Increase ROI with Solar Power?

[John Berekoff]

So I had this idea the other day and wanted to know what others thought. 

If you place solar panels on a property of yours, and pay them off (or buy them outright) so that all of the energy savings coming from them are not going to making lease payments, would you be able to somehow meter the tenants and charge them the market rate for the electricity being used, keeping the difference as profit?

Keep in mind this is assuming that the panels were actually efficiently producing electricity and significantly reducing the cost of power (solar panels are not always that good at reducing costs in some situations, but for this particular theoretical lets assume they are 100% efficient).

Is anybody doing this? Is it even legal? Or is it just some silly thing I thought of while I was bored? lol 

What do you guys think?