[antpls]

Not 7000km if you settle at one of the pole :

https://en.m.wikipedia.org/wiki/Colonization_of_the_Moon#Pol...

Quote from Wikipedia : "the Moon's axis of rotation is sufficiently close to being perpendicular to the ecliptic plane that the radius of the Moon's polar circles is less than 50 km. Power collection stations could therefore be plausibly located so that at least one is exposed to sunlight at all times, thus making it possible to power polar colonies almost exclusively with solar energy. Solar power would be unavailable only during a lunar eclipse, but these events are relatively brief and absolutely predictable."

[jvanderbot]

Calculate watts/kg for the total system, and be sure to include cost of heating, which comes nearly free with nukes, and you'll lean back to nuclear. The barrier to nukes is usually programmatic, not cost or technical.