Posted by Sherman in Idaho [72.47.153.28] on Tuesday, July 01, 2014 at 02:29:47 :
In Reply to: one more ot--saw this on fbook posted by clueless [201.202.105.247] on Monday, June 30, 2014 at 20:55:00 :
Total solar flux in bright noonday sun is about 1 kW/sq m (or square yard for Americans). Total global energy consumption was close to 150,000 billion kW-hours per year in 2008, or 17 billion kW. Round it up to 20 billion kW and you probably have a reasonable guess for today's usage. Given that in the Libyan desert, the sun doesn't shine with full brightness perpendicular to the earth 24 hours a day, a fair approximation, perhaps on the optimistic side, is to say that the sun shines with full brightness 8 hours a day in any given place. So, we need pave 60 billion square yards of land with solar panels. That's about 20,000 square miles, or an area 140 miles square. There are plenty of places where there's that much land with not much on it. Of course then you have to run wires to the rest of the planet, allow for maintenance, bad weather, and boys with bb guns. But say it took twice that much land -- it's still not complete bunk. Other relevant questions might be how much fossil fuel it will take to mine, fabricate, transport, and install those panels. There's also the problem that much of the world's 20 billion kilowatt energy demand is not for electricity. It's for space heating and transportation.
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