Illinois's electricity costs are climbing fast, driven by a growing capacity shortfall, an interconnection backlog measured in years, and surging data center demand. This page walks through how the market works, why bills are rising, and what Springfield is doing about it.
Before the data on rising costs, understand who actually controls what in Illinois's electricity system, because no single company controls your whole bill.
Nobody sells you electricity end to end. Illinois splits the job between a company that delivers power and a company that generates it, and they're regulated completely differently.
Those generators don't sell directly to Illinois either. They sell into one of two regional wholesale markets, and which one depends entirely on where in the state you live.
| MISO (Ameren Territory) | PJM (ComEd Territory) | |
|---|---|---|
| What it is | Regional Transmission Organization (RTO) | Regional Transmission Organization (RTO) |
| Primary role | Operates the grid, transmission coordination, and energy markets | Operates the grid, reliability and transmission planning, energy markets, and capacity markets |
| Market emphasis | Energy markets & transmission coordination | Energy markets and forward capacity auctions |
| Illinois zone | LRZ 4 (Ameren) | ComEd |
Illinois is split between these two territories: ComEd (northern Illinois, in PJM) and Ameren Illinois (central and southern Illinois, in MISO), plus a number of electric cooperatives and municipal utilities that fall outside both investor-owned systems.
Once electricity is generated and delivered, it shows up on your bill as two very different line items, and only one of them is regulated the way most people assume.
Your electric bill is composed of supply costs (2/3) and transmission costs (1/3).
Default supply provided by the Illinois Power Agency is often procured lower than retail offers. Municipal utilities like CWLP in Springfield control their own supply, avoiding retail supplier costs entirely.
This structure, delivery separated from generation, is the direct result of Illinois deregulating electricity supply in the late 1990s. The flow below is how that choice moves through to your bill.
*Only applies to for-profit utilities. The physical delivery of electricity does not change even if a customer switches suppliers.
Illinois formally deregulated electricity supply in the late 1990s. Recent legislation reflects a clear shift back toward greater state control, centralized planning, and utility regulation.
SB25 expands ICC authority over utility planning, establishes a subsidized state-directed battery storage build-out, and integrates storage and reliability planning into state energy policy. (Full detail on the resulting law, CRGA, follows below.)
The Public Utilities Act consists of compiled statutes that have governed Illinois utility infrastructure since the 1980s, including the creation and authority of the Illinois Commerce Commission.
Critics argue CEJA has accelerated the retirement of reliable power generation without ensuring enough replacement capacity to meet Illinois's growing electricity demand.
Critics argue CRGA focuses on planning and oversight rather than increasing the dispatchable electricity generation needed to meet rising demand.
Illinois energy authorities have expanding power over the energy market because of CEJA and CRGA legislation, moving Illinois toward re-regulation.
"The ICC's mission is to balance the interests of consumers and public utilities to ensure adequate, efficient, reliable, safe, and least-cost utility services, while promoting the development of an effectively competitive energy supplier market."
– Illinois Commerce Commission Mission Statement"The Illinois Power Agency is committed to the planning and procurement of reliable, efficient, and cost-effective electricity for residents and businesses in an ethical and objective manner, insulated from improper influence."
– Illinois Power Agency Mission StatementIllinois faces a growing gap between how much electricity it can reliably produce and how much it needs. Here is how the state's own study measured that gap, one step at a time.
Generation measures energy produced over time, while capacity measures the maximum power available at any given moment. Both are necessary to understand electricity supply and reliability. Fossil fuel and nuclear plants have higher capacity factors/ELCCs than most renewable power plants.
| Capacity (Reliable Energy) | Generation (Total Supply) | |
|---|---|---|
| What it is | Maximum power output at full power | Total electricity produced over time |
| Unit of measure | Megawatt | Kilowatt/Megawatt/Terawatt Hour |
| Time scope | Instantly | Hours, days, or years |
| What it answers | How much could be produced under ideal conditions? | How much was actually produced? |
| Policy focus | Reliability, resource adequacy, peak demand | Annual supply, emissions, clean-energy share |
Section 9.15(o) of the Illinois Environmental Protection Agency Act directs the IEPA, the Illinois Power Agency, and the Illinois Commerce Commission to jointly prepare and publicly release a report examining the state's current and projected resource adequacy for the 5 years ahead (the "Resource Adequacy Study"). The figures in the next two steps reflect the study's "Base Case," continuing current laws, policy, and development trends.
