Published on March 15th, 2012 | by Joshua S Hill0
Hydrogen Vehicle Cleaning Switzerland Streets
The premise was simple: discover what it would take to put a hydrogen drive into a practical situation and whether it would be technologically feasible and as environmentally friendly as everyone has hoped. The situation provided itself in Basel, Switzerland, where a street-cleaning vehicle was retrofitted with a hydrogen drive and put to work on the streets of the third most populace city in the country.
Prior to taking to the streets were 18 months in which the drive was developed and undershot in laboratory conditions.
“It became clear relatively quickly that the fuel cell system, which had been developed as a one-of specially for the project, was not yet ready for use in a real-life setting,” explains project leader Christian Bach, head of Empa’s Internal Combustion Engines Laboratory. “On top of that, the various safety systems kept interfering with each other and bringing everything to a halt.”
The vehicle achieved its targets both in terms of energy consumption and performance, and allowed the project team to go ahead and replace the fuel cell system originally used with a more mature product, as well as a single centralised safety module. The resulting system — the “Fuel Cell System Mk 2″ — has been in use since the middle of 2011 and has subsequently proven to be more robust.
There was once the need to take the vehicle out of service as a result of a defective water pump. However, at that point, other problems arose as a result. The voltage converter between the fuel cell system and the battery died, then the sensing system for the electric motor drive and two cooling water pumps had to be replaced shortly after the vehicle was initially repaired.
The city has, nevertheless, been using the vehicle on an everyday basis, just as they would a “normal” vehicle.
The results and figures from the test case speak for themselves — instead of 5 to 5.5 liters of diesel per hour (equivalent to an energy consumption of 180-200 MJ per hour) the hydrogen powered vehicle needs only 0.3 to 0.6 kg of fuel per hour (that is, 40-80 MJ per hour).
Even the carbon dioxide emissions show improvement, performing at better than 40% than a diesel-powered equivalent even when the hydrogen is produced by the steam reforming of natural gas (using fossil fuels). Swap that to renewable sources and the carbon dioxide reductions would be even greater.
The drivers were able to refuel the vehicle themselves, and there has never been a problem caused as a result of hydrogen leaks. The vehicle is much quieter to use, and the only real-world difficulty was the lack of enough heating to keep the cabin warm during the cooler months.
The test phase in Basel will draw to a close this month before it is moved on to St Gallen for further practice trials.