The value for each of these three metrics is shown as a function of the variables in a series of three “spider plots” (Figures 6.1.1-6.1.3). In each plot, the x-axis is the ratio of the variable to its Case 1 value (shown in Table 6.1.1.). (The normal Case 1 input is represented by a value of “1” on the x-axis. So, an HFCV incremental cost of $3,600 corresponds to an x-value of 1, while an HFCV incremental cost of $6,800 corresponds to an x-value of 6,800/3,600 = 1.88.) When the input parameter is varied from its low to its high values, the value of x changes from 0.5 to 2. The metric varies as the input changes. This shows the sensitivity of the results to changes in the input variables.

As expected, the breakeven year is delayed and buydown costs are higher if the HFCV price is higher, the HFCV is less efficient, or hydrogen costs more than in Case 1. Breakeven occurs faster and the buydown cost is less for higher oil prices.

For example, if hydrogen costs $1/kg more than expected, there is relatively little impact on the breakeven year or the transition cost. However, if the cost of hydrogen is $2/kg higher than expected, this delays breakeven by 12 years (from 2023 to 2035) and raises the breakeven cost by almost a factor of three (from about $23 billion to $61 billion). If the oil price is 1.3 times the AEO’s projected high-price case (e.g., about $100 to $160 per barrel of oil in the transition period between 2012-2030), the breakeven year is accelerated slightly. However, if oil prices drop to 70 percent of the AEO projections (e.g., about $55 to $85 per barrel of oil during the transition period 2012-2030), breakeven is delayed 5 years (from 2023 to 2028) and the buydown cost rises from $23 billion to $31 billion. If oil prices drop to 50 percent of the AEO high-price case ($40 to $60 per barrel during the transition), breakeven is delayed further to 2035, and the buydown cost almost triples to $61 billion.

FIGURE 6.1.1 Sensitivity of breakeven year to changes in HCFV fuel economy, HFCV price, H₂ cost, and gasoline price.

FIGURE 6.1.2 Sensitivity of buydown cost (billion dollars) to changes in HFCV fuel economy, HFCV price, H₂ cost, and gasoline price.

FIGURE 6.1.3 Sensitivity of capital investment to breakeven year (incremental price of HFCVs + H₂ infrastructure capital, billion dollars).