Exhibit 99.1 NRG Energy, Inc. Reports Full Year 2023 Financial Results • Exceeded revised guidance on Free Cash Flow before Growth and achieved high end of Adjusted EBITDA revised guidance • Delivered exceptional operational performance through volatile summer and winter conditions • Expanded margins and grew customer count in both the Energy and Smart Home portfolios • Completed $300 million Direct Energy synergy program and approximately $40 million toward current $250 million cost savings program • Ahead ...