H2Tech - Q2 2022 - 29

SPECIAL FOCUS: HYDROGEN INFRASTRUCTURE DEVELOPMENT
Cracking the chicken-and-egg problem
of large-scale H2
refueling networks
J. LI, NICE America Research Inc., Mountain View, California; and
A. KU and J. MCROBIE, Clear Skies Hydrogen, Mountain View, California
As of December 2021, only 53 public
H2 fueling stations (48 retail, 5 transit)
were present in the U.S., concentrated in
clusters around California urban centers
or existing as standalone stations.1
large-scale deployment of H2
For the
fuel cell vehicles
across the U.S. to be feasible, tens
of thousands more stations are needed
and geographic coverage must drastically
expand. This creates a " chicken-and-egg "
investment problem: vehicle operators
need confidence that fueling capacity will
be readily available before investing in an
H2
-fueled vehicle, but fuel suppliers need
assurance that sufficient H2
-fueled vehicles
will be deployed to justify capital investment
in refueling stations. How, then,
can we grow fleets and refueling stations
with confidence?
This article proposes a practical path
for establishing a large-scale H2
refueling
network by focusing on heavy duty
vehicles-more specifically, on truck
fleets-whose operational profiles favor
the fast refueling times and long vehicle
ranges afforded by fuel cell vehicles, and
on the creation of a fueling network along
long-haul trucking corridors using a new
liquid H2
(LH2
) pumping technology.
Once established, such a network could
provide the backbone of a larger-scale
network open to both private fleet and
retail consumers.
Modular LH2
stations as building
exists across the U.S. in supis
energy intensive, the
is liq;
by
FIG. 1. Modular refueling system based on a submergible pump (top); three configurations of a
refueling system, in order of increasing size (bottom).
H2Tech | Q2 2022 29
blocks. A robust commercial infrastructure
for LH2
port of industrial processes. While liquefaction
of H2
added costs can be offset by savings from
distribution and onsite storage: H2
uefied at large, centralized facilities and
delivered to end users by tanker truck.
Liquid tankers carry about 4 t of LH2
contrast, the tube trailers used to transport
H2 as a compressed gas can carry
per day, liquid deonly
1 t of product at a time. For operations
using a few t of H2
livery can be competitive with delivery by
pipeline or onsite production. Storing H2
onsite as a cryogenic liquid is also safer,
less costly and has a smaller carbon footprint
than pressurized gas storage.2
Already a cost-competitive option
refueling stations on a small scale,
for H2
LH2 delivery is becoming increasingly atsupply
have been actractive
to larger operations. Announced
investments in LH2
celerating over the last 3 yr, resulting in
the addition of nearly 200 tpd of capacity
globally, and a majority of U.S. public transit
agencies operating fuel cell buses have
opted for LH2
-based refueling stations.3, 4
Although their designs may differ in other
areas, all such stations have one feature
in common: the use of an LH2
deliver fuel to the dispenser. LH2
pump to
pumps
are an area of active technology development,
and one recently demonstrated 4,5
new pump design could potentially enable
modular refueling stations at scale.
The modular refueling system shown
in FIG. 1 uses this pump, which was adapted
from LNG applications, to deliver
cold, high-pressure gas to a fuel dispenser.
LH2
is drawn from the tank and pressurized
by the pump. The outlet stream
then flows through a vaporizer to produce
high-pressure, gaseous H2
, and the
temperature is adjusted using a thermally
integrated circuit before delivery to the
vehicle. This system operates in a " direct
fill " mode in which fuel is transferred directly
from the onsite storage tank to the
vehicle without the need for intermediate
high-pressure storage, reducing both
capital cost and energy demand. The direct
fill system can operate continuously
as long as there is fuel in the onsite tank.
Together with the pump, this represents a
significantly simplified refueling process
that allows modularization of the refueling
station where it is used. These fueling
systems are capable of delivering SAE
J2601-compliant fills at 35 MPa pressure;
versions capable of delivering 70 MPa
fills are in development.

H2Tech - Q2 2022

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