Relating to supplemental environmental projects authorized by the Texas Commission on Environmental Quality.

HB 4400 allows local governments in Texas to use supplemental environmental projects funded through the Texas Commission on Environmental Quality (TCEQ) for specific clean energy initiatives. It directly affects local governments by permitting them to cover the full cost of purchasing alternative fuel vehicles (like buses and trucks), related heavy equipment, and energy efficiency upgrades for public buildings. Key provisions require TCEQ to approve projects covering entire vehicle/equipment costs (not just cost differences from conventional options) and mandate minimum 5-year contracts renewable for additional 5-year terms. The bill takes effect September 1, 2025, aiming to streamline adoption of cleaner transportation and building technologies.