Exhibit 99.1 Sunnova Reports Fourth Quarter and Full Year 2023 Financial Results Fourth Quarter 2023 and Recent Highlights • Deployed over 34,000 customers in the fourth quarter; bringing total customer count to 419,200 as of December 31, 2023; • Increased single customer economics as expressed through fully burdened unlevered return; • Continued to execute a cost reduction plan for 2024 enhancing cash generation; and • Initiated 2025 cash generation guidance between $200 million and$500 million. HOUSTON, ...