CSAPR Allowance Allocations

Under each of the emission allowance trading programs established in the CSAPR, CSAPR Update, and Revised CSAPR Update rulemakings, after the first control period, states generally have the option to adopt SIP revisions to determine how the allowances in their trading budgets are allocated among their units. However, for the first control period of each trading program, and by default for later control periods where a state has not provided state-determined allowance allocations under an approved SIP revision, EPA determines the unit-level allocations.

EPA’s default unit-level allowance allocations under a given trading program are determined differently for units that are considered “existing” or “new” for purposes of that trading program. The amounts of the initial allocations to the “existing” units in each state were determined in the respective rulemakings, while the unit-level allocations of the portions of the trading budgets reserved for potential allocation to “new” units (new unit set-asides or NUSAs) are determined for each control period by applying procedures in the trading program regulations to recent emissions data.

A unit is generally considered an “existing” unit for purposes of a given trading program if the unit commenced commercial operation before a date specified in the rulemaking for that trading program. The relevant dates for the trading programs established under CSAPR, the CSAPR Update, and the Revised CSAPR Update, respectively, are:

  • January 1, 2010 for the CSAPR NOX Annual, NOX Ozone Season Group 1, SO2 Group 1, and SO2 Group 2 Trading Programs (CSAPR).
  • January 1, 2015 for the CSAPR NOX Ozone Season Group 2 Trading Program (CSAPR Update).
  • January 1, 2019 for the CSAPR NOX Ozone Season Group 3 Trading Program (Revised CSAPR Update).

Spreadsheets showing the default initial allocations to “existing” units and the allocations from the new unit set-asides for each control period are provided below, along with links to the associated notices of data availability published in the Federal Register.

Initial Allocations to Existing Units

CSAPR: CSAPR NOX Annual, NOX Ozone Season Group 1, SO2 Group 1, and SO2 Group 2 Trading Programs

CSAPR Update: CSAPR NOX Ozone Season Group 2 Trading Program

Revised CSAPR Update: CSAPR NOX Ozone Season Group 3 Trading Program

Allocations from New Unit Set-Asides

For control periods through 2020, allocations from the new unit set-asides (NUSA) were made using a two-round process, with the first round during the control period and the second round after the end of the control period. Starting with the 2021 control period, allocations from the new unit set-asides are being made in a single round after the end of the control period.

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Last updated on March 20, 2025