Batteries have won this so hard (if you ignore CNG busses, which have existed forever and are "almost as good as hydrogen could be") - because even when they hadn't won it, you just needed more busses.
Is it nice if the bus can do a driver's entire shift without a recharge? Sure! But if it can't, you just design the route so that the driver can switch busses and buy another bus. That means the technology problem is now a money problem.
Busses are also already quite heavy, so battery weight doesn't affect them as much as it might in a small car.
The stop-start nature of city busses makes them a real low hanging fruit for battery electrification, benefiting from instant torque to start and regen to stop and, as you say, fixed known routes within larger fleets.
The only nation that seems to have capitalised on this basic fact is China which bootstrapped its EV industry on busses, pulling ahead from 2010 and hitting 90% of global market share for EV busses in 2020, and now a big exporter.
For the same reason the electric mail trucks are a good idea. You can probably expect UPS and FedEx to start replacing their fleets over time as the existing vehicles age out, now that all electric vans are starting to become available.
I'd say 95% of Amazon delivery vehicles I see in NYC are the electric type. Amazon are known to be really concerned with the bottom-line efficiency, so I suppose it must make clear economic sense.
(At least in King County Metro) the newer diesel-electric buses are series hybrids that use electric motors for traction, and diesel generators to power a small battery. So the low hanging fruit of electric traction was already “picked”. You can look up the bus model online - New Flyer XDE class
> But if it can't, you just design the route so that the driver can switch busses and buy another bus
Oof, that's a huge 'just' in many cases.
That said, current electric buses have sufficient range that this mostly isn't an issue. The unnervingly silent double-deckers I mention have a claimed range of 320km, which, at least here, is sufficient.
The big problem with Dublin's electric buses, ridiculously, was that the operator was late in applying for planning permission for the substations required to charge them. With the result that for about a year, there were about a hundred of them stored and unusable.
This depends a lot on local climate and topography.
Seattle has kind of been a bust with them because the hills really reduce the amount of charge, and on top of that the existing bus depots are already full, so switching to electric only would mean having to find and locate space for more bus depots, which is quite difficult.
I wonder if trolley busses will make a great comeback now. Seems so obvious to just put the overhead lines near a few central bus hubs, so buses can recharge during the shift.
Hills should never reduce the range, because the energy lost during climbing up is recovered when going downhill.
This is one of the great advantages of electric vehicles with batteries, when properly designed.
Electric buses with batteries are even more suitable for cities with hills than for cities without hills, because they provide greater energy savings over buses with ICEs.
While I have never used buses with batteries, I have lived in cities with electric trolley buses. Even with the primitive technology of many decades ago, they were doing great in cities with hills, recovering most of the energy when going downhill, unlike the buses with ICEs, which had excessive fuel consumption because of the hills.
Regenerative breaking is not perfectly efficient, so you may loose a significant portion of the additional energy needed. Better EV systems are what, 70-80% efficient on the breaking efficiency?
Okay, but gasoline is far more energy dense than batteries and a gas tank is a whole lot cheaper than a battery pack, so vehicles can have a gas tank big enough that that doesn't cause range problems. I don't know about buses, but you can buy a pickup with a 48 gallon tank. Even after assuming only about 1/3 efficiency, that's still equivalent to some 500 KWhr, which is several times more than any consumer EV I'm aware of.
That's efficiency, not range. Suppose hilly terrain reduces range by a third for electric vehicles and half for diesel. The diesel bus just fills up twice as often. The electric bus needs a 50% bigger battery in order to finish the same route without stopping to charge, and then it becomes 70% because it has to lug the bigger battery up the hills.
You can just... do that, but that doesn't mean it's not a thing you have to do, and it's not free.
It is impossible for a hilly terrain to reduce the range by a third for well-designed electric buses.
The efficiency of regenerative braking increases with the power of the vehicle. The electric efficiency should be well over 90%, perhaps even 95%. The mechanical losses will lower the total efficiency to much smaller values, but even so, the total efficiency should be over 80%.
A bus with an ICE will consume 5 times more extra energy for climbing the hill and it will also consume energy while going downhill.
