At a typical US energy cost of ~$0.10/kiloWatt hour, an average cubic light-year of space generates $460,000,000 worth of power, according to a post by Phil Plait, Bad Astronomer.
The bright side of a Moon
At a typical US energy cost of ~$0.10/kiloWatt hour, an average cubic light-year of space generates $460,000,000 worth of power, according to a post by Phil Plait, Bad Astronomer.