Solar Energy Farms

This all started at Instapundit, who quotes:

"Energy is one of the greatest challenges of the century," Claude Canizares, MIT's Bruno Rossi Professor of Physics, told attendees of the conference produced by the American Society of Mechanical Engineers' (ASME's) Nanotechnology Institute. "We need significant breakthroughs in science and technology. The promise of nanotechnology provides fertile ground for such breakthroughs." . . .

MIT's Vladimir Bulovic said that nanotechnologies such as nanodots and nanorods are potentially "disruptive" technologies in the solar field. That means they could cause a major switch in a primary energy source, potentially proving more efficient than the silicon used in most solar energy devices today. Bulovic is fabricating quantum dot photovoltaics using a microcontact printing process.

... then follows with Truth Laid Bear:

Um, ok. Glenn notes "Two percent is a LOT of land", but that's understating the case a bit I think.

Let's do some math! (I was told there would be no math. Shhh!)

According to this page, the total land area of the U.S. is 3,537,379 square miles. Take away Alaska and Hawaii to get the continental U.S., and you are left with 2,959,005 square miles. Two percent of that is...

Fifty-nine thousand, one hundred and eighty square miles. That's 59,180.

For perspective: Over half of the fifty states are smaller in area than 59,180 square miles. The closest in size to that number are Iowa (55,869), Michigan (56,804), and Georgia (57,906).

So: who's for paving over Georgia?

Because unless I'm missing something, that is what we're talking about: literally paving over that much area, and I have to assume utterly destroying any flora, fauna, or other living things that are unlucky enough to have been previously occupying it. Unless they happen to, you know, not require sunlight.

Now that would be one hell of an Environmental Impact Study.

Professor Bulovic seems to have thrown out this statistic as a positive for solar energy, but he's obviously never negotiated with a local zoning board. If that's the best future we can hope for with solar as our primary energy source, I suspect even the most strident environmentalists will cry out, "Bring on the coal!"

... and I started to comment at the Bear, but decided why do it there when I can do it here?

First, 10 percent is pretty low efficency: that's less that the typical efficiency of multicrystalline Si (11-14 percent), and way less than the maximum observed efficiency of single-crystal Si (almost 25 percent). Get 25 percent and we're already down to a little less than 30,000; get 40 percent, which the new nanotube stuff is suggesting, and you're down to 13,000.

Second, the Bear is looking at little states. Colorado, Arizona, and New Mexico alone account for 338,000 square miles. Add Kansas and Nebraska, another 112000 square miles roughly, for a total of about 450,000 square miles. There's lots more than 13,000 square miles of uneconomical farm land currently fallow in Kansas and Nebraska alone.

(I'll leave the desirability of paving over Nebraska as an exercise for the interested reader.)

Third, the solar collectors don't have to be over land: there's a lot of shallow water off the eastern US coast, in the Gulf of Mexico, and in the Caribbean.

And fourth, you don't need to pave over any particular piece of land of 13,000 -- or even 60,000 -- square miles in order to get a total of 60,000 square miles of collectors. You wouldn't even want to -- you would be at the mercy of a single cold front. But rows of solar collectors 10 meters off the ground, spaced 50 meters apart, across much of Kansas and Nebraska, would give you pretty close to 13,000 square miles of collectors.

Then let the land underneath go fallow. Reintroduce the buffalo.

How many barrels of oil does 25 percent of the US energy consumption replace?