Cryptocurrency mining firm Marathon Digital Holdings is using warmth generated at one of its data centers in Finland to power a district heating system.

The pilot scheme will see heat from the company’s 2MW data center in the Satakunta region of Finland put to use in a heating network for some of the area’s 11,000 residents.

Selling recycled heat is seen as a potential “new revenue stream” for Marathon, according to the company, and represents “its mission to leverage its expertise in digital asset compute to support the energy transformation.” It has not disclosed whether it is receiving a fee for the heat being used in the pilot scheme in Finland.

“This pilot project in Finland is a critical step forward in our strategy to expand globally and innovate sustainably,” said Fred Thiel, Marathon’s chairman and CEO. “We are not just producing digital assets; we are heating homes and integrating sustainable practices into our business model. We believe that this kind of innovation can drive the advancement of the digital asset compute industry and further strengthen Marathon's leading position in the field."

Cryptocurrency mining is a hugely energy-intensive process. Cambridge University’s Bitcoin Electricity Consumption Index estimates that the creation of new Bitcoin alone consumes 150tWH of electricity a year.

Marathon Digital claims to have 760MW of mining capacity at its disposal, and though some of this is powered by renewable energy, most of its electricity comes from the main grid in the US which is 80 percent reliant on fossil fuels. As recently as 2021, one of Marathon’s data centers in Montana was receiving low-cost power from a coal-fired power station through a deal with its operator, though the company says it has since moved its mining rigs elsewhere.

Last year it launched a small pilot in Utah, which saw a 280kW Bitcoin set up powered by landfill methane gas.

Adam Swick, Marathon’s chief growth officer, commented: “Following the success of our pilot project in Utah, where we demonstrated that it is both economically viable and environmentally beneficial to use landfill gas for digital asset compute, we have continued to experiment with innovative ways that our operations can add value beyond securing distributed ledgers, like Bitcoin’s.

"This pilot project in Finland is our first attempt to convert the heat that we produce as a byproduct of our operations into a valuable resource for a local community.”

Mawson expands in Pennslyvania

Meanwhile, another cryptocurrency mining business, Mawson Infrastructure, has expanded its data center in Midland, Pennslyvania, by 20MW.

The company signed a colocation customer agreement with Krypton Technologies LLC, and as a result, Mawson is expected to deploy about an additional 5,880 mining units that will further expand its digital colocation services platforms business.

It will take the Midland site’s total operating capacity to 120MW, with a capacity for about 38,810 miners for self-mining or colocation business services.

Rahul Mewawalla, CEO and president of Mawson, said: “Our accelerated growth in our colocation platforms business is driven by our optimizing reliable, efficient, scalable, and sustainable carbon-free digital infrastructure solutions for our enterprise-class customers.”

Mawson also runs an 8.8MW facility in Bellafonte, Pennsylvania.

TeraWulf continues work on Lake Mariner data center campus

Elsewhere, work on a fourth data center building at cryptocurrency company TeraWulf’s Lake Mariner data center campus in New York state is nearing completion.

The company said “building 4” at the campus, which is on the site of the former Lake Mariner coal-fired power station, will be finished this month, and that work on a fifth structure will begin shortly afterward, according to a report in the Niagara Gazette.

TeraWulf says the site draws 90 percent of its energy from hydropower, and that it will eventually offer a capacity of 500MW.

It has been building out capacity at Lake Mariner since it raised $215m across two funding rounds in 2022. The company’s investors include actress Gwyneth Paltrow and other celebrities.