Modern pumpjacks are powered by a prime mover. This is commonly an electric motor, but internal combustion engines are used in isolated locations without access to electricity, or, in the cases of water pumpjacks, where three-phase power is not available (while single phase motors exist at least up to , providing power to single-phase motors above can cause powerline problems, and many pumps require more than 10 horsepower). Common off-grid pumpjack engines run on natural gas, often casing gas produced from the well, but pumpjacks have been run on many types of fuel, such as propane and diesel fuel. In harsh climates, such motors and engines may be housed in a shack for protection from the elements. Engines that power water pumpjacks often receive natural gas from the nearest available gas grid.