Electric Generating Units and Large Greenhouse Gas-Emitting Units

​Private Gas Facility Requirements in P.A. 102-662

(printable version)

Electric Generating Units (EGUs) and Large Greenhouse Gas-Emitting Units (LGUs) that use gas as a fuel that are not public GHG-emitting units are required to permanently reduce all CO2e and co-pollutant emissions to zero no later than January 1, 2045, according to a statutory schedule based upon the NOx and SO2 emissions of the unit and the unit's geographic location. Certain units must also reduce emissions in advance of the zero-emission deadline. 

Zero Emission Deadlines

  • By January 1, 2030:

    • NOx emissions rate greater than 0.12 lbs/MWh or SO2 emission rate greater than 0.006 lb/MWh; and

    • Located in or within 3 miles of an environmental justice (EJ) community designated as of January 1, 2021, or an equity investment eligible community (EIEC).

  • By January 1, 2035:  

    • Began operation prior to September 15, 2021;

    • NOx emission rate of 0.12 lb/MWh or less and an SO2 emission rate of 0.006 lb/MWh or less; and

    • Located in or within 3 miles of an EJ community designated as of January 1, 2021, or an EIEC

  • By January 1, 2040:  

    • NOx emission rate greater than 0.12 lbs/MWh or an SO2 emission rate greater than 0.006 lb/MWh; and

    • Not located in or within 3 miles of an EJ community designated as of January 1, 2021, or an EIEC.

  • By January 1, 2040:  

    • All remaining units that have a heat rate greater than or equal to 7000 BTU/kWh.

  • By January 1, 2045:

    • All remaining units.

Interim Emission/Operational Reduction Deadlines

  • By January 1, 2030, the following units must reduce CO2e emissions by at least 50% from its existing emissions for CO2e:

    • Began operation prior to September 15, 2021;

    • NOx emission rate of 0.12 lb/MWh or less and an SO2 emission rate of 0.006 lb/MWh or less; and

    • Located in or within 3 miles of an EJ community designated as of January 1, 2021, or an EIEC

  • After January 1, 2035, the following units shall reduce CO2e emissions by at least 50% from its existing emissions for CO2e; be limited in operation to, on average, 6 hours or less per day measured over a calendar year; and not run for more than 24 consecutive hours except in emergency conditions, as designated by a Regional Transmission Organization (RTO) or Independent System Operator (ISO):

    • NOx emission rate greater than 0.12 lbs/MWh or an SO2 emission rate greater than 0.006 lb/MWh; and

    • Not located in or within 3 miles of an EJ community designated as of January 1, 2021, or an EIEC

  • By January 1, 2035, the following units must reduce its CO2e emissions by at least 50% from its existing emissions for CO2e: 

    • All remaining units that have a heat rate greater than or equal to 7000 BTU/kWh.

Limit on Existing Emissions

As of the effective date of the Act, no unit may emit, in any 12-month period, CO2e or copollutants in excess of that unit's existing emissions for those pollutants.

The rolling 12-month period begins with the first full month following the legislation's effective date, September 15, 2021. The first full 12-month period runs from October 1, 2021 to September 30, 2022, though it is possible that a source could exceed its total prior to a full 12 months.  Any unit that exceeds its emissions limit without a statutory or regulatory exception in a 12-month period may be subject to IEPA's existing enforcement authority under Section 31 of the Environmental Protection Act.

Notifications/Reporting

All sources are required to keep records of CO2e and criteria pollutant emissions and to notify the Illinois EPA if they exceed their allowable emissions. Almost all impacted sources already report hourly CO2, NOx, and SO2 emissions to USEPA on at least a quarterly basis.  All sources report emissions annually to the Illinois EPA.

 The affected sources are all subject to Clean Air Act Permit Program (CAAPP) permitting standards.  New obligations pursuant to P.A. 102-662 will be established in the applicable sources' CAAPP permits upon either submission of an application for revised operating permit, or operating permit renewal.

Exceptions to Zero Emissions Deadlines and Emissions Restrictions

Notwithstanding any applicable zero emissions or emissions reduction deadline, or 12-month rolling average emissions restriction, EGUs and LGUs are allowed to temporarily continue emitting GHGs if it has been determined that ongoing operation of the EGU is necessary to maintain power grid supply and reliability or ongoing operation of the LGU that is not an EGU is necessary to serve as an emergency backup to operations, consistent with the following:

  • If a unit that is a participant in an RTO intends to retire, it must submit documentation to the appropriate RTO by the appropriate deadline that meets all applicable regulatory requirements necessary to obtain approval to permanently cease operating the unit;
  • If a unit that is a participant in an RTO receives notice that the RTO has determined that continued operation of the unit is required, the unit may continue operating until the issue identified by the RTO is resolved.  The unit must cooperate with the RTO in resolving the issue and must reduce its emissions consistent with the applicable zero emissions, emissions reduction, or 12-month rolling average emissions restriction requirements as soon as practicable when the issue identified by the RTO is resolved;

  • Any unit that is not a participant in an RTO is allowed to continue emitting GHGs after the zero-emission date if necessary to serve as an emergency backup unit if approved by the Illinois Commerce Commission.

The purpose of these exceptions is to permit ongoing operation regardless of an applicable zero emissions deadline, emissions reduction deadline, or 12-month rolling average emissions restriction to maintain power grid supply and reliability. Since ongoing operation due to power grid supply and reliability determinations might impact both CO2e and copollutant emissions, it follows that these exceptions are applicable to emissions of both CO2e and copollutants.

PJM and MISO have outlined defined scenarios in which they would utilize the statutory provisions that enable generators to run units in the event that the rolling emissions limits needed to be exceeded to maintain grid reliability and stability.  Each unit will be responsible for accounting for their own emissions and reliability exceptions.

If PJM or MISO foresee the need to run an EGU or LGU in Illinois for any of the defined reliability scenarios, they will communicate the need to the applicable generation owner, monitor system conditions, and communicate to the generation owner when the unit is no longer needed for reliability and should be taken offline and stop generating. 

Within 30 days of an exception event, the generation owner or operator shall submit to the Illinois EPA Bureau of Air Compliance Section, with a copy to the applicable RTO, a Notice of Exception Event that provides the following information:

  • The unit committed;

  • The time the unit began operating;

  • The time the unit stopped operating; and

  • The emissions attributable to this window of time.

Documents and Links

PJM Reliability Guidance

MISO Reliability Guidance

Response to Monitoring Analytics Letter - 01/21/22     Monitoring Analytics Letter - 12/22/21

Response to PJM Letter - 02/04/22    PJM Letter - 02/03/22