CNG

In the field of transportation, biogas is a fuel produced from organic substances by biological processes. For the purposes of powering motor vehicles, all undesirable additives, especially carbon dioxide and hydrogen sulfide, must be removed to ensure that biogas meets the quality requirements for natural gas (methane content of over 95%, comparable calorific value).

The main disadvantages of using biogas in transportation are:

• its limited quantity,
• local production (biogas stations are rarely located in places where they are needed – bus depots, etc.),
• the high cost of refining biogas to the quality of natural gas.

In most European countries, biogas is used for heating or co-generation purposes. Only a handful of countries use biogas in transportation – Sweden, Switzerland, France, and Iceland.

Sweden
Sweden has a long tradition of biogas use. For many years, this source of energy has been produced by water treatment plants, and more recently (during the past two decades) by a growing number of co-fermentation stations that use various organic substances and materials. The highest proportion (60 %) of biogas is produced by 200 stations that process sludge from water treatment plants. Another source (30 %) is waste disposal sites, and the remaining quantity comes from industrial wastewater and co-fermentation stations. The total annual production of biogas is approximately 1,400 GWh.
More than 130 buses in Swedish cities are powered by biogas. Linköping has the highest number of them – 62.
Biogas is exempt from taxation based on an annex to the "EU Petroleum Directive".

Switzerland
Naturgas is a biogas (compogas) treated so that it has the quality of natural gas. Public fuel stations where biogas can be purchased are located in the following Swiss cities: Bachenbülach, Meilen, Otelfingen, Rümlang, Wädenswil, Zurich (two stations), and Winterthur (two stations).
The 520 vehicles in Switzerland that use methane are served by 27 filling stations. Biogas is tax-free.

France
As part of the European project Civitas, Lille uses biogas as a fuel in its city buses. The first biogas buses were put into service in 1996. At present, Lille has 42 buses in operation and an additional 65 on order from IRISbus. The city intends to increase the number of biogas buses fourfold by 2005, when their share should correspond to 50 % (currently 13 %). Lille plans to build a new biogas plant, which is expected to be completed in 2005 and produce four million cubic meters of biogas annually. Biogas is currently produced by the Marquette water treatment plan located in Lille's suburbs. The initial cost of the project was paid by the European Commission, regional funds, and the City of Lille.

Iceland
Biogas is produced by Metan Ltd. and sold through an ESSO fuel station. There are 20 VW automobiles powered by biogas in Iceland.