Bitcoin's energy use

Bitcoin mining uses a lot of electricity. Nobody can meter every miner, so all figures are estimates. In late October 2026 the University of Cambridge's running index put it at about 176 terawatt-hours a year, within a wide range of 90 to 338. Its 2025 report, using data mostly from mid-2024, found about 138, roughly half a percent of the world's electricity. The energy use is by design: the work behind it is what makes the record expensive to rewrite. Whether it is worth it is one of the most argued-about questions in Bitcoin.

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Guesses per second, all miners

…exahashes: billions of billions, estimated from the last 2,016 blocks, about two weeks

Average time between blocks

…this two-week period

Every one of those guesses uses a little electricity. The total rises when more machines switch on and falls when they switch off.

See it on satoshis.watch →

Why it uses energy at all

To add a block, a miner has to show that real work went into it; see how mining works. Anyone wanting to rewrite past payments would have to redo that work faster than all other miners together.

Supporters say this cost is what keeps the record safe: the more work goes into mining, the more an attack would cost. Critics reply that safety depends on no one gathering most of the mining power, not on the amount of electricity itself, and that other designs, such as proof of stake, aim to secure a shared record without heavy energy use. Supporters answer that those designs make different trade-offs.

How much, and from where

Estimates of how much, and when they were made:

Estimate	Figure	Who and when
Running estimate	About 176 TWh a year, range 90 to 338	Cambridge index, read 26 October 2026
Survey	138 TWh a year, about 0.5% of world electricity	Cambridge report, April 2025, survey run June to September 2024
Different model	About 204 TWh a year	Digiconomist, read 26 October 2026

Cambridge's April 2025 report surveyed mining firms behind about 48% of mining power, three quarters of it in the United States. For those firms it found:

Measure	Estimate
Renewables, including hydro	42.6% of their power
Nuclear	9.8%
Natural gas	38.2%, the largest single source
Coal	8.9%, down from 36.6% in 2022
Greenhouse gases	About 40 million tonnes of CO₂ a year, about 0.08% of the world's total. The same report's other method, based on where miners' internet addresses are, gave about 70 million.

These figures come from what miners chose to report, or from models built on assumptions about their machines. They are estimates, not measurements, and none covers all miners.

What critics say

Critics say the electricity is wasted on guessing numbers, and that a large share still comes from fossil fuels. They say mines can raise local power prices and noise, and that the machines become electronic waste within a few years. They point out that the energy-mix figures come from miners themselves, and that clean power used for mining could have gone to other uses. Some countries and regions have limited or banned mining for these reasons.

What supporters say

Supporters say mining can use power nobody else wants: surplus hydro and wind at night, or gas that would otherwise be burned off at oil wells. They point out that mines can switch off quickly when a grid needs the power, and that Cambridge's surveys show the sustainable share rising, from 37.6% in 2022 to 52.4% for the firms it surveyed in 2024.

Energy per payment?

You will see figures for the energy "per transaction", such as about 740 kWh from one widely quoted tracker. People disagree about what they mean. Those who call them misleading say the energy goes into mining blocks, and a block costs about the same to mine whether it holds 500 payments or 5,000, and one transaction can pay many people at once. Those who use them say they are a fair way to share the total among the people using the network, and that as the reward for new coins shrinks, fees from payments will pay for a growing share of mining. Both sides agree that more payments don't directly mean more electricity.