Term Meaning Appalachian Consumer Rate Relief Funding Appalachian Consumer Rate Relief Funding LLC, a wholly-owned subsidiary of APCo and a consolidated VIE formed for the purpose of issuing and servicing securitization bonds related to the under-recovered ENEC deferral balance. APTCo AEP Appalachian Transmission Company, Inc., a wholly-owned AEPTCo transmission subsidiary. APSC Arkansas Public Service Commission. ARAM Average Rate Assumption Method, an IRS approved method used to calculate the reversal of Excess ADIT for rate-making purposes. ARO Asset Retirement Obligations. ASU Accounting Standards Update. CAA Clean Air Act. CAA of 2021 Consolidated Appropriations Act of 2021 signed into law in December 2020. Cardinal Operating Company A jointly-owned organization between AGR and a nonaffiliate. The nonaffiliate operates the three unit Cardinal Plant and wholly-owns Units 2 and 3. CARES Act Coronavirus Aid, Relief, and Economic Security Act signed into law in March 2020. CLECO Central Louisiana Electric Company, a nonaffiliated utility company. CO  Carbon dioxide and other greenhouse gases. Conesville Plant A retired, single unit coal-fired generation plant totaling 651 MW located in Conesville, Ohio. The plant was jointly-owned by AGR and a nonaffiliate. Cook Plant  Donald C. Cook Nuclear Plant, a two-unit, 2,288 MW nuclear plant owned by I&M. COVID-19 Coronavirus 2019, a highly infectious respiratory disease. In March 2020, the World Health Organization declared COVID-19 a worldwide pandemic. CRES provider Competitive Retail Electric Service providers under Ohio law that target retail customers by offering alternative generation service. CSAPR Cross-State Air Pollution Rule. CSPCo  Columbus Southern Power Company, a former AEP electric utility subsidiary that was merged into OPCo effective December 31, 2011. CWA Clean Water Act. CWIP Construction Work in Progress. DCC Fuel DCC Fuel IX, DCC Fuel X, DCC Fuel XI, DCC Fuel XII, DCC Fuel XIII, DCC Fuel XIV and DCC Fuel XV, consolidated VIEs formed for the purpose of acquiring, owning and leasing nuclear fuel to I&M. Desert Sky Desert Sky Wind Farm LLC, a 170 MW wind electricity generation facility located on Indian Mesa in Pecos County, Texas in which AEP owns a 100% interest. DHLC Dolet Hills Lignite Company, LLC, a wholly-owned lignite mining subsidiary of SWEPCo. DIR Distribution Investment Rider. DOE U. S. Department of Energy. EIS Energy Insurance Services, Inc., a nonaffiliated captive insurance company and consolidated VIE of AEP. ENEC Expanded Net Energy Cost. Energy Supply AEP Energy Supply LLC, a nonregulated holding company for AEP’s competitive generation, wholesale and retail businesses, and a wholly-owned subsidiary of AEP. Equity Units AEP’s Equity Units issued in August 2020 and March 2019. ERCOT  Electric Reliability Council of Texas regional transmission organization. ESP Electric Security Plans, a PUCO requirement for electric utilities to adjust their rates by filing with the PUCO. ETT  Electric Transmission Texas, LLC, an equity interest joint venture between AEP Transmission Holdco and Berkshire Hathaway Energy Company formed to own and operate electric transmission facilities in ERCOT. Excess ADIT Excess accumulated deferred income taxes. FAC Fuel Adjustment Clause. 2 ii