Sustainable Energy Powers Over 52% of Bitcoin Mining as Cambridge Report Confirms Industry Shift

A landmark report from the Cambridge Centre for Alternative Finance (CCAF) published on August 29, 2025, confirms that 52.4% of Bitcoin mining now runs on sustainable energy sources, marking a pivotal milestone in the industry’s ongoing transformation from its coal-powered origins to a cleaner, more efficient future.

TL;DR

• Cambridge CCAF report confirms 52.4% of Bitcoin mining uses sustainable energy
• Natural gas (38.2%) overtakes coal (8.9%) as the dominant energy source
• Bitcoin hashrate holds at 930 EH/s with 60% controlled by Foundry USA and AntPool
• Ethereum staking reaches 38 million ETH (31% of supply) with compressed yields
• Antminer S21 Pro and WhatsMiner M66S+ drive network efficiency to record 13.5 J/TH

The Energy Mix Revolution

The numbers tell a striking story of transformation. According to the Cambridge data, natural gas at 38.2% has officially dethroned coal — which now accounts for just 8.9% of the mining energy mix — as the single largest energy source powering the Bitcoin network. The rapid adoption of flared-gas mitigation technologies, which capture and utilize methane that would otherwise be burned off at oil wells, has been a major driver of this shift.

Hydroelectric power continues to contribute significantly, particularly in regions like Sichuan, Quebec, and parts of Scandinavia. Solar and wind installations at mining sites in Texas, West Texas, and the Australian outback have also scaled considerably throughout 2025, aided by declining renewable energy costs and favorable regulatory frameworks in several jurisdictions.

The 52.4% sustainable threshold is notable because it represents a tipping point — for the first time, the majority of Bitcoin’s energy consumption can be classified as environmentally preferable. This figure has climbed steadily from roughly 39% in early 2023, driven by miner migrations away from coal-heavy regions and aggressive investment in renewable infrastructure.

Hashrate Consolidation and the Efficiency Arms Race

The Bitcoin network’s hashrate holds at approximately 930 EH/s on a 7-day moving average, slightly below the April 2025 peak that briefly touched 1 Zettahash per second. But behind the headline number, the composition of that hashrate is changing dramatically.

Foundry USA and AntPool now control a combined 60% of global Bitcoin hashrate, reaching a new peak in mining pool consolidation. Smaller pools are struggling to keep pace as the deployment of next-generation hardware — particularly the Bitmain Antminer S21 Pro (234 TH/s) and the MicroBT WhatsMiner M66S+ — requires capital investments that only the largest operators can sustain.

These new machines have pushed average network energy efficiency to a record 13.5–17 J/TH, a dramatic improvement from the 25–30 J/TH range that was standard just two years ago. The efficiency gains partially offset the revenue compression that followed the 2024 halving, allowing well-equipped miners to maintain profitability even as block rewards sit at 3.125 BTC.

Ethereum Staking Reaches Saturation Point

On the proof-of-stake side, Ethereum’s staking ecosystem is approaching a critical inflection point. The total ETH supply staked has reached 38 million ETH, approximately 31% of the total supply, creating a record-long entry queue for new validators. Annualized staking yields have compressed to 2.83%–3.03%, a natural consequence of increasing participation diluting individual rewards.

Institutional staking providers are adapting to this environment. Bit Digital (BTBT) reported that 86% of its 121,252 ETH holdings are actively staked, generating nearly $100 million in annualized revenue at current prices above $4,300. Meanwhile, Bitmine launched its MAVAN platform targeting institutional stakers with sophisticated yield optimization strategies and risk management tools.

The compressed yields are pushing staking providers to explore additional revenue streams, including MEV (Maximal Extractable Value) optimization and restaking protocols that allow validators to secure multiple networks simultaneously, amplifying their effective yield beyond the base staking rate.

The Carbon Paradox

Despite the encouraging shift toward sustainable energy, the Cambridge report highlights a sobering paradox. The total carbon footprint of the Bitcoin network for 2025 is estimated at 98 million metric tons of CO2, roughly equivalent to the annual emissions of Qatar. The sheer scale of the 900+ EH/s hashrate means that even with a majority-clean energy mix, absolute emissions remain significant.

This tension between relative improvement and absolute impact is likely to define the next phase of the sustainability debate. Mining advocates point to the 52.4% figure as evidence of genuine progress, while critics argue that the network’s total energy consumption — estimated at 175 TWh annually — continues to grow in absolute terms as hashrate expands.

Why This Matters

The Cambridge report is the most credible and widely cited source on Bitcoin’s energy consumption, and crossing the 50% sustainable threshold fundamentally changes the narrative around mining’s environmental impact. For institutional investors considering exposure to Bitcoin mining — whether through direct investment, public mining companies, or the newly announced ABTC listing — the improved energy mix reduces ESG-related risk and makes the sector more palatable to a broader range of capital allocators.

At the same time, the concentration of hashrate in two pools and the hardware efficiency arms race underscore the increasingly industrial nature of Bitcoin mining. The days of hobbyist miners contributing meaningfully to network security are effectively over, replaced by professional operations running multi-megawatt facilities with sophisticated energy procurement strategies.

This article is for informational purposes only and does not constitute financial advice. Always do your own research before making investment decisions.