Values like a 50% greater battery are unrealistic, and a heavier battery adds much less to the consumption than by how much it is heavier, even when going up the hill (because most of the extra energy consumption is also recovered).
In a certain city, it may happen that the bus routes are so long that batteries are not competitive with ICEs, at least for now. However, the presence of hills in any city can only make electric buses more advantageous, not less advantageous, due to much greater cost savings for fuel and maintenance. Buses with ICEs that are operated on hilly routes also need extra maintenance, besides increased fuel costs. Well-designed electric buses do not care whether they are operated in conditions requiring higher torque.
Like I have said, I have lived in cities with hills and with electric trolley buses and there was no doubt that the trolley buses were superior to buses with ICEs exactly on the routes that were going up and down over hills.
> The efficiency of regenerative braking increases with the power of the vehicle. The electric efficiency should be well over 90%, perhaps even 95%. The mechanical losses will lower the total efficiency to much smaller values, but even so, the total efficiency should be over 80%.
It's not just about conversion efficiency. Moving a vehicle up a hill requires several times as much power as traveling on level terrain, which heats the battery. Reaching the top of the hill and starting regen when going back down again, also heats the battery. On normal terrain that isn't all hills there will be level sections in between that allow the battery to cool. If the terrain doesn't have that then the battery gets too hot and the vehicle will disable regenerative braking and use friction braking to allow the battery to cool off. The steeper the hills are, the more heat is generated per unit time.
Batteries also have charge curves. In the extreme case you start at a higher elevation, go down a hill and can't use regen at all because the battery is full and there is nowhere to put it, but then you have to spend energy later to get back to where you started. The same is true even if the battery isn't fully charged, because extreme charge levels require charging to be done gradually and the battery might not be able to take as much power right now as a heavy bus would generate descending a steep grade.
> A bus with an ICE will consume 5 times more extra energy for climbing the hill and it will also consume energy while going downhill.
Modern engines will cut fuel entirely when descending a grade.
> the presence of hills in any city can only make electric buses more advantageous, not less advantageous, due to much greater cost savings for fuel and maintenance.
That doesn't contradict the point that they'll need to have larger batteries to achieve the same range on hilly terrain.
Regenerative braking is nice but as sibling pointed out it doesn't nearly recapture everything. Another factor is that the additional load whether accelerating up a hill or braking down one puts more current through the system. In fact nearly every part of the drivetrain will experience accelerated wear under those conditions, mechanical or electrical. Cooling systems, too. Properly spec'd, it's of course very doable, but it's true hilly terrain is more difficult.
The problem is that the hills in Seattle are quite large, so you are going up for a long period of time and possibly not able to regenerate before you run out of batteries.
The other problem is that because battery weight is so large, that in itself becomes a limiting factor for hilly operation where it is not really relevant for trolleybuses. And trolleybuses can feed current from uphill buses to downhill buses through the wires, but there's no such connection on battery buses.
> The problem is that the hills in Seattle are quite large, so you are going up for a long period of time and possibly not able to regenerate before you run out of batteries.
Is this deadpan sarcasm? Seattle isn't a mountain pass. The biggest hills are a couple hundred feet bottom to top. The "High Point" neighborhood, which is, uh, the highest point above sea level, is at 522 feet. Every other hill is smaller than that.
Total ascent time is measured in double-digit seconds, discounting lights/stop signs.
Not related to vehicle battery energy consumption, transit agencies have been reporting their BEBs struggling up hills due to drivetrain components not being good fits for their terrain. Surprising finding, with the OEM sending replacement parts as a result.
This is a weird multi-paragraph evangelical lecture seeing as any EV owner that’s driven in a hilly climate will tell you that this isn’t how things work.
Alternatively, you could add charging infrastructure in more places. Eg, partially have trolley-like lines on the route to "top up". This could make sense on dedicated buslanes, especially when multiple lines use that stretch (eg near central stop).
Many bus routes have a 5-10ish min break at some point (usually the main station) in the route. If you can utilize those ten minutes to do a top-up, you can go a lot further on the same sized battery.
