#3 wouldn't fix anything in most cases.

If the cost of energy went down, why would they allocate less money to mining? They would still try to allocate the same amounts and reap the maximum reward they can. If all miners had access to cheap energy, then this would happen in tandem with all miners.

The difficulty going down would be a result of miners making the decision to go out of business or temporarily spend less. Over the long run, miners will always use all their allocated energy to mine unless they can predict a future drop in the hashrate where saving energy for a more opportune time makes sense. This would probably only happen if they pay a predictable price for energy rather than generate it themselves since producing and storing energy for later is expensive.