Since 1977, the people of the U.S. Department of Energy have been delivering the science, innovation and expertise required to advance America's energy, economic and national security. In this photo taken in June 1988, former Secretary of Energy John Herrington takes the wheel of a clean natural gas vehicle in front of the Energy Department in Washington, DC. Today, natural gas powers over 112,000 vehicles in the United States and roughly 14.8 million vehicles worldwide. Natural gas vehicles, which can run on compressed natural gas, are a good option for high-mileage, centrally-fueled fleets that operate within a limited area. | Photo courtesy of the Department of Energy.