Natural gas was first used as a transportation fuel in Italy in the 1930s after World War II. There are more than 14.8 million vehicles on global roads today. Most located internationally in countries such as Iran, Pakistan and Argentina; these three countries make up the largest users of natural gas vehicles (NGVs). The U.S. has been slow to join the alternative fuel vehicle (AFV) market. Unfortunately, less than 120,000 vehicles are running on natural gas in the U.S. The average global growth rate is about 30 percent since 2000, however America’s NGV growth rate is only about 3.7 percent per year.

Over the past forty years, natural gas has increased in pressure four times, from 2,000 pounds per square inch (psi) to 2,400; 3,000; and most recently 3,600 psi. These increases of pressure, have advanced tanks to hold more and more fuel in smaller and smaller spaces. These advanced pressures were accomplished by new technologies in tank designs.

Todays tanks have advanced into four main categories: