This section describes the results of a "best case" analysis, and sensitivity analyses conducted using the life cycle cost model.
The best case scenario was intended to evaluate the potential for near-term fuel cell bus cost reductions if current federal performance goals can be met. The sensitivity analyses were intended to explore the effect on total life cycle costs of several major fuel cell bus cost drivers, including bus purchase cost and hydrogen fuel cost.
The assumptions used for the best case scenario are primarily based on meeting the Federal Transit Administration's near-term National Fuel Cell Bus performance objectives, and the U.S. Department of Energy's 2015 goal for the cost of hydrogen fuel.
The FTA fuel cell bus performance objectives include:
DOE's 2015 goal for the delivered cost of hydrogen is ≤ $3.00/kg (untaxed) in 2005 dollars. This is equivalent to $3.39/DEG, a greater than 50% reduction compared to the base case assumption.
In order to meet the FTA fuel economy goal, the best case scenario assumes that any fuel cell bus would need to be a Fuel Cell Hybrid bus.
While not included in the FTA and DOE goals, the best case scenario also assumes that hydrogen infrastructure and fuel cell bus maintenance costs will be reduced compared to the base case. The best case scenario assumes that $/mi propulsion maintenance costs for Fuel Cell Hybrid buses will be ≤ 2x $/mi propulsion maintenance costs for diesel buses, that hydrogen fuel station costs will be ≤ 2x the cost of a similar capacity CNG fuel station, that fuel cell stack replacement will cost one half of the base case cost, and that hybrid battery replacement will cost two thirds of the base case cost.
Table 17 shows all of the assumptions used in the best case analysis, compared to the parallel base case assumptions. All other assumptions used by the model that are not listed in Table 17 are the same for the base case and the best case.
Under the best case scenario, total per-mile life cycle costs for Fuel Cell Hybrid buses fall by 40% compared to the base case, to $8.88/mile. If only local costs are included best case average per-mile life cycle costs for Fuel Cell Hybrid buses fall to $5.49/mile - $0.58/mile more than local life cycle costs for Diesel buses.
Under the best case scenario the single largest contributor to higher life cycle costs for Fuel Cell Hybrid buses is still capital amortization due to a higher bus purchase price and higher infrastructure costs for hydrogen fueling. Under the best case scenario capital amortization accounts for almost 48% of total life cycle costs for Fuel Cell Hybrid buses, compared to 15% for diesel buses.
The life cycle cost model was used to evaluate the "break-even" capital cost for Fuel Cell Hybrid buses. With all other best case assumptions held constant, a Fuel Cell Hybrid bus would have to cost no more than $350,000 (less than the price of current CNG buses) for total life cycle costs to fall to the level of costs for Diesel buses. In order to match local life cycle costs for Diesel buses a Fuel Cell Hybrid bus could cost no more than $500,000 (approximately the current price of diesel hybrid buses).
Under the base case scenario all life cycle cost elements are higher for Fuel Cell and Fuel Cell Hybrid buses than for Diesel buses. Under the best case scenario, while all other cost elements are still higher, life cycle fuel costs are significantly lower for Fuel Cell Hybrid buses than for Diesel buses. This fuel cost savings partially off-sets the increased life cycle costs for capital amortization, maintenance, and overhauls: The lower the price of hydrogen fuel, the greater the reduction.
The life cycle cost model was used to evaluate the effect of hydrogen fuel price on total life cycle costs. This analysis is summarized in Figure 11. As shown, even if hydrogen fuel were free the fuel cost savings from Fuel Cell Hybrid buses would not fully off-set the increases in other cost categories compared to diesel buses.