Why are Hydrogen cars not popular?

[yungman]

I have no idea about this, I hope it's not a controversial subject. I know it's been around, it's not new. All I know is H2 is dangerous. Other than that, I have no idea. Just want to hear from people with scientific knowledge.

Thanks

 

[Borek]

As far as I am aware safe storage is the main problem. You don't want to drive with a pressurized tank of a gas waiting to leak and explode.

 

[russ_watters]

Two main reasons:

1. They are inefficient compared to electric cars.

2. Hydrogen storage density is low.

 

[sandy stone]

When I see what people routinely do with gasoline, the idea of those same people going to a service station and filling up their cars with 3000 psi hydrogen makes me very afraid.

 

[Vanadium 50]

OP, do you drive a hydrogen car? If so, what do you see as the advantages over gaslone, electricity, etc.?

If not, why do you think other people should?

 

[yungman]

OP, do you drive a hydrogen car? If so, what do you see as the advantages over gaslone, electricity, etc.?

If not, why do you think other people should?

I just want to understand why H2 car is not popular after all these years. EV has a lot of disadvantage I think people don't think of.

We already starting to have black outs and brown outs in our area. this is with only about 5% of cars are EVs. If we have more EVs, infrastructure are not going to support and result in constant rolling blackouts. People cannot charge their cars.

Because of anticipating more and longer blackouts, I am putting in solar panels and battery backup right now costing me $60K(need to replace roof) AFTER the 30% tax credit(90K up front). Daly City just had black out for 3 days because of the storm. When people buy more EVs, it will get worst, the only reliable way is to put solar panels and battery on their houses. That's a lot of money.

Also, battery in EV is NOT exactly safe. When they catch on fire, they cannot be extinguished with water. I almost bought an EV until I heard on news during flooding in Florida. I want EV for totally different reason, I don't drive that much. My SUV is 9yrs old and only 17K miles on it. I spend more effort to drive it once every 2wks, drive long enough to totally warming up and good circulation of all fluids. This is getting OLD. EV don't need this, it has no motor oil, radiator fluid or transmission fluid. You literally can move it a few ft every so often and it won't hurt the car. Gas car is HIGH MAINTENANCE.

I know H2 is EXPLOSIVE. Other than that, I want to know is there any other reason preventing it from being more popular? I want to ask people in scientific field, I don't want to hear speculation. That's why I post here. I don't want to hear politics, I want to get opinion from people using SCIENCE.

 

[russ_watters]

I know H2 is EXPLOSIVE. Other than that, I want to know is there any other reason preventing it from being more popular? I want to ask people in scientific field, I don't want to hear speculation. That's why I post here. I don't want to hear politics, I want to get opinion from people using SCIENCE.

Two main reasons:

1. They are inefficient compared to electric cars.

2. Hydrogen storage density is low.

 

[yungman]

Two main reasons:

1. They are inefficient compared to electric cars.

2. Hydrogen storage density is low.

What do you mean by storage density is low. You mean say 1gallon of H2 won't go as far as 1 gallon of gas? Or because it's dangerous, you need thick steel tanks that are heavy that make it inefficient?

 

[russ_watters]

What do you mean by storage density is low. You mean say 1gallon of H2 won't go as far as 1 gallon of gas?

Yes.
[edit]
....though googling this I'm finding some concept/limited production cars with surprisingly good ranges.

Also, the "efficiency" question is a bit deep. For example, most of the hydrogen used commercially is made from natural gas, so a hydrogen car is mostly a natural gas car. If you use electricity to make hydrogen then a hydrogen car is an electric car with extra steps and lower efficiency.

 

[Lnewqban]

Refueling infrastructure seems to be the key popularity problem.
Please, see:
https://www.caranddriver.com/features/a41103863/hydrogen-cars-fcev/

https://www.idtechex.com/en/researc...re-not-the-problem-the-hydrogen-fuel-is/25913

https://www.idtechex.com/en/researc...-2023-2033-technologies-forecasts-players/922

https://www.idtechex.com/en/researc...-2023-2033-technologies-forecasts-players/922

 

[Nugatory]

We already starting to have black outs and brown outs in our area. this is with only about 5% of cars are EVs. If we have more EVs, infrastructure are not going to support and result in constant rolling blackouts.

how much of these rolling blackouts are due to the 5% of cars that are EVs?

