The digital asset sector is under pressure to improve its environmental record, despite new data showing Bitcoin now sources 52% of its energy from sustainable inputs while consuming close to 1% of global electricity.
Industry leaders warn that the remaining 48% reliance on fossil fuels continues to weaken sustainability claims, with calls for faster progress across the crypto ecosystem.
Speaking on the Blockchain Bulletin Unchained podcast, Kirstine Harrison, Sustainability Director at Zumo, said electricity remains the sector’s only material environmental input, making emissions, not just consumption, the key metric.
Bitcoin accounts for around 80% of total sector electricity use, producing an estimated 40 megatons of CO2 annually, roughly half of UK transport emissions.
“My challenge back to the industry is we say we are one of the biggest users of renewable electricity, but we can do better,” Harrison said. “If 48% cannot be classed as sustainable, there is still work to do.”
Regulation is tightening. The EU’s Markets in Crypto-Assets (MiCA) framework now requires token issuers to disclose sustainability metrics in white papers, while Crypto Asset Service Providers must report energy use and carbon footprint data for listed assets.
The sector has highlighted progress in other areas. Ethereum reduced its electricity consumption by over 99% following its shift to proof-of-stake. However, Bitcoin’s decentralised model limits similar protocol changes.
Instead, improvements are operational. Mining firms are using stranded renewable energy, capturing methane emissions, and supporting grid stability through flexible load balancing, particularly in markets such as Texas.
Harrison added that while innovation remains strong, the sector must move beyond isolated gains and deliver consistent, measurable reductions in emissions to support long-term sustainability claims.
