The criteria for sustainability and greenhouse gas emission reduction will stay within the urban mobility policies in Curitiba, Brazil, even after the State Court of Auditors (TCE) defended a recall of thirty hybrid buses. This and thirteen other decisions by the TCE depend on the evaluation by Curitiba’s public transport company, Urbs.
However, regardless of the future of these discussions, which depend on agreements established by the city and various entities involved in electromobility, the trend experienced with hybrid buses, which entered the fleet in October 2012, suggests expansion in the coming years.
Currently there are 20,000 passengers per day carried by the thirty hybrid buses in circulation on the lines Interbairros I, Detran/Vicente Machado, Água Verde/Abranches, Juvevê/Água Verde and Jardim Mercês/Guanabara. Of the thirty models, two combine an electric motor with biofuel (B100), and the others use diesel coupled with an electric motor.
The Tariff Review Commission, established in 2013, has noted that the risk in adopting hybrid buses due to loss of efficiency of the new technology was not confirmed. According to Urbs, the cost savings, which was only confirmed for diesel vehicles, is 35% compared to conventional buses.
The project for electric-powered buses, tested in Curitiba for three months on the Barreirinha line at the end of last year, has not been entirely discarded. The vehicle, produced by the Chinese company BYD, was approved in aspects such as passenger comfort, non-polluting, low noise, and energy consumption, which is 75% lower than a similar vehicle powered by a diesel engine. It holds 80 passengers, 22 seated and 58 standing, in addition to providing space for wheelchair users.
However, the vehicle is heavier, requires tougher pavement, and calls for further studies on economic feasibility. The city, along with other entities, is continuing to develop a biarticulated vehicle that is also electric to be used on the lines.
Regarding emissions, the vehicles in circulation recorded a 35% reduction in carbon emissions, with decreases of 80% in nitrogen oxide and 89% in particulate matter.
The electric motor of the bus allows for speeds of up to about 20 kilometers per hour. The equipment allows the electrical part to recharge at each braking, and is recommended for lines with many stops. For the Ligeirão line, for example, this technology is still not recommended because it depends on other diesel or biodiesel powered motors that can attain higher speeds.
According to Volvo Brazil, the manufacturer of the hybrids, the option of combining the two engines depends on its commercial viability. If it was 100% electric, the bus would require rapid recharging plug-in stations, which are still operationally very expensive.
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Original article, originally published in Portuguese, here.
Credits: Data and images linked to sources.