You could always generate your own electricity. I have successfully built large clusters that are nothing more than a stack of motherboards with low power (consumption) CPUs.
These systems are all DC (every computer is DC under the hood) and can be powered easily 12VDC with some 5v regulators in there. Systems like these can be easily powered with arrays of batteries with solar or wind generation to trickle charge the batteries during the day/windy periods.
Essentially I could generate/participate cheaper (in the long run of course) with a setup like this one. Assuming that electricity prices will climb over the next 10 years and that I’d only have to change out the obsolete systems every 4 or so I could possibly come out ahead.
Still haven’t ran all of the math yet. 😛 Also predicting future electricity costs is a hard thing to do.