Abstract: Two LNG storage tanks receive LNG from a fill station. The two storage tanks are connected to an overflow tank into which the LNG flows during pressurization of the system. The overflow tank is connected to the use device, i.e. the vehicle's engine, through a heat exchanger to provide high pressure natural gas thereto. The fill station initially delivers LNG to the two storage tanks until the tanks are substantially filled with LNG whereupon the fill station automatically stops delivery of LNG and begins to deliver natural gas vapor to the storage tanks until the pressure in the system reaches a predetermined maximum that is equal to or greater than the pressure required by the use device. During the pressurization of the system some of the LNG in the two storage tanks is forced into the overflow tank by the incoming natural gas vapor.