COSTS ASSOCIATED WITH COMPRESSED NATURAL GAS VEHICLE FUELING INFRASTRUCTURE - Natural Gas-powered Cars and Trucks: Options and Issues - page 33

number of vehicles, the amount of fuel required, and the throughput of
the compressor. Vehicles are unattended during the fueling process,
which may take several minutes to many hours.

 Combination-fill : At combination-fill stations, users have the ability to

time-fill or fast-fill vehicles on demand. Many fleets use the
convenience of time-fill as the primary method of fueling, with fast-
fill available as needed.

A CNG station may be accessible only to a private fleet, open to the
public, or a combination of the two. Private stations are only available for use
by one fleet or several fleets that have contracts with the station owner. Fleets
use private stations so they can ensure their vehicles have priority for fueling
and maximize vehicle operation time. Public stations are openly accessed by
fleets and retail consumers; some public stations are only open during
specified business hours. They have fuel management systems that allow for
payment processing via credit card and fleet fuel card. Public stations are
utilized by fleets that prefer not to build, operate or maintain their own
infrastructure. Public-private stations are designed for a fleet to fuel its
vehicles with fast-fill or time-fill privately, while also providing publicly
available (or limited prearranged use) fast-fill dispensers on the street side of
the fence. A fleet may choose a public-private design to meet fuel supplier
throughput requirements, to benefit from economies of scale, or to meet
requirements of a grant or incentive.

Photo from Jeremy Talbot, Phoenix Energy Corp, NREL 28228.

FuelMaker FMQ-8 compressor and dual hose time-fill post in Gulf Breeze, Florida.