NIAGARA MOHAWK POWER CORPORATION D/B/A NATIONAL GRID -PURPOSE: THE FILING OF NEW TARIFF AMMENDMENTS TO P.S.C. NO. 220 ELECTRICITY TO COMPLY WITH THE COMMISSION’S ORDERS DATED JANUARY 19, 2023, IN P.S.C. CASES 14-M-0565 AND 20-M-0266. TEXT: Notice is hereby given that Niagara Mohawk Power Corporation d/b/a National Grid has filed new tariff amendments with the Public Service Commission to comply with the Commission’s Orders dated January 19, 2023, to become effective February 1, 2023. ELECTRIC Niagara Mohawk Power Corporation d/b/a National Grid (“NMPC”) filed tariff revisions in response to the New York State Public Service Commission (“PSC”) Order Authorizing Phase 2 Arrears Reduction Program (“PSC Order”). Phase 2 of the Arrears Reduction Program provides automatic relief through direct bill credits to residential non- Energy Affordability Program (“EAP”) and small-commercial customers who have eligible arrears and who did not receive relief under the Phase 1 program, by issuing a one-time bill credit to reduce or eliminate accrued arrears through May 1, 2022. Notice is hereby given that starting on February 1, 2023, the AMP Surcharge will include recovery of Phase 2 program costs through customer bills and will be included in the Delivery line item. The AMP Surcharge Statement can be found on the Company's website. For Residential customers: https://www.nationalgridus.com/upstate-ny-business/Rates/Rate- Statements.aspx and Business customers https://www.nationalgridus.com/upstate-nybusiness/ Rates/Rate-Statements.aspx. Copies of the proposed revision are available for public inspection and can be obtained or on the Company’s website at: http://www.nationalgridus.com. 2471118 2-2-9-16-23-4t