Every now and then, one hears complaints about solar energy: “But it takes too much land!” “An entire Idaho!” “Three Californias!”
Nevada Solar One takes up about 400 acres, mostly for mirrors and heat engines. You would have to mine about 5,300 acres to feed a coal-fired powered plant producing the same amount of electricity. Even acre for acre, I’ll take Solar One’s pleasant campus over a coal mine.
Math below the fold.
The 400-acre Nevada Solar One produces around 134,000,000 kWh per year. About three quarters of this is mirrors and heat engines, the rest support services and access.
This pencils out to 7.69 kWh per square foot per year, or slightly less than 154 kWh over the course of 20 years.
According to the EIA, one ton of coal produces about 2,000 kWh of electricity. Per acre yields for coal vary a lot, but in Appalachia it appears that mountaintop removal produces about 10,000 tons of coal per acre. So a coal plant produces around 11.5 kWh of electricity per square foot consumed in a single year. And then you need to consume a second square foot the next year. So producing the 154 kWh per square foot that Solar One produces over the course of 20 years would require mining 13.4 square feet.
Ignoring everything after the decimal point (this kind of calculation is not that precise, in any case), for coal to produce the same electricity Nevada Solar One will provide over the course of 20 years would require 13 times that 400 acres, or 5,300 acres.