Bitcoin uses a lot of electricity. That is not a bug: proof of work turns real-world energy into security, so rewriting history would cost an attacker the same energy again.
The numbers (dated)
- The Cambridge Centre for Alternative Finance (CCAF) estimated annual use at about 138 TWh, roughly 0.5% of global electricity (report of April 2025, data mid-2024).
- The same report puts related emissions at about 39.8 Mt CO₂e, about 0.08% of global greenhouse gas emissions.
- For the US, the EIA's preliminary estimate (Feb 2024) was 0.6–2.3% of national electricity use.
Why estimates differ
No one meters every miner. Researchers combine the network hashrate with assumptions about which machines are running. Cambridge keeps a live model (CBECI) with lower, best-guess and upper bounds.
Getting more efficient
CCAF estimated average machine efficiency at 28.2 J/TH in June 2024, 24% better than a year earlier. Efficiency does not shrink total use, because miners add machines while it pays. What it changes is how much security each joule buys.
The honest frame
The question is not "is this a lot?" but "is it worth it?" Bitcoin offers money no one can print or freeze, secured without a central party. Whether that is worth 0.5% of the world's electricity is a judgment each reader can make with the numbers in hand.