80 ~ 500 kw/h of power, more than enough to supply a typical family's home for a week is required for each of over 350,000 bitcoin transactions per day. The consumption can literally power a small city! In the primary countries where mining farms are set up, cheap power is supplied by burning coal or oil releasing tons of carbon emissions into the atmosphere. Needless to say, Bitcoin is not a green currency in the slightest.
The "Proof of Work" concept for mining requires ever more expensive equipment producing more waste heat and resulting in the disposal of electronic waste in record quantities. Most electronic components (silica, gold, lead, copper, various acids) are not easily broken down naturally and are difficult to extract and recycle without releasing more toxins into the air.
Between power consumption and the continuous outmoding of equipment, Bitcoin's growth is killing the earth.
What are the Solutions
PoS
Currencies like Ethereum and Cardano have introduced possible solutions to the energy sink by proposing "Proof of Stake" algorithms for verifying blocks. Unfortunately, PoS gives an advantage to miners/pools who carry greater balances of coins, this creates the threat of centralizing a currency that should be decentralized.
Intel's PoET
PoET (Proof of Elapsed Time), is a potential solution except that it relies on a proprietary technology to prevent cheating the chip and again centralizing the currency.
Alternative energy
Using wind, geothermal, solar, or even heat recovery generators (mining creates a lot of heat that can be reused) can help to offset the damage. Unfortunately, increasing difficulties still means used equipment waste.
Changing the Standard
Bitcoin is outgrowing itself, quickly. If we as a community don't take steps to improve it and reduce its negative impact it will burn hot, fast and then out. Either we need to create a system for better and less power/equipment intensive transactions or move to a currency that's better for our world.
