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Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

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Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#161

Post by michaelt »

foota wrote: post #147
ErroneousBosh wrote: post #138

Earlier quoted context omitted.

Apparently 1kg of hydrogen is about 60 miles range, which seems like a lot, but apparently fuel cells are that good. Currently hydrogen fuel if you can get it is about 15 quid a kilo in the UK, giving a tank range of around 400 miles for £80. This makes it a little more expensive than diesel, considerably more expensive than petrol, and roughly the same price as electric. By comparison Autogas LPG is around 92p/litre…

> This makes it a little more expensive than diesel, considerably more expensive than petrol, and roughly the same price as electric Is electric charging more expensive in the UK than petrol? That's nuts.

According to [1] it breaks down like this:

EV at rapid/ultra-rapid chargers: 25p/mile

Petrol, diesel: 15p/mile

EV charging at home: 8p/mile

This is because there's a government price cap on home electricity, but not on commercial electricity - and rapid chargers are all commercial (and of course for-profit).

[1] https://www.rac.co.uk/drive/electric-cars/charging/electric-...

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#163

Post by Tuna-Fish »

BadBadJellyBean wrote: post #10

I don't think hydrogen will ever be a thing for personal cars. Apart from the abysmal "well to wheel" efficiency it's also just such a hassle to create a fuel network for it. Gasoline is bad enough but a gas that will just leak away whatever you do seems like a stretch. It is just so much simpler with electricity. Pretty much every gas station already has it. No driving it around with trucks. Just maybe once install…

And more to the point, if you want to use synthetic fuels, why on earth would you pick hydrogen?

Yes, it burns to clean water, but if the carbon feedstock is renewable, synthetic hydrocarbons are renewable too. The efficiency loss from doing the additional steps to build hydrocarbons is not large compared to the efficiency losses of using hydrogen, and storage can be so much easier with something denser.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#164

Post by WalterBright »

dehrmann wrote: post #120
aunty_helen wrote: post #60

Kinda glad this is the case. When people go out of their way to avoid common sense they should be punished. Hydrogen is such a terrible idea it was never getting off the ground. There seems to be some kind of psychosis around it being the next oil and therefore greedy people want to get in early on. But this blinds them to the basic chemistry and physics.

> Hydrogen is such a terrible idea it was never getting off the ground. It's coming from Toyota because Toyota can't wrap its head around not making engines. Ironically, the place hydrogen might work is airplanes where the energy density of batteries doesn't work.

> the place hydrogen might work is airplanes where the energy density of batteries doesn't work.

How is that going to work? Cryogenic liquid hydrogen? High pressure tanks? Those don't seem practical for an airplane.

What does work for airplanes is to use carbon atoms that hydrogen atoms can attach to. Then, it becomes a liquid that can easily be stored at room temperature in lightweight tanks. Very high energy density, and energy per weight!

(I think it's called kerosene.)

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#165

Post by breve »

Plasmoid wrote: post #154
dehrmann wrote: post #120

Earlier quoted context omitted.

> Hydrogen is such a terrible idea it was never getting off the ground. It's coming from Toyota because Toyota can't wrap its head around not making engines. Ironically, the place hydrogen might work is airplanes where the energy density of batteries doesn't work.

We're actually not that far off. Right now, liquid fuels have about 10x the energy density of batteries. Which absolutely kills it for anything outside of extreme short hop flights. But electric engines are about 3x more efficient than liquid fuel engines. So now we're only 3x-4x of a direct replacement. That means we are not hugely far off. Boeing's next major plane won't run on batteries, but the one afterwards def…

> Boeing's next major plane won't run on batteries, but the one afterwards definitely will.

Jet engines work better. Boeing's next major plane will have jet engines, just like their previous major planes.

Synthetic, carbon neutral jet fuel will be the future for commercial jets.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#166

Post by TheSpiceIsLife »

Plasmoid wrote: post #154
dehrmann wrote: post #120

Earlier quoted context omitted.

> Hydrogen is such a terrible idea it was never getting off the ground. It's coming from Toyota because Toyota can't wrap its head around not making engines. Ironically, the place hydrogen might work is airplanes where the energy density of batteries doesn't work.

We're actually not that far off. Right now, liquid fuels have about 10x the energy density of batteries. Which absolutely kills it for anything outside of extreme short hop flights. But electric engines are about 3x more efficient than liquid fuel engines. So now we're only 3x-4x of a direct replacement. That means we are not hugely far off. Boeing's next major plane won't run on batteries, but the one afterwards def…

More accurately, the calculation needs to factor in the fact that battery weight doesn’t decrease as charge is used.

