elysia hates battery electric buses

2024 07 22

Battery electric vehicles have, for the last decade, been pitched as a solution to climate change and air polution. This is despite in heavily polluting countries like the United States, transportation accounts for only a quarter of all emissions, with industry and electricity generation occupying equal parts of the pie as well (and let's be very clear, a signficant amount of a vehicle's lifetime emissions come from manufacturing it in the first place).

But battery electric public transport vehicles rub us particularly the wrong way.

Public transport vehicles have been able to be electric for over a hundred years, and in the case of passenger railways, this is standard. Battery buses in particular though also have extreme diminishing returns on their use, and aren't very good at the things they claim to be excellent at. And, it really sucks, because there exists signficantly better alternatives, that we've all just forgotten about.

It somehow feels as if we as a society have been distracted by the flashy marketting that electric vehicles have championed, since a lot of folks where we live don't realise how we've been electrifying our shit for over a century. The way we've done this in the past, though has been through creating a direct link to mains along the entire route a vehicle operates. This is what the wires above railway tracks are for; they provide electricity direct from generation plants elsewhere in a region. Diesel trains are actually somewhat uncommon on passenger rail lines, especially within cities (every subway system in the world that I know of, is entirely electrified). What may be surprsing, though, is that you can do the exact same thing on buses.

Putting wires over a bus route lets a bus be fully electric. It offsets some of the flexibility benefits of using a bus, but also dramatically improves the performance of the bus route. And, really, the flexibility of a route shouldn't matter that much in a good public transport system, because making sure the bus goes where people think it will go is kinda the whole point. And you can still weave and change line when on wire, so you can still avoid minor disruptions on the route.

the technology to do this has actually existed for decades. It far predates battery electric buses, which still haven't seen even a full lifecycle.

a big benefit of a battery electric bus compared to a wired trolleybus is that it can be deployed imediately and on any route, and can handle detours. but, we think with a lot of the supposed benefits of a battery bus, they aren't actually that good at achieving what they set out to do.

we think the main reasons why a public transport agency would buy a battery electric bus is for: fuel savings and reduced maintenance, positive press (and hopefully increased ridership and interest as a result), taking advantage of gov subsidies to replace aging fleet, and to reduce emissions, in that order.

You see the second one come through a lot as a user of public transport. Most electric buses, at least in the anglosphere, have unique full body redesigns that advertise the fact that they are electric, or media that only ever focuses on the fact they are electric, and none of the other features of the bus.

Beyond these, there are a couple of other strengths of electric buses. They are very good at acceleration and decelleration, which is incredibly useful in speeding up the trip time and capacity on tons of different routes. They can traverse steep inclines much better too, and are able to put a lot more power into their wheels than diesel vehicles can. They make sitting in a bus or at a bus station a lot more comfortable for a passenger, since the bus isn't constantly bouncing from the force of the engine, making a loud rumbling noise, or putting exhaust into the air.

the historic barrier to electrifcation is just how much it costs upfront and how you get very little range for what you put in, relatively. battery buses seek to solve these two flaws, so in theory, battery buses should just be the strenghts listed above. but ! they also introduce their own issues.

In fact, they have a lot of issues. Charging infrastructure is expensive, and, using Toronto as an example, the amount they spent on electric bus chargers alone (ie, not including the cost of the buses, which themselves were way more expensive than regular buses) could've gotten them many kilometres of wired bus routes. and a huge difference between electric wires and chargers, is that a bus needs to sit at a charger for an hour, doing nothing, whereas a wired bus can keep running. this means you need more buses to run a single service, since at any given time you will have buses charging.

but you don't actually want to charge the bus in the first place. charging a lithium battery permanently damages it. Electric vehicles do make a bigger effort to make the batteries and chargers more robust than in say, cell phones, so this isn't as big of a deal, but charging still introdcues a limited life time on these batteries. over time, recharging a lithium battery cell dramatically reduces its overall capacity, until a point where it is nearly useless. for buses, this can look like a 400km battery turning into a 100km battery a couple years down the line. trolleybuses fundamentally do not have this issue, and since they don't have much mechanical equipment on board, they can actually last signficantly longer than normal buses, up to a decade or two longer.

this in and off itself can make lifetime costs of a battery bus much higher than a trolleybus, negating a battery bus' financial strength from the perspective of a transit agency. but beyond finances, battery buses are just more complex than trolleybuses, and require rare earths metals, so repairing and replacing them is a bigger ordeal. Never mind the ethical and environmental concerns that sourcing these massive batteries introduces.

in addition, battery buses are heavy. a regular diesel bus can be anywhere from 10-15 tonnes, at least based on what we've looked at. a battery can add another 2-4 tonnes to that, and this reduces a little bit of the performance benefits seen with an electric vehicle. it doesn't totally eliminate them, to be clear, but this, along with the fact that they need to be power consumption consious, make them less performant than trolleybuses.

but, of course trolleybuses have problems as well! mainly from the wires, and not the vehicles themselves, though. a bus that de-wires has historically been a pain in the ass, and trolleybuses need to be careful not to dewire, sometimes requiring heavy speed restrictions. as well as this, a lot of people consider wires aesthetically ugly and unsightly, and don't really like them.

