World's Largest Solar Array to use Stirling Engine
An anonymous reader writes "Stirling engines are not a neglected or forgotten technology after all, according to a story at PESN. With 20 years of in-the-field fine-tuning, Stirling Energy Systems is now ready to go big -- real big. They signed a purchase agreement Tuesday with Southern California Edison (SEC), to install a 20,000 dish array that will cover 4,500 acres and will be capable of generating 500 megawatts of electricity -- more than all other U.S. solar projects combined -- making this the largest solar installation in the world. Each collector has a 37-foot-diameter array of mirrors to focus the sun's rays on the Stirling engine, which turns the heat into rotational torque for electricity generation. According to a spokesperson for SCE, this purchase will be in their commercial interest, requiring no subsidy in order to compete, implying that the efficiencies of the technology will give them an edge in the market."
I'm glad to see alternative energy sources being developed, I just wish public opinion would change faster so we can get some more nuclear plants as well.
OK, here are some notes on this:
1. It's not like you are covering 4500 acres (that's 7 sq. miles) with solid concrete. The actual footprint of these dishes is fairly small; the main impact will be the amount of sunlight hitting the ground. judging from the area, this may not be such bad thing. Shade for the desert tortoises and the like.
2. It's reasonably scalable. Using SGS's numbers, and being conservative, let's say these things can crank out 400 kWh/m2 per annum. At 2004 US electrical consumption of roughly 1.2 trillion kWh (source: EIA), you're talking about needing ~30 billion sq. m. of collectors, which is about 12,000 square miles, to supply 100% of current electrical needs. You could fit that in about 5% of Texas- not an insignificant amount of land, but doable (you don't have to have all the collectors in one place, and you can probably install them on under-utilized land- say, parking lots- just jack up the collectors a few feet to provide SUV clearance).
So although I'm sure some people will get bent out of shape, I don't see the land area requirements as a big deal. If these things are truly economically competitive, as the article suggests, watch out.
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