Re : Lunar Solar Power Stations vs. The Glaser Proposal

For what it's worth, here's the reply I wrote out a couple of years ago
to somebody else who had asked about the Lunar Power system proposal.
===
I like Dave Criswell; I agree completely with the approach of doing
wide-ranging thinking and considering ideas that are beyond the current
technological horizon. There are certain to be some great ideas out
there we haven't yet thought of, and it's important not to circumscribe
our thinking a-priori.

Nevertheless, Criswell and Waldron's concept of Lunar-Solar power is an
idea that is unworkable on so many different levels that I am
flabbergasted that anybody seriously proposes it. I like thinking about
grand concepts like this, but once you've done the back of the envelope
calculations and show that it isn't workable, the idea is to sort out
the ideas that don't work and move on.

Half of the moon is in shadow at any given time. Lunar solar power
loses by a factor of two right off the bat. You lose another factor of
pi from the fact that lunar solar power has to be flat on the surface
(you run against the thinned-array curse if it's not). You lose another
factor because temperature goes up by the fourth-root-of-two because a
flat solar array doesn't radiate off the back. So before you've even
started, you're down by something like a factor of ten in power per
unit area.

Because of the day-night cycle of the moon, even if you put one power
station on the east limb and one on the west, you're going to get a
significant variation in power level over the course of a month, and
power will drop to ZERO during the new moon. If you know anything about
electrical power price structuring, you know that you can't have your
power system go down once a month for a couple of days. If you do, you
will be selling junk power, which gets sold at avoided-cost prices--
essentially, you're selling into a very low-paying market.

Worse, the moon is ten times farther than geosynchronous orbit. This
means beaming aperature areas go up by a factor of a hundred (counting
that you need a minimum of two stations, two hundred.) The economic
viability of large projects depends entirely on the initial investment,
and I don't think that there's any possible way to increase initial
investment by a factor of two hundred (at least!) and make it pay. Not
at current interest rates, and not at any possible discount rate I can
imagine-- certainly not at venture capital rates!

Worse yet, the moon doesn't stay over any particular point on the
Earth. You are going to need power relays, probably in geosynchronous
Earth orbit, or else your power doesn't get to the ground station. I've
seen analyses of geosynchronous relay stations. It's almost much as
expensive to make a relay station as it is to make a solar power
satellite.

The idea just doesn't make sense.

If you really are interested in promoting lunar solar power, however,
and think that these objections may be overcome one way or another, it
is quite obvious that the initial stepping stone is orbiting solar
power. Lunar solar power beamed the Earth, if it works at all, would be
a follow-on to GEO solar power beamed to Earth, not instead-of. The
stepping stones are
1. terrestrial solar niche markets
2. terrestrial solar baseload markets
3. orbital solar (SSPS)
4. lunar solar.
--
Geoffrey A. Landis
http://www.sff.net/people/geoffrey.landis

.

Relevant Pages

  • Lunar Solar Power and Supplying global commercial power
    ... I just read your 14 June 2006 comments on the Lunar Solar Power System ...
    (sci.space.policy)
  • Re: Solar powered airplanes
    ... Solar Cells have been around for 40 years or so. ... sats use solar power. ... Having said that solar powered aircraft may potentially fly higher ...
    (rec.aviation.military)
  • Solar Az.
    ... would be the single largest solar power plant on the ... Solana, with its thermal energy storage, will be able to ... solar power generated in the world's deserts could ...
    (alt.gathering.rainbow)
  • Re: Farking Canadian Eco Sabotage
    ... energy per capita as we are presently doing not to mention the ... So we could probably set up a really nice power grid that MIGHT work ... I doubt you could buy a new copy of the current global power generation ... so solar power wouldn't be all that scary. ...
    (rec.bicycles.racing)
  • PATAKI BACKS WIND AND SOLAR POWER
    ... Pataki Backs Wind and Solar Power ... Although New York already produces more renewable energy than many ...
    (sci.energy)