Talen Energy Corp

Adjusted EBITDA. Net income (loss) adjusted, among other things, for certain: (i) nonrecurring charges; (ii) non-recurring gains; (iii) non-cash and other items; (iv) unusual market events; (v) any depreciation, amortization, or accretion; (vi) mark-to-market gains or losses; (vii) gains and losses on the NDT; (viii) gains and losses on asset sales, dispositions, and asset retirement; (ix) impairments, obsolescence, and net realizable value charges; (x) interest expense; (xi) income taxes; (xii) legal settlements, liquidated damages, and contractual terminations; (xiii) development expenses; (xiv) noncontrolling interests, except where otherwise noted; and (xv) other adjustments. Such adjustments are computed consistently with the provisions of our indebtedness to the extent that they can be derived from the financial records of the business.

Annual Financial Statements. The audited consolidated balance sheets of TEC as of December 31, 2025 and December 31, 2024; the related audited consolidated statements of operations, statements of comprehensive income, statements of cash flows, and statements of equity for the years ended December 31, 2025 and December 31, 2024, for the period from May 18, 2023 through December 31, 2023, and for the period from January 1, 2023 through May 17, 2023; and the related notes included in the Company’s Annual Report on Form 10-K filed with the SEC on February 26, 2026.

AOCI. Accumulated other comprehensive income or loss, which is a component of stockholders’ equity on the Consolidated Balance Sheets.

ARO. Asset retirement obligation.

ASR. Accelerated share repurchase.

AWS. Amazon Web Services, Inc. and its affiliates.

Board of Directors. The board of directors of Talen Energy Corporation.

Brandon Shores. A Talen-owned and operated generation facility in Curtis Bay, Maryland.

Brunner Island. A Talen-owned and operated generation facility in York Haven, Pennsylvania.

Capacity Performance. The sole class of capacity product that electricity providers within PJM can offer to satisfy PJM’s capacity obligation and thereby receive capacity payments from PJM. Auctions for this opportunity, generally referred to as capacity auctions, are scheduled by PJM periodically, up to three years in advance of the applicable PJM Capacity Year and in accordance with the terms of PJM’s Tariff and the FERC’s orders. Capacity Performance providers assume higher performance requirements during system emergencies and are subject to penalties for non-performance.

CCR. Coal Combustion Residuals, including but not limited to fly ash, bottom ash, and gypsum, that are produced from coal-fired electric generation facilities.

Colstrip. A generation facility comprised of four coal-fired generation units located in Colstrip, Montana. Talen Montana operates Colstrip, owns an undivided interest in Colstrip Unit 3, and has an economic interest in Colstrip Unit 4. Colstrip Units 1 and 2 were permanently retired in January 2020. See Note 7 to the Annual Financial Statements for additional information on jointly owned facilities and Talen Montana’s ownership interests in Colstrip.

Cornerstone Acquisition. Our acquisition of Waterford (Waterford Township, Ohio), Darby (Mount Sterling, Ohio), and Lawrenceburg (Lawrenceburg, Indiana) generation facilities from affiliates of Energy Capital Partners, which closed in June 2026. See Note 17 to the Interim Financial Statements for additional information.

Credit Agreement. The Credit Agreement, dated as of May 17, 2023, by and among TES, as borrower, the lending institutions from time to time parties thereto, Citibank, N.A., as administrative agent and collateral agent, and the joint lead arrangers and joint bookrunners parties thereto, which governs the RCF, TLB-1, TLB-2, TLB-3, and LCF, as the same may be amended, amended and restated, supplemented, or otherwise modified from time to time.

Credit Facilities. Collectively, the RCF, TLB-1, TLB-2, TLB-3 and LCF.

DOE. U.S. Department of Energy.

EPA. U.S. Environmental Protection Agency.

EPA CCR Rule. The national regulatory standards required by the EPA for the management of coal combustion residuals in landfills and surface impoundments.

