So how much does it cost to mine one Bitcoin? Assuming a 76% increase in difficulty per month, .15$/kWh, and a 2% pool fee:
So. 76% per month. Thats 88238% per year.
So in 5 years the hashrate will be ~3,765,807,437,718,645,270,000,000,000,000 hashes per second, and with the current 110MH/j miners thats a power consumption of 34,234,613,070,169,502,454,545 watts.
This is the energetic equivalent of exploding 8182 gigatonns of TNT every second.
But since the sun produces 4e26 watts, I can't see how this isn't totally feasible... we just need to build a solar array with a radius of roughly the same radius of the earth to trail us in orbit and catch light from the sun.