Best miners to mince Bitcoin with renewable energy sources like water energy z solar energy and other such energy that can be generated free.
I would not call them free energy. Especially if OP needs to set it up on his own. It might be even more expensive compared to a traditional electricity source, at least in the beginning. At the end of the day, what matters the most is profit and how long it takes to break even so you can start earning money from mining, so if OP can only get power from the grid but it is cheap enough then it is fine to do so.
Also, be careful of those hosted mining services. Some of them have unclear backgrounds and even if they have photos of their mining site, they might be fake. I've seen many scams centered around this kind of service where at the end of the day they stop the business without giving any meaningful ROI to its users.
OP, other than electricity cost, you might want to also look for their stance on Bitcoin, taxes, mining regulation, and so on in general. Some country has detailed regulation for mining while others don't. As far as I know, your earnings might be affected by this, especially if you need to do taxes. CMIIW.
