Objective
Market introduction and test of CNG technology concerning :
- energy and environmental effects
- noise emission reduction
- collection of long-term experience
- costs and economic feasability
- passenger and technical staff acceptance
- collection of maintenance and operation properties (range, fuel consumption, emissions, service life) of the system and its components
- examination of economic viability - direct comparison with diesel buses
- dissemination of experiences and results
Economic results :
The operational costs of the CNG solo buses were slightly higher than those of the diesel bus. For the articulated buses, the additional costs for CNG buses are less than 20% if compared to the respective diesel buses. The reason for this are :
- firstly to be found in the more expensive purchasing price and
- secondly in the higher fuel costs for CNG buses (lower price of diesel in Berlin, higher specific consumption of CNG buses and local filling situation in Berlin. This means that the local situation influences these costs comparatively strongly.)
It is hoped that CNG buses will become more economically viable within Europe in the future. Above all, three aspects are given importance :
- lower consumption motors. The potential increase in efficiency compared to the CNG motors that are currently in use is estimated at up to 20%.
- higher mileage of CNG vehicles. However, the mileage of CNG vehicles is limited by the lower energy content of CNG compared to diesel.
- low vehicle costs through larger numbers of CNG vehicles. In Hannover a considerable increase in the proportion of CNG vehicles in the buse fleet is planned and in the city of Lubeck in northern Germany the whole bus fleet will be converted to CNG. This will clearly lower the purchasing costs and the costs of keeping buses in reserve for each vehicle.
Comparisons of CNG buses with diesel-powered buses on the European level have shown that, to a large extent, the economic viability of CNG buses depends on the rate of taxation, charged on these buses and the fuel.
Environmental results :
- The measurements for air pollutants showed that the expected values (i.e 50% of the Euro II norms) can be achieved (except CO emissions)
- The noise measurement showed that outside the noise production is significantly lower for CNG buses than from diesel buses . Inside the buses, no important difference between can be noticed.
1.Technology : The natural gas engine, which is intended to be implemented, works like a normal engine with a high density relationship with a three-way Lambda=1 control. The emissions are virtually free of particles and considerably lower in CO, NOx and HC and the buses are quieter. CNG technology is already well below the EC emission norms "EURO " and "EURO II"; emissions are even lower than the "EURO III" norm to be introduced in 2000 and suggested by the German Ministry of the Environment (CO/HC/NOx/PM = 2.0/0.6/5.0/0.1 g/kWh). The gas mixer, the pressure controller and the electronic control unit are completely new developed for this application for CNG.
2. Context : In large European cities, traffic is almost the single reason for carbon monoxide emissions. It is also responsible for 60% of the nitrogen oxide concentration and for 60% of the concentration of other particulates. These particulates can have either a direct or an indirect influence on human health and the environment. Inner city pollution from diesel-powered buses in Berlin for example makes a contribution of at least 20% to the particulates. It has to be noted that a reduction in emission from buses causing summer smog (high ozone concentration) in cities can only be brought about by introducing an environmentally-friendly bus fleet (first step : 10 buses) running with the alternative fuel CNG. These buses are 4 Mercedes-Benz Natural Gas Low-Floor Standars Buses, 2 Mercedes-Benz Natural Gas Low-Floor Articulated Buses and 4 MAN Natural Gas Low Floor Articulated Buses. 3. Economic aspects : In this period, the operational costs of the CNG solo buses have been analysed ; During the last measurement period the operational costs of the CNG solo buses were slightly higher than those of the diesel bus (8%) 4.Monitoring : The buses have been in regular scheduled service since 15th May 1995. The continuous monitoring of the project results allows the development of a database on all the results.
Programme(s)
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
10787 Berlin
Germany