In the ComEd territory, PJM is expected to experience a capacity shortfall beginning around 2029–2030, and that gap only widens from there.
By 2035, the projected shortfall reaches 28 GW, roughly enough capacity to power several million homes that the region cannot reliably generate or import on its own.
In the Ameren territory, the picture holds a bit longer: MISO remains resource adequate through 2030, but a shortfall is projected to emerge in 2031 and grow quickly after that.
By 2035, MISO's projected shortfall reaches 32 GW, even larger than PJM's, on a resource base the IPA itself describes as "fundamentally constrained by capacity scarcity."
The two regions are heading in opposite directions. Put their generation outlooks side by side and the divide becomes clear.
The Ameren/MISO region can replace its coal and gas resources with wind and solar development, even to the point of growing net exports. The ComEd/PJM region sees demand grow tremendously as it hosts some of the largest data-center growth in the world; it only slightly grows its renewable resources and becomes a net importer of electricity by 2035.
PJM and MISO use different methodologies for assessing how much "credit" a resource gets toward meeting reliability requirements. Renewables like wind and solar have much lower accreditation because they're less reliable during peak-load hours, exactly the hours these shortfalls matter most.
| Resource Type | MISO Accreditation | PJM Accreditation |
|---|---|---|
| Nuclear | 93% | 95% |
| Pumped Hydro | 98% | 74% |
| Gas | 89% | 70% |
| Hydro | 89% | 40% |
| Coal | 88% | 83% |
| Other | 86% | 50% |
| Oil | 76% | 78% |
| Battery Storage | 61% | 50% |
| Solar | 33% | 11% |
| Wind | 8% | 41% |
Even once a shortfall occurs, like the ones mentioned under resource adequacy, new power plants cannot simply plug in. Here is why the queue itself has become part of the cost problem.
The interconnection queue is the list of new energy projects waiting to be studied and approved for connection to the electric grid. Before a project can start sending electricity to the grid, the grid operator must determine whether the existing system can safely handle the additional power.
Generator construction, transmission upgrades, and reliability studies all require years of planning and large investment, and Illinois' two grid operators don't even study projects the same way.
| Ameren | ComEd |
|---|---|
| Interconnection studies in batches by bundling generators and consumers for reliability assessment | Larger concurrent interconnection studies |
New entrants, generators and large consumers alike, are required to pay for the grid upgrades their connection triggers, not just their own equipment.
The capacity crunch documented in the resource adequacy studies is already showing up in historical rates, auction prices, and household bills.
Ameren Illinois rose from 10.46¢ in 2021, the year CEJA was enacted, to 23¢ in 2025 — a 120% increase in four years.
Residential rate, cents per kWh. Source: U.S. Energy Information Administration.
According to the EIA, the average residential utility bill in Illinois in 2025 was $109.99, projected to increase up to 40% by 2030 and roughly 100% by 2050 under current conditions, according to national ICF analysts.
Illinois has historically earned between $13–17 billion in revenue from retail sales (in-state consumption) of its electricity generation.
Illinois has added nearly 13,700 MW of renewable energy capacity to the interconnection queue. Most of the growth has come from wind and solar projects across the state.
AI, streaming, and online services are increasing electricity demand right as the grid is already stretched thin.
PJM's independent market monitor has now put a hard number on the data-center share of the capacity auction costs covered in the Prices & Bills section.
of the $16.4 billion 2028/29 PJM capacity auction cost is attributable to data centers, according to Joseph Bowring, president of Monitoring Analytics, PJM's independent market monitor. Across the last four auctions combined, data-center-driven costs to PJM ratepayers total nearly $30 billion.
"This year's auction confirms an unacceptable trend: data center load growth is outpacing new electricity supply, degrading reliability, and keeping prices at the cap… New power supplies simply can't keep up with the pace of data center load growth, and everyone is paying the price."
– Claire Lang-Ree, Natural Resources Defense Council"Such a shortage does not necessarily mean that the PJM system will be unable to serve load reliably in the delivery year. It means that PJM would have to operate with slimmer reserves and a greater level of risk."
– PJM Interconnection, official statementBowring has argued PJM should run a separate capacity auction specifically for data centers so consumers aren't left covering costs their own electricity use didn't create. Attention now shifts to an emergency procurement mechanism PJM must file with FERC by the end of July 2026, intended to shift more of that burden directly onto the "hyperscalers" — the small handful of giant tech companies (Amazon, Microsoft, Google, Meta, and similar) that build and operate the largest data centers — plus a July 23, 2026 FERC conference on PJM grid governance called amid pressure from consumer groups, data centers, generators, and state officials.
