Core42 Lake Mariner data center, Barker, New York

TeraWulf is converting a former coal-fired power plant on Lake Ontario in Barker, New York, into a large AI data center campus called Lake Mariner, built on 180 acres it leases from the original 1,800-acre Somerset power plant site. At its peak, the coal plant paid about $20 million a year in taxes to Barker and its school district, and its workforce had fallen to 55 people by the time it closed; TeraWulf now employs 120 people on site, including 20 former coal plant workers.

Core42, a unit of Abu Dhabi's G42, signed long-term leases with TeraWulf for more than 70 megawatts of data center capacity at Lake Mariner, released in phases between the first and third quarters of 2025, with room to expand by another 135 megawatts. "This is the fastest ongoing data center build in the US right now," said Sean Farrell, TeraWulf's chief operating officer.

Noise from early cryptocurrency mining equipment at the site brought complaints from neighbors, and the newer buildings now use quieter cooling equipment after the company added noise controls. The campus draws its power from the regional New York grid zone that includes Niagara Falls hydropower, which is 89 percent carbon free, and its closed loop cooling system takes no water from Lake Ontario, though the old plant's water intake is still in place.

In July 2026, Governor Kathy Hochul signed an executive order banning new state permits for data centers for a year and said she wants to end tax breaks for hyperscale data centers, including ones issued by local industrial development agencies. Investigative Post reported that TeraWulf is not paying state or local sales tax on its multi-billion dollar expansion at Lake Mariner and gets discounted electricity from the New York Power Authority, and that Niagara County officials are looking into how much revenue they are missing.

Hochul said a ban on data center subsidies could come in next year's state budget, which puts the question before the governor and the state Legislature.