An engine designed almost 200 years ago could be the future of solar energy. At least that’s what San Diego county is banking on, along with Phoenix-based Stirling Energy Systems, which will be building a 1,000-MW solar plant run off of Stirling engines in the county’s desert thanks to the California Public Utilities Commission’s approval this morning of the Sunrise Powerlink project.
Sunrise will essentially be a big ole power line through the deserts and mountains, running from Stirling’s plant in the Imperial Valley to the cities of San Diego and Chula Vista. Without the line, Stirling Energy was prepared to call it quits on its proposed plant and contract with San Diego Gas & Electric, stating that it would have no way to get power from the plant to local residents. Stirling was also relying on approval of the line to raise more funding, the company said during the CPUC meeting.
Approval of the line was not unexpected. CPUC President Michael Peevey issued a proposed decision last month supporting the project with no restrictions. The decision was supported by most of the mayors in San Diego County, as well.
The Stirling engine was developed in the 19th century as an alternative to the steam engine. In the context of solar energy, the engine is attached to a large dish-style solar concentrator, which focuses the sun’s rays in order to heat helium, which expands and drives the engine’s piston. The piston moves back and forth, and an alternator captures the power created and converts it to AC power.
The engine has been used in pacemakers and on spaceships, but the solar application has yet to be proven at a commercial scale; Stirling’s project was conveniently planned to leap over pilot testing the technology at scale. Skipping such a massive step had many concerned that Stirling’s plant was doomed to be the largest solar failure of the decade.
The approval of Sunrise represents a big step toward the large-scale commercialization of some of the first Stirling solar technology on the market. It will also have implications for other companies exploring solar as an application for Stirling engine technology. Washington-based Infinia, for example, tested its systems alongside Stirling Energy Systems at Sandia National Labs and received $50 million in funding from GLG ventures last year to begin mass manufacturing its Stirling-based solar systems.
Beyond the affect on Stirling, the renewable energy community, including Californians for Renewable Energy, are happy to see transmission lines for renewable energy projects approved, period. The majority of CPUC commissioners echoed this sentiment, expressing concern that failure to approve this line would lead to difficulties securing financing for other transmission lines related to renewable energy. And the construction project could create a significant amount of jobs, which representatives from Imperial County took care to mention at the CPUC meeting this afternoon.
Detractors, amongst them Commissioner Dian Grueneich and representatives from the Sierra Club criticized President Peevey’s alternate decision for not including a mandate that the line be used for renewable energy, and cited rate increases, wildfires, and destruction of natural habitat as additional concerns.