we don't really consider these problems in practice, though. de wiring shouldnt be an issue with modern bus and wire engineering. and we think wires are only unsightly in places with lots of visual noise and complexity, like the city centre or on local streets, but these aren't the places we think they are best suited, for one reason... let me introduce the range extended trolleybus

it's a trolleybus, with a small battery. or if you'd prefer (or view trolleybuses as a dated technology), a electric bus with in motion charging.

these take the strengths of both forms of electrifcation while complimenting each others' weaknesses. dewiring is a complete non issue if you still can move around while off wire for a bit. it also means you can run on battery in places where the wires would be unwanted! on the other hand, a smaller battery is much easier and less expensive to source than a large one, and you don't reach the diminishing returns threshold seen in large batteries. smaller batteries are also much lighter! it also lets trolleybuses go anywhere in a city they want, provided a few core wired spines exist

plus! you can actually do things while charging, meaning you can have a smaller fleet and make better use of the vehicles you have!

and this is where i bring in the surprise case study of this weblog that annoyed us so much into writing this.

OTTAWA

Ottawa relies heavily on its articulated and double decker bus fleet, for primarily capacity reasons. It operates the Transitway, a relatively extensive bus rapid transit system that has built the city into having a very high transit mode share, at least when compared to elsewhere in anglo america.

Most of these transitway routes are use fixed infrastructure along a corridor, that is usually restricted access to buses only. they are mostly trenched and elevated, or operate in very suburban areas. The city's core fleet of articulated buses is also rapidly, and the city needs to electrify the full fleet soon. it also wants to expand public transport in the suburbs and needs to reduce its operating expenses, and also also has some horrendously close stop spacing.

this city feels like a almost perfect fit for range extended trolleybuses. the transitway routes create core spines for buses, and are unlikely to draw negative reception for being under wire, and therefore it has the ability to do in motion charging across vast swaths of the city. it needs the performance to accelerate the large, nearly 30 tonne-when-full buses (reminder: average car in this city is around 1-2 tonnes!), especially with the frequent stops outside of the transitway requiring many starts and stops. it needs a puller architecture articulated bus, with the power in the middle axle, so that it doesn't jackknife itself in winter conditions (the current bendy buses have power in the very back wheels, and are pushers), and the only way to have a puller bus do that while keeping a step free interior is to have most of the power be offboard the bus ( at least to unimaginative north american bus manfufacturers). it needs to bring the operating costs per bus way down and therefore needs higher capacity and more fuel efficent vehicles, ones that batteries would struggle accomodating on their own.

and we're saying this, because this is not what ottawa is currently doing. they have zero plans to do trolleybuses again, and have equally zero plans to get high capacity battery buses. The diesel articulated fleet is basically at end of life and has been for a while, and the city has only ordered regular electric buses, and seems to be ordering more of those. What. what is the city going to do when it doesn't have enough capacity to run its bus rapid transit routes anymore? double frequency? but then theyd need a signficantly larger fleet if thats their plan, since a bunch of their buses has to be stationed at the depot charging for an hour each day (provided there are actually enough chargers to charge any bus that needs it at any time!), and it also doesn't acknowledge the fact that bus drivers are (rightfully) payed very well (perhaps not enough), and doubling trunk route frequency effectively double OC transpo's operating expenses while also not providing any additional useful service. the brt routes are mostly already at turn up and go frequency, the main purpose of increasing frequency beyond this is to increase capacity.

never mind the fact they are exclusively battery electric and therefore need to carry their power on board, with the performance, capacity, and accessibility limitations that comes with that. and they're still paying for the charging infrastructure anyways, its just isolated far away.

in our eyes, ottawa should actually be doubling down in the opposite direction it's currently headed. Get as many high efficency and high capacity vehicles as possible so that you can move the smaller vehicles onto new routes to service suburb to suburb trips with better frequencies. the main things holding ottawa transit back is the size of the bus fleet and its operating cost. O-train line 1 exists purely so that the city was able to move its buses away from the city centre and provide better bus service in the suburbs. trains are just more efficent than buses, in basically all aspects, and the core of the transitway had hit capacity and was demanding the entire bus network's resources.

but its unlikely that ottawa will continue to expand the subway network for a long time after stage 2 is completed. it would be politcally and financially difficult, and so ottawa should be putting as much effort as possible in getting as much from the bus network they already have.

they should probably be getting bi articulated (bendy buses with two bends) range extended trolleybuses, and if they did, maybe they'd finally be forced to purchase buses that aren't the lowest quality possible, cus they'd need to import.

the secret purpose of this weblog is to express our concern and shock with ottawa's bus electrification

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something very interesting to us is that Ottawa created the Transitway in an era where many Canadian cities still used trolleybuses (1980s, vancouver, toronto, hamilton, edmonton), and so we decided to look into if the transitway ever had wires over it in the past. turns out, though, that ottawa retired its trolleybuses in the 1950s, only a couple years after introduction.