Diesel fuel is refined from crude oil at petroleum refineries. Most freight and delivery trucks as well as trains, buses, boats, and farm, construction, and heavy automobiles have diesel engines. Some small trucks and cars also have diesel engines. Diesel fuel is also used in diesel engine generators to generate electricity in remote villages among other locations around the world. Many industrial facilities, large constructions, institutional facilities, hospitals, and electric utilities have diesel generators for backup and emergency power supply.