As other resources retire, nuclear power is drawing renewed attention, and renewed scrutiny.
Nuclear energy is becoming more important because it can provide steady electricity with lower carbon emissions and higher capacity ratings than fossil fuels. Many experts believe nuclear energy could help support future electricity demand while reducing dependence on foreign energy sources. Nuclear plants also have a 70–80 year lifespan, far longer than most other generation sources.
Illinois barred construction of new large-scale nuclear reactors (over 300 MW) for roughly 40 years. CRGA (covered in the Regulation section) ended that prohibition when it was signed into law in January 2026 — meaning new large reactors are legally possible in Illinois for the first time in decades. That change is exactly why the Nuclear Executive Order covered in the Solutions & Legislation section exists: Illinois can now formally study new large-scale nuclear development, but as of this writing no site, developer, or financing plan has been announced.
Multiple bills and executive actions are moving through Springfield to address reliability and cost, but not all of them add capacity or prevent the emergencies the current energy climate is creating.
Co-sponsored by Sen. Balkema. Filed October 28, 2025 (104th General Assembly). Unlike the two measures above, SB2727 has an immediate, concrete effect: it directly prevents the reliability emergency created by CEJA's compliance deadlines colliding with insufficient battery storage, by delaying emission-enforcement when storage falls below 10% of installed capacity and letting peak-shaving gas units keep running during grid emergencies instead of forcing shutdowns that risk blackouts.
Co-sponsored by Sen. Balkema. Bipartisan. Ties CEJA emission-compliance enforcement to battery storage availability and allows temporary gas peaker operation during grid emergencies, directly preventing the reliability emergencies the current energy climate risks creating.
Co-sponsored by Sen. Balkema. Speeds up interconnection for public schools and community renewable projects facing multi-year interconnection delays.
Co-sponsored by Sen. Balkema. Allows Illinois natural gas peaker plants to operate continuously, despite state restrictions, until at least 21,000 MW of new utility-scale renewable capacity is online.
Co-sponsored by Sen. Balkema. Extends Illinois's 100% clean energy goal from 2050 to 2060, delays related deadlines by 10 years, and gives coal, oil, and large power plants more time to meet emissions requirements.
Every energy-related bill Senator Balkema has co-sponsored this session, touching siting, interconnection, emissions timing, and ratepayer relief. Search by bill number or keyword below.
| Bill | What It Does |
|---|---|
| HB1640 | Underground Tank Cleanup BiddingUpdates bidding requirements for underground storage tank cleanup projects, requiring public notices on an EPA-approved electronic procurement website at least 14 days before bids are opened, replacing newspaper-only notice. |
| HB5524 | Utility Charge TransparencySigned into law as Public Act 104-0541. Requires the Illinois Commerce Commission to maintain a public website detailing electric utility charges beyond delivery and supply costs, including how collected amounts are remitted to the state or retained by the utility. |
| SB0038 | Grandfathered Wind/Solar ZoningAllows counties to keep existing wind and solar zoning ordinances in place before January 27, 2023, and lets older wind farm zoning rules adopted before August 16, 2007 remain in effect. |
| SB0160 | Township Wind/Solar AuthorityGives townships authority to regulate or prohibit commercial wind and solar facilities via zoning; township rules take precedence over county rules but not municipal regulations. |
| SB0195 | Wind Turbine Light MitigationRequires wind farms built in 2019 or later to install FAA-approved light mitigation technology by June 1, 2027, with fines up to $1,000/day for noncompliance; research/test towers exempt. |
| SB1234 | Grid Reliability Task Force & Carbon Capture FundCreates a task force to monitor Illinois power grid reliability and issue annual reports, and establishes a new Carbon Capture Infrastructure Fund, transferring $10 million for grants to carbon capture and storage projects at power plants. |
| SB1235 | Emissions Rule RollbackAmends the Environmental Protection Act. Reverts greenhouse gas provisions to the language existing before P.A. 102-662 and repeals the statutory definition of "clean energy." |
| SB1527 | Lifts Large Nuclear Reactor MoratoriumAmends the Public Utilities Act. Removes the ban on constructing new nuclear reactors larger than 300 MW until the Illinois Emergency Management Agency and Office of Homeland Security find the federal government has approved a means of disposing of high-level nuclear waste. |
