Bitcoin Forum

Bitcoin mining is often criticized for consuming far too much electricity, especially considering how high current prices are in most parts of the world. For many people, the electricity costs far outweigh any possible earnings from Bitcoin mining, unless they have access to cheaper electricity. The time has come for Bitcoin miners to take a closer look at renewable energy sources, as this seems to be the way forward as far as generating electricity is concerned.   

http://themerkle.com/news/is-renewable-energy-the-future-of-bitcoin-mining/

Even with free electricity from renewable sources, it is still very diffecult to make profit from mining because efficient miner are expensive and to produce renewable energy it needs some expensive tools