Hydrogen-powered street cleaner (Empa)
A pilot test in Switzerland of a street cleaning truck powered by a hydrogen fuel cell shows the vehicle saves energy and is environmentally friendly, but the high costs of the vehicle do not yet make it financially feasible. The test was carried out by the Swiss materials science and technology research institute Empa, with other collaborating institutes and companies.
Empa developed the prototype street cleaner and began the pilot test on the streets of Basel in 2009. The test showed the street cleaner saves considerable energy over its conventionally powered counterparts. Internal-combustion street cleaners use 5.0 to 5.5 liters of diesel per hour — the equivalent of 180 to 200 MegaJoules (MJ, an international unit of derived energy) per hour — while the hydrogen fuel cell vehicle uses 0.3 to 0.6 kg of fuel per hour, which translates to 40 to 80 MJ per hour.
The hydrogen vehicle also reduced CO2 emissions by 40 percent compared to the diesel-powered street cleaners, even with the fuel cells converting natural gas as the raw material to generate hydrogen. If the fuel cells used renewable feedstocks, says Empa, the CO2 emissions from the hydrogen vehicle would probably be even lower.
The test showed the fuel cell vehicle to be safe and practical. Drivers refuel the vehicle from a mobile hydrogen fuel station, and so far encountered no fuel leaks. The vehicle also runs much quieter than conventional diesel street cleaners, which makes it less stressful for the drivers.
One practical disadvantage of the hydrogen vehicle is the lack of waste heat normally generated by diesel-powered trucks and captured to heat the driver’s cabin on cold days, which is also a problem with electric-powered vehicles. The developers had to outfit the hydrogen vehicle with an electric heater for cold days.
The developers discovered that routine maintenance on parts for a one-of-a-kind vehicle took longer than with a production vehicle, which resulted in longer periods out of service. For example, they had to replace the original fuel cell and implement a single centralized safety module. The new hydrogen power system has been in operation since the summer of 2011, however, and has proven to be more robust, enabling the Basel city authorities to run the vehicle every day for the past three months.
The costs of the fuel-cell vehicle could be a factor limiting their day-to-day use on city streets. Empa says a vehicle of this kind is currently about three times as expensive as a conventional street cleaner, with the prices of fuel cells, pressurized storage tanks, and electric drives the most costly items. Empa notes, however, the costs of fuel cell systems alone have dropped by a factor of ten over the past few years, and are expected to drop further.
The Paul Scherrer Institute, vehicle manufacturer Bucher Schoerling, the electric drive specialist Brusa, the hydrogen manufacturer Messer Schweiz, and the city of Basel city environment and street cleaning services collaborated on the project. The vehicle next goes to St. Gallen, Switzerland for further trials.
Read more: Fuel Cell Powered Forklifts Built for Demo Project
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