No bus route should be more than 15 minutes between full and empty. That is you start at some station, go 15 minutes, then turn around and go back. There are many systems that attempt to do more, but there is no point: people have places to be: on the bus is not on that list. That 15 minutes means an average of 7 minutes, now they walk to some other express bus that gets them nonstop (at faster speeds) to someplace, but you still only get 15 minutes to get there before it isn't worth the bother, than 7 more minutes on some other bus. Add in 5 more minutes of walking time (and transfer time!) and we are at 45 minutes - this is unreasonably long for normal trips already, but it is the best you can do!.
In short there are plenty of places to switch buses if you need to.
There are two critical aspects to the bus routing problem. One is that no matter how well you design your system, there is always variance in the arrival times of a bus at any given stop. If you expect people to switch buses, then you need to account for this variance, and this means adding buffers. Nothing makes people stop using buses faster than missing your connection because your bus was late.
The other aspect is the what city topology you are dealing with. In square grid cities, you can probably put a tram on every road, and with one switch over, get to where ever you need to get to.
But many organically grown cities end up using the hub-and-spoke model, where there are main stations where many different buses meet. People switch over to the next connection (and you need a buffer here). Critically, you need all the buses to meet at roughly the same clock time, say every 30 min. Now, one thing you realize immediately is that not all routes are equal. One route might be only 25 min, Either you make it longer and waste fuel, and time for everyone sitting on the bus, or you wait an extra 5 min at the main station.
Bus scheduling is very difficult problem in real cities with weird topologies and real traffic issues. Buffers are a necessary part of any reasonable solution.
I'm coming from a different perspective: regardless of all else (all those issues you raised are very real), people need to get where they are going in a reasonable amount of time. Most bus service fails to account for that, but if you can't get people there in a reasonable amount of time there is no point in trying.
I agree that a system that does not deliver is going to fail. Transit systems can have improved scheduling in two ways:
(1) Better scheduling system. My opinion is that most real world systems are not too far away from the optimal trade-off curves. There is always room for improvements, or choosing better trade-offs, but it will rarely drastically improve things.
(2) More ridership: Most problems with speed just disappear if more people ride. For example, you do need a solid buffer when buses come every 30 min or more. But buses that come every 10 min or less, you can get rid of all buffer. A lot of scheduling problems are just not-enough-users problem.
No transit system has the money needed to provide great transit to their entire city even though if they did it would save all residents a large pile of money. They compromise on only the densist areas which are easy but mean that you can't get anywhere else reasonably. Of course some areas will always be easier than others to get to, but far too much of any city is not reasonably reachable without a car and that is a problem.
Am I misunderstanding you about the 15 minutes interval?
Every workday I take a one-seat King County Metro bus ride that lasts about 1 hr. The bus starts at a layover facility and ends at a different layover facility.
I don’t see how this 15 minute interval maps to my actual commute?
I don't think you're misunderstanding. I think the person you're responding to is misunderstanding that we were referring to trip end points (layover locations).
You put in a different depot for the 20 minute trip. With express buses the trip between the two depots may only be 5 minutes.
People through history have always considered about half an hour a reasonable daily commute. Doesn't matter if it is a hunter-gatherer going to their gathering grounds (if they follow herds they will move camp if the herd moves more than half an hour), or "modern man" going to the office, half an hour is what you get. Everything I said is based on making as many of those half hour trips possible as I can - but not all trips can be done that way and some locations will be left out.
You would then be subjecting people to indirect paths with multiple transfers. Instead of going from A to B you'd have to go from A to the first bus depot to the second bus depot to B, waiting for another bus at each transfer. If the trip was 30 minutes to begin with, now you've made it 45 (at best).
Have you though? You're at A, near but not at the first bus depot. If there is a bus that originates at the depot, stops at A and then takes you all the way to B, you get there in 30 minutes. If it only takes you half way to B, you have to go half way, wait there for another bus from a different depot, take it back to that depot and wait for a third bus from the depot to B.
Not only is that slower, having the first bus stop there and turn around instead of going all the way to B hasn't benefited anyone else either. The route from the first depot to the halfway point is still being covered by the same bus route. The interval is determined by how many buses cover that route and not just by its total length, and another bus that covers that section of the route might even go somewhere other than B after reaching the point you'd have had it turn around to go back, also giving a faster option than multiple transfers for people who want to go from A to C. When A, B and C are all high density areas, creating direct routes between them makes sense even if they're each more than 15 minutes apart.
