FIGURE 6.3 Reference case: Number of light-duty vehicles in the fleet.

FIGURE 6.4 Reference case: Assumed fuel economies for gasoline ICEVs and gasoline hybrid vehicles (HEVs). (The “dip” in hybrid fuel economy in 2004 occurred when hybrid sport utility vehicles and vans entered the market.)

Hydrogen Cases 1, 1a, 1b

Table 6.1 lists cost and performance assumptions for hydrogen fuel cell vehicles and a gasoline reference vehicle for each hydrogen case. HFCV costs are based on an 80 kW fuel cell “engine” with 5 kg (165 kWh) of compressed hydrogen gas stored on board.4 (The drivetrain includes the fuel cell and auxiliaries, a hybrid battery, electric motor, wiring, and hydrogen storage.) This is consistent with the following assumptions:

FIGURE 6.5 Reference case: Assumed biofuel use.

  • For Cases 1 (Hydrogen Success) and 1a (Accelerated Hydrogen), the fuel cell drivetrain (the fuel cell system, hybrid battery, motor, and auxiliaries) costs the automaker (original equipment manufacturer, or OEM) $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 plant. Hydrogen storage costs the OEM $10/kWh. A model from Kromer and Heywood (2007) shows the total OEM manufacturing cost for drivetrain plus storage to be $71/kW, or a retail price of about $100/kW, giving a drivetrain plus storage price of $7,920.

  • For Case 1b (Hydrogen Partial Success), the fuel cell drivetrain costs the OEM $62/kW corresponding to a fuel cell system cost of $50/kW plus added costs for a hybrid battery, electric motor, and other components. Of the $50/kW fuel cell system cost, about 40 percent is due to the fuel cell stack and 60 percent to the balance of plant. Hydrogen storage costs $15/kWh. The total OEM manufacturing cost is $93/kW or a retail price of about $130/kW, giving a drive-train plus storage price of $10,400.

The drivetrain and fuel storage for a reference gasoline internal combustion engine car are assumed to have an OEM cost of $35/kW plus $300 for the exhaust system. For an 80 kW engine, the OEM cost is $3,100 and the retail price $4,300 ($54/kW). The price for each vehicle is broken down into a drivetrain and a “glider” (the rest of the vehicle). For all vehicles the glider price is the same, $18,750. The HFCV price is assumed to decrease according to a learning curve model developed by Oak Ridge National Laboratory researchers (Greene et al., 2007), based on automobile manufacturers’ estimates of fuel cell vehicle costs in mass production (Figure 6.6).

Cases 1 and 1a assume that the HFCV has twice the fuel economy of an efficient gasoline ICEV, described in Case 2 (ICEV Efficiency) below. (The evolving efficient gasoline ICEV in Case 2 has fuel economy of 25.2 miles per gallon

economy. Second, the net oil displacement and CO2 emission reduction are much less certain than for fuel economy improvements. These factors are discussed in Chapter 4.

4

The 2006 reference gasoline vehicle is based on a midsized five passenger car, with a curb weight of 1,570 kg. As efficiency improves over time, the weight is reduced to about 1,280 kg by 2030. The weight of the corresponding HFCV is 1,320 kg, reflecting heavier components. This reference vehicle is about average for the current new car fleet and is assumed to represent the fleet. Similarly, the HFCV that replaces it is assumed to be representative. HFCVs, like conventional vehicles, will range from small to large, but the fuel savings can still be determined from the average.



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