What Are They? NGVs, or Natural Gas Vehicles, look like any other vehicle. The difference is, NGVs operate on natural gas as opposed to the fuel we typically pump into our vehicles’ tanks. Found in reservoirs deep below the earth’s surface and ocean floors, natural gas is formed by the decay of organic matter. Natural gas reserves come from large quantities of plant and animal remains that have accumulated between layers of sediment on the bottoms of lakes and oceans over millions of years. The pressure from the layers of sediment and the heat from the earth's core convert the organic materials into natural gas, petroleum and coal. All oil deposits contain natural gas, although natural gas is often found without oil. NGVs typically use one of two varieties of natural gas: Compressed Natural Gas (CNG) or Liquefied Natural Gas (LNG). The preferred fueling method for light to medium NGVs, CNG stations dispense between five and ten gallons per minute. Heavy-duty NGVs with weight and range requirements typically fuel up on LNG, which allows them to store more fuel on board with less tank weight. L/CNG stations can service both types of NGVs by converting LNG into CNG.