Exelon, the owner-operator of Illinois’s six nuclear power plants, has announced that the Byron and Dresden nuclear plants will continue operating rather than retire this autumn as previously planned. The announcement came after the Illinois state legislature and governor approved a clean energy bill supporting carbon-free energy resources. 

Illinois Senate Bill 2408, signed into law on 15 September 2021, aims to move the state to 50% clean energy by 2040 and 100% clean energy by 2050. The legislation defines clean energy as energy generation that is at least 90% free of carbon dioxide emissions, and that definition includes nuclear generation. 

Illinois has more nuclear generating capacity than any other state. In 2020, nuclear power plants accounted for 58% of its ‘home grown’ electricity generation. Byron and Dresden combined supplied 20% of the total.

The bill also supports nuclear power plants in the state through a carbon credit plan, where utilities that serve more than 300 000 residential customers are required to purchase electricity credits generated from certain nuclear plants. SB 2408 provisions are in addition to an existing Zero Emission Credits (ZEC) programme that began in 2017 and provides revenue to participating nuclear power plants in Illinois. 

Prior to SB 2408, the Byron and Dresden plant operators reported to the Energy Information Administration, EIA, that they had planned to retire the plants in September and November 2021, respectively. For power plants of 1 MW capacity or more, plant owners and developers report planned capacity retirements and additions to EIA, which it publishes monthly and annually.

In addition to providing revenue to nuclear power plants, SB 2408 requires the state’s remaining fossil-fuelled plants to reduce carbon emissions in stages, beginning in 2030 and to be completed by 2045. In 2020, 18% of in-state generation in Illinois came from coal; natural gas-fired plants generated another 14%. 

As of August 2021, close to 6000 MW of electric generating capacity in Illinois had reported plans to retire by 2027. Almost all of those planned retirements are coal-powered generating facilities. After 2027, about 4000 MW of coal-fired capacity will remain operating in the state. Most of this capacity, along with more than 15 GW of natural-gas fired capacity, will face deadlines to reduce emissions, switch to a non-fossil fuel, or retire no later than 2045. Illinois may grant exceptions for units needed to support grid reliability.