Zero emission

Zero emission refers to a motor or engine that, by virtue of being powered by electricity or more exotic means, generates no by-products other than water. The EV1 automobile built by General Motors is often cited as an example of a zero-emissions vehicle, or ZEV. Technically, the EV1's motor, as well as other battery-powered electric propulsion units that rely on a national power grid for charging, are displaced-emission powerplants. True zero-emission power includes solar power, wind power, tidal power and hydroelectric power. Nuclear fusion would, in theory, fall into this category as well.