Proof of work (POW) is data that is costly and time-consuming to produce but easy for others to verify. The Bitcoin POW mechanism is so costly that it consumes the same amount of electricity it takes to power a country like Switzerland in one year. Bitcoin’s current estimated annual electricity consumption is 61.4 TWh, which is also equivalent to 1.5% of the electricity consumed in the United States.
EOS, another cryptocurrency, is leading the way to fix that, but let's first dive into issues with POW.
https://digiconomist.net/bitcoin-energy-consumption
Energy consumption.
Miners contribute computing power (hashes) to the network, which essentially means one hash = one chance. In order for participants to stand a chance to be rewarded, they will contribute a large amount of computing power with hardware setups (mining rigs) to solve cryptographic puzzles. The mechanism for POW introduced qualified voters in a system of anonymous and untrusting parties.
Mineable cryptocurrencies have more than 71% of market value of the top cryptocurrencies . Key players for the ecosystem are miners, developers, decentralized applications (DApps), companies and users leveraging cryptocurrencies as a store or exchange of value. This ecosystem is great, except mining impacts society in terms of overall electricity costs incurred.
Impetus And Challenges For Proof Of Stake
Most non-mineable cryptocurrencies use forms of the proof-of-stake (POS) mechanism. With POS, one coin is equivalent to one chance. In order for anyone to control the network, they will need to own more than 51% of the coins. Anyone can obtain rewards from the network for staking their coins, with some additional factors such as length of time they have staked and so on.....https://www.forbes.com/sites/shermanlee/2018/04/19/bitcoins-energy-consumption-can-power-an-entire-country-but-eos-is-trying-to-fix-that/#7bddc8131bc8
