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Hydrogen (H2) is being aggressively explored as a fuel for passenger vehicles. It can be used

in fuel cellsto power electric motors or burned in internal combustion engines (ICEs).

It is an environmentally friendly fuel that has the potential to dramatically reduce ourdependence on imported oil but several significant challenges must be overcome before itcan be widely used.

Benefts

Produced Domestically.Hydrogen can be produced domestically from several sourcesreducing our dependence on petroleum imports.

Environmentally Friendly.Hydrogen produces no air pollutants or greenhouse gases whenused in fuel cells! it produces only nitrogen oxides ("#x) when burned in ICEs.

Challenges

Fuel Cost & Availability.Hydrogen is currently expensive to produce and is only availableat a handful of locations mostly in California.

Vehicle Cost & Availability.$uel cell vehiclesare currently far too expensive for mostconsumers to afford and they are only available to a few demonstration fleets.

Onboard Fuel Storage.Hydrogen contains much less energy than gasoline or diesel on aper%volume basis ma&ing it difficult for hydrogen vehicles to go as far as gasoline vehicles

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between fillups'about miles. *echnology is improving but the onboard hydrogenstorage systems do not yet meet si+e weight and cost goals for commerciali+ation.

,everal challenges technical and otherwise mustbe overcome before fuel cell vehicles ($C-s) willbe a successful competitive alternative forconsumers.

Onboard Hydrogen Storage

,ome $C-s store enough hydrogen to travel as far as gasoline vehicles between fill%ups'about miles'but the storage systems are still too large heavy and expensive.

$C-s are more efficient than conventional cars and hydrogen contains three times moreenergy per weightthan gasoline does. However hydrogen gas contains only a third of theenergy per volumegasoline does ma&ing it difficult to store enough hydrogen to go as far asa gasoline vehicle on a full tan&'at least within si+e weight and cost constraints.

Hydrogen can be stored in three basic ways

As a gas in high-ressure tan!s.Current $C-

designs use high%pressure (/% to 0%psi)tan&s to store hydrogen. *hese systems are largeheavy and costly but they are the most cost%

effective solution in the near term. As a li"uid at sub-#ero temeratures $-%'(F).,ince hydrogen is densest as a

li1uid this method allows more hydrogen storage than gaseous high%pressure storage

but costs times more and suffers from safety and performance issues. i1uidstorage isn3t li&ely to be commercially viable for more than a decade.

*aterials-based storage.Hydrogen can be stored inside solid materials throughabsorption adsorption and chemical reactions. 4aterials%based systems have the

potential to be small and lightweight and may prove to be the best solution in the longterm. However they are still in the early stages of development.

Vehicle Cost

$C-s are currently too expensive to compete with hybrids and conventional gasoline and

diesel vehicles. 4anufacturers must bring down production costs especially the costs of thefuel cell stac& and hydrogen storage.

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$uel cell system costs have decreased significantly over the past several years but are stillnearly twice as high as those for internal combustion engines.

i&ewise onboard hydrogen storage costs are currently 50/65078&9h for high%pressuregaseous storage while the commerciali+ation target is 528&9h. *here is potential to reduce

this cost using lower%cost carbon fiber tan&s or materials%based storage technologies such asmetal hydrides.

Getting Hydrogen to Consumers

*he extensive system used to deliver gasoline from refineries to local filling stations cannotbe used for hydrogen. "ew facilities and systems must be constructed for producingtransporting and dispensing hydrogen to consumers.

Competition with Other Technologies

4anufacturers are still improving the efficiency of gasoline% and diesel%powered engineshybrids are gaining popularity and advances in battery technology are ma&ing plug%inhybrids and electric vehicles more attractive. $C-s will have to offer consumers a viablealternative especially in terms of performance durability and cost to survive in this ultra%competitive mar&et.

Saety

Hydrogen li&e any fuel has safety ris&s and must be handled with caution. 9e are familiar

with gasoline but handling compressed hydrogen will be new to most of us. *hereforedevelopers must optimi+e new fuel storage and delivery systems for safe everyday use andconsumers must become familiar with hydrogen3s properties and ris&s.

Public cceptance

$inally fuel cell technology must be embraced by consumers before its benefits can bereali+ed. Consumers may have concerns about the dependability and safety of these vehicles

:ust as they did with hybrids.