(mpg) in 2015 and 42.4 mpg in 2050). The hydrogen fuel cell vehicle has about 1.4 times the fuel economy of the gasoline hybrid in Case 2 (which is assumed to get 36.5 mpg in 2015 and 60.3 mpg in 2050). In Case 1b (Hydrogen Partial Success), the fuel vehicle has 1.75 times the fuel economy of the efficient gasoline ICEV.
Analysis of all three hydrogen cases is detailed in Appendix C. Case 1b (Hydrogen Partial Success) gave rise to only modest reductions in oil use and CO2 emissions by 2050. The cost of making a transition was roughly twice that of Case 1 (Hydrogen Success) and took several years longer to complete.
Case 1a (Accelerated Hydrogen ) gave rise to a marginally faster transition, and the resulting reductions in oil use and CO2 emissions were 25-33 percent greater than Case 1 (Hydrogen Success) by 2050. However, the estimated transition cost for Case 1a was many times that for Case 1, because it assumed that more of the expensive early vehicles are pushed into the market in the early years of the transition.
For these reasons the committee chose Case 1 (Hydrogen Success) as the maximum practicable case as requested in its statement of task. Cases 1a and 1b are not considered further in this chapter.
The UC Davis SSCHISM steady-state hydrogen supply pathway model (Yang and Ogden, 2007b) is used to design hydrogen infrastructure and estimate delivered hydrogen costs for Case 1 (Hydrogen Success). Hydrogen equipment costs and performance are from the H2A model developed by the Department of Energy (Paster, 2006). The H2A component-level data are combined into complete hydrogen supply pathways from hydrogen production through refueling using the SSCHISM steady-state pathways model developed at the University of California-Davis (Yang and Ogden, 2007b). SSCHISM employs an idealized spatial model of infrastructure layout in cities to design and cost alternative infrastructure pathways. Inputs include information about the level of demand (market fraction of hydrogen vehicles), the city population and size, the number of stations, local feedstock and energy prices, and constraints on viable types of supply. Outputs include the delivered hydrogen cost to the vehicle, hydrogen infrastructure costs, and energy use and CO2 emissions for different supply pathways. Cost and performance data about hydrogen production and delivery technologies are discussed in Chapter 3.
The committee makes several assumptions in designing the hydrogen infrastructure.
Phased introduction. There is a phased introduction of hydrogen vehicles and stations in selected large cities, beginning with cities such as Los Angeles and New York (with interest and motivation to implement hydrogen) and moving to other cities over time. This so-called lighthouse concept reduces infrastructure costs by concentrating development in relatively few key areas termed “lighthouse cities.” A possible schedule for phased introduction of hydrogen vehicles in various U.S. cities is shown in Figure 6.7. The list of 27 cities was chosen based on hydrogen scenario development work by DOE (Gronich, 2007; Melendez, 2006).
Station “coverage.” Initially, when hydrogen is introduced in each lighthouse city, some minimum number of hydrogen stations is needed to ensure adequate coverage and consumer convenience. This constraint is imposed to help deal with the “chicken-and-egg” problem of assuring hydrogen fuel availability to early non-fleet vehicle owners. This is assumed to be 5 percent of existing gasoline stations in cities (Nicholas et al., 2004; Nicholas and Ogden, 2007). The percentage of hydrogen stations and station capacity over time are shown in Figures 6.8 and 6.9. For the initial introduction of hydrogen vehicles, it is assumed that 100 kg/d stations are