Bitcoin mining takes a lot of computation, and therefore, a lot of electricity. After the initial Bitcoin boom in China, the lure of cheaper electricity and a more stable power grid has lured many of the world’s Bitcoin mines to the United States. With that shift comes a corresponding shift in the greenhouse gases and other pollutants created by the energy production required for Bitcoin mining.
Now, researchers from Harvard University have shown that Bitcoin mining has added more energy production to the U.S. grid than the amount required by the city of Los Angeles, and brought the accompanying air pollution and environmental concerns as well. They published their work in March in Nature Communications.
Energy Impact of Bitcoin Mining
Bitcoin mines are specialized data centers designed to solve complex cryptographic algorithms. Bitcoin, like any cryptocurrency, runs on a blockchain—a decentralized ledger of transactions. “Mining” Bitcoins is the process of adding an extra “block” at the end of the chain. Adding this extra block is done by solving a cryptographic sequence—which takes a lot of energy due to the amount of computation required.
To understand just how much energy was being used by Bitcoin mines in the U.S., the Harvard researchers analyzed a database of the 34 largest Bitcoin mines in the country—which combined are responsible for 80 percent of U.S. Bitcoin mining capacity. The database contained both the mines’ locations and how much energy was required to operate them. “With that information, we were able to estimate the power plants that were generating more electricity for the Bitcoin mines, find out how much air pollution those plants create, and find out where that pollution goes,” says Scott Delaney, a researcher at the Harvard T. H. Chan School of Public Health.
The study was conducted between August 2022 and July 2023. The researchers found that 32.3 terawatt-hours of electricity were consumed by the 34 Bitcoin mines—for comparison, 33 percent more electricity usage than the entire city of Los Angeles. 84 percent of that power was generated by plants burning fossil fuels. In other words, Bitcoin mining has essentially added a large city’s worth of electricity consumption—and the accompanying pollution.
One of the key findings was that the power plants supplying the Bitcoin mines were often located hundreds of kilometers away. That means that the worst environmental impacts of large-scale Bitcoin mining aren’t occurring near the mines themselves. “The air pollution created by Bitcoin mining is not being breathed by the people near the mine,” says Delaney. “The pollution effects are often felt several states away.”
Health Risks from Bitcoin Pollution
The researchers discovered four key hotspot pockets of air pollution: within New York City and Houston, on the border between Illinois and Kentucky, and northeast Texas, where the concentrations of pollution that can be attributed to Bitcoin are sufficient enough to impact the health of the local population. That means those places could experience increased rates of asthma and other respiratory diseases, cardiac events, hospitalization, and premature mortality.
The researchers found that about 1.9 million people were exposed to more than 0.1 micrograms per cubic meter of additional fine particulate matter pollution from Bitcoin mines. Fine particulate matter, also known as PM2.5 because it is 2.5 micrometers or less in diameter, poses significant risks to human health. That said, Delaney says that the overall concentrations they can attribute to Bitcoin mining are probably not high enough to trigger any health concerns over short-term exposure.
That’s not the case for long-term exposure. After one year of exposure, the researchers expect that people living in the regions with heightened pollution will have measurable health effects―increased mortality or hospitalization rates―due to Bitcoin mining.
There are potentially cleaner options for the future of Bitcoin mining. AI data centers, for example, are turning to nuclear energy. The same strategy could be used to power Bitcoin mines.
However, the cryptocurrency industry has long been contentious, and it remains a largely unregulated industry with no restrictions on environmental impacts. “We need to think about the social value of Bitcoin,” says Delaney. “Not all data centers have the same social value, and we might be less willing to tolerate air pollution from some types of data centers in the future. The social value of Bitcoin is currently up for debate, whereas cloud data centers has already showed their worth.”
Bitcoin mining is only likely to increase in the future as the mining operations have already doubled since this study began in August 2022―especially as it takes more energy and computation to mine Bitcoins as fewer become available in the blockchain. (There’s an upper limit of 21 million Bitcoins that can ever be mined.)
Delaney says that they plan to do a similar kind of study for all types of data centers, including ones dedicated to AI, cloud computing, and data storage. They also want to quantify the specific health impacts of Bitcoin attributable air pollution in the U.S., and hope to create a web-based tool that will help policy makers, data center owners, data center builders, and Bitcoin mining operators to optimize the siting of Bitcoin mines in areas where they will have the least environmental impact.
From Your Site Articles
Related Articles Around the Web