EPA CSAPR. The Cross-State Air Pollution Rule, a federal program that aims to reduce power plant emissions that cross state lines and contribute to ground-level ozone and fine particle pollution in other states. A cap-and-trade system for both annual and ozone season periods is used to reduce the target pollutants—sulfur dioxide and nitrogen oxides. CSAPR regulations have been changed over time, and different versions of the regulations have been referred to as the “CSAPR Update,” the “Revised CSAPR Update,” and the “Good Neighbor Plan.”

EPA ELG Rule. The effluent limitation guidelines, which are national regulatory standards required by the EPA for wastewater discharged from specific industrial categories, including but not limited to coal-fired electric generation facilities, to surface waters and municipal sewage treatment plants.

EPA GHG Rule. An EPA rule that establishes carbon dioxide limits for new electric generating units and GHG guidelines for certain existing electric generating units.

EPA MATS Rule. The Mercury and Air Toxics Standards, the EPA technology-based emissions standards for mercury and other hazardous air pollutants emitted by generation units with a capacity of more than 25 MW.

EPS. Earnings per share.

Exchange Act. The Securities Exchange Act of 1934, as amended.

FERC. U.S. Federal Energy Regulatory Commission.

Freedom. A Talen-owned and operated generation facility in Salem Township, Luzerne County, Pennsylvania.

GAAP. Generally Accepted Accounting Principles in the United States.

Guernsey. A Talen-owned and operated generation facility in Byesville, Ohio.

GW. Gigawatt.

H.A. Wagner. A Talen-owned and operated generation facility in Curtis Bay, Maryland.

Interim Financial Statements. The condensed consolidated balance sheets of TEC as of September 30, 2026 and December 31, 2025; the related condensed consolidated statements of operations, statements of comprehensive income, and statements of equity for the three and nine months ended September 30, 2026 and 2025, the consolidated statements of cash flows for the nine months ended September 30, 2026 and 2025; and the related notes.

ISO. Independent System Operator.

LC. Letter of credit.

LCF. The $1.5 billion stand-alone letter of credit facility established under the Credit Agreement.

Martins Creek. A Talen-owned and operated generation facility in Bangor, Pennsylvania.

MMBtu. One million British Thermal Units.

Montour. A Talen-owned and operated generation facility in Washingtonville, Pennsylvania.

MW. Megawatt.

MWd. Megawatt-day.

MWh. Megawatt-hour.

NAV. Net asset value.

NDT. Nuclear facility decommissioning trust that is expected to fund Talen’s proportionate costs associated with the future decommissioning activities of Susquehanna.

NRC. U.S. Nuclear Regulatory Commission.

PEDFA Bonds. The following series of Pennsylvania Economic Development Financing Authority (“PEDFA”) Exempt Facilities Revenue Refunding Bonds: Series 2009A, due December 2038 (“PEDFA 2009A Bonds”); Series 2009B, due December 2038 (“PEDFA 2009B Bonds”); and Series 2009C, due December 2037 (“PEDFA 2009C Bonds”). The PEDFA 2009A Bonds were extinguished at emergence from bankruptcy in 2023; the PEDFA 2009B Bonds and PEDFA 2009C Bonds remain outstanding and are guaranteed by certain subsidiary guarantors which guarantee the obligations of TES under the Credit Facilities and the Unsecured Notes; and (ii) the obligations of TEM under the Secured ISDAs.

PJM. PJM Interconnection, L.L.C., the RTO that coordinates the movement of wholesale electricity in all or parts of Pennsylvania, New Jersey, Maryland, 10 other states, and the District of Columbia.

PJM BRA (or “BRA”). PJM Base Residual Auction, a component of PJM’s capacity market intended to secure power supply resources from market participants in advance of the PJM Capacity Year. It is usually held during the month of May three years prior to the start of the PJM Capacity Year. Under PJM’s “pay-for-performance” model, generation resources are required to deliver on demand during system emergencies or owe a payment for non-performance.

