I would consider finding a partner instead, and then going to your local power company and asking for a cheaper rate for offpeak service. You are probably going to need more volume for this however. If you can get your usage high enough, you can get very good deals for offpeak power, which is incidentally also when temperatures are the coolest.

By doing this, you can conceivably get your average power cost down, and then the ROI will be much better. There are stories of people in Texas being able to get free power in many cases during the wee hours of the morning, when the power companies would otherwise have to pay surrounding states to take it off their grid. I know that sounds counter intuitive, but shutting down baseload generators can be very expensive, so power companies are occasionally put in the position of needing to pay in order to keep the grid functioning above minimum.

So my advice would be to think bigger. Raising money is never fun, but it can make the difference between being profitable and just losing money.