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Can We Run The World Off The Sun?

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Can We Run The World Off The Sun?

Technology

Can We Run The World Off The Sun?

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ALEX CHADWICK, host:

This is Day to Day. I'm Alex Chadwick.

Happy birthday NASA. Fifty years old today. Wonder how that feels? A former NASA engineer thinks this now middle-aged agency should try something new. Solve the energy crisis by collecting solar power through a space-based energy system. He's Glenn Smith. He oversaw science and applications experiments for the international space station when he was at NASA. We spoke earlier about his proposal.

Mr. GLENN SMITH (Former NASA Engineer): You have very large solar cells, solar rays in space, probably 22 thousand miles out, so it circles the earth at the same speed that the earth rotates. It stays above one spot on the earth, and you convert that electric power into microwaves, and you beam it down near cities where large amounts of power are used. Receives it, converts it back to electric energy and feeds it into the existing power grid.

CHADWICK: And that wouldn't be dangerous to anyone who got in the way of that ray coming down, or airplanes flying by, or anything?

Mr. SMITH: Well, I've got a lot of questions about that. But here's what we have. The highest power level of the beam is only about one-fifth of the energy density of summer sunlight at noon. One-fifth. Tests have been run on bees and birds twice that level and they haven't found any effects yet.

CHADWICK: So, how much energy would you get from one of these satellites hovering over the earth?

Mr. SMITH: Oh, you'd get a lot. Maybe 1,000 megawatts.

CHADWICK: And how much is that?

Mr. SMITH: That's enough to serve a medium-size city. That's each satellite, so you'd have numerous of these satellites if you want to make a significant impact into the energy needs of the U.S. or of the earth.

CHADWICK: So you'd produce 1,000 megawatts of power every day?

Mr. SMITH: Oh, not only every day. Continuously, at all times.

CHADWICK: Glenn, I know you've worked for NASA and you're an engineer, but wouldn't it be simpler to make these just ground-based solar collectors, rather than up in space, and save all that bother of converting and beaming down?

Mr. SMITH: Ground-based solar is only good when the sun is shining. And this applies to wind energy, too. It's only good when the wind is blowing. You have to have fossil fuel generators, standing by to pick up the load when the wind stops blowing, or the sun stops shining. So that has to be figured into the economics of wind- and ground-based solar. And, of course, you don't have either of those problems with a solar power satellite.

CHADWICK: What would my electricity bill look like if I were getting solar power beamed down from satellites? What would it cost me?

Mr. SMITH: That is hard to come by, but the best estimates we have, it's somewhere between eight to 20 cents a kilowatt hour.

CHADWICK: Well 20 cents a kilowatt hour would be very expensive electricity.

Mr. SMITH: It would be, but where are we headed with the 130 dollar a barrel oil? And it may be lower. It may be toward eight or 10.

CHADWICK: How long do you think it would take you to build, and get operating, a system of the kinds of satellites that could deliver a significant amount of electrical power down to earth?

Mr. SMITH: It might be quite a few years, maybe in 10 years. It's an enormous job. In fact, it's comparable in size to another moon landing and place a base on the moon. But it has a very significant output if we are successful.

CHADWICK: Former NASA engineer, Glenn Smith, on his plan for space-based satellite collectors to beam solar power down to earth. Glenn, thank you.

Mr. SMITH: OK, Alex. Good day.

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