Tuesday, July 05, 2011

Solar issues

Solar Thermal Plants Losing out to Photovoltaics - Technology Review

The article notes that big solar thermal plants are still (mostly) semi-experimental and therefore hard to finance, and also the "power tower" types that use large arrays of carefully aligned mirrors to concentrate the sun onto one point tend to involve bulldozing a lot of animal habitat. With PV, you can build above the critters.

Someone in comments notes, though, that the article doesn't consider another solar option: arrays of tracking dishes which power their individual stirling engines. Here's one such array with 60 dishes in Arizona. (Yeah, that's still not so big at 1.5 MW, and I'm not sure how they deal with cloudy days when the sun keeps coming and going.)

I used to follow Inifinia Corporation in the US, because I thought it had the coolest looking design for a stirling engine solar power dish. I see they are still around, and have added a website for their "Powerdish" which claims 24% peak conversion efficiency. They still aren't into the domestic market (and the dish is kinda large for your average house yard anyway,) but with a 25 year life, and claiming to be cheaper than other solar alternatives, they look like a good option for rural properties (and even in arrays.)

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