Tex. Health & Safety Code § 394.002

The commission shall establish and administer the Texas natural gas vehicle grant program to encourage an entity that has a heavy-duty or medium-duty motor vehicle to repower the vehicle with a natural gas engine or replace the vehicle with a natural gas vehicle. Under the program, the commission shall provide grants for eligible heavy-duty motor vehicles and medium-duty motor vehicles to offset the incremental cost for the entity of repowering or replacing the heavy-duty or medium-duty motor vehicle.