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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

#291

Post by thrownthatway »

mapontosevenths wrote: post #287
thrownthatway wrote: post #282

Earlier quoted context omitted.

What must have been the composition of the atmosphere all those hundreds of millions of years ago for all that carbon dioxide to have been removed from the atmosphere and sequestered as biological matter, to then be buried and reacted to form vast quantities of hydrocarbons. The bind moggles.

Your mind should boggle. It's all pretty amazing. 2.5 billion years ago the earth would have been uninhabitable to most modern life. Single celled life evolved in those conditions and began creating glucose and oxygen from CO2 and water. When those primitive lifeforms died some of them became oil and the CO2 was sequestered. Over time the CO2 levels dropped until about 20 million years ago the CO2 levels fell to abou…

What role, if any, did carbonate mineral formation have in sequestering carbon dioxide from the atmosphere?

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

#292

Post by cyberax »

AngryData wrote: post #187
foota wrote: post #145

Earlier quoted context omitted.

> Hydrogen is such a terrible idea it was never getting off the ground. See: the Hindenburg disaster afternote: There's the potential for an amazing pun in here, but I don't think I quite did the opportunity justice.

Ehh, the Hindenburg had a flammable skin. Barrage balloons from the World Wars were most often filled with hydrogen and yet were extremely difficult to ignite or take down even with purpose build incindiary ammo for that purpose shows hydrogen balloons can be safe. Often they would be riddled with dozens of holes but still take many hours for them to lose enough hydrogen to float back down to the ground. The only rea…

That's because regular bullets are actually pretty cold, especially by the time they reach the height of anti-air balloons.

But hydrogen itself is SCARY. It has an extremely wide range of ignitable concentrations, and it has very low ignition energy. It also tends to leak through ~everything.

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

#293

Post by fragmede »

b112 wrote: post #263
matthewdgreen wrote: post #38

Earlier quoted context omitted.

H2 from electrolysis is wildly expensive. H2 from natural gas is more affordable. Both are alternatives to BEVs, which are the better approach to electrifying transport. If Toyota had gone all in on BEVs when it began its H2 strategy, it would be selling more EVs than Tesla. Instead it entirely ceded the field to others, first Tesla and BYD.

H2 from electrolysis is wildly expensive. H2 from natural gas is more affordable. Irrelevant. It seems like everyone who argues against H2 is stuck on "now". Had that been the case with battery powered cars, they'd have never got off of the ground. Batteries were terrible, wildly expensive, extremely unreliable. It's only been the immense research poured into them, that has brought their costs down. Meanwhile, the co…

You raise dying some good points, but hydrogen is really hard to store. It leaks out of everything. You have to very carefully design three containment vessel in order for it not to go wrong.

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

#294

Post by KennyBlanken »

thrownthatway wrote: post #286
MagicMoonlight wrote: post #257

Earlier quoted context omitted.

You can’t make and store bulk hydrogen at home

You can’t. I’m willing to give it a go. I’ve got the excess solar from the rooftop solar panels, the electrical and electronic knowledge, and the gas fitter and metal fabrication experience. I have an oil free air compressor, and anyone can by a helium based cryo-cooler. I have an account with an industrial gas supplier. Just enough knowledge to be dangerous. If Nile Red hasn’t blown his lab up by the time I publish…

Round trip efficiency of hydrogen is at best 50% and at worse half that. You have the horrendous efficiency of electrolysis and then the equally bad efficiency in the fuel cell.

Efficiency pumping your excess solar into the EV itself is more like 80-85%, most of which is loss in the electronics, not the battery - those typically have a coulombic efficiency of over 95%.

Hydrogen a boondoggle. It's not nearly as stupid as making ethanol from corn (which is an energy-negative process) but it's close.

Also, "gas fitter and metal fabrication" experience isn't worth anything unless it was hydrogen-specific. It is far leakier than natural gas/propane. One of the biggest hassles of a hydrogen fuel chain is that the stuff leaks through everything.

