TerraWatt proposes 1GW data center at former Illinois steel mill

TerraWatt has proposed a data center of up to 1GW at the former Alton Steel mill site in southern Illinois. The 381-acre project would be built in 200MW blocks, with the land sale expected to close in 2027 and full operation by 2031.

• Campus capacity up to 1GW, developed in 200MW blocks
• Sale of the 381-acre site to close in 2027 after rezoning
• First block to be built from late 2027 into early 2029
• TerraWatt says it will pay for grid upgrades and site cleanup