The Bitcoin Mining Council's (BMC) energy data, claiming 59.9% sustainable power use in H1 2023, has faced scrutiny from third-party audits. Reports, such as one from Batcoinz, highlight discrepancies, with the Cambridge Centre for Alternative Finance (CCAF) estimating a lower 37.6% zero-emission energy share. The variance stems from BMC's reliance on self-reported data, potentially inflating figures, while CCAF excludes off-grid and flared-gas mining. Batcoinz's analysis, using public data, suggests Bitcoin’s sustainable energy proportion is around 52.6%, indicating BMC’s data may be overstated by roughly 7.2%. Critics argue BMC's methodology lacks transparency, and no comprehensive third-party audit has fully validated their claims, leaving the exact proportion of questioned data unclear but significant.