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STM - Autobus hybrides


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Dans la Gazette  :
https://montrealgazette.com/news/local-news/montreal-hybrid-buses-outperformed-by-those-in-laval-longueuil-outaouais

Montreal hybrid buses outperformed by those in Laval, Longueuil, Outaouais

With the same buses and the same climate, transit agencies in Laval, Longueuil and Outaouais are able to achieve far greater fuel economy

JASON MAGDER, MONTREAL GAZETTE

Updated: July 31, 2019

0801-city-hybrids.jpg?quality=80&strip=a
An STM hybrid bus makes it's way along St-Michel on Wednesday July 31, 2019. Montreal's hybrid buses are not achieving the savings that had been originally promised.
PIERRE OBENDRAUF / MONTREAL GAZETTE

The city’s transit agency can’t blame harsh winters or its supplier for the poor fuel economy of its hybrid buses, because other Montreal-area transit agencies save far more fuel using the same buses.

Société de transport de Montréal documents have revealed that the agency’s diesel-electric hybrid buses don’t deliver the promised fuel savings of 30 per cent compared with conventional diesel buses. Instead, the actual savings is between 11 and 15 per cent. However, with the same buses and the same climate, transit agencies in Laval, Longueuil and the Outaouais are able to achieve far greater fuel economy.

STM figures show that its newest Series 7 hybrid buses consume 47.5 litres to travel 100 kilometres on average for a year, compared with its most efficient diesel buses that consumed 53.5 L/100 km — an 11.2-per-cent savings.

Figures obtained from Longueuil show its hybrid buses consume 37.8 L/ 100 km, compared with its conventional diesel buses that consume 49.1 L/100 km — a savings of 23 per cent.

In Laval, hybrid buses consume 39.85 L/ 100 km, compared with its diesel buses that consume 52.9 L/ 100 km — a savings of about 25 per cent. Speaking for the agency, Société de transport de Laval’s Estelle Lacroix said it’s difficult to compare data from different agencies in the Montreal region, because routes and passenger numbers vary.

However, Laval, Longueuil and Montreal all rely on hybrid buses built by St-Eustache-based Nova Bus. So, too, does the Société de transport de l’Outaouais. That agency’s standard-sized Nova Bus hybrids achieve a fuel consumption of 40.5 L/ 100 km.

The STM has been criticized from many corners for not revealing the doubts about fuel efficiency before a historic purchase of hybrid buses last year. In June 2018, the agency ordered 830 new hybrid buses at the cost of nearly $1 billion, to be delivered over five years starting in 2020. By the time the delivery is complete, hybrids will make up about half the city’s fleet. Included in that figure are 300 additional buses Montreal Mayor Valérie Plante promised during the last election campaign to boost the agency’s overall fleet by 15 per cent.

While the Plante administration has stood by the major purchase, the opposition in Montreal city hall has called for the order to be put on pause until the city can be sure that the technology is the best choice available.

Lionel Perez, the interim leader of the opposition Ensemble Montréal, told the Montreal Gazette recently he’s alarmed that the STM’s experts appear to have lied to board members in order to ram through the purchase.

“It’s very disconcerting that the STM has been hiding this information from the public, from the board and from elected officials,” Perez said. “If they fudged the numbers because of political pressure (from the Plante administration), then someone has to be accountable.”

This week, Marvin Rotrand, an opposition councillor for Snowdon, and the former vice-chairperson of the STM, said the agency owes the public an explanation.

“How can it be that Laval and Longueuil (get far better fuel consumption)?” Rotrand said. “We bought the buses because of their promised fuel savings; we were told the extra charge for the buses would be recuperated through fuel savings. I think the STM has to tell the public what the problem is.”

The STM has said the low average speed of its buses, and the short distance between stops makes hybrid technology ideal for the city, because of regenerative braking technology that converts the vehicle’s kinetic energy to electric energy, essentially charging its battery. The battery also takes over for the diesel engine when the bus is idling or stopped, which is supposed to further reduce fuel consumption.

However, several studies have cast doubt over the actual savings of hybrid buses in urban settings.

In one, commissioned by the environmental protection department of Hong Kong, double-decker hybrid buses achieved a fuel savings of only six per cent in that city. Surprisingly, the buses scored the worst performances on routes with a lot of hills and in congestion when the average speed was low — around eight kilometres per hour. The hybrids also performed poorly when their air-conditioning units were turned on. STM documents show air conditioning reduces the efficiency of its hybrid engines by 15 per cent.

“They saw that in real conditions in Hong Kong, it doesn’t make sense, cost-wise at least, because the cost of the buses is about 40 per cent higher, and they would not be able to make that up with fuel consumption benefits,” said Leonidas Ntziachristos, an associate professor in mechanical engineering at the Aristotle University of Thessaloniki in Greece. He explained that because they have smaller diesel engines, hybrids generally need more fuel to achieve the same power as conventional buses.

