QUESTION:
What kind of power will they use on Mars?

ANSWER from Geoff Briggs on October 28, 1999:
This is a key question regarding ultimate self-sufficiency of a human crew
at a Mars base -- and no certain answer is yet available.

A nuclear reactor, transported to Mars cold and started up there, would be
perfectly safe and would be a very compact source of power.  So, this would
probably be the ideal power source for early human missions to initiate a
Mars base.   Lifetime would be about 10 years.  Used reactors would have to
be safely disposed of and replaced.

Solar panels would have to cover very large areas (because the intensity of
sunlight at Mars is about half that at Earth) to provide power in quantity,
would require a power storage capability to deal with night-time and with
dust storms.  The panels would also have to be cleaned of accumulated dust.
And present panels don't last forever.  So, we have to look for
improvements here to make a system practical.  Maybe solar cells could be
manufactured at a Mars base one day.

Windmills may not be out of the question but the martian atmosphere is very
thin and so windmills would have to be very large to generate significant
power.  I have not seen a quantitative analysis but I suspect windmills are
too challenging.

Perhaps we may find hydrothermal areas on Mars where the internal heat of
the planet (in effect subsurface volcanism) heats subsurface water as in
places like Yellowstone National Park.  A source of hot water would be a
very useful source of power.  We don't know whether Mars has such activity.

Conceivably we might find sources of subsurface methane on Mars but you
could not burn this gas in the carbon dioxide atmosphere so such "natural
gas" even if discovered would not be a a power source.