’s modular Compact Linear Fresnel Reflector (CLFR) solar design with Sandia’s molten salt storage system. It will be the first CSP integration with Sandia Labs’ Molten Salt Test Loop System at the US Department of Energy National Solar Thermal Test Facility in Albuquerque, New Mexico.
Incorporating thermal energy storage enables CSP plants to provide power generation over longer periods of time or to shift power delivery to another time period, Areva notes. This gives plant operators more flexibility, allowing them to accurately match electricity supply with demand as well as support grid reliability. “Using molten salt storage to extend daily solar electricity generation is not new. But combining it with CLFR technology is,” explains Bill Gallo, CEO of AREVA Solar.
The firm’s CLFR design consists of an array of mirrors that concentrate the sun’s energy to heat a working fluid in an elevated receiver. However instead of using water as its working fluid, this new system uses molten salt in an elevated vacuum tube receiver. The system draws molten salt from a cold (290°C) tank, uses the heat from the mirrors to heat it to as high as 550°C, and passes that hot liquid to a separate tank for storage.
When needed, the high-temperature molten salt passes through a heat exchanger to produce steam for electricity generation. The molten salt then returns to the cold tank and the process is repeated in a closed-loop system. “The result is a dependable, lower-cost storage system that provides users the advantages of CLFR technology along with the benefits of extended dispatchability through molten salt storage — day and night,” according to Gallo.
The CLFR molten salt storage system will become commercially available in 2013.
Written by Robin Whitlock