Commercial aviation’s profitability hinges on being able to carry only as much fuel as strictly[1] required.

How can batteries compete with that constraint?

Also, commercial aviation aircraft aren’t time-restricted by refuelling requirements. How are batteries going to compete with that? Realistically, a busy airport would need something like a closely located gigawatt scale power plant with multi-gigawatt peaking capacity to recharge multiple 737 / A320 type aircraft simultaneously.

I don’t believe energy density parity with jet fuel is sufficient. My back of the neocortex estimate is that battery energy density would need to 10x jet fuel to be of much practical use in the case of narrow-body-and-up airliner usefulness.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#167

Post by aunty_helen »

ssl-3 wrote: post #116
ForHackernews wrote: post #88

Earlier quoted context omitted.

Why is it such a terrible idea? In theory you can generate it via electrolysis in places with plentiful renewable energy, and then you've got a very high-density, lightweight fuel. On the surface, it seems ideal for things like cars or planes where vehicle weight matters. Batteries are huge and heavy and nowhere near as energy dense as gasoline.

Ignoring some of the other issues: Imagine we have this electrolysis plant, splitting up water to produce the hydrogen we need for an area. That's fine. But it needs fed electricity to keep the process going. Lots of it. It needs more electrical power to split the water than combining it again produces. So it starts off being energy-negative, and it takes serious electricity to make it happen. Our grid isn't necessar…

It’s not even the grid, by the time you’ve done the electrolysis you’d be better off just charging a battery.

Also, compressing and cooling a gas takes another huge hit at the efficiency. Electrolysis comes out at atmospheric pressures.

Oh and the platinum electrodes you need…

I’m also just now visualising a hydrogen pipeline fire… terrible terrible idea.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#168

Post by aaronbrethorst »

Spooky23 wrote: post #148
formerly_proven wrote: post #133

Earlier quoted context omitted.

Toyota sells bad EVs and was the last OEM to offer one. It’s the most anti-EV OEM by far and engages/engaged in the most EV FUD.

The bZ4X was particularly bad. Toyota adopted a combo of NIH syndrome and DNGAF. They didn’t anticipate cold weather. The batteries lost like 30% of their capacity in the cold and the resale value of it tanked.

They’re also just phenomenally ugly cars.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#169

Post by WalterBright »

Plasmoid wrote: post #154
dehrmann wrote: post #120

Earlier quoted context omitted.

> Hydrogen is such a terrible idea it was never getting off the ground. It's coming from Toyota because Toyota can't wrap its head around not making engines. Ironically, the place hydrogen might work is airplanes where the energy density of batteries doesn't work.

We're actually not that far off. Right now, liquid fuels have about 10x the energy density of batteries. Which absolutely kills it for anything outside of extreme short hop flights. But electric engines are about 3x more efficient than liquid fuel engines. So now we're only 3x-4x of a direct replacement. That means we are not hugely far off. Boeing's next major plane won't run on batteries, but the one afterwards def…

> So now we're only 3x-4x of a direct replacement.

The math leads out an important factor. As the liquid fuel burns, the airplane gets lighter. A lot lighter. Less weight => more range. More like 6x-8x.

Batteries don't get lighter when they discharge.

Re: Toyota’s hydrogen-powered Mirai has experienced rapid depreciation

#170

Post by WalterBright »

capitainenemo wrote: post #160
Plasmoid wrote: post #154

Earlier quoted context omitted.

We're actually not that far off. Right now, liquid fuels have about 10x the energy density of batteries. Which absolutely kills it for anything outside of extreme short hop flights. But electric engines are about 3x more efficient than liquid fuel engines. So now we're only 3x-4x of a direct replacement. That means we are not hugely far off. Boeing's next major plane won't run on batteries, but the one afterwards def…

Well, there's also burning regular fuel in a fuel cell, a FCEV. That doubles the efficiencies over ICE, so I guess that bumps it back up to 8x away? Given the great energy densities and stability in transport of hydrocarbons, there's already some plants out there synthesising them directly from green sources, so that could be a solution if we don't manage to increase battery densities by another order of magnitude.

> there's already some plants out there synthesising them directly from green sources

I didn't realize that a "green" carbon atom is different from a regular carbon atom. They both result in CO2 when burned.

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