Initiated by the Fuelcell Propulsion Institute and led by Vehicle Projects LLC, a government-industry consortium developed the world’s first fuelcell-powered locomotive, an underground mining haulage vehicle, during the period 1999-2002. The technical consortium consisted of the 12 members listed in the accompanying table. Powered by proton-exchange membrane (PEM) fuelcell stacks, coupled with reversible metal-hydride storage (see Technology Tutorial), the 3.6-tonne locomotive underwent extensive analytic and surface safety tests before being demonstrated in a working underground gold mine of Place Dome Inc in Ontario.

The platform vehicle was a commercial 3.6 tonne battery locomotive manufactured by RA Warren Equipment. The battery vehicle employed a 104 V (nominal) lead-acid traction battery, series traction motor, smart motor controller, hydraulically assisted disc brakes, and unitized body/chassis. A design objective for the fuelcell powerplant was for it to fit into the same volume as the battery. Powerplant packaging largely accomplished this objective except that the metal-hydride storage subsystem, shown to the right in the vehicle photo, rises about 20 cm above the top of the vehicle. The cause of the extra height is the need to place shock-absorption hardware below the subsystem. This is of no practical consequence, and later generations of the vehicle could accommodate the shock-absorption units more compactly.

Although low-temperature metal-hydride storage is too heavy for light-duty vehicles, it is substantially lighter than lead-acid batteries. Our hydride-fuelcell locomotive was 30% lighter than the battery version, and ballast of approximately 1100 kg was required to bring the locomotive up to its specification weight of 3.6 tonne.

The hydride storage system, designed and fabricated by Sandia National Laboratories-CA, stores 3 kg of hydrogen, sufficient for eight hours of locomotive operation at the empirically determined 6 kW average power of its duty cycle. The bed uses 213 kg of C-15 alloy (an alloy of manganese, titanium, zirconium, iron, and other constituents from GfE in Germany) and has an operating pressure of 1-2 bar. Measured capacity of the metal-hydride material is 1.4 weight percent of hydrogen; the storage system as a whole has a capacity of 0.6 – 0.7%. Hydride subsystem design allows for rapid change-out (swapping) of a discharged bed with a freshly charged unit. In situ recharging utilizing gaseous hydrogen at seven bars requires approximately one hour.

The locomotive’s fuelcell power system used commercially available proton-exchange membrane (PEM) stacks manufactured by Nuvera Fuel Cells Europe (Milan, Italy). No traction battery is employed, and the vehicle is thus a pure fuelcell vehicle. Two stacks in electrical series provide 126 V and 135 A at the continuous rated power of 17 kW gross power. Each stack, with integral humidifier, weighs 30 kg and has a volume of 25 L. The air cathode operates at 0.5 bar above ambient pressure using a modified Roots-type air pump. Although Roots compressors are normally not highly efficient, the design used in our powerplant is a modern, efficient design, and parasitic losses for air handling are less than 10%. Waste heat from the stacks provides the heat to desorb hydrogen from the metal-hydride bed. A heat exchanger links the two isolated thermal systems: (a) the hydride-bed heating/cooling loop and (b) stack cooling loop. The bed loop uses a circulating anti-freeze medium, whereas the stack loop uses de-mineralized water. Stack cooling water also passes through a forced-air excess-heat radiator. Coolant pumps and the stack air pump are powered at system startup by an auxiliary battery recharged by the stacks.

Comparison of the performance of fuelcell and battery versions of the locomotive is provided in the accompanying table.

The underground demonstration, with the fuelcell locomotive working alongside conventional battery locomotives, led to the following conclusions by CANMET (Canada Minerals and Energy Technology), operator of the demonstrations:

"The locomotive, in both surface and underground tests at CANMET's Experimental Mine and at Placer Dome's Campbell Mine, accumulated a total of 43 hours of operation in fuelcell mode and 6.5 hours in traditional battery mode, for a grand total of almost 50 hours of monitored operation. . . . In this fully productive environment, over 1,000 tons (760 tons on fuelcell and 240 tons on battery) of material were hauled, covering a total cumulative distance of over 65 kilometres going up and down the Campbell Mine's different tramming routes.

"The fuelcell-powered locomotive proved to be as reliable and productive as the battery-powered version . . . . It is also foreseeable . . . that the fuelcell-powered version will give steady, 100% power availability for around 8.5 hours of operation, compared to the battery-powered version, because running on stored energy will give a steadily decreasing performance curve for around 7 hours of operation.
". . . . refuelling has the potential to easily being achieved within an hour time frame if a proper underground hydrogen refuelling area can be (found), compared to the 7 - 8 hours needed to fully recharge a traditional locomotive battery.

"Based on these performance tests, this prototype fuelcell-powered underground locomotive proves to be as effective as the same battery-powered unit regarding power generation/tractive effort/ daily production basis for a continuous 6.5-hour production window. However, the potential of increasing daily production levels is much greater using the fuelcell-powered unit. It is not an overstatement to say that an off-the-shelf manufactured fuelcell power plant will be more efficient as for power/volume ratio, and therefore will prove to be much more productive on a long-term basis than battery-powered locomotives. If the fuelcell-powered locomotive outperforms the battery-powered locomotive based only on production issues, one must also take into consideration the advantages compared to an underground diesel-powered locomotive when adding ventilation-related economies, noise, health, etc." [Pierre Laliberté, Electrical Engineer, Natural Resources Canada, CANMET Mining and Mineral Sciences Laboratories].

Summary

In summary, in working-mine operation, compared to the conventional battery locomotive, the fuelcell locomotive provided equal acceleration, more than twice the power, the ability to pull longer trains, longer operational time (potentially two labor shifts), and required shorter recharge (refueling) time. Accordingly, we believe the fuelcell mine vehicle would couple the health benefits of an electric vehicle with the productivity of a diesel. While fuelcells are currently more expensive per kilowatt than diesel engines, one could expect lower recurring costs (e.g., maintenance costs) and decidedly lower mine ventilation costs.

To view a video of the mine locomotive during tests in Reno, Nevada, download Flash Player 6 (Earlier
Flash versions are not compatible), then click on either the DSL version or 56k version of the video:


Flash Player 6
Mine Locomotive Video (DSL)
Mine Locomotive Video (56k)

Bibliography

A. R. Miller, “Tunneling and Mining Applications of Fuelcell Vehicles,” Fuel Cells Bulletin, May 2000.

A. R. Miller and D. L. Barnes, “Fuel Cell Locomotives,” Fuel Cell World, Lucerne, Switzerland, 1-5 July 2002.

Acknowledgements

We thank the following funders for their generous support of this project: US Department of Energy (contracts DE-FC36-99GO10458, DE-FC26-01NT41052, and DE-FC36-01GO11095); Natural Resources Canada (Emerging Technologies Program contracts 23440-991022-001 and EA9730-F01-01); subcontractors to Vehicle Projects LLC who contributed project cost-share. Disclaimer: Funding support from the US Department of Energy or Natural Resources Canada does not constitute an endorsement by same of the views expressed in this paper.

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