SUPPLEMENTARY INFORMATION:

Preamble acronyms and abbreviations. Throughout this document, the use of “we,” “us,” or “our” refers to the EPA. The EPA uses multiple acronyms and terms in this preamble. While this list may not be exhaustive, to ease the reading of this preamble and for reference purposes, the EPA defines the following terms and acronyms here:

CFR Code of Federal Regulations

CSAPR Cross-State Air Pollution Rule

EPA Environmental Protection Agency

FR Federal Register

NODA Notice of data availability

NOX Nitrogen oxides

The regulations for each CSAPR trading program contain “assurance provisions” designed to ensure that the emission reductions required from each State covered by the program occur within the State. If total emissions from a State's affected units exceed the State's assurance level, the State must surrender two allowances for each ton of emissions exceeding the assurance level (in addition to the ordinary obligation to surrender one allowance for each ton of emissions). In the emissions reports covering the 2025 control period, Virginia units participating in the CSAPR NO_X Ozone Season Group 2E Trading Program reported emissions exceeding the State's assurance level under the program by 70 tons, resulting in a requirement to surrender 140 additional allowances.

When a State exceeds its assurance level, the EPA apportions the responsibility for surrendering the required additional allowances among groups of units in the State represented by “common designated representatives” based on the extent to which each group's emissions exceeded the group's share of the State's assurance level.^[1] Applying the procedures in the regulations for the 2025 control period, the EPA completed preliminary calculations that indicate that the responsibility for surrendering 140 additional allowances in Virginia should be apportioned primarily to the group of units operated by Hopewell Power Generation, LLC and Dominion Generation, with smaller shares apportioned to the groups of units operated by Wolf Hills Energy, LLC and Calpine Operating Services Company, Inc.

In this notice, the EPA is providing notice of the data on which the Agency relied to determine the amounts of the exceedance of the Virginia assurance level and the notice of the preliminary calculations of the amounts of additional allowances that owners and operators of certain Virginia units must surrender as a result of the exceedance.^[2] By October 1, 2026, the EPA will provide notice of the final calculations of the amounts of additional allowances that must be surrendered, incorporating any adjustments made in response to objections received.^[3] Each set of owners and operators identified pursuant to the notice of the final calculations must hold the required additional allowances in an assurance account by November 1, 2026.

The data and preliminary calculations are available in an Excel spreadsheet titled “2025_CSAPR_assurance_provision_calculations_prelim.xlsx” at https://www.epa.gov/​Cross-State-Air-Pollution/​csapr-assurance-provision-nodas. The spreadsheet contains data for the 2025 control period showing, for each Virginia unit identified as affected under the CSAPR NO_X Ozone Season Group 2E Trading Program, the unit's reported amount of NO_X emissions and the amount of CSAPR NO_X Ozone Season Group 2E allowances allocated to the unit, including any allowances allocated from new unit set-asides. The spreadsheet also provides 2025 control period calculations showing the total reported NO_X emissions from all such units in Virginia and the amounts by which those total reported NO_X emissions exceeded the State's assurance level under the program. Finally, the spreadsheet includes calculations for the 2025 control period showing, for each common designated representative for a group of such units, the common designated representative's share of the total reported NO_X emissions, the common designated representative's share of the State's assurance level, and the amount of additional CSAPR NO_X Ozone Season Group 2E allowances that the owners and operators of the units in the group must surrender.

Objections should strictly be limited to whether the EPA identified the data and performed the calculations in the spreadsheet correctly in accordance with the regulations. Objections must include: (1) precise identification of the specific data or calculations the commenter believes are inaccurate, (2) new proposed data or calculations upon which the commenter believes the EPA should rely instead, and (3) the reasons why the EPA should rely on the commenter's proposed data or calculations and not the data and calculations referenced in this notice.

91 FR 49430