PJM Capacity Year. PJM capacity revenues for each delivery year covering the period from June 1 to May 31.

PJM Reliability Pricing Model. PJM’s capacity market, or the Reliability Pricing Model, formed under PJM’s Open Access Transmission Tariff, which is intended to ensure long-term grid reliability by securing the appropriate amount of power supply resources needed to meet predicted energy demand in the future. Under PJM’s “pay-for-performance” model, generation resources are required to deliver on demand during system emergencies or owe a payment for non-performance.

PP&E. Property, plant and equipment.

RCF. The senior secured revolving credit facility that provides $1.35 billion in aggregate revolving loan and LC commitments under the Credit Agreement.

RCRA. The Resource Conservation and Recovery Act, a federal law enacted in 1976 giving the EPA authority to control hazardous and non-hazardous solid waste from its creation to its disposal.

RGGI. The Regional Greenhouse Gas Initiative, a mandatory market-based program among certain states, including Maryland, New Jersey and Massachusetts, to cap and reduce carbon dioxide emissions from the power sector. RGGI requires certain electric power generators to hold allowances equal to their carbon dioxide emissions over a three-year control period. Pennsylvania has proposed joining this program.

RMR. A generation unit that is otherwise slated to be retired but agrees with PJM to remain operational beyond its requested deactivation date as a reliability-must-run resource to mitigate reliability concerns until necessary upgrades can be established.

RTO. Regional Transmission Organization.

Secured ISDAs. Certain bilateral secured International Swaps and Derivatives Association (“ISDA”) agreements and Base Contracts for Sale and Purchase of Natural Gas as published by the North American Energy Standards Board (“NAESB”) of Talen.

Secured Notes. The 8.625% Senior Secured Notes due 2030 issued by Talen Energy Supply, which were redeemed in full in April 2026.

SRP. The share repurchase program, under which the Board of Directors has authorized the Company to repurchase shares of TEC’s outstanding common stock.

Susquehanna. A nuclear-powered generation facility located near Berwick, Pennsylvania. A subsidiary of Talen Energy Supply operates and owns a 90% undivided interest in Susquehanna.

Talen (or the “Company,” “we,” “us,” or “our”). Talen Energy Corporation and its consolidated subsidiaries, unless the context clearly indicates otherwise.

Talen Energy Corporation (or “TEC”). Talen Energy Corporation, the parent company of Talen Energy Supply and its consolidated subsidiaries.

Talen Energy Marketing (or “TEM”). Talen Energy Marketing, LLC, a direct subsidiary of Talen Energy Supply that provides energy management services to Talen-owned and operated generation facilities and engages in wholesale commodity marketing activities.

Talen Energy Supply (or “TES”). Talen Energy Supply, LLC, a direct subsidiary of Talen Energy Corporation that, thorough subsidiaries, indirectly holds all of Talen’s assets and operations.

Talen Montana. Talen Montana, LLC, a Talen subsidiary that operates Colstrip, owns an undivided interest in Colstrip Unit 3, and is party to a contractual economic sharing agreement for Colstrip Units 3 and 4.

TLB-1. The $870 million senior secured term loan B facility, due November 2032, under the Credit Agreement.

TLB-2. The $850 million senior secured term loan B facility, due December 2031, under the Credit Agreement.

TLB-3. The$1.2 billion senior secured term loan B facility, due November 2032, under the Credit Agreement.

Unsecured Notes. Collectively, TES’s (i) 6.125% Senior Unsecured Notes due 2031; (ii) 6.375% Senior Unsecured Notes due 2033; (iii) 6.250% Senior Unsecured Notes due 2034; and (iv) 6.500% Senior Unsecured Notes due 2036.

WECC. The Western Electricity Coordinating Council, a non-profit corporation that assures a reliable and secure bulk electric system in the Western Interconnection, covering all or parts of Montana, 13 other U.S. States, Canada, and Mexico.