Bitcoin, energy & the environment: what the data really shows

Nobody disputes that Bitcoin uses a lot of electricity. What is disputed is exactly how much, where the electricity comes from and what that means for the climate.

Why Bitcoin needs electricity

MinersGlossaryMiningThe process in which specialised computers create new blocks using proof of work. In doing so, miners confirm transactions and are rewarded with newly created bitcoin plus the fees of the transactions in the block.In the glossary →× bundle transactions into blocks. For each block they have to solve a computational puzzle that can only be cracked through a huge number of attempts – a process called proof of workGlossaryProof of workThe method by which miners prove that they have done real computing work for a new block. It lets the network agree on the valid chain without a central authority, and makes rewriting old blocks extremely expensive.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →×.^[11] Anyone who wanted to change the blockchainGlossaryBlockchainBitcoin’s public ledger: a chain of blocks in which each block refers to its predecessor. Anyone wanting to change an old entry would have to recreate all the blocks that follow it.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →× after the fact would have to redo this work for the altered block and every block after it, while overtaking the honest miners. That is exactly what makes attacks so expensive.^[11] How the puzzle works is explained in Mining & proof of work.

How much electricity flows in total depends mainly on miners’ revenue from the block reward and fees.^[5] If the price rises, more mining becomes worthwhile, and consumption tends to rise with it.

How much electricity? The Cambridge estimate

The most frequently cited source is the Cambridge Bitcoin Electricity Consumption Index (CBECI). It estimates consumption from the network’s hashrateGlossaryHashrate (computing power)How many hash attempts per second a mining device or the whole network makes. The network hashrate shows how much computing work secures Bitcoin.In the glossary →× (currently 969 EH/s) and the efficiency of the machines that still pay off at an assumed electricity price of $0.05 per kWh.^[1]

≈ 153 TWh

electricity consumption per year (best estimate)

CBECI, as of 28 September 2026

79–295 TWh

range between lower and upper bound

CBECI, as of 28 September 2026

≈ 29%

of Germany’s electricity consumption in 2025

own calculation: 153 of 526 TWh

The lower bound assumes that all miners use the most efficient machines, the upper bound the least efficient ones that are still just about profitable.^[1] No one knows exactly which machines are running around the world. The only serious statement is therefore one with a range.

For comparison: Germany’s gross electricity consumption in 2025 was around 526 TWh.^[2] Cambridge’s best estimate comes to almost 30% of that (own calculation).

The figure fluctuates considerably, partly because the index is based on the machines’ profitability. On 18 October 2025, the best estimate was still around 227 TWh (own analysis of the index data).^[1]

Other estimates compared

Source	Method	Electricity per year	As of
Cambridge CBECI	hashrate × machine efficiency	≈ 153 TWh (79–295)[1]	28 Sep 2026
Digiconomist (de Vries)	derived from miners’ revenue	≈ 204 TWh, comparable to Thailand[5]	accessed 28 Sep 2026
Cambridge survey	mining companies’ data, extrapolated	≈ 138 TWh, around 0.5% of global electricity[3]	mid-2024

The figures are of the same order of magnitude. The differences come from the assumptions.

Where does the electricity come from?

For the climate, what counts is how the electricity is generated. Cambridge worked this through in 2022: the same consumption would produce around 2 million tonnes of CO₂ equivalent a year with pure hydropower, and around 95 million tonnes with pure coal power – more than 47 times as much.^[4]

What the miners themselves report

In mid-2024, Cambridge surveyed 49 mining companies that together account for around 48% of global hashrate. The results were published in April 2025.^[3]

Energy source	CBECI model (2022 location data)	2024 survey
Sustainable (renewables and nuclear)	37.6%	52.4% – of which 42.6% renewables, 9.8% nuclear
Natural gas	25.0%	38.2%
Coal	36.6%	8.9%

Extrapolated to the whole network, that comes to around 39.8 million tonnes of CO₂ equivalent a year, about 0.08% of global greenhouse gas emissions. 75.4% of the reported activity is in the USA.^[3]

The coal share is far below the model figure. Cambridge attributes the gap mainly to the model still using location data from early 2022, while mining locations have shifted considerably since then.^[3] The survey’s limits: the data are self-reported, and just over half of the hashrate is missing.

