If this is true, I would kill for this opportunity. If you truly have free electricity, it's a no brainer in my opinion.
I would probably invest in S7's, you get warranty, better GH/J, and more GH/m2.
If you are not limited by m2/squaremeters, and could get used S5+ from a trusted source, it would probably be a good idea to get some, as they probably give better GH/$.
Surely you have a limit on your free power? In that case I would go for the S7's.
Btw, if this real, I want in.
