Exhibit 99.1 NRG Energy, Inc. Reports First Quarter Results and Reaffirms 2024 Financial Guidance • Strong financial and operational performance in the first quarter of 2024 with GAAP Net Income of $511 million and Adjusted EBITDA of$849 million • Diversified supply strategy performed well across all segments resulting in margin expansion in the East and West while mitigating the impacts of mild winter weather conditions in Texas • Consumer Energy and Smart Home platforms increased customer counts year ove ...