Asking because EV recharging is one of the better candidates for off-peak consumption. If the power distribution infrastructure in a sunbelt city can handle the afternoon air conditioning peak, there will be substantial excess capacity in off-peak hours. Every EV owner I know is driving during the day and charging at night, often taking advantage of off-peak rates.
Of course this works because home chargers are readily available and affordable…. which tends to reinforce the point others have made in this thread, that the adoption of a technology depends on much more than just its merits considered in isolation.

 

[Vanadium 50]

I don't see an answer to my question. Let me be more direct: if you don't drive a hydrogen car, you must have your reasons, Wouldn't other people have the same reasons?

 

[russ_watters]

I don't see an answer to my question. Let me be more direct: if you don't drive a hydrogen car, you must have your reasons, Wouldn't other people have the same reasons?

I don't see that as a valid question, or rather its superficial, assuming that the buyer has more control than they do and not addressing why the downsides are what they are. For example, one downside might be "there aren't any hydrogen cars available for purchase in my area". That's really not a very useful answer.

 

[Vanadium 50]

how much of these rolling blackouts are due to the 5% of cars that are EVs?

Probably none.

First, "EVs" have a squishy definition. These usually include PHEVs which can have a great deal of variation in their electricity/fossil fraction. Next, 5% of cars is not the same as 5% of energy use or even 5% of electrical use - it's smaller than that.

Second, California's (I assume we are talking about California) problems stem from other factors:

• They are not self-sufficient in electricity. They need to import.
• Power is generated far from the coasts where it is used, so they are particularly reliant on the grid.
• Grid maintenance over such a large area is expensive and has been continually deferred to keep prices low.
• Warning signs, like blackouts and brownouts inland were ignored until they hit the coastal elites.

None of these have to do with EVs or hydrogen cars.

 

[yungman]

how much of these rolling blackouts are due to the 5% of cars that are EVs?

Asking because EV recharging is one of the better candidates for off-peak consumption. If the power distribution infrastructure in a sunbelt city can handle the afternoon air conditioning peak, there will be substantial excess capacity in off-peak hours. Every EV owner I know is driving during the day and charging at night, often taking advantage of off-peak rates.
Of course this works because home chargers are readily available and affordable…. which tends to reinforce the point others have made in this thread, that the adoption of a technology depends on much more than just its merits considered in isolation.

I just look at my PG&E, I use about 22KWh a day, I have AC and all that, my bill is like $400/mo. Now compare to the small Tesla 3 battery, it's 57.5KW
https://ev-database.org/car/1555/Tesla-Model-3
Meaning one charge use like 2 1/2days of my electric bill. That's for driving around 236miles.

If you get a bigger EV like Model S, the battery size is 100KW. One charge is 4.5days of my usage on PG&E.

People do commute to work, I drove like 100miles a day before. meaning my electric usage will be DOUBLE easily if I have an EV.

So back to the question, can the grid support 50% increase if 50% of the cars are EVs?

Also, I think people use more electricity in the modern days, all the AC, big screen tv, computers, phone chargers. Each might be peanuts, but a lot of peanuts do add up. Not like the days when the majority of the transmission lines were built.

 

[russ_watters]

I just look at my PG&E, I use about 22KWh a day, I have AC and all that, my bill is like $400/mo. Now compare to the small Tesla 3 battery, it's 57.5KW
https://ev-database.org/car/1555/Tesla-Model-3
Meaning one charge use like 2 1/2days of my electric bill. That's for driving around 236miles.

Even for California that sounds high by a factor of 2. Please check/verify the numbers on an actual bill. But even still, 236 miles is a lot of driving in 2 days. On a per charge vs per gallon basis an electric is always much cheaper than gas.

So back to the question, can the grid support 50% increase if 50% of the cars are EVs?

No, it can't. Upgrades are required.

Also, I think people use more electricity in the modern days, all the AC, big screen tv, computers, phone chargers. Each might be peanuts, but a lot of peanuts do add up. Not like the days when the majority of the transmission lines were built.

