> Once all Bitcoin is mined (yes, there's a built-in maximum), or it becomes prohibitively expensive to mine, there won't be any mining costs.
In that future you will still mine blocks, but there won't be any new bitcoin generated in that block. Sure, you might want to use a different word for that than "mining", but it will still have very real and significant energy.
Re:Bitcoin Energy Consumption Index
by tylersmith on Saturday August 26, 2017 @05:33PM
(#15107605)
"Validators" is the more generic for term what are also called miners or stakers.
Not quite, even when the cap is reached, new blocks will still need to be created for new transactions, which will require proof-of-work to achieve consensus, and thus energy expenditure.
Once all bitcoin is mined, there will still be mining costs, but they'll be 100% paid by tx fees.
Bitcoin will probably look extremely different by then, so most bets are off anyway.
Mining always needs to happen. Once it stops producing coins, the cost burden just moves over to the people using the currency. The mining cost only decreases if the proof-of-work difficulty decreases.
If mining becomes less profitable, fewer people will mine and the proof-of-work will tune to be less difficult, but the cost never disappears and there's still a huge amount of energy wasted in the selection process for adding blocks. If too few people mine the currency will be totally destabilized.
You can look at the current Bitcoin energy costs as the startup cost to establish a new gold mine or a new country with its own currency.