Commonwealth Edison

Solar Energy Information Hub 

ComEd is the largest electric utility in the state of Illinois. The Illinois Commerce Commission governs how ComEd administers distributed generation (DG) applications. These rules dictate many aspects of the interconnection process, including the application form, fees, and review guidelines.  ComEd has a thorough understanding of their responsibilities as a regulated utility and the need for a team structure and sophisticated application tool to handle the volume of applications received. The legislative rules can be limiting – they require that utilities have a single point of contact for applications, and that some aspects of the process, such as the layout of the application form, follow a specific format. However, these rules can be advantageous, as they also provide a clear delineation of responsibilities between the utility, contractor/installer, and customer, which allows employees to focus on necessary tasks. 

Application volumes are expected to increase in the coming years as technology improvements make the equipment cheaper and storage becomes economically viable. Expected changes to the federal income tax credit rules are also expected to lead to an increase in applications. ComEd has adopted a customized online application tool, which helps reduce time, improve customer satisfaction, and maintain scalability during the solar enrollment process. ComEd also allows application forms to be submitted by contractors on behalf of customers, which helps to improve the quality of submitted applications. While ComEd has some process in place to support their large application volumes, they have opportunities to improve quality of applications received by training contractors and creating an online checklist of requirements, and an opportunity to better manage the application process by growing their interconnection team and creating a database of existing DG systems.


  • Western Edison Light Company under the ownership of Thomas Edison
  • Commonwealth Edison was born in 1907
  • Since 2000, through a merger with PECO, ComEd has been owned by Exelon

Company Profile (as of October, 2015)

  • Based in Chicago, IL
  • Provides electrical transmission and distribution services to customers across Northern Illinois
  • More than 5,000 employees

Customers Served (as of October, 2015)

  • Serves 3.8 million customers in an 11,400 square mile territory across Northern Illinois
  • Over 90,000 miles of powerlines
  • As of October 2015, more than 1,200 interconnection applications had been received

Renewable Portfolio Standard

ComEd is subject to Illinois’ Renewable Portfolio Standard (RPS), the Illinois Power Agency Act:

  • 25% of their power must come from renewable energy sources by 2025
  • This includes a 6% minimum carve-out for solar energy and a 1% minimum carve-out for distributed generation (1.5% and 0.25% respectively of the total power distributed)
  • These sources must be located within Illinois and the adjoining states as much as possible