[ExI] High power orbital greenhouses

[Adrian Tymes]

On Wed, Mar 2, 2011 at 4:40 AM, Eugen Leitl <eugen at leitl.org> wrote:
> On Tue, Mar 01, 2011 at 08:22:22PM -0800, spike wrote:
>> Oy that's a lot of people.  I am surprised this old planet can feed all of
>> us.
>
> It can't, actually. Not with today's technology. Not on the long run.

So we improve the technology over time, just like we've always done.

To rip a thought experiment from the game SMAC: suppose you had a
kilometer-long orbital greenhouse, with a vast array of solar panels to
provide all the power you'd need.  (If you need a number, then
extrapolating near-future photovoltaic panels to square kilometer sizes,
assume a few gigawatt-hours per day, distributed among the entire
greenhouse.  More is possible.)  How would it work?  What types of
mass inputs and outputs could you have?  Would capturing a comet
for local water ice help?

Most importantly, could you entirely replace the energy contribution
from fossil fuels with electricity (and locally converted forms thereof,
such as light from electric lamps)?