State seal of Illinois

Illinois’s Renewable Portfolio Standard (RPS) is intended to increase use of renewable resources in the state by establishing the minimum amount of renewable energy that the state’s electricity providers must sell in a given year. This legally-established renewable energy procurement goal gradually increases over time to meet the overall target of 25% renewable power by 2025.

The state profile below explores the design of this policy, highlighting the factors that influence the success of Illinois’s RPS goals and the tradeoffs inherent to it. Once you’re comfortable with the information on this page, you can evaluate the policy’s expected viability with the RPS Feasibility Calculator. You can also use the calculator to change the policy requirements, trajectory, cost cap, and more, to see how altering Illinois’s policy design affects its success.

RPS Snapshot


  • 25% of the state’s retail electric sales from must be from renewable sources by 2025, subject to the cost cap
  • Carve-outs for wind, solar, distributed generation
  • Explicit cost cap at 2% of sales


Carve-outs can create economic opportunities in the state by introducing new or promising technologies into the market. However, these standards limit the utilities’ ability to substitute between renewable energy sources, potentially increasing the cost of the policy. Illinois’ wind technology requirement comprises the majority of its RPS goals at 75% of the standard each year. Smaller requirements for solar and distributed generation exist at 6% and 1% of the annual requirement, respectively.

RPS Progress

Compare the goal established in the RPS to what is being achieved.

Energy Details

Grid Mix

The following chart compares the variety of sources currently used to generate Illinois’s electricity. The color of each bar is indicative of the carbon intensity of each source.

Cost Cap Details

Illinois has an explicit cost cap at 2% of the customer’s annual bill. Renewable energy procurement is limited to cost-effective resources. The cost cap is set at ‘the greater of an additional 0.5% of the amount paid per kWh during the year ending in 2010, or 2% of the amount paid per kWh during the year ending May, 2007.’ If exceeded, RPS requirements are placed under a ‘freeze’. In addition, a second cost-effectiveness test: cost of procurement of renewable energy must not exceed benchmarks based on market prices for renewable energy in the region (determined by the IPA). Estimate how Illinois’ cost cap can effect their RPS’s efficacy

Historic retail prices (¢ / kWh)

The above chart presents historical data from the Energy Information Administration (EIA) on the price at which residential customers can purchase electricity. Typically, states set explicit cost caps relative to the retail price (as opposed to the lower wholesale price).



The current RPS was enacted in 2007 through creation of Illinois Power Agency (IPA). The IPA’s purpose was to develop electricity procurement plans for renewable power. The legislation has two compliance schedules; a primary and a secondary. The primary states that for investor-owned utilities (IOUs), 75% (equal to 18.75% total power sales in 2025) of the requirement must be from wind, and the secondary requires 60% for alternative retail electric suppliers (ARES) by 2020. The 6% annual solar carveout (equating to 1.5% of total retail sales) ramps up for IOUs in 2013, and in 2016 for ARES. A 1% carve out for distributed generation. Renewable generation limited to ‘cost-effective’ resources. Renewable energy may be bundled with RECs. In 2011, anaerobic digestion was added to eligible resources. A second efficiency portfolio standard exists.

RPS Technical Details

Eligible Technologies Solar Thermal Electric, Photovoltaics, Landfill Gas, Wind, Biomass, Hydroelectric, Anaerobic Digestion, Biodiesel
Geographic Eligibility (Only IOUs) Through 2011: in-state (if insufficient cost-effective resources, can procure from adjoining states, or regions). After 2011: equal preference to in- and out-of-state.
Percent of Total Load Primary RPS: 39.9%, Secondary RPS: 49%
Technology Requirements Wind (IOUs)—75% of annual req.; Wind (ARES)—60% of annual req.; PV (all)—6% of annual req.; Distributed Generation (IOUs)—1% of annual req.
Sectors Investor-Owned Utilities, Retail Suppliers. Municipal electric companies and Electric Cooperative exempt from RPS.
Penalty For Com-Ed: $0.946/MWh (for hourly customer loads). For Ameren: $0.973/MWh - adjusted annually


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