Propane, also known as liquefied petroleum gas (LPG or LP-gas), or autogas in Europe, is a high-energy alternative fuel. It has been used for decades to fuel light-duty and heavy-duty propane vehicles.
Propane is a three-carbon alkane gas (C3H8). Stored under pressure inside a tank, propane turns into a colorless, odorless liquid. As pressure is released, the liquid propane vaporizes and turns into gas that is used for combustion. An odorant, ethyl mercaptan, is added for leak detection.
Propane has a high octane rating and excellent properties for spark-ignited internal combustion engines. It is nontoxic and presents no threat to soil, surface water, or groundwater.
Propane is produced as a by-product of natural gas processing and crude oil refining. It accounts for about 2% of the energy used in the United States. Uses include home and water heating, cooking and refrigerating food, clothes drying, powering farm and industrial equipment, and drying corn. Rural areas that do not have natural gas service commonly rely on propane. The chemical industry uses propane as a raw material for making plastics and other compounds. Less than 2% of U.S. propane consumption is used for transportation fuel.
Visit the Alternative Fuels and Advanced Vehicles Data Center to learn more about propane.