Monday, August 31, 2009

How much?

My solar panels: They're allright. But this is not how the future will be powered.

A very chirpy article from on the normally excellent claims the following:
The sunlight falling on our deserts, parking lots and rooftops has (...) power -- enough to supply 69% of U.S. electricicty by 2050 according to published studies."
This sounds wonderful. And that part about "69%" is taken from Scientific American, not from some stoned college kid called Chad. But to someone who gets all his electricity from solar panels already these numbers still sound really, really strange.
The average American household uses 11256 Kwh of electricity per year, according to the Energy Information Administration.
If you get on average six hours of direct sunlight a day, and thus 1 kw pr year pr 0,66 square metre of pv, this means the average household would need almost 17 054 square metres of solar panels to meet their household needs, or 183 567 square feet. (I have maybe 6 square metres, 65 square feet, of solar panels. And no diswasher, that's for sure.) And we're not even talking about transport or industry here, we're just talking about residential needs, the fridge and the game console and that kind of thing. Let's keep the Tesla out of this for now. And your workplace.
Let's say the US continues it's population growth. This means it will be doubled by the time we reach 2050. So if there's three people to every household we get two hundred million households. Let's be very, very nice and presume that the demand for power in the average household, bizzarely, will not increase during this time.
Something might be horribly wrong with my maths, but it seems the US will need 1 316 911 square miles of solar panels. And the size of the US? 3 794 066 square miles.
So a third of the country has to be coverd by panels.
But wait, Sciantific American said only "69% of US electricity"! So that's all right then, we're down to roughly one million square miles of glass and silicon.
And pv panels are getting a couple of percent more efficient every year, so by 2050, you'll only need half as many, five hundred thousand square miles or so.
That's still a seventh of all of the entire US. Something like Montana, New Mexico, Arizona and Colorado put together. Have you ever tried to drive through those places? Now fill it all up with glass and wires.
And that's just to let you kick back at home. Getting to work, getting to the mall, not to mention keeping the ice cream cool at the food mart, is not factored into this.
So come on.
One very good reason to get people using pv panels is that they will never believe this otherwise wonderful technology will enable the Western Shopping Show to go on.
Read the quote again, and you'll see that SA is not really claiming that pv panels can utilise the necessary power. They're just saying that a lot of solar power does fall on "deserts, parking lots and rooftops". But this power is mostly good for growing food and getting a nice tan.

1 comment:

Hudson Gardner said...
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