This has always seemed to me like an obvious setup for anyone with enough solar capacity to routinely run a surplus - particularly in states where the local utilities have purchased legislative support for near-punituve connection charges or effectively zero rates for anyone interested in selling surplus power back into the grid.
Edit: Not an outdoor setup but a setup to use all electricity surplus to regular needs for mining instead.
How does that compare to selling the excess power then putting the money into a (let's say) index fund? I have no data right now, so I don't have the answer.
I'm thinking specifically about states like Arizona, though I'm not sure of the current situation there being >1000 miles away. I know they had attempts to add a $100/month fee for connecting solar systems to the grid, plus assorted other licensing and regulatory requirements.
Mining equipment can also be older models no longer cost effective to mine with when you're paying for utility power.
If anyone's still checking a thread a few days old, I was talking about things like Florida's requirement that even if you're capable of being fully independent you be connected to the grid: http://www.wftv.com/news/local/want-solar-panels-you-still-h...
A side effect of that is that if the grid is down, you're also required to shut down your solar system (which makes complete sense, it's a safety thing to not have power sources connected while there's work being done) except that you're apparently not allowed to disconnect.
Discussion on [1] notes that disconnectable systems can be quite a bit more expensive, but it sounds like that's not even a legal option - no connection, no occupancy.
Seems inefficient as your mining equipment deprecates if not in use.
A more reasonable solution is to just sell that electricity than buy more reasonables. If you pull say a net 5% ROI you double energy produced every 15 years. With the added bonus of creating an income stream for retirement etc.
Edit: Not an outdoor setup but a setup to use all electricity surplus to regular needs for mining instead.