Current data suggest Montreal hybrid buses save 15.4% on fuel, STM says

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The Société de transport de Montréal has not done any recent studies or commissioned reports to show the 830 diesel-electric hybrid buses on order for nearly $1 billion will actually result in fuel savings.

In an interview on Friday, Renée Amilcar, the STM’s executive director of buses, said the agency decided on the strength of a 2009 study that it would no longer buy conventional diesel buses, as the study reported an average of 31 per cent fuel savings, according to a summary posted online.

“We made the choice to no longer buy 100-per-cent diesel buses,” Amilcar said. “Starting from 2016, all the buses we have bought are hybrids.”

Amilcar would not provide any verifiable studies done more recently than 10 years ago about fuel consumption. However, she said fuel consumption data taken from computers on board Montreal’s hybrid buses on the road in the last three years yielded only a 15.4 per cent savings on fuel, compared with the pure diesel buses in the STM’s fleet. She said the hybrids purchased in 2016 will consume 44 litres per 100 kilometres travelled, compared with conventional diesels, purchased in 2013, which consume 52 L/100km.

Amilcar did not know if newer diesel buses on the market offer better fuel consumption than those purchased by the STM in 2013. However, a document posted last year on the website of bus supplier New Flyer referred to a study that showed diesel buses built by that company consume 4.8 miles per gallon, which translates to 49 litres per 100 kilometres.

Amilcar spoke to the Montreal Gazette in hopes of answering some of the questions raised in a report released this week that cast doubt on the advertised fuel efficiency of hybrid buses. The report, based on a study done in the city of Hong Kong, found that hybrid buses in that city only saved six per cent on fuel. As a result of the finding, the city of Hong Kong elected not to buy any diesel buses.

When asked last week if the STM’s diesel buses save on fuel, director general Luc Tremblay told the Montreal Gazette it was “too soon to tell.”

On Friday, however, the STM sent the Montreal Gazette a chart that showed the fuel consumption of hybrid buses improves by between 8 and 30 per cent within the island of Montreal. The STM also issued a statement on its website refuting some of the claims contained in a Montreal Gazette article that cast doubt on the fuel efficiency of hybrid buses.

Amilcar added that the reliability of the STM’s fleet of hybrid buses was improving in recent weeks. In the statement posted on its website, the STM claimed hybrids were “36 per cent more reliable than the average of our fleet since the end of 2018.”

The chart produced on the website, however, also showed that until the middle of last year, hybrid buses, the newest in the STM’s fleet, were breaking down significantly more often than average. The oldest hybrids in the STM’s fleet were delivered in 2016, while the average age of all the STM’s buses is nine years.

Amilcar, who in the past has admitted to problems with hybrid buses, said on Friday, she believes the problems experienced in the past were due to growing pains — maintenance workers getting used to repairing a new bus.

Still, she said the newest buses in the fleet are breaking down more often than she would like.

“I still have problems (with the hybrid buses). When I buy a new bus, I don’t expect that it will have to go and get repaired,” Amilcar said. “We could see improvements. That’s why we’re working with the supplier to come up with changes so they will be more reliable.”

Among the improvements the STM expects to see in the next fleet of buses are doors that break down less often, Amilcar said.

Montreal Mayor Valérie Plante has been getting criticism this week about the handling of the bus purchase — which will result in half the STM’s fleet being hybrid buses by 2024.

Plante said she is confident the buses will help the city reduce its overall carbon emissions.

“There is no way as a city we could have ordered 300 more buses that were not even a little bit electric, because of our targets for the environment,” Plante said.

Opposition leader Lionel Perez called on Plante and the STM to be more upfront about the actual costs of the buses.

https://montrealgazette.com/news/local-news/current-data-suggest-montreal-hybrid-buses-save-15-4-on-fuel-stm-says