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Transitions to Alternative Transportation Technologies — A Focus on Hydrogen
same space envelope and correspondingly provide almost 50% more range.”
The DOE goal for hydrogen storage systems is enough fuel to travel about 300 miles (a similar range to that of today’s gasoline ICEV). The amount of hydrogen needed for this depends on the fuel consumption of the HFCV. Toyota demonstrated in September 2007 a 4,145-pound, five-passenger HFCV with 700-bar compressed hydrogen storage that traveled 350 miles in real-world on-the-road conditions in a drive from Osaka to Tokyo. Toyota calculated that the vehicle is now capable of achieving a cruising distance of 466 miles. It appears that the latest HFCV designs using high-pressure hydrogen storage can meet the 300-mile goal.
Less progress has been made in meeting the cost targets for such a system. The 2005 NRC review of the Freedom-CAR and Fuel Partnership listed the circa 2004 cost status as $15/kWh and $18/kWh for the 350- and 700-bar systems, respectively. The 2008 NRC review of the FCFP did not update these costs, and discussions with auto companies indicated that little has changed with regard to costs for compressed hydrogen storage.
Based on these facts, the committee concludes that compressed hydrogen storage systems that provide practical driving ranges (300 miles) should be available in 2015, but the cost will be higher than that of the current FreedomCAR targets. There is potential to lower the costs in the future through the use of lower-cost carbon fiber tanks or by using future solid storage systems.
In summary, onboard hydrogen storage to achieve a 300-mile driving range has been the greatest technical challenge of all in trying to develop an HFCV. The quest to identify solid storage materials to achieve the DOE-FCFP 2015 goals, including the cost goal of $2/kWh, is in the research stage. It is not clear at this time whether a suitable material will be identified that can meet these goals and timing targets, but to achieve the desired driving range between refueling stops, the industry is prepared to use more expensive high-pressure hydrogen storage tanks that consume more space and add to vehicle weight while research progresses toward a commercially viable solid hydrogen storage material.
Technology Basis for the Scenario Analysis
The committee concludes that not all the FreedomCar goals for 2015 are likely to be met, but the technology may be good enough for high-volume HFCVs to be introduced then anyway. For the scenarios analyzed in Chapter 6, the committee assumes that the hydrogen storage system will be larger and more costly than the targets but will be able to provide adequate driving distance. The fuel cell system will be more costly than the target initially but will provide the necessary performance expected of an early commercial vehicle. Although the initial costs will be high, there is considerable scope for continued cost improvement through technology improvements and high-volume production. For the maximum practicable case, the committee estimates that the fully learned out cost for the fuel cell drive train (the fuel cell system, hybrid battery, motor, and auxiliaries) for the automaker (OEM) will be $50/kW. This corresponds to a fuel cell system cost of $30/kW plus added costs for a hybrid battery, electric motor, and other components. Of the $30/kW fuel cell system cost, about half is due to the fuel cell stack and half to the balance of the plant. Hydrogen storage costs the OEM $10/kWh compared to DOE 2015 goal of $2/kWh for solid storage. The fuel cell cost is the same as the 2015 DOE goal, while the storage costs are higher than the DOE 2015 goal because high-pressure hydrogen gas storage was assumed in the latter.
CONCLUSION: If appropriate policies are adopted toaccelerate the introduction of hydrogen and HFCVs,hydrogen from distributed technologies can be providedat reasonable cost to initiate the maximum practicablecase. If technical targets for central production technologies are met, lower-cost hydrogen should be available to fuel HFCVs in the latter part of the time frameconsidered in this study. Additional policy measures arerequired to achieve low-carbon hydrogen production inorder to significantly reduce CO2emissions from centralcoal-based plants.
CONCLUSION: Lower-cost, durable fuel cell systemsfor light-duty vehicles are likely to be increasingly available over the next 5-10 years and, if supported by stronggovernment policies, commercialization and growth ofHFCVs could get underway by 2015, even though allDOE targets for HFCVs may not be fully realized.
Considerable progress has been accomplished since TheHydrogen Economy (NRC, 2004) toward a commercially viable hydrogen fuel cell vehicle due to the concentrated efforts of private companies and governments around the world. Although considerable progress is still required in fuel cell costs, durability, and storage before commercialization can begin, the automotive industry appears committed to the technology for the long run. Thus, lower-cost, durable fuel cell systems for light-duty vehicles are likely to be available in a growing number of vehicles over the next 5-10 years, but meeting all 2015 DOE commercialization targets will be difficult.
Bereisa, J. 2007. Energy Diversity: The Time Is Now. Presentation to the committee, June 25.
Brunner, T. 2006. BMW Clean Energy—Fuel Systems. Presented at the CARB ZEV Technology Symposium. Sacramento, California.
Burns, L. 2007. Quoted in Reuters dispatch, May 17.