Illinois Electricity 101: The Grid, Solar, and What Comes Next
Welcome to Part 1 of our Illinois energy series — where we’ll explore how electricity reaches your home, who’s in charge, and why this matters. In Illinois, we’re witnessing a transition: more people are adopting solar panels, demand is rising, and new policies are being proposed to modernize the grid. One such proposal, the Clean & Reliable Grid Affordability Act (CRGA), aims to make sure the grid is ready — clean, reliable, and affordable. Over this series, we’ll show how our energy system works, who the key players are, and how solar and smart policy can help Illinois power its future.
In the state of Illinois, there are different types of electric utilities that serve Illinoisans. Some utilities are operated by local municipalities, while others are under a cooperative structure (where customers are also members and owners). Most of Illinois, however, are served by two investor-owned utilities. These two utilities are Commonwealth Edison (ComEd) and Ameren Illinois. All these utilities must deliver electricity to customers reliably, and they must also maintain the electric grid (that you can see the poles, wires, and transformers outside your window!). We normally call this part of the electric grid the “distribution grid”. Utilities plan and invest in this distribution grid, shaping how quickly Illinois can plug in more solar, batteries, and other clean energy. Ultimately, utilities decide how much Illinoisans are able to benefit from these technologies.
Illinois customers of the investor-owned utilities (IOUs) can choose a company (called an energy supplier) to generate, or supply, their electricity. If no company is chosen, then the customer will automatically be receiving “default supply” (more on that later).
With this in mind, let’s turn back to the electric grid. Energy suppliers are not operating wholly separate from other utilities. Instead, they are all connected in various ways with the generation plants that supply electricity to everyone. In fact, the poles and wires coming from your home are connected to a wider grid that is connected to other states! If Illinois creates more electricity than needed or if the generation plants can’t supply enough electricity, Illinois can buy or sell electricity from other states. Illinois is, in fact, connected to two regional grids, also called “Regional Transmission Operators” or RTOs. Illinois is connected to the MISO (Midcontinent Independent System Operator, pronounced “My-So”) RTO and the PJM (used to stand for Pennsylvania-New Jersey-Maryland) Interconnection RTO. PJM overlaps with northern Illinois, and MISO overlaps with the rest of the state. Each of these RTOs connect to various states across the USA.
By now, you might wonder: who is responsible to make sure that utilities are doing their job and customers are protected? That is the job for the Illinois Commerce Commission (ICC)! The ICC is a state agency, led by five individuals appointed by the governor. These individuals, named Commissioners, oversee presiding and regulating all things related to electricity, gas, telecommunications, and other topics related to public utility services. When IOUs want to raise your rates, they must file an application to the ICC (where consumer advocates and other interested groups can then formally “intervene”, or fight, the application). When utilities want to alter various customer programs or propose huge grid upgrades, they must file an application to the ICC. The Commissioners, weighing the utilities’ position and consumer advocates’ alternate data and perspectives, will make a final decision that the utilities follow. Individuals can also file utility complaints to the ICC if an electric company is not doing its job.
There is one more state agency that supports Illinois’ electric grid: the Illinois Power Agency (Agency or IPA). The IPA has a direct role to help facilitate the growth of renewable energy, and the Agency oversees providing the “default electric supply” for customers that do not choose a company that supplies their electricity. Since the majority of Illinoisans use default energy supply, the IPA chooses how much clean energy goes to everyone’s home.
The agencies and regulators we’ve introduced here don’t just keep the lights on; they make key decisions and set the course for Illinois’ entire energy future. Their decisions determine whether the state doubles down on fossil fuels or opens the door to more solar, wind, and batteries. In the next part of our series, we’ll dive into how these choices are made and how their choices shape affordability, reliability, and Illinois’ clean energy future.