Exelon Corp's ComEd Livening Major Substation Expansion to Power Illinois' Renewable Future

On December 11, 2025, Exelon Corporation's subsidiary, ComEd, announced the successful livening of its expanded 765 kilovolt (kV) Wilton Center substation, located in southern Will County, Illinois. This substantial enhancement is pivotal for integrating the state's largest cluster of utility-scale onshore wind and solar projects into the ComEd grid and the broader PJM energy market, with operational capacity expected to commence in 2026.

Gil Quiniones, President and CEO of ComEd, emphasized the importance of this development, stating, “The livening of the Wilton Center expansion project marks a major milestone. The expansion will enable ComEd to deliver more than 2,000 megawatts of new renewable generation through our transmission system to meet growing demands for electricity among residential and business customers.” Quiniones further highlighted that this initiative will help apply downward pressure on rising energy costs by increasing the availability of renewable energy sources.

The Wilton Center substation expansion has significantly increased the facility's yard size by 50% to a total of 1.5 million square feet. In a bid to minimize environmental impacts, ComEd reused approximately 80,000 tons of topsoil and 90,000 tons of on-site clay, effectively avoiding the need for extensive soil transportation. The upgrade also includes new equipment such as 765 kV circuit breakers, current and voltage transformers, disconnect switches, surge arresters, and extensive upgrades for protection and control systems. To address stormwater management, a new detention pond capable of holding 2.8 million gallons was constructed.

Originally built in 1968, the Wilton Center substation is critical for supporting ComEd’s highest voltage transmission lines. These 765 kV lines are essential for efficiently transmitting large amounts of electricity over long distances, minimizing energy loss throughout the process. Notably, less than 1% of existing transmission lines in the United States operate at this highest voltage level, underscoring the significance of the Wilton Center's capabilities.

Following an additional minor upgrade planned for the second quarter of 2026, the expanded substation will support a total capacity of up to 2,450 megawatts (MW) of renewable energy from five wind farms and two solar farms. This upgrade is anticipated to boost the energy output available to the ComEd transmission system and the PJM energy market, which serves parts of 13 states and the District of Columbia.

The newly enhanced Wilton Center substation will facilitate a range of upcoming renewable projects, including:

The Wilton Center expansion project witnessed collaboration between ComEd crews and Lindblad Construction, with Burns & McDonnell providing engineering support throughout the design and construction phases.

As a unit of Chicago-based Exelon Corporation (NASDAQ: EXC), ComEd plays a crucial role in the energy landscape by serving over 10.7 million electricity and natural gas customers. In northern Illinois alone, ComEd powers the lives of more than 4.2 million customers, representing 70% of the state's population. This recent project reinforces Exelon’s commitment to advancing renewable energy solutions and enhancing infrastructure to meet future energy demands.

For further information about the company and its initiatives, visit ComEd.com and engage with them on various social media platforms.