ComEd to expand 765 kV substation in Illinois to support wind, solar interconnection

Published on December 14, 2023 by Chris Galford

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New support is coming for utility-scale onshore wind and solar projects in Illinois and the larger PJM energy market thanks to planned substation upgrades announced this week by ComEd that will improve upon the 765 kV Wilton Center substation.

That substation was first built in 1968 near Joliet, Illinois. It supports ComEd’s highest voltage transmission lines, used for long-distance power transmission while minimizing the amount of power lost as electricity moves from one location to the next. The facility will expand by approximately 50 percent when work finishes, as new circuit breakers, transformers, relay switches, network data and control systems are all added.

When expansion finishes up, the substation should be able to support five wind farms and two solar farms with the capacity for up to 2,450 MW of renewable energy.

“Policymakers, stakeholders and customers want a cleaner energy future, and we’re powering the grid modernization that will make this future a reality,” Gil Quiniones, CEO of ComEd, said. “Investments like the expansion of the Wilton Center substation will ensure the successful interconnection of new renewable energy generation to the grid so that it can be delivered through our transmission system to communities across Illinois.”

ComEd is currently working on 13 wind projects throughout the state, amounting to 3,120 MW of potential wind generation. One of those to be supported by Wilton Center is the 850 MW Heritage Prairie wind farm – which includes 300 MW of solar generation as well – which will be the largest wind interconnection in northern Illinois and largest onshore wind project to date for PJM territory.

The expanded substation is expected to be operational in late 2026.