Could we run the U.S. on solar power?
February 25th, 2008 by Jim JustRobert Rapier at his R-Squared Energy Blog reports that the Spanish company Abengoa Solar is building a 280-megawatt solar thermal power plant southwest of Phoenix.
“Solano will use parabolic mirrors to follow the sun across the sky and concentrate its energy, heating a fluid to 700 degrees Fahrenheit, and using the fluid to make steam that will spin turbines to generate electricity. The plant will use an unspecified heat storage technology so the plant can continue generating electricity for six hours after sunset.”
The site will occupy 1,900 acres.
Rapier wonders how much land area would be required to replace all U.S. generating capacity with solar thermal.
“Peak U.S. demand, according to the EIA, is almost 800,000 megawatts. Actual available capacity is 900,000 megawatts. So let’s make our solar capacity equal to today’s total installed electrical generating capacity.
“Assuming the entire 1,900 acres is needed for the plant (maybe not a good assumption, but all I have), then this breaks down to (280 megawatts)/(1,900 acres), or 0.147 megawatts per acre. * * *
“Then to get 900,000 megawatts is going to take (900,000 megawatts)/(0.147 megawatts per acre), or 6.1 million acres . . . [or] 9,531 square miles, which is equivalent to a square of just under 100 miles by 100 miles (which would be 10,000 square miles).”
An area equivalent to a little more than two Lane Counties (~4,600 square miles) could thus supply the entire U.S. with thermal solar.
Rapier cautions that his back-of-the-envelope calculation doesn’t make any provision for the electrification of transport, which would require a lot more power. But on the other hand, we already have a lot of installed electrical capacity in the form of hydroelectric (78,000 megawatts) and other renewables (24,000 megawatts) – not to mention nuclear (100,000 megawatts).