Construction

The SOO Green HVDC Link will be built along an operating railroad from the Mason City, Iowa area to the Chicago, Illinois area.

Placing transmission cables underground in a secure, monitored operating railroad line provides additional security. Unlike AC transmission lines, HVDC underground cables do not radiate fluctuating electromagnetic fields or generate induced currents. This modern DC technology is insulated and self-contained, efficient and safe for humans, animals and the environment.

The project will use two 5-inch diameter (about the size of a wine bottle), 525KV extruded cross link polyethylene (XLPE) insulated cables installed in a 2 ½’ wide x 5’ deep trench.

SOO Green HVDC Link will construct two VSC power converter stations at either end of the 350-mile HVDC line. These VSC stations, which will be the largest ever built in the U.S., will convert Alternating Current (AC) power produced by wind and solar generators in MISO to Direct Current (DC) to enable transmission over the line and then back to AC power for distribution to customers in PJM.

SOO Green estimates a three-year development phase and a three-year construction phase concluding in 2024 when operations begin.