Green buses set to conquer Europe’s cities

In a few years' time green buses could be as familiar a sight in EU cities as the red Routemaster bus was on the streets of London.

But unlike their London counterpart, green buses will not be recognisable by their colour. This new generation of European buses could be painted any shade but the thinking behind them will be green, as governments and local authorities look for ways to make public transport more environmentally friendly.

"Countless cities have started moving towards cleaner buses," says Jos Dings of environmental campaign group Transport and Environment (T&E).

EU buses are required to meet the same emission standards as cars for four pollutants: nitrogen oxides (NOx), particulates (PM), hydrocarbons (HC) and carbon monoxide (CO). No EU-wide limits currently exist for carbon dioxide (CO2).

The European Commission has funded research into public transport powered by hydrogen fuel cells but so far only a few dozen of the EU's hundreds of thousands of buses rely on hydrogen.

Several other options exist for greening bus fleets, according to Arno Kerkhof of public transport representatives UITP. These range from fitting exhaust filters to old buses to replacing entire vehicles with a new, cleaner model.

Kerkhof adds that in itself shifting from private cars to public transport was good news environmentally. "We can't repeat this often enough. Travelling on the average EU bus means using three times less energy per passenger than making the same trip by car."

But there is still potential to make the existing urban public transport greener. Attention usually focuses on buses, because trains are already considered comparatively green.

The majority of technologies available to reduce bus emissions and fuel consumption are only possible for new buses, explains Kerkhof.

The number of buses in an urban fleet varies greatly, with 500 in Brussels and 6,000 in Greater London. Since replacing a standard 12-metre long city bus today costs at least €200,000, greening every vehicle, even in a small fleet, is not a short-term option.

"The new large EU member states, particularly Poland and Hungary, are having severe problems renewing their stock because of a lack of funds," Kerkhof points out.

A much cheaper alternative is fitting modern diesel filters to bus exhaust pipes. Filters cost less than €7,000 each and can reduce emissions of the four EU-regulated pollutants by about 30%.

CO2 emissions can be brought down by using more fuel-efficient buses. These include emission-free trolley buses, powered by electricity, and hybrid vehicles, which use a combi- nation of diesel and electric power.

Petrol buses do not exist in Europe. But some countries have started to investigate several other alternatives to diesel. Sweden runs 500 buses on ethanol, considered to be carbon neutral since it emits less CO2 than conventional fuel and the crops used to produce it can absorb greenhouse gases.

Some countries including Sweden, Germany and France are also developing new type of biogas for buses and trains: made from garbage, sewage or animal entrails.

In a few years' time green buses could be as familiar a sight in EU cities as the red Routemaster bus was on the streets of London.

• Primary Source