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

#295

Post by KennyBlanken »

marcosdumay wrote: post #78
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.

> There seems to be some kind of psychosis around it being the next oil There's a very well financed propaganda campaign.

Same with nuclear. The most expensive form of electricity generation there is. No grid operator wants to touch it, but the nuclear industry has been very busy lobbying congress and both the current and last administration.

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

#296

Post by Qwertious »

WalterBright wrote: post #169
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…

> 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.

It's not that simple.

Batteries are inherently more aerodynamic, because they don't need to suck in oxygen for combustion, and because they need less cooling than an engine that heats itself up by constantly burning fuel. You can getvincredible gains just by improving motor efficiency - the difference between a 98%-efficient motor and a 99%-efficient motor is the latter requires half the cooling. That's more important than the ~1% increase in mileage.

Also, the batteries are static weight, which isn't as nightmarish as liquid fuel that wants to slosh around in the exact directions you want it not to. Static weight means that batteries can be potentially load-bearing structural parts (and in fact already are, in some EV cars).

The math leaves out a lot of important factors.

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

#297

Post by AngryData »

cyberax wrote: post #292
AngryData wrote: post #187

Earlier quoted context omitted.

Ehh, the Hindenburg had a flammable skin. Barrage balloons from the World Wars were most often filled with hydrogen and yet were extremely difficult to ignite or take down even with purpose build incindiary ammo for that purpose shows hydrogen balloons can be safe. Often they would be riddled with dozens of holes but still take many hours for them to lose enough hydrogen to float back down to the ground. The only rea…

That's because regular bullets are actually pretty cold, especially by the time they reach the height of anti-air balloons. But hydrogen itself is SCARY. It has an extremely wide range of ignitable concentrations, and it has very low ignition energy. It also tends to leak through ~everything.

But hydrogen is also so easy to produce on demand that you can design your balloon to be at small positive pressure all the time and always leaks outwards into the open air. If oxygen is allowed to leaked in undetected, yeah that's a death trap. The same if hydrogen leaked into semi contained oxygen enclosures. But leaking through the skin of the balloon to open sky even with decent size holes and a bit of positive pressure doesn't ignite particularly well, despite hydrogen's wide range of ignition conditions.

It is not such a fool proof technology that everybody should have one, but to me building and operating a hydrogen balloon isn't dissimilar to running a steam locomotive. It can be dangerous if done badly or incorrectly, but it can also be done safely with pretty well known and understood technologies and methods and practices. And considering the massive efficiency of lighter-than-air transport I find it hard to dismiss its potential even so long after their heyday and previous problems.

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

#298

Post by jeffbee »

WalterBright wrote: post #234
jeffbee wrote: post #207

Earlier quoted context omitted.

Its the time shift. Burning a plant releases CO2 and it is still considered to be carbon neutral.

Sorry, that's just verbal sleight of hand. There's no such thing as "green" CO2.

How do you justify exhaling then?

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

#299

Post by Qwertious »

SideburnsOfDoom wrote: post #98
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.

Hydrogen is the minimum viable atom: one proton, one electron. H2 is a tiny molecule. "hydrogen embrittlement" is when it's small enough to diffuse into solid metal, because it's that much smaller than iron atoms. It's hard to work with because of this, and what's the point? For most uses, electricity supply is already everywhere.

>Hydrogen is the minimum viable atom: one proton, one electron.

Wait until you hear about H+

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

#300

Post by m463 »

It's really simple.

1 Kg of hydrogen is SUPER EXPENSIVE (equivalent ~ 1 gallon of gas)

$17/gallong when I looked at the pumps

When the Mirai first came out, owners didn't care because the fuel was free.

But after that ended, they had to buy it for themselves.

who wants to pay that?

(also, stations weren't plentiful like EV chargers, and even though you could fill up faster than an EV charge, who cares when you can't go very far (distance-wise from home).

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