Here are a few simple facts.
1. Approx 90% of bitcoins mined are sold to pay for the electric.
2. That equates to $5 million a day on electric costs, sure some might be green, but some of that that electricity could be used by someone else that subsequently didn't have the green electric.
Miners aren't generating the electricity. They're consuming it. This is an important distinction to make.
To prevent an unreliable power grid, power plants generate electricity above and beyond demand. Miners can actually make power generation less wasteful through
load balancing agreements with power plants.
We should be asking not only what percentage of mining is green, but how much miners are increasing electricity demand
beyond what is already generated. Where miners are causing utility districts and power companies to purchase electricity beyond normal capacity,
that's relevant. The sum total of all mining inputs is
not relevant.
So basically bitcoin must be wasting $2 Billion a year that is in effect environmental damage.
If you actually account for the above, it's probably far less. Miners have incentive to operate where there is excess capacity because electricity costs will be cheaper.
You should also consider what Bitcoin might be replacing. The gold mining and banking industries require huge amounts of energy too, much of which is not green.
