Maybe cars, but the weight of batteries is a problem for larger vehicles that need long range, like a bus, truck, or plane. For those hydrogen might be better.
> the weight of batteries is a problem for larger vehicles that need long range, like a bus, truck, or plane. For those hydrogen might be better.
China is already leading the world in electric busses. They work great. Busses are such good vehicles for batteries, that for some routes it may even make sense to run them with super-capacitors, with chargers embedded in the road at stops.
Trucks are always going to be a problem. This is probably the area where H2 might have the best shot. The big problem, however, is that they are a relatively small portion of vehicles. If they're the only ones running H2, it's probably not going to work.
Airplanes, for the most part, aren't going to be electric (although I've heard rumblings of short-range commuter electric aircraft being planned). I doubt they'll be hydrogen powered either. While they aren't as encumbered by the rocket equation as... rockets, they do feel pressure from additional weight. Additionally, the added volume of H2 compared to something like avgas (on a MJ normalized basis) would negatively affect the aerodynamic efficiency of airplanes. Probably going to stay with petroleum for the foreseeable future.
> Busses are such good vehicles for batteries, that for some routes it may even make sense to run them with super-capacitors, with chargers embedded in the road at stops.
I would think busses are a very poor fit for batteries: their economics favours driving around for as long as possible (switching drivers in shifts). Any time spent charging is a waste.
This is less favourable than a consumer car, which sits around unused for most of the time (hence easily charged) and usually only makes a few short trips a day (e.g. commute).
I can understand the desire for supercapacitors on busses, since they are much quicker to charge than batteries. Putting chargers in the stops is a way to mitigate the low energy density of supercapacitors: they only need to last as far as the next charging point.
I think supercapacitors + fast charging stops makes busses very suited for electricity; but I don't think they're best suited for batteries (the fact that there are battery-powered busses shows that there's enough wiggle-room in the economics that they can work despite this unsuitability).
For aircraft, fuel characteristics relative to airframe and payload also matters.
Liquid hydrocarbons store readily in wing tanks at temperatures from (roughly) -50C to 50C. Pasengers and cargo can be allocated to fuselage, arranged in a contiguous space for the length of the craft.
Pressurised hydrogen favours cylyndrical or spherical tanks, located near the fore-aft midpoint of the craft, effectively segmenting the (pressurised) fuselage in two; before-pressure-vessel and aft pressure-vessel . Cryogenic hydrogen would require Dewer vessels and venting with considerations for mitigating hydrogen explosion risk -- present over a wide range of concentrations.
And in both cases, metal embrittlement and molecular leakage occur.
Adding a few carbon chains mitigates all these factors.
>If they're the only ones running H2, it's probably not going to work.
Aren't they practically the only ones running diesel currently? Maybe Trains + other diesel vehicles is a surprisingly large percentage, but... I'd be surprised.
A small percentage of vehicles by sheer number perhaps, but not by miles travelled. An average truck is working 50 hr weeks, plus commute time for the driver etc. As opposed to your average car which runs twice a day for 30 mins.
Still a small percentage. While the average car is 30 minutes twice a day, the small percentage of cars that are not average are still more than the trucks. People on vacation can drive all day. The average car is used for a dentist appoint in the middle of the day once in a while - this all adds up to a lot of cars on the road.
> China is already leading the world in electric busses. They work great. Busses are such good vehicles for batteries, that for some routes it may even make sense to run them with super-capacitors, with chargers embedded in the road at stops.
Alberquerque had to return electric buses because they didn't perform up to the range requirements.
Electric bus range goes down the moment you introduce any sort of elevation, which is why Shenzhen, a relatively flat city, has them, and Hong Kong, an extremely hilly and mountainous city, considered the pilot a failure.
Shenzhen has quite severe elevation differences (which is why a lot of it is unbuilt, even though land values are extremely high) but the bus network was planned to run mostly on the flat bits. HK, being heavily built up already, does not have the luxury of being able to do such planning.
I think that's backwards. Size and weight of batteries is more of a problem at smaller scales - electric motorcycles get up to around 220 miles (Zero SR) compared with electric cars at 370 miles (Tesla Model S). The Tesla Semi has an advertised range of up to 500 miles.
They're a little cagey about that (https://www.zeromotorcycles.com/charging/) but it looks like it can fast charge in ~1hr and charge off a standard wall outlet "overnight".
Some buses need long range, such as that from Munich to Baku. That's not the common case: the common case is more like line 59 in Munich, whose route is about 14km long. A lot more people take the 59 to work than take the bus towards Baku.
Trucks: There are different kinds, but you can separate them into "ones that could be replaced by trains" and "ones that don't really need long range" and not be very wrong. There are exceptions, such as sparsely populated areas, but they're tautologically minor.
Presumably the bus running on line 59 doesn't run once a day; it makes lots of loops back and forth on line 59. Electric charging is not so fast that you can do it in the short amount of time that buses are required to turn around, which is usually measured in minutes.
A rail network rarely has capacity for both decent freight (America) and decent passenger service (Europe). There are some exceptions to this rule, like China. But on their end that necessitated building an entirely new national rail network so that they could make room for freight trains on the old one.
Are you saying that the 59 can't be electric because then it would have to wait empty at its two destinations for twenty minutes instead of ten before starting its next route, and that's impossible?
Nothing is impossible, but it's certainly more difficult.
If charging time is twenty minutes and the bus needs to be out in ten, you need two additional buses on standby to maintain the current schedule (one for each direction.) Except you need more than two, because transit agencies keep a "spare factor" of buses in case a bus breaks down or is otherwise unexpectedly available, and so you probably need ~2.2 buses for this single route.
Scale this up across an entire bus network and that could easily be a hundred or two additional buses. And when you're talking about increasing the fleet by that much, you need to consider storage space for said buses. It's incredibly hard to site bus depots, because you want to minimize the distance from the depot to the start of the line, but you also have to consider the price of land and whether or not a land parcel's best use is a parking lot for buses. And this is before you consider that very few people want a parking lot they can't use as a neighbor.
And so what seems to be a small problem can very quickly snowball into a large one. Public transit agencies aren't exactly flush with cash to buy a larger fleet than otherwise necessary, or land to store said larger fleet. And even if they had this money, is it best spent going electric? Money that is spent going electric is money not being used to keep the fare down or boost services.
There's a big difference between US, Canada or Australia, and say Europe regarding this. In Europe the majority of buses and trucks don't need to travel long distances. And as the population in Europe is generally much more dense soon there will be a local infrastructure of recharging stations available everywhere, so even those that need to cross long distances won't have a big problem recharging more often. The regulations in EU are really strict on bus and truck drivers, so they have to make a lot of stops and take regular breaks anyway (every 4.5 hours IIRC)
Buses travel long distances because they run the same route throughout the day, and the turnaround time of a bus is expected to be minimal.
Alberquerque, New Mexico had the not unreasonable requirement that a bus should have a range of 442 km, but the buses that were delivered could not reliably meet that goal on a route that has some elevation gain and in a hot climate. https://www.abqjournal.com/1246094/abq-rejecting-all-byd-art...
Call me when we have transpacific or transatlantic high speed rail, or when we have a route linking Europe to Asia or Africa that doesn't take the better part of two days.