“Because they accelerate much faster, the hybrid buses consume more fuel than the conventional ones,” he said.

Nigel Clark, a professor of mechanical and aerospace engineering at West Virginia University, who has studied hybrid bus technology, said the battery life appears to be their main disadvantage. He said batteries on hybrids tend to be replaced more often than on conventional diesel buses and at a very high cost that can wipe out any cost savings from fuel economy.

A 2015 STM report obtained by the Montreal Gazette through an access-to-information request recommends hybrid buses be configured to limit the number of times electric batteries take over for the diesel engines. The recommendation is for the engines to be automatically shut off only when the onboard electric batteries are charged at 100 per cent, when the bus is stationary, and when its doors are open.

 

Entrevue avec Marvin Rotrand à ce sujet ce matin à Radio-Canada

Autobus hybrides de la STM économies en-deçà des objectifs : Le point de M Rotrand https://ici.radio-canada.ca/premiere/emissions/matinale-ete/episodes/439477/audio-fil-du-jeudi-1-aout-2019/32

 

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Le problème est exactement ce que Mentionne M. Rotrand pendant l'entrevue. La STM a un programme de sauvegarde des batteries qui fait que le moteur thermique tourne plus a la STM. Parce que le moteur s'arrête seulement quand les batteries sont pleine a 100% et quand le véhicule est a l'arrêt porte ouverte. Sinon le moteur tourne. Et moindrement que tu appuis sur l'accélérateur le moteur se remet en marche même si le système électrique est plein. De ce que nous savons c'est que le RTL et la STL peuvent faire 7 à 9km en mode complètement électrique avec leur programmation mais a la STM le moteur tourne toujours. Donc moins d'économie de carburant.

Décision de gestion puisque c'est la programmation que la STM a choisie.

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Il y a 13 heures, berlude a dit :

Le problème est exactement ce que Mentionne M. Rotrand pendant l'entrevue. La STM a un programme de sauvegarde des batteries qui fait que le moteur thermique tourne plus a la STM. Parce que le moteur s'arrête seulement quand les batteries sont pleine a 100% et quand le véhicule est a l'arrêt porte ouverte. Sinon le moteur tourne. Et moindrement que tu appuis sur l'accélérateur le moteur se remet en marche même si le système électrique est plein. De ce que nous savons c'est que le RTL et la STL peuvent faire 7 à 9km en mode complètement électrique avec leur programmation mais a la STM le moteur tourne toujours. Donc moins d'économie de carburant.

Décision de gestion puisque c'est la programmation que la STM a choisie.

Mais pourquoi avoir pris cette décision là? À Montréal, pour diverses raisons, la vitesse moyenne des bus est plus basse et les arrêts sont plus fréquents... c'est le type de ligne de bus où un hybride est le plus optimal! 
Est-ce qu'il y  a une usure prématurée des batteries?

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2 hours ago, berlude said:

Justement c'est que la STM ne fait aucune gestion de flotte précises. C'est a dire que les bus sont envoyé n'importe où peut importe. Aucune distinction si c'est un hybride ou pas. Donc tu as des hybride sur des ligne qui roule est des gros vieux diesel sur des lignes pris dans le traffic au centre-ville. Des rack a baggages du 747 sur des lignes régulière etc. Parfois il y a des notes du genre si le bus rentre après 23h il doit avoir des caméras fonctionnel etc. Mais sans plus. Et des fois même si ton passage est signalé comme un passage de bus avec rampe avant, tu as une rampe non fonctionnel.

Et la STM a adopté ce type de gestion pour les hybrides justement pour ne pas usé les batteries. De ce que j'ai pu comprendre les batterie s'ils doivent les changer c'est un coût supérieur a 50 000$ par bus. (je ne me rappel plus le chiffre exact) Alors ils veulent les garder le plus longtemps possible donc le moteur tourne plus, donc il consomme plus. Et c'est un plus petit moteur qui tourne presque toujours a fond, parce que le bus fait 2 tonnes de plus qu'un régulier pour un plus petit moteur. Ceci apporte cela.

J'te mets un like pour l'information très utile.  Par contre je mettrai bien 10x dislike à la STM pour ce genre de planification..

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Just now, danny12345 said:

J'te mets un like pour l'information très utile.  Par contre je mettrai bien 10x dislike à la STM pour ce genre de planification..

Ça va devenir essentiel avec des autobus à recharge lente. 

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Je l'ai toujours dit: la STM est une organisation sclérosée avec un président qui dort sur la switch. Juste à voir la réno de Berri Uqam depuis 10 ans pour réaliser l'ampleur de la gestion à la ptite semaine, sans planification décente, de cette société. Je fouterais tout le CA et la haute direction dehors!

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Il y a 3 heures, danny12345 a dit :

J'te mets un like pour l'information très utile.  Par contre je mettrai bien 10x dislike à la STM pour ce genre de planification..

Bof ca fait des années qu'ont le dit. Le problème c'est la gestion. Et pas de premier niveau. 

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