How many cards can you run off of that 1600watt psu? How long would it take you to recover the almot $10,000 it would take you to set it up? Also, wind turbines would help tremendously, they're a bit cheaper than solar I think. They're not really an option in my area as we don't get much wind unless it's raining. You could also just go grid-tied and mine for free during the day. That would cut your bill in almost half. Just a thought.