useful links:
https://navcoin.org/
https://navtechservers.com/
sources:
https://digiconomist.net/bitcoin-energy-consumption
https://digiconomist.net/ethereum-energy-consumption
https://www.raspberrypi.org/forums/viewtopic.php?t=18043
https://motherboard.vice.com/en_us/article/ywbbpm/bitcoin-mining-electricity-consumption-ethereum-energy-climate-change
https://www.greentechmedia.com/articles/read/bitcoin-uses-more-energy-than-ireland
https://blockgeeks.com/guides/proof-of-work-vs-proof-of-stake/
https://motherboard.vice.com/en_us/article/d3zn9a/ethereum-mining-transaction-electricity-consumption-bitcoin
https://hackernoon.com/what-is-proof-of-stake-8e0433018256