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Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

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Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#361

Post by wglb »

hydrogtehd wrote: post #250
baybal2 wrote: post #166

Earlier quoted context omitted.

How many people would be ready to drive a hydrogen bomb?

“Hydrogen bomb” is a little exaggerated. But to your detractors: “More than a gasoline bomb, hopefully. Gasoline is more dangerous.” Citation needed. How is gasoline more dangerous? While gasoline is very dangerous, gasoline is a liquid and will not burn until vaporized; Gasoline is dangerous because it vaporizes quickly. H2 is already a gas and has a ridiculously low spark energy. Furthermore H2 is under pressure. G…

And you can't see a hydrogen flame.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#362

Post by merb »

martini333 wrote: post #356

For everyone here comparing Teslas range to this: It takes less than 10 minutes to fill a tank with hydrogen. It takes 40+ minutes to fill a Tesla to 80%.

Superchargers can only take around 25 minutes for a model y, it heavily depends how many people are on a charging station. of course not every car can be "filled" with 250kW, it also is a huge wear on the battery.

btw. hydrogen energy cells are also subjected to wear, especially when doing a really really long trip. energy density of course is still in favor for hydrogen, especially since they do not need to store oxygen, which means a hydrogen car only needs to keep half the fuel, but battery technologies are expanding way faster than hydrogen can keep up.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#363

Post by merb »

Robotbeat wrote: post #150
nobleach wrote: post #130

Earlier quoted context omitted.

I think the two biggest sellers of Hydrogen electric over battery electric, are the fact that batteries have a useful life. That life degrades over time. Hydrogen doesn't have this characteristic. Secondly, cold weather doesn't affect Hydrogen electric vehicles the way that it does with battery electric. If one lives in a cold weather climate, owning a Tesla isn't as advantageous.

absolutely wrong. Hydrogen fuel cells absolutely degrade over time (they are batteries! Just with more maintenance required due to needing fluids pumped through them). Their lifetime for automotive applications is about 5000 hours, or 150,000-200,000 miles, which is less than what a Model 3’s battery will last. https://www.hydrogen.energy.gov/pdfs/progress18/tahi_lohse-b... Cold weather isn’t a major problem, either,…

they even need a battery aswell which will wear. since the cell is too sluggish to be fed directly to the electric motor.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#364

Post by ajmurmann »

beyondcompute wrote: post #228

Hydrogen is the future of electric transportation! Imagine you are driving and you have several cartridges of magnesium hydride and when you pass by a refueling station a drone catches up with you and swaps nearly-depleted cartridges one by one all while you continue going! How cool is that! B-) And then you can refuel by stuff that you produce yourself using photo catalyst solar panels in your back yard.

Why couldn't you do that with batteries?

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#365

Post by Skunkleton »

epistasis wrote: post #195
nobleach wrote: post #110

Earlier quoted context omitted.

This is true. The current production techniques are basically using water. This is producing a ton of CO2 - the very opposite of what we're hoping to attain by running Hydrogen-powered vehicles. The hope is that we're able to leverage methane from animal droppings in the near future. Toyota is leading the research on this I believe.

Current production methods use natural gas, specifically methane. Animal droppings will never supply enough methane to be a significant source of energy. The goal is to eventually produce hydrogen from water, through electrolysis. We have tech for this, but it's very expensive compared to our methane methods. Current electrolyzers are used for industrial applications. Spain is currently planning a huge deployment of…

Animal droppings are not our primary source of methane. Not sure if that was meant to be sarcastic.

Electrolysis is expensive and energy inefficient. It is unlikely to be a primary source of hydrogen unless there is some breakthrough.

If the limiting factor is clean electricity production, it makes sense to use it more efficiently with a BEV than it does to use it inefficiently with a HFCV.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#366

Post by semi-extrinsic »

abakker wrote: post #273
eternauta3k wrote: post #259

Earlier quoted context omitted.

> the weight of high pressure tanks goes up with their surface area while the energy stores goes up with volume. Nope, tank mass scales with volume because bigger tanks need thicker walls: https://en.wikipedia.org/wiki/Pressure_vessel#Scaling

With hydrogen this is especially problematic due to hydrogen embrittlement. https://en.wikipedia.org/wiki/Hydrogen_embrittlement

Nope, because you don't make hydrogen tanks out of materials that are susceptible to hydrogen embrittlement.