Sorry, but, what the hell? This is Hacker News at its finest: completely talking out of its ass.
This isn’t how bus routes work, and this isn’t how people ride busses, on most if not all of the…many PT systems I’ve used in multiple states / countries.
There is a reason people complain about buses and prefer to drive in so many cases. Operators try to compromise on cheap and end up with service for those who after 5 DWIs can't get their friends to drive them anymore.
Forcing more people to change busses more often for their routes just to fit some 15 minute max route ideal is going to make more people hate the busses.
You're not necessarily making more destinations available. You're potentially just requiring more changes to go to the same destinations.
Imagine a metro area with somewhat grid-like streets (or at least common paths) that go on for an hour+ in each direction. People still generally cluster to 20-30min from the destinations they care to go to, so it doesn't break that standard. Breaking it up into four 15-minute stretches isn't making it better for anyone. All you're doing is forcing people to get off one bus at an edge and hop on another. Just run more busses on the full path so there's still ample service for the changes.
How does forcing the 15-minute max path make more destinations available?
It doesn't inherently make more lines. You might (you probably will) just have the same lines more broken up.
You could also just have more lines even if they're long. The length of the lines doesn't change the number of them. It's just a question of how many busses and drivers do you really have and what service interval are you trying to hit.
If you're arguing they should have like a 15 minute hub and spoke model, you might also be forcing some really inefficient routes and once again force people to change busses more when one bus route could have better served the community.
This is highly regional - any major city with a decent transit system will have excellent bus routes in dense areas. Also, “operators” usually means bus drivers, not transit agencies
Only dense areas. Some cities are ignoring dense areas that other cities have proven can support great service because they are not the densest there. People have places to be, and large parts of any city do not have reasonable transit options even though the density is there. Too often you are foced to take the long trip downtown and then back out even though your destination is just barely beyond walking distance.
> That means the technology problem is now a money problem.
This is such an odd insight. Most problems in the world can be described as a "money problem", and it's usually the problem that problem solvers are pushing up against.
> That means the technology problem is now a money problem.
And not even a horrible one. A bus that is driven half as much per day will wear out (about) half as fast. Which means, although you do have to buy twice as many buses up front, the number of buses you have to replace per year won't change.
So in the steady state, the cost of buses isn't actually that much worse.
There is still some penalty for needing more buses, though. For example, you have to pay more to store buses. Also some maintenance is more of a function of time than mileage driven. And you're tying up more capital, which may mean more bonds or opportunity costs.
It's a lot of infrastructure investment but the per-mile running costs are so much lower that it should eventually pay off, especially as buses get cheaper when volume ramps up.
As someone who has witnessed EV buses in person, I think the local pollution and to a lesser extent noise benefits are really great for cities that have or want to move more toward human-friendly streetscapes. They just eliminate so much bus engine stench that just can't be good for breathing in.
It also seems to me that they have to be a lot more reliable. I have seen so many broken down buses with the engine compartment open on the side of the road in my lifetime.
> (if you ignore CNG busses, which have existed forever and are "almost as good as hydrogen could be")
In most of the US yes, in dense big cities they're still quite a bit worse (especially if they run at night too) because they're very noisy compared to electric or hydrogen.
I live in such a place where the buses were all CNG and are now shifting to electric. Unfortunately the switch isn't going too quickly, but every time an electric bus goes by the peace and quiet is blissful. I think every new bus they buy is electric, but I get that they don't want to throw out all of the existing CNG stock.
CNG buses were about a 10-year experiment in Toronto. There were a number of bus terminals where CNG vehicles were prohibited, either due to clearance or because of the associated explosion risk.
A second batch of buses were converted to diesel so that the fuelling station could be decommissioned.
Is it nice if the bus can do a driver's entire shift without a recharge? Sure! But if it can't, you just design the route so that the driver can switch busses and buy another bus. That means the technology problem is now a money problem.
Busses are also already quite heavy, so battery weight doesn't affect them as much as it might in a small car.