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Examing the effectiveness of biogas in Lille's buses (France)

By News Editor / Updated: 05 May 2015

Lille has been developing a policy to enhance the use of public transportation systems over the last 20 years. More particularly, since 1990 an urban programme has been working towards exploiting biogas produced by biomass accumulated at a local sewage treatment plant - resulting in an emission-free fuel that can be used for transport. In addition to the eight buses that are operating under this scheme, the city has a fully automated and accessible modern tramway network.


The objectives of the project are to: 

  • Construct a pilot unit for the production of biogas at the Marquette sewage treatment plant. The plant produces methane, which is similar to natural gas that was being distributed by Gaz de France (now GDF Suez);
  • Transform a normal diesel bus into one that runs on biogas - an experimental application that will pave the way towards commercial exploitation in a fleet of new buses constructed to run on biogas.

The idea to operate buses fuelled by biogas produced in Marquette was initiated in 1990 by the City of Lille, following a proposition from Solagro - a French energy, agriculture and environmental non-profit. The project was supported by the European Union’s DG XVII THERMIE programme); the Regional Council of North Pas de Calais and the Agency for the Environment and Energy Management (ADEME).

Transpole is Lille’s metropolitan public transport operator and has 300 buses. Lille’s CNG- biogas bus tests were one of the most important trials being conducted in France, together with tests in Marseilles and Lyon. The first CNG bus entered service in March 1994 and since 1996 it has been regulated to run on biogas. The project actually proved the feasibility of producing biogas that conforms to the physio-chemical composition of CNG and its utilisation as motor-vehicle fuel. During the pilot phase Solagro monitored the technical, ecological, energy and economic performance of the biogas buses as well as of the treatment plant in Marquette. As of the start of 1997, the bus has operated exclusively on biogas produced at this local station.

In action 

The implementation of the programme took into consideration the parallel transformation of the bus to run on biogas and the development of the Marquette treatment plant to produce biogas (methane) suitable to be used as vehicular fuel. In this way the relevant deadline was met more easily. The transformed Renault bus was in service for 12 months and has covered 100 000 km (2012). The bus was operated by Transpole, while the Marquette biogas station was operated by SEMeN. 

The project cost a total of 6m French Francs (1990):

  • European Union - 1m FF
  • Regional Funds for Energy Management (Regional Council North Pas de Calais and ADEME) - 1.5m FF
  • ADEME - 0.5m FF
  • Lille Urban Community - 3m FF
Technical issues 
The biogas bus provides operating services comparable to those provided by a conventional diesel bus. Drivers confirmed that the vehicle is quicker in acceleration and that it can be driven more gently. But the fuel tank for the experimental bus has led to greater inclines when turning. The reduction of the weight of tank and the respective improvement of suspension was resolved in the commercial version of the bus called Agora. The users could easily identify the biogas bus and could not identify any performance difference in comparison to diesel bus. The users also appreciate the reduction of emissions in terms of pollutants, smell (odours) and noise. Meanwhile the biogas production unit has proved its capacity to produce an excellent quality of gas. Future R&D efforts have to be directed towards improving the cost/performance relation of electromechanical equipment, most notably compression equipment.
Ecological/Environmental issues 
The utilisation of a biogas bus sharply reduces the gas emissions that are responsible for air pollution such as ozone, particulates, hydrocarbons and nitrogen oxides. When initially using CNG, particle emissions were reduced by 10 per cent, hydrocarbon emissions by 2 per cent and NOx emissions by 15 per cent. Only CO emissions remained similar to those of diesel. Similarly noise was reduced by 2 per cent, there were no odours, black smoke or hydrocarbon vapours. These results were improved even more when using the Marquette biogas. Particle emissions were reduced by 17 per cent, while the non-methane hydrocarbons were reduced by 13 per cent. No additional CO2 is produced, given that any unconsumed CO2 would be either burned on torch or released to the atmosphere where it disintegrates into carbonic gas.
Energy issues 
The production chain for the methane-based biogas produces three times more energy value than the primary non-renewable energy input for this production. This performance could be further bettered with improved means of gas treatment. Finally, the consumption of biogas by the buses would be further reduced when the weight of the tank is reduced by utilising proper composite compounds.


Economic issues 
The cost of biogas bus was initially estimated to be 580 000 FF more than the cost of a conventional bus. This increase was actually limited to 230 000 FF during the production of the experimental bus. Similarly the costs of biogas production including depreciation are considerably reduced due to the improvement of the feasibility of the installations. The cost of 1m3 of gas produced by the biogas production unit is 5 FF. Taking into consideration the numerous improvements that have already been identified, especially in the context of developing a larger scale biogas production unit and the expected reduction of fixed costs due to the industrialisation of the unitised technology, it is certain that this unit price will prove to be even smaller in the future.

Finally it should be mentioned that the biogas fuel complies with the EURO 2 and EURO 3 standards for emissions while the residual emissions of methane are odourless, colourless and non-toxic.

Challenges, opportunities and transferability 
Barriers and conflicts 
  • Difficulty to obtain circulation permits of the buses from the appropriate Ministry;
  • The buses are not yet mass-produced.
The Lille biogas bus scheme is fully transferable to other cities under the condition that the cities are involved in methane production in their own sewage treatment plants, or respective biogas distribution systems may be utilised to cover urbanised areas.

Lessons learned 
The critical factors of success include :
  • Involving many actors such as cities, regional authorities, local and regional associations which share common objectives for urban ecology, and increased utilisation of urban mass transportation systems;
  • Support from  strong technological and industrial partners such as car manufacturers (Renault) and gas producers (Gaz de France);
  • Support by the local mass-transport workers' union;
  • An integrated plan for the exploitation of sewage treatment plants and their by-products.
Clean and energy-efficient vehicles
18 Sep 2012
05 May 2015
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