ENVIRONMENT-BRAZIL: Take the Squeaky Clean Hydro Bus

• by Fabiana Frayssinet (sao paulo)
• Thursday, July 16, 2009
• Inter Press Service

Developed by the Empresa Metropolitana de Transportes Urbanos (EMTU), a mixed company controlled by the state government, the hydrogen bus will shortly be transporting passengers in the state capital, Sao Paulo, a city of 20 million people.

The bus will run on the metropolitan corridor, a dedicated busway linking Sao Paulo suburbs, between the districts of Sao Mateus and Jabaquara, a 33-kilometre journey one way, and will cover an estimated distance of 278 kilometres a day.

The coordinator of the Brazilian hydrogen bus project, EMTU's Carlos Zundt, said this is the first hydrogen-powered public transport vehicle in Latin America. 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, Zundt told IPS.

'When hydrogen reacts with oxygen, water and electricity are produced, but no polluting carbon dioxide,' he said. 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.

The big difference is that hydrogen is a 'totally clean' source of energy, Zundt said. 'An internal combustion engine burns fuel for energy to drive the motor, but it also produces exhaust fumes, which means pollution and particles.'

The 480 pollutants in the exhaust fumes of diesel vehicles are the main cause of air pollution in Sao Paulo, according to the expert. In contrast, the hydrogen bus releases only water vapour, in other words it produces 'zero polluting emissions,' he said. 'Nowadays pollution in Greater Sao Paulo is due to diesel vehicles, so hydrogen technology could provide zero-emission public transport in future, using environmentally friendly vehicles like this one,' he said.

The hydrogen bus is still more expensive than traditional vehicles - by an undisclosed amount - but its designers say that savings are made in other ways.

'We would have to take into account all the cases of respiratory illnesses being treated in hospitals in Brazil's big cities, like Sao Paulo, which cost the government a great deal,' said Zundt.

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 kilometre, which is equivalent to '180 litres emitted in fumes,' according to Zundt.

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.

Another advantage of hydrogen technology is that it does not produce noise pollution. Since the motor is electric and does not rely on fuel ignition and expansion like an internal combustion engine, it is extremely quiet, which is an important advantage for bus drivers like Bras Minuceli, who will drive the first hydrogen bus.

'This bus is much more pleasant than the others to work in all day. It makes no noise and it's easy to drive, so it's not as tiring,' Minuceli told IPS.

An EMTU report says that 'Brazil is one of five countries in the world that have mastered this technology and developed hybrid buses,' 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, according to Zundt, and has some unique technical features.

In the first place, it is a 'hybrid' vehicle, with electric batteries to supplement the hydrogen fuel cell; these are recharged whenever there is energy to spare. Even the heat produced during braking is captured and stored in the batteries, enhancing fuel economy.

The bus can be driven autonomously for a distance of 300 kilometres on the hydrogen cell, and a further 50 kilometres on its additional batteries.

Because the Brazilian hydrogen bus is cheaper than those produced elsewhere, the government of Sao Paulo state, working in partnership with foreign and national private auto manufacturers, is interested in exporting it in future, which in turn could further reduce the unit cost.

In order to calculate its cost to public transport systems like that of Sao Paulo, the useful life of the hydrogen bus must also be considered.

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

The top speed of EMTU's bus was specified at 70 kilometres per hour, which is the speed limit on the metropolitan corridor where it will operate.

The first stage of the project envisages putting three hydrogen buses on the road by 2010. The authorities estimate that the project will become economically viable from 2020.

Zundt predicts that, in the same way that horse-drawn vehicles were replaced by fossil-fuel driven automobiles in the past, by 2080 most vehicles throughout the world will be powered by hydrogen and other clean energy sources.

The EMTU operates a fleet of 4,800 buses in Greater Sao Paulo, and a total of 7,000 including its units in the cities of Campinas and Santos in the state of Sao Paulo. Other bus companies operate another 14,800 buses within the metropolitan area of Sao Paulo alone.

Zundt says that fuelling hydrogen vehicles is very simple and can be done anywhere that hydrogen can be manufactured.

For Brazil's project, hydrogen will be made by electrolysis, or 'splitting water molecules' by passing electric current through water, he said.

'Even here, in our dealer's garage, we will have a hydrogen factory. Hydrogen can be made wherever water and electricity is available,' he concluded.

More than 95 percent of the new cars sold in Brazil can run on a biofuel that is less harmful to the environment than gasoline: ethanol, or fuel alcohol, made from sugarcane.

© Inter Press Service (2009) — All Rights ReservedOriginal source: Inter Press Service

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