In particular, pressurized automotive-size hydrogen tanks aren't made from metal at all, they are typically epoxy/kevlar/carbon fiber composites.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#367

Post by merb »

Gravityloss wrote: post #11
mrweasel wrote: post #3

It doesn't say anything about the size of the tank, which seems a little weird. Technically you could break that record by adding a bigger tank. Does anyone know what this means: "It purified 449,100 litres of air on the journey – enough for 33 adults to breathe in a day." Why is the car purifying air while driving? Is this a side effect of hydrogen powered cars?

You don't want your fuel cell chemistry to be contaminated. The fuel cell needs oxygen from the air. That's also why it's so light, since in H2O, 90% of the weight is the oxygen.

> That's also why it's so light, since in H2O, 90% of the weight is the oxygen.

which also makes it unsuitable for moon cars.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#368

Post by semi-extrinsic »

Mvandenbergh wrote: post #244
SigmundA wrote: post #117

This is at 66.9 km/h (40 mph) in order to greatly increase its range due to lower drag compared to normal highway speeds. As a comparison a Tesla Model 3 got 975km (606 miles) at 40 km/h (25 mph) [1]. I can't seem to find any range tests at a similar speed as the Nexo. I found an EPA dyno test for the Model 3 at 77 km/h (48mph) for 708 km (440 miles). The Nexo and Model 3 have similar dimension and weight and price,…

>It doesn't seem like current fuels cell have much of a energy density / range advantage even though hydrogen itself is much more energy dense, the fuel cell weight and efficiency and high pressure liquid hydrogen tanks must be accounted for. Hydrogen has a better gravimetric scaling than batteries - as stored energy increases, the fixed weight of the fuel cell is amortised over more energy and the weight of high pre…

For trucks and other heavy duty applications, liquid hydrogen starts to win out over pressurized. In LH2 tanks, the scaling becomes advantageous as you are optimizing against heat ingress, which goes down as 1/R when you increase the radius R.

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#369

Post by merb »

Diggsey wrote: post #73
cogman10 wrote: post #26

Earlier quoted context omitted.

Here a few major issues hydrogen would need to solve. * There isn't a fuel distribution system. The reason BEVs work is because everywhere has power, setting up power distribution is generally just plugging into the local grid. * Hydrogen escapes any container it's placed in. That's a pretty hard thing to deal with. Most approaches have looked at chemically binding hydrogen to something in order to keep it from escap…

> Because electrolysis is highly inefficient Actually it's pretty efficient. According to wikipedia, efficiency ranges from 70% for the cheaper method, to 80% with more expensive catalysts. Theoretical efficiency is 94%.

well theoretical efficiency can never be achived, also it might be more efficient than gasoline cars it can never be more efficient than BEV, because you need to convert power into hydrogen and back, converting anything always has losses

Re: Hyundai Nexo sets new world record 887.5 km travelled on single tank of hydrogen

#370

Post by foxyv »

jacquesm wrote: post #230

FWIW: the material challenges for hydrogen are such that I do not think that it will ever be a mainstream storage medium for vehicular use (it's not a fuel, it is a battery). - hydrogen embrittlement - leakage from whatever container you plan to use - very low activation energy -> always danger of explosion So it's a great thing in the lab and to get subsidy for but it sucks for large scale deployment, and deploying…

I think if you are going to go with a highly energy inefficient storage medium then methane makes more sense. It's a lot more practical to transport and store. It can be carbon neutral as well if you use sabatier generators or bio reactors instead of fossil fuels. You can convert existing ICE engines to use it too.

It's definitely not ideal, but it's still a fair bit better than the hydrogen options which generally just kind of suck. (3000PSI vs 5000PSI for CNG vs H2) If you can source something to dissolve it in you can also store it as LNG. Busses have been using it for ages now. Although I've seen what happens when an CNG tank goes on those busses and it is scary as heck. I can't imagine a similar issue with hydrogen. That stuff is scary.

https://www.youtube.com/watch?v=vHf2o9oVY24

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