Reported from CSPPLAZA: SEGS I and II belong to the nine Solar Electric Generating Station plants in California’s Mojave Desert. In late 2015 when 30-year power purchase agreement(PPA) expired, the two plants were officially decommissioned. Now SEGS I & II have been torn down, and equipment been disposed of.
Cogentrix Energy is the owner and operator of SEGS I and II, and Luz acts as a developer. Before the expiration, Cogentrix had planned to thoroughly upgrade the two plants, including equipping them with advanced and low-cost TES system. But ultimately, the contract renewal failed.
The nine plants, which have a combined peak capacity of 354 megawatts, and an average output of around 75 megawatts, comprise the largest solar installation in the world. SEGS I and II were completed and placed in service in 1984 and 1985 and are located in San Bernardino County, California. They deliver up to approximately 43 megawatts of electric capacity under contract to Southern California Edison (“SCE”).
Henry W. Price, the operations manager with SEGS plants said in an interview with CSPPLAZA, during the 30-year operating period, actual power generating capacity of SEGS I and II didn’t reach the estimated output. But it’s not because they were underperformed. To some extent, estimated output had been overrated.
SEGS I and II represent the first two utility-scale solar trough plants built in the world. All items of equipment they used, such as solar receiver tubes, reflector and bracket cannot be equated with those today. But still they had operated smoothly for 30 years. There are important lessons to be learned from SEGS I and II, Price added.
In a word, the aging process of CSP plant is slow, and its long lifespan provides exciting possibilities for increasing revenue of plant.
Image: SEGS parabolic trough project
The PPAs of SEGS III, SEGS IV and SEGS V will expire one after another by the end of the year. Their owner NextEra is striving for the renewal of contracts. But the final result would depend on the situation in California.
SEGS I and II were torn down after decommissioning. Actually, the disposal method is not typical. The lifespan of CSP plant depends on its cost. TES and innovative technology will help to reduct costs and gain higher profits.
Price said, as far as I’m concerned, the lifespan of a well-designed CSP plant can reach 40, even 50 years, being on a par with a thermal power station or nuclear power station. With more than 30-year operating period, SEGS III-IX are best examples. But it should be noted that some technological bottlenecks need to be solved in the future.