Getting power from the moon

spaceref.com ^ | 16 Apr 02 | Press Release - AIP

[Dinsdale]

Another ex traveler player checking in.

One problem is going to be the monthly cycle of lunar power available. When there is a new moon none of the solar collection stations on the near side (there is not a dark side of the moon, there is a near and far side) will have any power to transmit. Therefore you would need a transmission network on the moon to ship power to the near side month round.

More basically the solar flux on the moon is only higher then on earth by the atmospheric loss. If solar cells become economic (which is closer then most think, one more halving of cost, cost per watt looks kind of like Moores law) why not just put them on the earth. The duty cycle is no higher on the moon (in the light half the time) and production costs are going to be higher up there short of scifi nanotech.

[Barry Goldwater]

there are no tidal forces on the moon. It doesn't rotate, it always faces the earth.

[Barry Goldwater]

microwaves will heat the atmosphere. By using ocean tides to generate power, one is tapping into the moon. If the tides are used for power the moon will slow its orbital speed. More nukes, less kooks.

[Rocky]

Wouldn't it be better to use a long extension cord?

[RightWhale]

microwaves will heat the atmosphere.

I don't know if this is true to a measureable degree. They may be partially absorbed by water vapor at some wavelengths. In any case, the intent is to use an infinitesimal portion of the sun's radiation that is now going to waste, which is not power from the moon's gravitational potential. Not to say there isn't considerable power stored in the moon's kinetic energy if it can be released.

[StriperSniper]

Shhh! LOL! ;-)

[RightWhale]

a long extension cord

Not far-fetched at all. Technology is getting close to being able to build the space elevator. That is based on a long, flexible fiber attached at the equator to the earth and reaching to geosync orbit and somewhat beyond. Getting power down a 20 thousand mile cord might be a chore since high tension power lines have a practical transmission limit of about 300 miles due to line losses, but that might be just another engineering problem.

[Dinsdale]

high tension power lines have a practical transmission limit of about 300 miles due to line losses

Not really true. Losses are a function of length, current and the resistance of the lines. But if you have a large enough price difference transmission lines can be any length.

[XBob]

22 - "It's just an engineering problem. Let the engineering department work up a solution or two and put a price on it. "

Well, how about doing some extrapolation for us. We just launched a single I-beam, 40 feet long, and 240 miles into space. It cost $600 million, for this one beam. I don't know if launch costs were included in that or not.

Now, how much do you think building a moon based power plant would cost?

[Brett66]

I could see space solar power becoming a substantial industry if it's done in incremental steps. One city may purchase a SPS to supply some or all of it's power needs. City by city the companies that supply the SPS can take over the world. This can't happen with NASA or the shuttle of course, it will require far more economical launch vehicles to begin this process and private industry has to do it. A government program simply isn't capable of doing this. I think any substantial future solar power stations on the moon will be there as a result of demand by space industries, not by central planning by some goofy government beuracrats.

I also wonder how solar power would compete with nuclear power on the moon. If a lunar nuclear facility sets up operation on the moon would it not be easier to build than a massive solar array? That power could be transmitted anywhere in cis-lunar space just as easily. If they built a integrated breeder reactor to make a virtually closed-cycle nuclear process, virtually no new material would have to be mined and perhaps the breeder reactor could recieve nuclear waste from Earth for a fee. It could make money recieving nuclear waste and transmitting the power to whoever needs it. From a business perspective, a nuclear power plant may make more sense, especially if it's not subject to a million enviro-luddite regulations.

[NotJustAnotherPrettyFace]

Yes, sounds like a scenario in Sim City, doesn't it? :-)

[Brett66]

Also a nuclear reactor can be producing power and generating revenue during the lunar night. That would be a huge advantage. Only a limited number of solar arrays could be built at the limited spots on the Lunar surface that provide sunlight 24/7.

[RightWhale]

how much do you think building a moon based power plant would cost?

I don't know. My space development field is asteroid mining; I can give you some numbers for asteroid mining.

[RightWhale]

From a business perspective, a nuclear power plant may make more sense

I agree totally. A compact nuclear plant versus a huge solar cell array would be no contest.

[LibWhacker]

The Moon receives 13,000 TW of power from the sun. Criswell suggests that harnessing just 1% of the solar power and directing it toward Earth could replace fossil fuel power plants on Earth.

Doesn't this imply that 1% of the Moon's surface would have to be covered with solar cells? If so, that's an ENORMOUS project, in as much as the Moon's surface area is about equal to that of Africa's (imagine panelling over the entire continent of Africa!). Just guessing, but I doubt that any engineering feat approaching even a fraction of that magnitude has ever been accomplished on Earth (ito man-hours, cost, you name it).

[RightWhale]

Doesn't this imply that 1% of the Moon's surface would have to be covered with solar cells?

Even more if they want a steady power output throughout the lunar diurnal cycle. It would be a huge project, but it might be manageable if they find efficiencies of scale.

[LibWhacker]

. . . imagine panelling over the entire continent of Africa

Oops! I meant 1% of Africa. What's that equivalent to, panelling over the entire state of Rhode Island? Still a mighty big project.

[supercat]

More basically the solar flux on the moon is only higher then on earth by the atmospheric loss. If solar cells become economic (which is closer then most think, one more halving of cost, cost per watt looks kind of like Moores law) why not just put them on the earth.

Putting a solar array in geosynchronous orbit would not only be much cheaper than putting one on the moon; it would also be much better. A solar array in geosynchronous orbit would produce energy all day long except for a brief time during the night when it was eclipsed by the earth. Much better than the 50% duty cycles available on earth or the Moon. Still probably not worth the extra cost compared with putting one on earth, but at least halfway reasonable.