The document discusses different types of alternative fuel vehicles: 1. Electric cars, which are zero-emissions and can be charged from renewable energy sources like batteries with a capacity of 25kWh. 2. Compressed air cars, which are also zero-emissions and can be charged from renewable energy sources, but store much less energy onboard than gasoline or lithium-ion battery electric cars. 3. The concept of a compressed air car involves doing a slow pre-charge of a local air reservoir followed by a fast transfer of compressed air from the local station to the vehicle's reservoir.