Why not charge electric cars directly with the output of those reactors? Even if you get to higher efficiencies with the electrolysis, the overhead for handling and transporting hydrogen remains.
My overall feeling is that BEVs and FCEVs will _both_ be used in the future. BEVs have some compelling advantages for short-distance travel like intercity commuting (like being able to charge them at home) while FCEVs have compelling advantages for long-distance travel, like higher range and efficiency and faster refueling.
One interesting point from that report is that it addresses the widely-quoted point ([1] for example) that generator -> wheel efficiency for FCEVs is lower. While this is true, it stops just short of the metric we really care about: generator -> miles driven efficiency.
A BEV has to spend a lot of its stored energy just moving its batteries around, while an FCEV uses a relatively light cylinder, so when you look at efficiency in terms of W/miles driven, the reduced weight of an FCEV can render it overall more efficient than a BEV.
FCEVs are also a relatively young technology compared to batteries, so there's likely to be some substantial efficiency improvements still on the table.
[0]: https://www.energy.gov/sites/default/files/2014/03/f9/thomas...
[1]: https://www.volkswagenag.com/en/news/stories/2019/08/hydroge...
I'd expect the business part of FCEV to be lighter. The tanks, fuel cell stacks, converter, etc vs a big ass Li-ion battery.
My first guess is the Mirai frame's safety features were double sized. Being the first product to market, Toyota was probably extremely risk adverse.
I haven't found any Mirai teardowns (a la Munro & Assoc, AvE).
I also couldn't find any weight comparisons of Tesla and Toyota electric motors.
What would a Model 3 with FCEV look like? Replace BEV with FCEV, keeping Tesla's motors.
We've seen that Tesla is obsessed with weight reduction and simplification. Like the Toyota of yesteryear. I'd love for Toyota to do it again for FCEV.
And FCEVs are still in their infancy. There are only 6 production FCEVs so far [2] with very few charging stations built yet. They haven't reached anywhere near the same level of maturity as BEVs. Just compare the first list [2] to the second list [3]. What was the available range when BEVs only had 6 production vehicles on the market?
So I think it's more accurate to say the theoretical advantage hasn't _yet_ been realized in practice.
[0]: https://www.fueleconomy.gov/feg/fcv_sbs.shtml
[1]: https://www.edmunds.com/car-news/2021-tesla-model-3-long-ran...
[2]: https://en.wikipedia.org/wiki/List_of_fuel_cell_vehicles#Pro...
[3]: https://en.wikipedia.org/wiki/List_of_production_battery_ele...
I have quickly glance through it, but some of the assumptions seem to be pretty wrong. If I look in Fig. 4, at a range of 300 miles, this is what the Tesla Model 3 offers. The Model 3 is about 1800-1900kg, so much less than shown in the graphic, and the only FCEV in that range, the Mirai, is even heavier than the Tesla at the same range. So the weight for the FCEV is just plain wrong. And yes, the pure hydrogen tank is much lighter than a battery, but you have to add the weight of the fuel cell and the buffer battery as well as a lot of piping towards it. While hydrogen certainly has the edge in for much larger storage capacities, I can't see an advantage for car sized tanks. Said Mirai also has the same range as a Model 3. Not mentioned is the space requirement: a Mirai has less interior space than a Model 3, because the Tanks have quite a volume and have to by cylindrical shaped. A battery can basically have any shape desired.
My overall feeling is that BEVs and FCEVs will _both_ be used in the future. BEVs have some compelling advantages for short-distance travel like intercity commuting (like being able to charge them at home) while FCEVs have compelling advantages for long-distance travel, like higher range and efficiency and faster refueling.
With the current state of technology, I don't see any disadvantage for BEV. Recharging on the road is much less frequent than refueling of a FCEV, because you can charge a BEV at any outlet. Especially when parking over night. Considering that, the recharge time at a fast charge is only mildly slower, Hyundai ist at 18 minutes already. The quoted fast refuel times assume that the fuel station has full pressure, which might not be the case if another car just refueld there. And why should a FCEV be any more efficient than a BEV? Currently, assuming it would use "green" hydrogen, it takes about 3-4x as much eletricity.
that generator -> wheel efficiency for FCEVs is lower. While this is true, it stops just short of the metric we really care about: generator -> miles driven efficiency.
Sorry, what should be the difference between those terms?
A BEV has to spend a lot of its stored energy just moving its batteries around, while an FCEV uses a relatively light cylinder, so when you look at efficiency in terms of W/miles driven, the reduced weight of an FCEV can render it overall more efficient than a BEV.
No, the weight of the car has only a neglible contribution to the energy used for driving. For driving at constat speed anyway not - at highway speeds the air resistance is the major facter. Only when in a stop-and-go situation, the weight makes a difference, but there the recuperation of the BEV gets back a lot of the energy.
And in practical terms: the Mirai weights more than the Model 3, where is even the possibility for a gain there? And the almost-obese EQS from Mercedes seems to be more efficient than the Model 3 even thanks to a really low air-resistance. Ironically, its larger size does help with air resistance.
FCEVs are also a relatively young technology compared to batteries, so there's likely to be some substantial efficiency improvements still on the table.
Some for sure. But the big problem is for example the energy used to compress the hydrogen. This is plain physics, how much energy you have to spend to compress a gas. And currently, FCEV use about 3x as much energy as comparable electric cars, I don't see where they should catch up with that.
BEVs are a relatively mature technology at this point. Tens of thousands (hundreds? millions?) of BEVs have been sold, there are many production BEV models and they've received decades of research at this point.
FCEVs are still in their infancy. There are only 6 production FCEVs and the technology hasn't received nearly the same level of R&D as BEVs.
Comparing the present-day Mirai to the present-day Model 3 is like comparing the Tesla Roaster to an early Prius. If you'd done that, you'd have concluded that BEVs are too expensive and impractical to ever be viable and that hybrids are the future.
Give the FCEVs some time and they'll get closer to their potential.
But the fundamental question now becomes: considering the performance of the electric cars you can already buy, what is the incentive to invest billions into FCEV development and even more so into fuel stations and distribution? Especially, as there isn't much green hydrogen anytime soon?