Warren aims at the environmental footprint of Bitcoin miner Greenidge

Senator Elizabeth Warren (D-Mass.)

U.S. Senator Elizabeth Warren questioned Greenidge Generation's (GREE) environmental footprint in its bitcoin mining business in New York State in a detailed letter to public company CEO Jeffrey Kirt on Thursday.

In the letter, Warren told Curt that she was concerned about the company's energy use and the impact on the environment and consumers.

"Given the unusually high energy use and carbon emissions associated with Bitcoin mining, mining operations at Greenidge and other plants raise concerns about their impact on the global environment, local ecosystems and consumer electricity costs," she wrote, asking for a detailed response by Dec. 17.

Earlier this year, Greenidge's New York mining facility came under a lot of criticism. Environmentalists object to the power station burning natural gas to extract bitcoins, and the alleged impact of its cooling system on local lakes. In May, the company announced that it would offset emissions from its rigs through carbon offset credit purchases starting June 1.

Bitcoin miners use a lot of energy to power their operations. To counter this claim, miners have recently been opting for more sustainable energy sources.

A recent survey by the Industry Forum Bitcoin Mining Council found that sustainable electricity has grown from 3 percent in the second quarter to about 58 percent of the industry's total global use in the third quarter. This growth is partly due to the rapid expansion of the North American mining industry and the shift toward sustainable energy and better mining technologies.

However, Warren said bitcoin miners consume as much energy as Denmark, Chile, Argentina and Washington state. "From the beginning of 2019 to May 2021, Bitcoin's estimated annual power consumption has more than tripled," she wrote.

The letter marks the first time Warren has asked miners for information about their operations. "From 2019 to 2020, greenhouse gas emissions from the Dresden plant increased nearly tenfold," she wrote, referring to operations in New York. "By 2020, it emits more than 220,000 tons of carbon dioxide into the atmosphere — the equivalent of 50,000 cars," she added.

Greenidge describes itself on its website as "the first and only carbon-neutral, vertically integrated generator and Bitcoin miner in the United States." The company is also establishing a mining operation in Spartanburg, S.C, which is expected to begin later this month or early next year.

"We look forward to providing a detailed response to senators' questions, sharing how the facility meets all of New York's leading national environmental standards, brings economic opportunity to underserved areas of the state, and is a widely supported local model of crypto mining," a Greenidge spokesperson said in an emailed statement Friday morning.

On Wednesday, Greenidge Generation said it plans to sell $35 million in senior notes that will mature in October 2026 after the company raised $55.2 million on a similar term on Oct. 13.