Exhibit 99.1 FOR IMMEDIATE RELEASE Contacts: Analysts: Charlotte Ancel, Charlotte.Ancel@Avangrid.com, 203-997-7366 Media: Leo Rosales, Leo.Rosales@Avangrid.com, 518-419-2401 AVANGRID REPORTS FULL YEAR 2023 FINANCIAL RESULTS • Delivered earnings of $2.03 per share and adjusted earnings of$2.09 per share (above Outlook range), representing +18% growth excluding 2022 offshore wind gain and upfront tax benefits from the enactment of the Inflation Reduction Act in 2022 • Secured multi-year rate plans in New Yor ...