re: Elon Musk: Tesla can build power grid for Puerto Rico

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Exactly what kind of engineer are you that you think the numbers for solar are even close to adding up?

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My god. Do you have the slightest idea of how much energy in the form of solar insolation is incident on earth?

The moon is responsible for tidal motion. But pretty much everything that moves on the face of the earth, from wind, to water currents, to little things like elephants, cows, and people wandering the face of the planet is due in the end to solar radiation (at a hella loss from primary energy along the way in some cases).

Geez. Earth circumference is about 22,000 miles at the equator. call earth diameter 7000 miles, so radius is roughly 3500 miles.

3500*5280 = 18,480,000 feet. Call it 1.8X10**7 feet.

Incident surface area of earth to solar insolation is Pi*(1.8X10**7)**2 square feet.

That is about 10X10**14 square feet. Call it 10**15 square feet.

Solar insolation at earth's surface is about 1 KW/M**2 (after atmospheric absorption). That is a honking lot of energy.

I might add that fossil fuels in the end trace their origin to solar energy as well. You might quibble and say that decay heat from radioactive elements in the earth's crust contributed slightly to the stored energy in fossil fuels, but this is minor. Very minor.

Now I could pull some numbers and list man's current energy usage, and calculate how much square area you need to generate that much with 18 or 20 percent efficient solar panels, but I got the feeling this board ain't interested.

And as I said, without effective energy storage it's not as useful as it could be. But the energy is definitely there.