| SB3409 | School & Community Solar StreamliningStreamlines interconnection for renewable projects on public school property, requires utilities to issue net metering credits within 90 days, and caps interconnection fees for co-ops and municipal utilities. |
| SB1276 | Local Zoning Grandfather ClauseAllows counties to keep enforcing local wind/solar zoning ordinances predating January 27, 2023, and certain wind farm rules from before August 16, 2007. |
| SB1277 | Solar Installer Surety BondRequires solar installation companies to maintain a $2 million surety bond with the Illinois Power Agency to cover unmet rebate and warranty obligations. |
| SB1365 | Wind/Solar Water Flow CompensationRequires owners of commercial wind or solar facilities to compensate landowners if the facility adversely affects water flow, including drainage tile, on their land. |
| SB1457 | Wind/Solar Siting SetbacksLimits county approval of wind or solar projects within 3 miles of a municipality, adds farmland protections, fire hydrant requirements for solar facilities, and 500-foot residential setbacks. |
| SB1648 | Local Approval for State IncentivesRequires local government approval before a new wind or utility-scale solar project can be designated a high-impact business eligible for state incentives. |
| SR0215 | Lineworker Appreciation DayDeclares April 18, 2025 as Lineworker Appreciation Day in Illinois, applauding the hard work, dedication, and bravery of the state's lineworkers. |
| SB3273 | School & Community Solar InterconnectionMakes it easier and faster for public schools and community renewable projects to connect to the grid, and requires utilities to pay out energy credits within a set time frame. |
| SB2180 | Pipeline Permit DisclosureRequires pipeline companies to submit federal pipeline permits to the ICC within two weeks of approval and publicly post permits and construction notices online. |
| SB2687 | Home Utility Rebate ProgramCreates a Home Utility Rebate Program transferring $500 million for electricity cost rebates for moderate-income households in FY2026–2027, administered by DCEO. |
| SB2690 | Grundy County Siting AuthorityAllows Grundy County or a municipality with planning jurisdiction to prohibit or regulate wind and solar facilities on the Brisbin Road commercial/industrial site. |
| SB2727 | CEJA Emissions FlexibilityTies certain greenhouse gas emission requirements to available battery storage; enforcement may be delayed and gas plants may temporarily exceed limits to maintain grid reliability in emergencies. |
| SB2736 | Gas Peaker Plant ExtensionAllows Illinois natural gas peaker plants to operate continuously, despite state restrictions, until at least 21,000 MW of new utility-scale renewable capacity is online. |
| SB2842 | CO2 Pipeline Eminent Domain BanProhibits carbon dioxide pipeline companies from using eminent domain to acquire private property, even with state approval to operate the pipeline. |
| SB2958 | Agrivoltaic System DefinitionDefines an "agrivoltaic system" as a solar project that simultaneously supports energy generation and active agricultural production on the same land; pollinator-only habitat does not qualify. |
| SB3450 | Municipal Solar Zoning AuthorityAllows municipalities to regulate or prohibit solar energy systems and low-voltage solar-powered devices, consistent with local comprehensive plans and zoning authority. |
| SB3664 | Energy Choice & Economic Impact CommissionCreates the Illinois Future of Energy Choice and Economic Impact Commission, sets its membership, and assigns it duties with respect to energy policy. |
| SB3665 | Energy Worker Tax CreditCreates a state income tax credit equal to 20% of wages paid to eligible Illinois energy workers by utilities and power generators significantly affected by clean-energy transition deadlines. |
| SB3929 | Clean Energy Deadline ExtensionExtends Illinois's 100% clean energy goal from 2050 to 2060, delays related deadlines by 10 years, and gives coal, oil, and large power plants more time to meet emissions requirements. |
| SB3970 | Gas Decarbonization Cost-Benefit ReviewRequires the ICC to conduct a cost-benefit analysis before approving natural gas decarbonization programs, weighing costs, reliability, equity, jobs, and ratepayer impact. |
| SB3979 | Gas Infrastructure Takings ReviewRequires independent regulatory takings assessments for natural gas decarbonization pilots and infrastructure plans before approval; rulemaking due by June 1, 2026. |
| SB4028 | Faster Solar/Storage InterconnectionRequires the ICC to update interconnection rules within 180 days to reduce barriers for mid-sized solar, battery storage, and hybrid projects; rules take effect by July 1, 2026. |
Bill numbers link to each bill's official status page on the Illinois General Assembly website (104th General Assembly).
View the full presentation containing much of the energy data and analysis featured throughout this site.