The fuel cell bus community expects improved availability to be a key achievement of this generation of demonstrations. Pre-2010 demonstration results showed availabilities of 55-80%. Availability issues are generally not a result of the fuel cell system, but rather due to problems in power electronics, energy storage systems, control systems and integration issues.
Key suppliers note that the components in themselves are largely meeting technical needs under test conditions. However, integration issues continue to be best worked through with full bus build out and real world operation. In 2010 US DOE/DOT FCB Workshop attendees concluded that individual sub-system work should not be performed in isolation but rather at an overall system level to optimize entire drivetrain performance
Drivetrain system level issues are highly related to those experienced with diesel hybrid vehicles, and expected improvements across hybrid technology will inevitably assist with fuel cell hybrid drivetrain issues.
The first steps towards lower bus costs are expected to be a result of decreased fuel cell system costs in 2010-2013 due to breakthroughs in stack durability. Currently, fuel cell warranty cost represents about 40% of the whole cost of the fuel cell system and reductions in this cost alone would significantly affect total fuel cell bus costs.
Small volume purchases in the range of low 100s buses/year between now and 2015 will allow bus manufacturers to experience cost savings through reduced risk and effects of economies of scale. Larger bus orders will reduce the costs associated with non-recurring engineering costs and high labor required for unique builds. The standardization of the hybrid drive train manufacturing process is also expected to decrease OEMs’ additional costs.
As described in the NEXT HyLIGHTS analysis, capital cost reduction includes two main features: reduction in fuel cell system costs and reduction in costs to the OEM to manufacture a novel technology.
Image Source: NEXT HyLIGHTS
The NEXT HyLIGHTS study developed a Total Cost of Ownership (TCO) model to help illustrate the pathway to commercialization. This model describes cost conclusions based on a few key projections within four time periods: 2010-2014, 2015-2018 and 2018-2022, 2023-2030.
Image Source: NEXT HyLIGHTS
2010-2014: Fuel Cell Durability Improvements
During the current period, fuel cell buses’ TCO is over three times that of a basic diesel bus, with high capital costs and component replacement costs representing the bulk of the margin of difference. Fuel cell bus capital costs are expected to begin to dramatically decrease in this period due to cost reductions in fuel cell systems.
2015-2018: Bus Manufacturing & New Technology
Increased sales volumes and standardization of the hybrid manufacturing process will allow OEMs to achieve savings in the total bus manufacturing through reduced risk premium, decreased non-recurring engineering and additional labor costs required to manufacture a novel product. Currently, these costs are estimated at up to 26% of the final bus cost. Experts predict capital costs in this period to range from €500,000 and €950,000.
2018-2022: Volume Sales
During this time period two possible cost reduction pathways are believed possible. Under both scenarios, capital costs could be reduced to affordable levels by 2022/25:
Both pathways would continue to need public subsidization during this period to achieve needed sales volumes.
2022/25-2030: Fuels Competition
Capital costs will continue to decrease due to reduced fuel cell costs, disappearance of OEMs’ costs associated with creating novel technology, and the continued advancements in hybrid drivetrain integration and manufacturing. Fuel cell buses will remain more costly than diesel buses (estimates are around €100,000-€200,000 more) and hybrid diesel buses (€50,000-€100,000 more).
However on a total cost of ownership basis, fuel cell buses will begin to converge or surpass diesel bus levels in this period. The relative hydrogen versus diesel costs will ultimately determine the balance. Recent analysis suggests that hydrogen costs will likely fall below diesel and, factored in with improved efficiencies, infrastructure will not be a major barrier to cost competitiveness.
In the US, the DOE and DOT released a current set of fuel cell bus performance, durability and cost targets in September 2012 shown below. Full report available here. These targets are based on stakeholder input and reflect near term and long-term goals.
1 Status represents data from NREL fuel cell bus evaluations. New buses are currently projected to have 8 year / 300,000 mile lifetime.
2 The power plant is defined as the fuel cell system and the battery system. The fuel cell system includes supporting subsystems such as the air, fuel, coolant, and control subsystems. Power electronics, electric drive, and hydrogen storage tanks are excluded.
3 According to an appropriate duty cycle.
4 Multiple sequential fuel fills should be possible without increase in fill time.
5 Cost projected to a production volume of 400 systems per year. This production volume is assumed for analysis purposes only, and does not represent an anticipated level of sales. 6 Excludes mid-life overhaul of power plant.
Image Source: DOE Fuel Cell Bus Targets