U.S. cryptocurrency miners would be required to report greenhouse gas emissions under a new bill submitted to the Senate, reflecting criticism among some lawmakers that the large amount of electricity used to verify transactions on proof-of-work blockchains such as Bitcoin is adding to use of fossil fuels blamed for global warming.

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Fast facts

  • U.S. Senator Edward J. Markey and Representative Jared Huffman said in a Thursday statement that they have submitted the Crypto-Asset Environmental Transparency Act that would require crypto mining operations that consume more than 5 megawatts of power — or most Bitcoin mining projects — to report their carbon dioxide emissions.
  • Senator Jeff Merkley cosponsored the proposed legislation.
  • The lawmakers said Bitcoin miners use as much as 1.4% of U.S. electricity, citing an August report from the White House Office of Science and Technology Policy that says this is equivalent to the power needed to light every home in the country.
  • The bill would also direct the Environmental Protection Agency to lead an interagency study of the environmental impact of crypto mining.
  • Crypto miners countered the criticism of fossil fuel use in an October report published by lobby group Bitcoin Mining Council (BMC) that said the miners had an estimated 59.4% sustainable energy mix in the third quarter of this year, up from the first quarter’s 58.4%.
  • In May, the BMC said in a letter, signed by MicroStrategy Chairman Michael Saylor, that data centers with miners are “no different” than the ones hosted or operated by Amazon, Apple, Google, Meta and Microsoft.

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