SOO Green, a 2.1-GW transmission project jointly developed by energyRe and Copenhagen Infrastructure Partners (CIP), has secured approval of its final municipal franchise agreement, clearing the way for construction in Iowa (US).

The merchant transmission project will link the PJM Interconnection and the Midcontinent Independent System Operator (MISO), delivering a mix of wind and solar power, balanced with energy storage, via a 525-kV high-voltage direct current (HVDC) line. The line will be buried underground along existing railroad rights of way.The bi-directional line will run between Mason City, Iowa, and Yorkville, Illinois, with converter stations located at each end. The project will operate under PJM’s control, enabling the grid operator to supply power into MISO during periods of extreme weather.

In additi on to its developers, the project’s key partners include Germany’s Siemens Energy, U.S.-based Jingoli Power and PPL Corp., and Italy’s Prysmian Group. Construction could begin as early as 2027, with commercial operations targeted for 2031.