Reply To: A new way of generating electricity

[Tulse]

I’ve done some back-of-the-envelope calculations from:

http://www.asi.org/adb/02/09/he3-intro.html

I get that to meet the energy requirements of the US for a year, one would have to strip mine 200 square kilometres of moon surface to a depth of three metres, digging up and processing using energy intensive processes about two billion tons of regolith to get the 25 tons of He3 needed (He3 is 13 parts per billion in the regolith). All of this will have to be done using heavy duty industrial mining equipment sent into space and landed safely on the moon, and the resulting material will need to be lifted off the moon surface and landed safely on earth.

For reference, strip-mined coal costs about $25/ton, which has to be close to how much it costs to simply move that much material. So if we were simply mining He3 on earth, it would cost approximately $50 billion just to move an amount equivalent to the regolith needed. This ignores the processing requirements, which are massive (since, unlike coal, all that regolith has to be heated to 600 C and the boiled off He3 captured), and ignores that we have to get equipment to move two billion tons of regolith onto the moon, and get the He3 back.

I cannot imagine any reasonable near-term technological advances that would make such a proposition anywhere near an affordable solution. Certainly it would be far cheaper to build solar power satellites, or thorium-based reactors, or vastly expand solar/wind/tidal/wave/geothermal generation.

Or successfully build pB11 fusion generators.