'Cheap' hydrogen-fuelled bus

Sao Paulo in southern Brazil has launched the first hydrogen-fuelled bus in Latin America – claimed to be the first step towards environmentally sustainable public transport of the future. The project is supported by public, private and international sponsors like the World Bank and the United Nations Development Programme (UNDP).

Unlike a diesel engine, in which fossil fuels are burned, combining with oxygen to produce energy and carbon dioxide – the main greenhouse gas - a hydrogen-powered motor relies on an electrochemical reaction where water is the only byproduct. The bus wheels are driven by traction motors fuelled by the electrical energy from this reaction. Hydrogen fuel is stored in tanks on the upper part of the bus.

A traditional diesel bus travelling the same route and distance as the hydrogen bus uses an average of 270 litres of diesel a day, or one litre per kilometer.

In contrast, the hydrogen bus has an energy efficiency of 90 percent, equivalent to 900 grams of hydrogen gas per kilometre. The other 10 percent is recycled and reused within the vehicle's system.

Brazil is one of five countries in the world that have mastered this technology along with the United States, China, Germany and Japan. But the bus made in Brazil, one of only 78 in the world, is the cheapest. It can be used alongwith electric batteries to supplement the hydrogen. Even the heat produced during braking is captured and stored in the batteries, enhancing fuel economy.

While a diesel bus has a useful life of five to eight years, a hydrogen bus will last an average of 20 years.

All that is fine but when you think of the fact that hydrogen is only a carrier of energy and not a source, questions arise on how it is produced. For the hybrid bus, hydrogen will be made by electrolysis, by passing electric current through water.

The claim of the company, that hydrogen can be made wherever water and electricity is available, is exactly the point. There is an amount of input electricity that is necessary. What is the EROEI? That should be studied. Any answers?

PS: Meanwhile, the world’s cheapest and most fuel efficient cars marketed towards developing economies, Tata’s Nano is stepping into foreign shores. Fiat and Tata have announced plans to market the car in South America.

The car also recently passed European safety standards and will start being sold there in 2011. It is capable of an incredible 23.6km/litre (55.5 mpg) and ultra-low carbon emissions of 101 g/km, one of the lowest in India.