Bitcoin mining’s power appetite surged 38% in six months, and hydropower is now the biggest single source of that electricity, according to preliminary data from the Cambridge Centre for Alternative Finance presented at the Energy Investors Forum in Dallas.
Key figures
- Annualized electricity demand for Bitcoin mining climbed to roughly 190 TWh in December 2025, up from 138 TWh in June 2024 — a jump of about 52 TWh. (Annualized demand extrapolates the December rate over a full year; it doesn’t mean miners consumed exactly 190 TWh during calendar 2025.)
- Low-carbon sources now make up 59.4% of the reported mining mix, up from 52.4% in the previous Cambridge study.
- Estimated greenhouse-gas emissions rose by ~20%, from ~40 million to ~48 million tonnes of CO₂ equivalent.
Hydro takes the lead
Cambridge’s preliminary update reverses the earlier ranking in which natural gas was the largest single fuel. In the 2025 Digital Mining Industry Report, natural gas accounted for 38.2% of surveyed miners’ electricity, renewables 42.6% and nuclear 9.8%, while coal had fallen to 8.9% (down sharply from ~36.6% in 2022). The new survey shows hydropower now ahead of gas, although Cambridge has not yet published a full source-by-source breakdown.
Part of the shift reflects expanded survey coverage in hydro-rich regions. Cambridge’s Alexander Neumueller pointed to stronger response rates from markets such as Ethiopia, where the Grand Ethiopian Renaissance Dam has been tapped to support low-cost mining. Cambridge’s latest estimates are based mainly on responses from miners representing slightly more than half of global Bitcoin hashrate, giving a larger sample than the first report — but final figures may be revised after further checks.
More power, cleaner mix — but emissions still up
Although miners reported a cleaner power mix, that improvement didn’t fully offset the surge in electricity consumption. Increased deployment of mining machines raised total hashrate; while newer rigs are more energy-efficient (more hashes per unit of electricity), efficiency gains didn’t fully counteract the rise in equipment and activity. Cambridge’s Bitcoin Electricity Consumption Index continues to model how prices, fees, equipment and network difficulty influence electricity demand.
Methodology caveats
Cambridge highlights how survey participation can distort geographic and fuel-share estimates. Heavy response from U.S. companies in earlier work likely overstated the U.S. share; better coverage from hydro-heavy markets likely pushed up hydropower’s reported share. The centre also notes wide variance between methods: its earlier survey-based emissions estimate (about 39.8 million tonnes CO₂e) diverged sharply from a location-based model that produced ~69.6 million tonnes — underscoring sensitivity to assumptions around miner location, grid mix, contracts and the use of stranded or flared energy.
Miners eye AI and HPC
The survey also found mining companies are increasingly exploring non-Bitcoin workloads. About 10% of respondents have already allocated some capacity to AI or high-performance computing (HPC), and more than 40% of the remainder are actively exploring it. Nearly nine in ten respondents expect AI and HPC diversification to grow over the next several years. Neumueller cautioned that intent isn’t the same as deployment: AI data centers require costly networking, cooling and reliability that basic mining sites often lack, and AI customers typically need steadier power and service guarantees. Public miners have nonetheless been aggressive: listed companies have announced over $70 billion in AI/HPC contracts, and TeraWulf reported more revenue from HPC hosting ($21m) than Bitcoin mining (under $13m) in Q1 2026.
What’s next
Cambridge plans to publish the second edition of its Digital Mining Industry Report later in 2026 with a full energy breakdown and final methodology. For now, the findings point to two concurrent trends: Bitcoin mining is consuming significantly more electricity, but a larger share of that energy is coming from hydropower and other low-carbon sources — even as total emissions tick upward.
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