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The City of Malmö, in
cooperation with a large Swedish energy company, Sydkraft, and the local public
transport company, Skånetrafiken, has been working actively with the fleet of
city buses for several years. This has resulted in one of Europe’s largest bus fleets run on
Compressed Natural Gas (CNG).
Today the fleet consists of
around 180 buses. As for the air quality, the improvements have been
considerable. At one of the sites for measuring the air quality in the city
centre the level of nitrogen oxides has decreased more than 40 % over a period
of seven years, following the large-scale introduction of CNG-buses since the
mid-90s.
In 2003 the next step was taken
in the form of a project aiming at producing hydrogen for a filling station in
the centre of the city. In 2003 the station was opened, and since then the
pumps can offer both pure hydrogen, and different mixtures of CNG and hydrogen,
so called ‘hythane’. This is the first station of its
kind in Europe.
The target of the project is to
convert two buses in the bus fleet from CNG to hythane and to evaluate the
influence of the fuel on emissions, fuel consumption and operability. Moreover,
the project sets out to develop a general understanding of the influence of
hydrogen/CNG mixtures when used in public transport. Since September 2003 one
bus is running on hythane consisting of 8% hydrogen and 92 % CNG.
In the next step, the second bus will be converted to run on 20 %
hydrogen mixture. This will require modifications of the control system in the
bus and also minor modifications of the engine in order to be able to cope with
the higher concentrations of hydrogen.
This second bus will be monitored both for fuel consumption and
emissions. Considerable positive effects on the air quality are expected. As
for nitrogen and carbon monoxide a 10 % decrease is anticipated. Furthermore, a
decrease of emissions of greenhouse gases of up to 20 % is foreseen. The launch
of this second bus is soon to come, and it will be running sometime during the
autumn of 2004. The project will end in 2005, when enough experience has been
gained from the operation of the two buses. |