Department of Agriculture

[shoju]

The solar power hitting the Earth is about 1000 Watts per square meter in full sun at sea level. The efficiency of solar panels is increasing, but let's assume 15% of that power can be converted to electricity. Early in the morning and late at night solar panels have a much reduced output with maximum output near noon. A good rule is you can get the equivalent of about 42% of maximum output per 12 hours of sunlight - less on cloudy days. So a one square meter solar panel should provide 0.42 x 12 hours x 150 watts = 756 Watt-hours per day.

The US consumed 3961559000000000 Watt-hours in 2009. So, 3961559000000000 Watt-hours / 365 days) / 756 (assuming 12 hours of sun every day) works out to 14356595640 square meters, or ~5540.3 square miles. That works out to a square area about 74.4 miles across. And, that would be a solid collection surface. Realistically you could double that for spacing of collectors, and what not. I believe in distributive networks, so rather than one mega site, I'd rather see about 20 or so distributed sites.

The down side is that the first 6 years would be used to pay back the energy costs of building the solar panels. After that, free energy. Well, perhaps not entirely free with maintenance (keeping the dust off them and etcetera... Then, they'd need to be replaced at end of life which may be 15 to 20 years I would guess. The approximate cost per square meter is £250 or about $390. That works out to a project cost just for the panels of 14356595640 * $392 = ~ $5.620 trillion

So, lets for simplicity we need about $7.5 trillion every 20 years to build and maintain the infrastructure to provide power for about 312 million people. That's $7.5 trillion / 20 years = $370.5 billion per year, and for 312 million people is about $1200 per person per year. Pretty good expensive. And, due to weather and seasons, and nighttime, we'd still need some other form of power production or storage for the non-sunny times.

Edit: Multiplied everything by 10... Thx Jester.

I'm curious what would happen if you took into account businesses, and what not. How low could you get the bill? I mean, I don't use nearly the electricity that my place of business uses, and they don't use as much as the big box retailers, and so on and so forth.

Then, assuming that this project would be a "pretty big frikken deal", you wonder if they could amp up the maximum output? Even a 10% improvement in quality, to 46.2% would have pretty drastic results:

.462 X 12 X 150 = 831.6 WHpD

I can see why a distributive would be best, I don't know if it is "possible" and achieve the results that you would in a place in the south in the desert, but To compensate, say you went with 20 sites. Each site is 500 SqMi of Solar. That gives you a distributive 10,000sq mi solar network. It's almost double the original size you came up with, but at 10,000 sq mi, even with a 10% boost in power, You then, would think that they would be able to store, and save power, and make it an almost self sustaining system.

It's a long way away from being something that could ever happen. I know that, but man... what would happen then?

I've been sort of a solar geek since I found out that my grandfather had installed a solar system on his house because he was mad at the city. He was never able to cut them out of the equation, but he was definitely able to put a dent in his electric bill.