What independent studies find

A study in Nature Communications examined the 34 largest US mines. From mid-2022 to mid-2023 they used 32.3 TWh, 85% of it from fossil-fuel power plants that responded to the additional demand. Around 1.9 million people in the USA were exposed to additional fine particulate pollution as a result.^[6]

The Digiconomist index arrives at around 114 million tonnes of CO₂ a year, comparable to Czechia.^[5]

The dispute over ‘electricity per transaction’

The Digiconomist index gives around 820 kWh per transaction – as much as a US household uses in about 28 days (as of 28 September 2026).^[5] Mathematically that is correct: total consumption divided by the number of transactions.

But consumption depends on miners’ revenue, not on the number of transactions.^[5] One additional transfer barely increases it, and the Lightning NetworkGlossaryLightning NetworkA second layer on top of Bitcoin for fast, low-cost payments. Amounts move off the blockchain via payment channels; only opening and closing a channel ends up in a block as a normal transaction.On the learning path: Stage 1 · Step 3 – How does Bitcoin work? →In the glossary →× can bundle many payments. So the figure works as a comparison of scale, not as a measure of your individual payment. Total consumption remains high all the same.

Dive deeperNot just electricity: electronic waste

Mining machines (ASICs) can only mine and become obsolete quickly. Digiconomist estimates around 21,000 tonnes of electronic waste a year, comparable to the small IT equipment waste of the Netherlands.^[5]

For 2024, Cambridge arrives at only around 2,300 tonnes: according to the survey, 86.9% of retired machines are resold, repurposed or recycled.^[3] Here too, self-reported data stand against a model calculation.

Flare gas and grid stability: the arguments in favour, checked

Flare gas and methane

Oil and gas wells release methane. Where a pipeline would be too expensive, it is flared or vented unused. Over 100 years, methane is 27 to 30 times as potent as CO₂; over 20 years, around 80 times.^[7]

Mining companies are testing ways to turn such methane into electricity at wells and landfill sites. The White House’s 2022 climate report distinguishes:^[7]

• Generating power from methane that was previously vented tends to help the climate, because methane is turned into the less harmful CO₂.
• If a mine merely replaces an existing flare, CO₂ emissions probably change little.
• Alternatives count too: the gas could be put to other uses, for example via a pipeline.

Critics such as development researcher Peter Howson warned back in 2021 that mining makes fossil energy more profitable instead of encouraging renewable infrastructure.^[8]

Grid stability and demand response

Miners can cut their consumption quickly. Grid operators pay large consumers to draw less electricity when supply is tight.^[7] An example from Texas: during a heatwave in August 2023, Riot Platforms cut its consumption at peak times by more than 95%. For this it received credits of $31.7 million – by Riot’s own calculation around 1,136 BTC, more than three times the 333 BTC it mined in the same month.^[9]

The flip side: mines add to the peak load that often makes such interventions necessary in the first place. The White House report sees perverse incentives here and calls for transparency about the payments. It also refers to media reports of mining companies keeping fossil-fuel power plants from closing or bringing them back into operation.^[7]

A modelling study of the Texas electricity market reaches a mixed conclusion: mining can encourage the expansion of renewable capacity, but increases CO₂ emissions. If miners curtail flexibly, this effect is largely mitigated.^[10]

What does this mean for you?

Whether the consumption bothers you is a question of values. Supporters see it as the price of a monetary system without an issuer; critics consider it disproportionate as long as a lot of fossil-fuel electricity is involved. Blanket verdicts such as ‘green’ or ‘climate killer’ don’t do justice to the data.

• Look for the range, date and method. A figure without them is almost always too simple.
• Read your exchangeTermExchange (crypto exchange)A trading platform where buyers and sellers trade bitcoin with each other via an order book.On the learning path: Stage 4 · Step 2 – Choosing a provider →In the glossary →AdLicensed providers with a paid linkProviders from our comparisonKrakenExchange · MiCA (Central Bank of Ireland)Visit Kraken* (paid link, opens in a new window)BitvavoExchange · MiCA (AFM, Netherlands)Visit Bitvavo* (paid link, opens in a new window)CoinbaseExchange · MiCA (CSSF, Luxembourg)Visit Coinbase* (paid link, opens in a new window)All 7 compared – including non-partners →*Paid link: if you sign up or buy through it, we earn a commission. Your price stays the same. How we make money →18+ · Crypto assets are highly volatile; you could lose all your money. No deposit protection.×’s mandatory disclosures. In the EU, crypto-asset service providers authorised under MiCA must publish prominently on their website the principal adverse climate and environmental impacts of the consensus mechanism – for every crypto-asset they offer.^[12]

What’s next?