Energy intensity (how much energy each person uses) peaked decades ago and has been dropping since. The shift to EVs will only drop it further because they are more efficient than gas cars. But per above shifting the source from gasoline to electric (and natural gas to electric for heating) will require a major increase in electricity production to compensate for the large drop in gas/gas for other uses.

 

[Vanadium 50]

It's probably worth pointing out that producing hydrogen consumes energy, so it's not clear how much this helps. Of course, Californians can buy it from other states, so it's not their grid that's being overstressed.

 

[yungman]

Even for California that sounds high by a factor of 2. Please check/verify the numbers on an actual bill. But even still, 236 miles is a lot of driving in 2 days. On a per charge vs per gallon basis an electric is always much cheaper than gas.

No, it can't. Upgrades are required.

Energy intensity (how much energy each person uses) peaked decades ago and has been dropping since. The shift to EVs will only drop it further because they are more efficient than gas cars. But per above shifting the source from gasoline to electric (and natural gas to electric for heating) will require a major increase in electricity production to compensate for the large drop in gas/gas for other uses.

I am very sure about my bill. I was looking at the bill to post. The reason is because I am putting in Solar panels right now, all these are important numbers to apply how may panels I need.

 

[russ_watters]

It's probably worth pointing out that producing hydrogen consumes energy, so it's not clear how much this helps. Of course, Californians can buy it from other states, so it's not their grid that's being overstressed.

Nor their grid that burns carbon based fuel. Convenient!

 

[russ_watters]

I am very sure about my bill. I was looking at the bill to post.

Neither 22 kWh/day nor "like $400" are numbers that could possibly have come from a bill. So please, give us the real numbers. And fyi, google says the average for CA is indeed half that:
https://www.energysage.com/local-da...residential electricity rate,rate of 20 ¢/kWh.

The reason is because I am putting in Solar panels right now, all these are important numbers to apply how may panels I need.

?? Are you saying that your bill isn't really a normal bill from PG&E and is higher than the normal cost of grid power because you're paying-off solar panels? That wouldn't shock me but isn't what you'd implied...

 

[Dale]

I know H2 is EXPLOSIVE. Other than that, I want to know is there any other reason preventing it from being more popular?

Frankly, hydrogen-powered vehicles are a bad idea on multiple fronts.

Hydrogen is very flammable

It is very difficult to store, particularly if you want that storage to be safe in the event of a severe impact

It tends to make metal brittle

It has no natural source so it must be manufactured

The usual way to manufacture it at scale is through stripping it from hydrocarbons, thus producing all of the usual carbon emissions of fossil fuels

The alternative method of manufacturing it, electrolysis, is highly inefficient and would produce huge demands in the electricity grid if done at scale. If the local power grid is based on fossil fuels then it still produces carbon emissions.

Hydrogen based internal combustion engines need very large pistons and have relatively little power

Hydrogen based fuel cells use a lot of expensive materials in decently large quantities

IMO, it is a gimmick for getting research funding rather than a realistic solution to any current problem. In any case, calling hydrogen a fuel is false, it is an energy storage technology, one that is vastly inferior to other existing energy storage technologies

 

[DaveC426913]

I mean, technically, we've been driving hydrogen cars for more than a century, its just that the recipe for energy storage has historically included more carbon and oxygen.

 

[yungman]

Neither 22 kWh/day nor "like $400" are numbers that could possibly have come from a bill. So please, give us the real numbers. And fyi, google says the average for CA is indeed half that:
https://www.energysage.com/local-data/electricity-cost/ca/#:~:text=Electric rates in California,-The easiest way&text=The average residential electricity rate,rate of 20 ¢/kWh.?? Are you saying that your bill isn't really a normal bill from PG&E and is higher than the normal cost of grid power because you're paying-off solar panels? That wouldn't shock me but isn't what you'd implied...

This is the graph of my average bill

High is 25KW, low is 18.74, I average to 22KW.

I know how much I paid every month on PG&E. You know there is penalty if you use over certain amount? Yes, if you conserve, bill will be DISPROPORTIONATELY lower.

As I said, I had to submit all these info, that's why I know it's real.

 

[yungman]

Thanks everyone, I have a pretty good idea now.

