Hydrogen buses not all hot air
Silvia Piviali - Science Network WA
In the photograph above the first bus is unloaded from the ship, with the pure steam rising from its exhaust pipe visible at the rear.
Photo - WA State Government's Department of Planning and Infrastructure (DPI)
Australia may not have signed the Kyoto protocol, as Al Gore points out in his popular film, but Perth is doing its bit to make the bus trip to work a clean, green ride.
Perth's most well known alternative energy initiative was the introduction two yeas ago of three Hydrogen Fuel Cell Buses, known as the 'EcoBus'.Two years later, the EcoBuses have covered more than 160,000 km and carried more than 200,000 passengers along metropolitan Perth bus routes, according to the project director at the Department for Planning and Infrastructure, Mr Glen Head.
"Further, in only two years, these buses have prevented 272 tonnes of greenhouse gas emissions," Mr Head said.
The buses emerged after the first ever State Sustainability Strategy was released for WA in 2003. One of the key elements of this strategy was to respond to the Transport Committee's call to move away from oils as a fuel to gases and hydrogen as alternative energy sources.
One of the results was a unique collaboration between the DPI (Department for Planning and Infrastructure), DaimlerChrysler, BP Kwinana Refinery, Ballard Power Systems, Path Transport, the Public Transport Authority and Murdoch University to help address this problem.
Hydrogen's characteristics of being colourless, odourless and non-toxic, compared to more traditional energy sources such as coal, oil, liquefied natural gas and diesel, make it much easier on the lungs.
BOC Gases, a leading provider of gases and related products in Australia, takes the crude H2 (Hydrogen) from the BP Refinery in Kwinana, then through various stages of purification, makes the Ultra High Purity Hydrogen (UHP H2).
Timothy Few, Major Customer Executive in the Process Gas Solutions Area of BOC Gases, said the UHP H2 was loaded into jumbo tube trailers and transported to Morley refuelling station, where it was then compressed into the storage facilities on the bus.
BOC Gases was forced to specially devise a unique 'cold filling' process, now used world wide, in order to fill the buses in a short space of time.
Mr Few has taken several rides on the EcoBuses and likes how it handles.
"I have personally ridden on the bus many times and from a user's perspective, it was a very comfortable ride,'' he said.
"The use of H2 in fuel cells is a very clean application because the only by-products of the process are water vapour and a small amount of heat.
"The only restrictive problem is the economics of running such a bus which no doubt in time will be resolved."
The hydrogen gets consumed by Fuel Cells, designed & constructed by Canadian based Ballard Power Systems. Since 2004, systems engineer, Mr Jamie Ally, relocated to Perth as a local representative of Ballard.
Mr Ally says the Perth EcoBuses are based on the latest Mercedes-BenzCitaro chassis, with a Ballard HY-205 fuel cell engine and Ballard Mk902 fuel cell stacks.
In regards to how they operate, Mr Ballard explains: "Fuel cells consume hydrogen and oxygen from air, and produce electricity, water vapour (steam), and heat. The voltage across each fuel cell is approximately 0.7V, so the fuel cells are "stacked" in series to create a useful voltage - hence the phrase "fuel cell stacks."
There are two stacks in the Ecobus, with nearly 1000 cells in each stack. There is also a data acquisition system on each EcoBus which collects information and is then stored and analysed in the Ballard Power Systems Headquarters in Vancouver, Canada. Mr Ally says this data is provided as input to future technological development.
Currently Path Transit, a contractor to Transperth based in Morley, is responsible for operating and maintaining all three EcoBuses.
Driver Paul Wroblewski is one of the original drivers who was chosen for the trial and has thoroughly been enjoying being part of the EcoBuses.
"At first, I was a little sceptical in how they would compare to the traditional buses I had been driving, but I soon noticed just how smooth and quiet they are to drive."
"Passengers generally enjoy their ride and also comment on the quietness of the bus."
In September this year, the Department hosted the Alternative Transport Energies Conference, which attracted international delegates and considerable focus was once again placed on the EcoBuses.
As the trial draws to a close in September 2007, the findings which will determine whether or not the EcoBus will be seen as an every day transport alternative, will be highly anticipated.
For further information about the trial, visit http://www.dpi.wa.gov.au/ecobus/ |