The CCNG facility has a large, multi-stage gas compressor that requires gas and lube oil cooling subsystems. Additionally, a regenerative gas drying system is required. This impact is further compounded by and the fact that very few CNG dispensers can compensate for the gas temperature within the cylinder. In the author's opinion, this phenomenon has not yet been acknowledged adequately by the CNG industry. It has resulted in the misrepresentation of the actual range of CNG vehicles when fast-filled.
Compressors require significant maintenance time.
High pressure CNG cascade storage systems can cause artificially high vehicle tank pressure readings at the CNG dispenser during fast-filling. This can cause the dispenser to cycle off and on near the end of the refueling process in order to reach the desired end pressure. These interruptions in the CNG filling prolong the time to refuel. The design is based on the fact that it takes a lot less power and equipment to pump a pound of liquid than to compress a pound of gas to the same pressure . At no time is LNG present in the CNG dispenser or vehicle tank.