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Natural Gas and Liquefied Natural Gas for Transportation In California


More vehicles in California are fueled with compressed natural gas (CNG) than any other alternative transportation fuel.* More than 33,000 vehicles are currently fueled with CNG or LNG in California. There are more than 150 public and private natural gas fueling locations in the state, and some households even have appliances that allow the driver to fuel at home.

Natural gas (methane) has been used as motor fuel in California for more than 20 years. Today, public and school buses, some package and beverage delivery applications (such as UPS and the U.S. Postal Service), as well as limited trash truck and port applications are fueled by natural gas The fueling infrastructure is in place for further expansion. However, fleets that refuel at a central location seem to be best suited for natural gas.

There are more than 130,000 natural gas vehicles (NGVs) on America's roads, including passenger cars and trucks, heavy-duty transit buses, school buses, and refuse haulers. According to the U.S. Department of Energy, more than ten percent of our nation's fleet of transit buses and 20 percent of new buses on order operate on natural gas. The number of natural gas refueling stations, currently numbering over 1,300 across the country, is growing.

When compared with gasoline and diesel fuel, CNG LNG are lower-carbon fuels and produce about 25 percent less greenhouse gas (GHG) emissions in on-road and off-road/marine applications. Natural gas has also been identified as economically contributing to the AB 1007 goals for petroleum fuel displacement and "no net material increase in emissions."

The NGV industry has grown significantly over the past two decades but some technical advancements remain that, if realized, would further accelerate NGV use and displace petroleum use and provid air quality and GHG reduction benefits.

CNG and LNG have been historically less expensive than gasoline and diesel fuel on an energy-equivalent basis. However, NGVs and fueling infrastructure are more expensive. Also, natural gas heavy-duty vehicles (HDVs) have historically experienced a fuel efficiency penalty relative to diesel counterparts. Therefore, the overall economics are favorable if the net fuel cost savings (i.e., total fuel savings over diesel) can amortize the additional equipment, operation, and maintenance costs. This equation favors high fuel use applications, particularly HDVs, which represent the fastest growing NGV segment in California.

LNG For Vehicles
Fewer vehicles are using LNG than CNG in California because of the need to keep the fuel at very low temperatures. Liquefied natural gas, or LNG, is natural gas in a liquid form that is clear, colorless, odorless, non-corrosive, and non-toxic. LNG is produced when natural gas is cooled to minus 259 degrees Fahrenheit through a process known as liquefaction. During this process, the natural gas, which is primarily methane, is cooled below its boiling point, whereby certain concentrations of hydrocarbons, water, carbon dioxide, oxygen, and some sulfur compounds are either reduced or removed. LNG is also less than half the weight of water, so it will float if spilled on water.

* Note: There are approximately 300,000 flexible fuel vehicles in the state that can use E85 (85% ethanol and 15% gasoline). Howver, there are only five public E85 fueling stations (as of June 2008).


Natural Gas Prices for Vehicles

The price paid for natural gas for a vehicle depends on how it is fueled. The rates/tariffs are set by the California Public Utilities Commission, which regulates the state's natural gas utility comapnies. Below is an example of the prices effective May 1, 2008, charged by PG&E. For the price that you would pay, please check with your local natural gas utility company.

Per Therm Per Gasoline
Gallon Equivalent
Procurement Charge: $0.96309 N/A
Transportation Charge: 0.93799 N/A
Total: $1.90108 $2.42579

Source: PG&E Schedule G-NGV2.
Note: Service is for compressed natural gas (CNG) at PG&E-owned natural gas fueling stations delivering CNG at approximately 3,000 pounds per square inch (PSI).