United States-based energy producer Exxon Mobil has reportedly been running a pilot program aimed at using the energy from excess gas to power crypto mining rigs — and it may be expanding its operations to four other countries.

In a Thursday report, Bloomberg said Exxon Mobil had inked a deal with Crusoe Energy to use excess gas from oil wells in North Dakota to run Bitcoin (BTC) miners. The project reportedly uses 18 million cubic feet of natural gas per month — roughly 0.4% of the oil giant’s reported operations in the state, producing 158 million cubic feet of natural gas each day.

The company launched the pilot program in January 2021 and is now reportedly considering expanding to Nigeria, Argentina, Guyana, and Germany in addition to launching a similar project in Alaska. Cointelegraph reported in February that oil and gas giant ConocoPhillips was running a program selling excess gas to third-party BTC miners for fuel.

Transporting natural gas requires pipelines which cannot always safely accommodate the amount produced. Companies are often forced to burn off any excess gas or vent it into the air, ultimately harming the environment and the firms’ profit margins.

“It is creating use of what would be otherwise wasted,” said Danielle Fugere, president of environmental shareholder advocacy group As You Sow, referring to the energy being diverted to Bitcoin miners.

According to a report from Argus Media, Crusoe Energy operated 60 data centers for crypto mining across four U.S. states as of September 2021 powered by “gas from the oil wells that would otherwise be flared on site.” Instead of burning off the gas, diverting it to crypto mining reportedly reduces carbon dioxide-equivalent emissions “by as much as 63%.”

3/ @CoinSharesCo estimates that 69 TWh of wasted power in the U.S. is lost annually to flaring

Through #Bitcoin mining data centers, like those provided by @CrusoeEnergy & @upstreamdatainc, wasted flared energy can be repurposed but it can also reduce CO2 emissions. pic.twitter.com/2XjeFynrI7

— Messari (@MessariCrypto) March 6, 2022

Related: Stranded no more? Bitcoin miners could help solve Big Oil’s gas problem

Though the Bakken shale basin in North Dakota is a major source of natural gas for the United States, Texas is also home to many oil and gas companies in addition to crypto mining firms seeing the potential for energy production in the state. In contrast, New York lawmakers have proposed suspending proof-of-work mining powered by fossil fuels in response to critics citing environmental concerns.