Challenges - Research and Innovative Technology Administration ...

Technology is just one of the challenges a transition to hydrogen faces. There also are public and private
sector constraints, commercial issues, safety codes and standards that need to be implemented, safety
and emergency response trainings to be developed, as well as sustained commitment to the goal. This
section explores each of these areas, the progress that has occurred to date, as well as the remaining
barriers to be overcome and/or strategies that need to be decided.
Te c h n o l o g y Ch a l l e n g e s
If the country is to reduce significantly the greenhouse gases that threaten the environment, technological
innovations in a variety of areas will be necessary. Current Federal research, development and deployment
programs are playing key roles in this transition.
A hydrogen infrastructure faces three important technology challenges:
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Developing a fuel cell that can match a traditional car’s useful life and performance.
Improving storage capacity, performance and rate of refueling for a vehicle’s on-board fuel supply.
Closing the gap between the cost of hydrogen vehicles and fuel when compared to traditional cars
and gasoline.
Fuel Cell Performance
The NRC reported that fuel cell “stack” operating life has grown from about 1,000 hours in 2004 to more
than 1,500 hours. In 2008, DOE’s National Renewable Energy Laboratory documented an independent
validation of 140 fuel cell vehicles that showed nearly 2,500 hours under real world conditions. 1 More
recently, fuel cells have lasted as long as 7,300 hours in laboratory testing. 2 The Federal goal is 5,000
hours, which is equivalent to 150,000 miles of engine life for gasoline-powered vehicles.
Fuel cells also are beginning to match the distances between refuelings for gasoline vehicles – about 300
miles. NRC noted that a 2007 Toyota test did exceed the 300-range goal. However, the NRC reported,
it did so at an estimated cost of $15 to $18 per kilowatt hour for on-board fuel storage systems, which is
much higher than the goal of $2 per kilowatt hour for commercial success.
These benchmarks are important because, according to the NRC, they are the performance measures for
consumer and market acceptance of this technology.
Figure 2.2 shows the gaps between current performance and goals for hydrogen storage. Research continues
to close the gaps between the different compression systems and pressures for refueling hydrogen
fuel cell vehicles or HFCVs. The amount of progress toward goal depends on whether compression
agents are cryogenic, chemical or some other compound. To date, liquid hydrogen is the closest to goal,
followed by cryo-compressed fuel cells using the higher pressure rate of 700 bars.
NRC also cautioned that the size and weight of current fuel cell systems must be further reduced to match
fossil-fueled operating efficiency. It added that this also applies not only to the fuel cell stack, but also to
the ancillary components and major subsystems (e.g., fuel processor, compressor/expander, and sensors)
making up the balance of the power system.
In its report, Transitions to Alternate Transportation Technologies – a Focus on Hydrogen, the NRC assessed
the current state of fuel cell technology as:
“Lower-cost, durable fuel cell systems for light-duty vehicles are likely to be increasingly available
over the next 5-10 years and, if supported by strong government policies, commercialization and
growth of HFCVs [hydrogen fuel cell vehicles] could get underway by 2015, even though all DOE
targets for HFCVs may not be fully realized.”
1 DOE 2008 Annual Report http://www.hydrogen.energy.gov/pdfs/progress08/v_c_1_debe.pdf ; National Renewable Energy
Laboratory’s latest durability Controlled Demonstration Project (CDP): http://www.nrel.gov/hydrogen/docs/cdp/cdp_1.ppt and
completed 2008 CDPs: http://www.nrel.gov/hydrogen/pdfs/44256.pdf slide 4, also the “max projection.”
2
http://www.hydrogen.energy.gov/pdfs/progress08/v_c_1_debe.pdf
12 Challenges of Building a Hydrogen Infrastructure