ComEd and Ameren Illinois Rate Increase History: What Businesses Can Expect Next

Illinois utility rates don't increase arbitrarily. They're subject to regulatory approval by the Illinois Commerce Commission (ICC), which reviews utility rate cases and approves or modifies requested increases. But the trend over the past decade is unmistakable: rates have risen substantially, and the structural factors driving those increases haven't gone away.

ComEd Rate Increase History (2015–2025)

ComEd has been operating under the Energy Infrastructure Modernization Act (EIMA) formula rate structure, which has enabled consistent annual rate adjustments tied to infrastructure investment. Key rate increase milestones for ComEd include significant multi-year distribution rate cases that have cumulatively added hundreds of millions of dollars in annual revenue requirements.

The Illinois Power Agency Act and subsequent legislation have also added renewable energy compliance costs—renewable portfolio standard (RPS) surcharges—to ComEd customer bills. These charges have grown as Illinois's RPS requirements have increased. Under CEJA (the Climate and Equitable Jobs Act), passed in 2021, Illinois committed to 100% clean energy by 2050, with intermediate targets that require ongoing investment in renewable energy procurement.

Ameren Illinois Rate Increase History (2015–2025)

Ameren Illinois has similarly pursued significant infrastructure investment programs, including its Integrated Grid initiative aimed at grid modernization across central and southern Illinois. Multiple rate cases before the ICC have resulted in substantial delivery rate increases over the decade. Ameren's service territory—which includes older industrial areas and rural communities—requires ongoing infrastructure investment that contributes to rate pressure.

Translating utility rate cases into real dollar impacts for businesses requires looking at both delivery rate increases (regulated) and supply rate trends (market-based). The combination tells the complete story of how much Illinois commercial energy costs have changed.

These figures represent all-in commercial rates including both supply and delivery components. The supply portion—which is negotiable in Illinois's deregulated market—has tracked closely with PJM wholesale prices. The delivery portion—regulated by the ICC—has risen consistently, driven by infrastructure investment recovery.

The Compounding Effect on Business Budgets

A business paying $100,000 annually for electricity in 2015 is now paying approximately $122,000 for the same amount of power—even if it has made no changes to its operations. Over 10 years, that compounding represents hundreds of thousands of dollars in additional costs that have come directly from the bottom line.

Understanding why rates have risen helps businesses forecast the future with more accuracy. The key drivers of Illinois utility rate increases are structural—they reflect long-term policy commitments and infrastructure realities that aren't going away in the near term.

Driver 1: Grid Modernization and Infrastructure Investment

Illinois's electrical grid was built largely in the mid-20th century. Aging transformers, substations, distribution lines, and control systems require continuous replacement and upgrade. ComEd and Ameren are investing billions of dollars in grid modernization—costs that are recovered through regulated rate increases approved by the ICC. This infrastructure investment cycle is not complete; it will continue for another decade or more.

Driver 2: Clean Energy Mandates Under CEJA

The Climate and Equitable Jobs Act (CEJA), signed into law in 2021, established Illinois's most ambitious clean energy framework to date. It mandates 100% clean energy by 2050, with significant renewable procurement targets along the way. The cost of procuring renewable energy certificates, funding clean energy programs, and retiring fossil fuel generation ahead of schedule contributes to rate increases. According to the Illinois Commerce Commission, CEJA-related cost recovery riders have become a growing component of Illinois utility bills.

Driver 3: Capacity Market Costs

PJM's capacity market has experienced significant price swings that directly impact Illinois commercial electricity costs. When capacity prices rise—as they did sharply in the 2024–2025 delivery year—those costs flow through to commercial bills either directly (in unbundled contracts) or indirectly (in supplier pricing for new contracts).

Driver 4: Interest Rate Environment

Utilities finance infrastructure investment through debt markets. When interest rates are high, the cost of that financing increases—and those costs are passed through to ratepayers via regulated rate cases. The interest rate environment of 2022–2025 has contributed to higher utility financing costs and, ultimately, higher rates.

While delivery charges (the regulated portion of your bill) are outside your direct control, supply charges are fully negotiable in Illinois's deregulated market. Here's how to protect your business from both.

Control What You Can: Lock In Your Supply Rate

The supply portion of your electricity bill represents approximately 40–60% of your total energy cost. By locking in a competitive fixed-rate supply contract now, you insulate that portion of your bill from market volatility for the contract term. In a rising price environment, a fixed rate contract becomes more valuable every month that wholesale prices increase.

Reduce What You Use: Energy Efficiency Investments

The only way to reduce the impact of delivery charge increases—which you can't negotiate—is to use less energy. Investments in LED lighting, efficient HVAC, building automation, and process optimization reduce your base consumption, making every rate increase hurt less. Both ComEd and Ameren offer energy efficiency incentive programs that can offset a significant portion of upgrade costs.

Generate Your Own: On-Site Solar or CHP

On-site generation provides the ultimate hedge against utility rate increases: power you generate yourself isn't subject to utility rate changes. CEJA's incentive programs have made Illinois one of the more attractive states for commercial solar investment. Our Solar Savings Calculator can help you estimate the potential return for your facility.

Work With an Advisor to Build a Long-Term Energy Strategy

The most financially resilient Illinois businesses don't react to rate increases—they anticipate them and build strategies in advance. An energy advisor can help you combine supply procurement, demand management, efficiency investments, and on-site generation into a comprehensive approach that protects your budget across multiple scenarios.