The county of Missoula in Montana has just issued new rules for Cryptocurrency mining that spells trouble in the future for proof of work(POW) coins. The new regulations state that you have to get certification and are only able to expand or establish new mining facilities in heavy or light industrial areas of the county and can only exclusively use renewable energy for mining purposes. This will make mining more expensive and if other areas follow, Proof of Work may soon go out of fashion.