"Sorry but there is nobody on the lunar surface able to buy 100 cents per KwH."

Nor is there anyone producing power on the Moon that can sell it on the Moon. But if there was power availiable on the Moon it would be quite easy to find parties interested buying and buying large quantities if the price was 100 cent per kw/h. I would say that 1000 cent per kw/h would be a very cheap price on the Moon- in near term.

"And just try raising the initial $9B for the prototype plane from private capital."

That's the Professor's problem. I'm simply pointing out the obvious- there is a better market on the Moon for power produced on the Moon

"There's a reason we don't have commercial space development.
Answer: Many many alternative lower risk, higher reward investments for pvt capital."

This is true, but it doesn't have to remain this way forever. If NASA could determine with more certainty the existance of water ice on the Lunar pole this could change the perception of risk. That alone may not be enough to foster commerical interest in space development, but if our government had any sense it could do various things which bring about an environment which would be favorable to commerical space development. The problem is not technological, or even economical but is mainly political. One political problem is do we actually want large economic growth which doesn't neccesarily revolve around cheap human labor or resources?
-gb