Investment firm 3i Infrastructure has acquired a majority stake in Norway’s Lefdal Mine Datacenter (LMD).

Announced this week, 3i has agreed to invest €300 million ($347.3m) to acquire a majority stake in Lefdal Mine. The deal is expected to complete in the summer of 2026.

The data center firm is being acquired from a fund managed by Columbia Threadneedle Investments. The largest investor in that fund will be reinvesting alongside 3i Infrastructure.

First announced in 2015 and opened in 2017, LMD is potentially Europe’s largest data center in floor space with up to 120,000 sqm (1.3 million sq ft) in 75 underground halls – although the vast majority of the old olivine mine caverns remain empty.

Columbia Threadneedle European Sustainable Infrastructure Fund (ESIF) acquired a majority stake in Lefdal Mine Datacenter in 2020 from Rittal.

In April 2023, Lefdal added 60MW power capacity to its underground data center campus, adding a connection to the regional 132 kV power network and increased the available power to the data center from 20MW to 80MW. The site could eventually reach 200MW.

3i said Lefdal has 37MW of operational capacity across its customer base, and a further 43MW of contracted capacity currently under construction.

“The company benefits from Norway’s low-cost and robust power supply, and the company leverages its underground location and closed-loop seawater cooling technology to deliver superior efficiency,” 3i said. “LMD has substantial future growth potential, with only one of its six mine levels currently utilized for data center capacity.”

A small portfolio of operating renewable assets is also being acquired as part of this transaction. 3i Investments plc, the company’s investment manager, will control the overall investment, which will total €400 million.

London Stock Exchange-listed 3i Infrastructure is a Jersey-incorporated investment company focused on investing in infrastructure. 3i’s Infrastructure’s other investments include German fiber firm DNS:NET, subsea cable firm FLAG, Norway’s Tampnet, and several energy and utility firms across Europe.

Bernardo Sottomayor, managing partner and head of European infrastructure, 3i Investments plc, investment manager of the 3i Infrastructure, said: “This transaction offers an attractive risk/return profile, whilst further diversifying our portfolio into a new subsector. The contracted existing capacity provides strong downside protection, and we see attractive growth opportunities to create value. We look forward to working with the management team to deliver a strong outcome for 3iN.”

TCR is an independent lessor of airport ground support equipment. 3i sold its 71 percent stake in the company earlier this month for €1.14bn.

3i Investments, the company’s manager, is a wholly owned subsidiary of 3i Group, a British multinational private equity and venture capital company formed in 1945 by the Bank of England.