The United States Department of Energy (DOE) has supported solar thermal concentrator technology since the 1970s, through programmes that develop and test systems for both low-power remote
electric generation and larger grid-connected generation. One of these programmes is the Dish-Stirling Joint Venture Programme (DSJVP), a three-phase project begun in 1991, and now into its third phase. The objective of DSJVP is to
commercialise a 7-kWe solar thermal electric system by the year 2000.
In developing its CPG-460 7-kWe
concentrator system, the company received technical assistance from Sandia National Laboratory on behalf of DOE. At present, ten of these solar concentrators are employed in the field. Four are under test at the company's test site in Abilene, Texas. Additional systems are being evaluated for off-site testing in Texas, Pennsylvania, California, France and Japan.
concentrator system can provide clean, low-cost energy for applications such as rural water pumping or remote village electrification. The system is unique in that it uses an externally-fired heat engine. This permits the use of any heat source that is capable of providing sufficient temperature.
The system is environmentally benign and releases no emissions from its engine. Instead of ingesting fresh, cool air and exhausting the residuals of hot expansion, the unit employs a fixed mass of fully-enclosed gas over
and over again. The ground space required for placement and construction of the concentrator foundation is minimal and presents no significant impact to the surrounding area.
One hybrid concentrator unit has been developed
that permits use of two fuel sources: sunlight and natural gas. This fuel flexibility helps overcome the intermittent nature of the solar resource and allows users to keep the dish-Stirling engine on line at all times, maximising
the potential of their capital investment.