Hydrogen - Energy Policy Analysis: A Conceptual Framework - page 200

reformers or electrolyzers to produce hydrogen fuel for personal vehicles, and they also incorporate a
hydrogen fuel cell that can provide heat and electricity for a home. One advantage of these stations is
they offer enhanced utilization of hydrogen gas and therefore help to defray some of the overall cost of
the hydrogen refueling station. Appliance-sized home energy stations are being developed by several
automobile manufacturers as a potential alternative to commercial refueling stations (USEIA 2008b).
There continues to be a lack of basic knowledge and information concerning failure rates for
components of the hydrogen infrastructure and especially for hydrogen tankers involved in transport
accidents. A salient and underexplored issue is leakage in enclosed structures, such as garages in
homes and commercial establishments. Hydrogen's explosion behavior following high-pressure
releases, and the related likelihood of occurrence, are poorly understood. Widely accepted stan-
dards, methodologies, mitigation techniques, and regulations are not yet available. “Accumulated
experience with hydrogen is presently limited to a number of industrial applications whose scale
and proximity to the general public are small” (Ricci, Bellaby, and Flynn 2010, 222-223). Many
hydrogen and fuel cell safety codes and standards in effect today are based on existing practices
from the chemical and aerospace industries. Efforts are under way by code and standards orga-
nizations to develop new, more appropriate codes and standards that will ensure the safe use of
hydrogen for transportation and stationary applications. Many of these new applications are in the
retail environment; new codes and standards reflect this transition from industrial to retail hydrogen
applications (USDOE 2011a). Improved hydrogen and fuel cell safety codes and standards are
needed before widespread adoption of hydrogen technologies by the general public.
FUEL CELL VEHICLES
Fuel cell vehicles, powered by hydrogen, have the potential to revolutionize our transportation
system. They are more efficient than conventional internal combustion engine vehicles and produce
no harmful tailpipe exhaust—their only emission is water. However, this exhaust water freezes at
low temperatures (Kawai 2004, 66), limiting the ability of fuel cell vehicles to start and operate
in cold seasons or climates. Fuel cell vehicles and the hydrogen infrastructure to fuel them are in
early stages of development. Fuel cell vehicles use electricity to power motors located near the
vehicle's wheels. In contrast to electric vehicles, which generally use electricity produced off the
vehicle to charge onboard batteries, fuel cell vehicles produce their electricity onboard using a
fuel cell. The fuel cell is powered by hydrogen from an onboard fuel tank (USDOE 2007).
Fuel cell vehicles can be fueled with pure hydrogen gas stored directly on the vehicle or ex-
tracted from a secondary fuel—such as methanol, ethanol, or natural gas—that carries hydrogen.
These secondary fuels must first be converted into hydrogen gas by an onboard device called a
reformer. Fuel cell vehicles fueled with pure hydrogen emit no pollutants, only water and heat.
Vehicles that use secondary fuels and a reformer produce small amounts of carbon dioxide, a
greenhouse gas. Due to its simplicity and weight-saving advantages, liquid hydrogen remains
the most convenient way to power hydrogen vehicles (Armaroli and Balzani 2011, 296). Fuel
cell vehicles can be equipped with other advanced technologies to increase efficiency, such as
regenerative braking systems often used today on electric vehicles, which capture the energy lost
during braking and store it in a large battery (USDOE 2007).
From 2000 to 2005, ninety-five light-duty fuel cell vehicles were placed in California and trav-
eled more than 220,000 miles on that state's roads and highways. These cars are still being tested
and are available to a few fleets and consumers (California Energy Commission 2011). Much
of the industry's fuel cell research and development information remains proprietary. In 2005,
General Motors and Daimler Chrysler acknowledged expenditures of more than $1 billion in fuel