A CNG refueling station can be installed wherever there is a natural gas pipe in the ground. Canada has an extensive pipeline network for the distribution of natural gas. Local gas utilities can provide information on line pressures and line locations for fleets who are considering installing their own CNG station. Canada has well-established codes and standards for CNG refueling stations.
There are two main types of CNG refueling stations that differ based on the speed at which they can fuel vehicles.
Fast Fill Stations
Fast fill stations dispense CNG at rates similar to liquid fuels. These stations have large compressors and high-pressure storage tanks to support rapid vehicle refueling. A fast fill station can be designed so that each vehicle is filled from the storage tanks. This is called a “cascade” fast fill station. The other option is to fill vehicles mainly from the compressor, which is called a “buffer” fast fill system.
- Compressor – to compress gas; typically run by electric motor
- Dryer – to remove moisture from gas
- Storage vessels – tubes or spheres to hold pressurized gas
- Dispenser – 1 or more hoses
- Control system – gas and electrical controls with remote access
Compressors are critical for CNG stations to be in service. Typically, stations are designed with more than one compressor. If a compressor needs to be taken out of service for maintenance, the station can still operate.
Time Fill Stations
Time fill stations refuel fleet vehicles over a period of eight to twelve hours. Vehicles are plugged in at filling posts at the fleet owner’s site for overnight refueling. A time fill system provides an operating advantage because vehicles do not need to line up for fuel at the end of a shift.
A combination time fill and fast fill station is also an option. This kind of station provides limited fast fill refueling if a vehicle must return to the yard to top up with fuel during a shift. Optional fuel storage tanks are needed for time fill stations that include some fast fill refueling capability.
No special training is required to refuel a vehicle at a CNG station. A sealed system is created when the dispenser hose is connected to the vehicle receptacle. Fuel will only flow out of the dispenser when it is connected. CNG stations are the most common type of natural gas refueling station.