The US Department of Energy (DOE) will begin collecting data on crypto mines’ electricity use, following criticism from environmental advocates over how energy-hungry those operations are.

“We will specifically focus on how the energy demand for cryptocurrency mining is evolving, identify geographic areas of high growth, and quantify the sources of electricity used to meet cryptocurrency mining demand,” Joe DeCarolis, administrator of the Energy Information Administration (EIA), said in a press release today.

The EIA, the statistical agency of the Department of Energy, announced that it is “initiating a provisional survey of electricity consumption information from identified cryptocurrency mining companies” starting next week. The cryptocurrency mining companies will have to comply, per an “emergency collection of data request” the Office of Management and Budget authorized last week.

Getting to this point has been a slog. After a ban on Bitcoin mining in China in 2021, the US became the world’s biggest hub for Bitcoin mining. The mining boom raised flags for lawmakers and activists because of the energy demands of the process. Bitcoin mines managed to resurrect fossil fuel power plants and raise electricity costs for some residents in New York.

In 2022, Democratic lawmakers asked the biggest crypto mining companies in the US to disclose their electricity consumption and associated pollution. None of the companies responded with all the data they were asked to provide, and Congress subsequently asked the DOE and EPA to require that crypto companies publicly share the information.

In letters between the agencies and Democratic lawmakers shared exclusively with The Verge last year, Secretary of Energy Jennifer Granholm wrote a letter to Senator Elizabeth Warren (D-MA) saying that the EIA has the authority to require crypto operations to report their energy use. Doing so would “require development of a new survey to collect this information,” the letter says. It looks like that’s what’s happening now. According to the letter, the EIA can potentially also require utilities to share information about how much electricity they sell to crypto companies.

A spokesperson for the Blockchain Association didn’t immediately respond to a request for comment.