Massive energy footprint
A comprehensive study identified 34 Bitcoin mining operations across the US that collectively consume 32.3 terawatt-hours of electricity annually—33% more than LA. Researchers found that 85% of this energy comes from fossil fuel sources, generating significant air pollution.
“Bitcoin mines, which are largely unregulated in the U.S., are an emerging and significant challenge to U.S. environmental health and air pollution regulation,” the researchers wrote in the study.
According to their estimates, 1.9 million people living in four regions were impacted by increased pollution from power plants supplying energy to Bitcoin mining facilities. Those plants are up to thousands of kilometers away from the mines.
Cryptocurrencies such as Bitcoin that run on blockchain can be mined by adding an additional block at the end of the existing chain, which is achieved by solving cryptographic algorithms. Bitcoin mines are data centers aimed exclusively at solving these difficult and multifaceted algorithms, which use enormous computing power, and draw significant amounts of energy.
Crossing state lines
Scott Delaney, who worked on the project, highlighted that air pollution crossing state lines creates regulatory complications inside the US:
“Residents in Metropolis, Illinois, breathe high concentrations of Bitcoin mine-attributable PM2.5 air pollution released from a power plant in Kentucky that supplies a Bitcoin mine in North Carolina. Yet, the Illinois state government has no jurisdiction to regulate activities in either Kentucky or North Carolina.”
These findings raise concerns as increased air pollution is linked to higher rates of mortality, morbidity, and hospitalization—outcomes that policymakers may now be evaluating in connection with cryptocurrency mining operations.
However, the study was not published without pushback. Bitcoin advocates argue that mining operations increasingly use renewable energy sources and are actively working toward decarbonization.
The Digital Assets Research Institute (DARI), which focuses on environmental, social, and governance (ESG) impacts of digital assets, issued a formal rebuttal to Harvard's study. DARI criticized what it called "selective use of data, a flawed method of attributing emissions, and the inappropriate application of marginal emissions calculations," arguing these limitations undermined the study's contribution to research on Bitcoin mining's environmental impact.
Policy gap
As cryptocurrency continues to evolve as a financial asset class, this research underscores the urgent need for coordinated environmental policy that addresses the industry's growing carbon footprint. US regulation that would constrain Bitcoin mining creates operational considerations for companies active in the process, as well as potentially impacting price if the incentive to mine decreases.
Harvard’s latest research was published earlier in Nature Communications.
