Natural gas offers tremendous opportunities for reducing the use of petroleum in transportation. Medium and heavy-duty fleets, which have significant potential to use natural gas, currently consume more than a third of the petroleum in transportation in the U.S. Natural gas is an excellent fit for a wide range of heavy-duty applications, especially transit buses, refuse haulers, and Class 8 long-haul or delivery trucks. In addition, natural gas can be a very good choice for light-duty vehicle fleets with central refueling. See the Alternative Fuels Data Center for a description of the uses and benefits of natural gas vehicles or its Laws and Incentives database for information on tax incentives. The Vehicle Technologies Office (VTO) supports the development of natural gas engines and research into renewable natural gas production.
VTO has supported the development of natural gas engines for heavy-duty vehicles since 1992. In fact, nearly all heavy-duty natural gas engines sold in the U.S. today can trace their roots to DOE's support of research and/or partnerships between VTO and industry. In particular, VTO's work with Cummins-Westport led to the development of their 8.9 L ISL G engine, which met EPA's 2010 emissions standards years before the requirement. More recently, VTO worked with the National Renewable Energy Laboratory (NREL), the California Energy Commission, and the South Coast Air Quality Management District to support projects to develop highly efficient natural gas engines for medium and heavy-duty trucks and buses. For example, Cummins-Westport has developed an 11.9 L natural gas engine that they are integrating into refuse trucks and Class 8 delivery trucks. These engines have been highly successful, with an increasing number of fleets adopting natural gas for a wider range of applications. VTO continues to work with stakeholders to discuss research needs for natural gas engines and vehicles through the Natural Gas Vehicle Technology Forum.
To increase the sustainability of natural gas, VTO has also supported research into the production of renewable natural gas. Renewable natural gas is a purified version of biomethane that results from decomposition at landfills, wastewater treatment plants, and livestock facilities. When it is used in vehicles in place of diesel, it reduces greenhouse gas emissions by 88 percent or more. For more information on this fuel's potential, see the AFDC's renewable natural gas resources. Collaborating with industry and national laboratories, VTO demonstrated the feasibility of purifying biomethane from landfills. This project also identified more than 300 landfills producing biomethane that could each produce up to 20,000 gallons of liquefied natural gas per day. Since then, further research has identified more than 8,000 livestock facilities that could also support renewable natural gas production. Building on this work and often with the assistance of Clean Cities coalitions, a number of companies have since implemented this technology. Now, landfills and livestock facilities are using this technology to produce fuel and power local natural gas vehicles, including refuse haulers, milk haulers, and transit buses. With VTO's support, the organization Energy Vision recently released a guide for developing renewable natural gas projects.