Enterprising the moon...

[Satanic Mechanic]

I'm using my lunch hour to answer some questions.  Deuterium or should I say Heavy Water(D₂O) is very expensive to harvest .  Canada is a big supplier and user of Heavy Water since they use it for their CANDU nuclear reactors as a moderator.  There are many ways to get it but the two most economic ways are through distillation and electrolysis.  If you have abundant hydroelectric power it is easy to setup a system to gather water and separate the light and heavy waters.  Deuterium on average exists 0.015% in water on Earth.

As for electric transmission lines, this is simple since I hear it all the time- it costs one million US dollars to build one mile of high voltage transmission lines.  This is for the steel, labor, land, and environmental impact fees/studies.  This is not including annual maintanance or disruption of service costs.

SM

[DonPMitchell]

Looks like heavy water is going for $600 per liter in bulk.  I have a small botter with a couple ounces of it.

Hydrogen fusion, it anyone ever finds a practical way to achieve it, would have an almost endless supply of fuel, much cheaper than enriched uranium.

[ijuin]

You do have a point there--two-thirds of our planet is underwater, and we have yet to do much with it besides catch the wildlife (fishing), traveling over it, and drilling for oil. Maybe living on/under the water in large cities is not worthwhile, but power generation as you have mentioned, as well as seafloor mining, seem promising.

[Johno]

Wikipedia (not a reliable source) says 85% microwave receiver efficiency, but there is also the transmission efficiency and the solar-to-electricity efficiency.

This is very true.  But since they're predictable, you just have to build a bigger collector.  And remember that the size of the collector is not as limited as it would be on Earth.

My guess is that the cost of building a space-base power generator of this size, plus the cost of building vast microwave collector fields would not be less than just building vast solar power collector fields.

Again, you are correct.  I simply point to the fact that an earthbound collector is useful (AT BEST)  during daylight hours only, assuming good weather all the time.  By comparison, the Space collector is available for power generation practically the entire time.  You get much more use out of each collector (though as you say, the [Still untried] power transmission system  could take a big bite out of those gains).

What surprises me about alternative energy is the apparent practicaly of windmills.  A few years ago I would have said that was a totally hippy dippy idea, but that seems to be where the economics is going, the thing that people are actually building.

I agree, but they're not going to be capable of base-load power, whereas projections of an orbital collector show promise of being able to do just that.  (again, untried - there may be difficulties we haven't foreseen).

[Johno]

With regard to Mr Obama . . I'm sorry to say this, but it would appear that (like Australia's most recent government change) you have selected a government which favours style over substance (though it's by no means certain you were offered an alternative. . .).

Looks good, smells good. . but little actual result.

(Same with our Mr Rudd, I'm afraid).

[Mr Cabal]

With regard to Mr Obama . . I'm sorry to say this, but it would appear that (like Australia's most recent government change) you have selected a government which favours style over substance (though it's by no means certain you were offered an alternative. . .)

Not everything falls on the elected leaders, society as a whole has become unresponsive to developing problems. Every one expects everyone else to fix thier problems.

[DonPMitchell]

I trust in General Electric more than in the government.  If wind turbines are profitable, they will happen.

[jdbenner]

Mr Cabal, I am a big fan of space mining and colonization, but the reality is that there are mager problems with every scheme made so far.

The biggest problem with all plans I have seen for using space resources, is that they turn the normal business plan on it’s head.  That is that instead of trying to look for sources of needed commodities and finding Space, they first choose Space, and then try to find a use for it.

To illustrate my point, let us suppose that someone wants to use the top of mount Everest, so they propose building a power station on the top of that mountain.

The normal way things work, is as follows: Someone finds gold on mount Everest, so there is suddenly new interest in Mount Everest.       

Books on this topic, that I own copies of, and recommend are as follows:

The High Frontier, by Gerard K. O’Neill, ISBN 0-688-03133-1
Colonies in Space, by T.A. Heppenheimer, ISBN 0-8117-0397-5
Moon Rush, by Dennis Wingo, ISBN 1-894959-10-8
And the “Space Manufacturing” series by the Space Studies Institute.  (I have not been able to collect the whole series)

P.S. Remote control machines could mine the moon and build a base without any human presence in space.