 

[russ_watters]

This is the graph of my average bill

The actual numbers would have been better than a hard to read graph, but clearly that bill includes natural gas, not just electricity.

 

[Bandersnatch]

The actual numbers would have been better than a hard to read graph, but clearly that bill includes natural gas, not just electricity.

He marked in red the relevant numbers for electricity only, didn't he?

 

[Vanadium 50]

nor "like $400" are numbers that could possibly have come from a bill

This is California, after all. If there were ever a state where the bills are "Like send us like $400, dude, Tubular!" that would be the one.

 

[russ_watters]

He marked in red the relevant numbers for electricity only, didn't he?

Not exactly. The other half of the equation for cost per kWh is cost per month, which I'd have to read from the hard to read graph.

(Edit: # of days can be gotten from the graph...).

 

[Vanadium 50]

Nor their grid that burns carbon based fuel. Convenient!

Well, that's kind of the point. Californians can pat themselves for being green by shifting emissions to other places, It's actually a very California thing to do. The undercurrent of this thread - shouldn't other people drive hydrogen cars - is also very California.

In principle, you still can win. If the whole system is more efficient - and I mean the whole system from natural gas well to fuel-cell based car - you could emit less carbon. That seems not to be the case, as @Dale points out,

Fuel cells are where batteries were 20-30 years ago. They'll be where batteries are today in a few decades, I am sure. But I also expect batteries to have improved in that time.

 

[yungman]

In Calif, they punish you for using too much gas or electricity. It is NOT linear. That's why I am spending over $80K out of pocket to put solar panels and battery before tax. Whole thing still over $60K after all the tax credit. Of cause it's for black out also as the battery is like $35K alone.

Also, they increase the charge very steep, big difference in 3 or 4yrs. It is still going up. This is copy of bill, you see the$120.07 for Silicon Valley Clean Energy charge? This amount varies with amount of ELECTRICITY used as PUNISHMENT.

This cost is only enough to take care of electricity of the house, It is NOT ENOUGH for charging an EV. I just absolutely REFUSE to buy EV because of the fire hazard. I literally need to double the amount of solar panel to support one EV.

It is NOT hard to use a lot of electricity, other than AC, I have LED lights all over the house already, we don't do cook much. Usage mainly on AC, Dryer and some stove. Even AC, I set to 76deg, not exactly that cold.

With solar, I have to use small space heater instead of central heat that uses gas in winter.

If not for family here, I'd move to Texas in a heart beat.

 

[russ_watters]

In Calif, they punish you for using too much gas or electricity. It is NOT linear....

Also, they increase the charge very steep, big difference in 3 or 4yrs. It is still going up. This is copy of bill, you see the$120.07 for Silicon Valley Clean Energy charge? This amount varies with amount of ELECTRICITY used as PUNISHMENT.

SVCE's website tells me they are an optional 3rd party generating company, which unless you're in some group that requires it means you've chosen for that charge to be put on your bill. And yep, generation charges (like most charges) are based on usage and in many cases aren't linear. They claim that rate is lower than PG&E's.

I still wish you'd provide just kWh per month and cost per month, because now the numbers on the kWh per day are too small for me to read. From the prior bill I'm getting something like $0.34 / kWh. It's in the ballpark of the $0.30 I'd guessed and that google tells me is average for San Francisco.

 

[Dale]

I am not sure why we are discussing any member’s utility bill information. Isn’t the average sufficient

 

[russ_watters]

I am not sure why we are discussing any member’s utility bill information. Isn’t the average sufficient

Mostly just because he claimed an impossibly - and inaccurately - high electricity cost.

 

[Vanadium 50]

I am not sure why we are discussing any member’s utility bill

The argument is that if other people drove hydrogen cars as opposed to electric cars, the OPs power bills would be lower. I think this has been exposed as, at best, oversimplifies.

The number that doesn't make sense to me is the $35K for batteries. That buys about 35 kwh of storage, or about a day and a half assuming full electric use during a blackout. That seems excessive, especially as electric use can be throttled during the outage.

 

[BWV]

There are two mechanisms to use H to power a vehicle - internal combustion engines (ICEs) and fuel cells. I am not aware of any serious attempts to build H ICEs, as they suffer from the inherent inefficiencies of ICEs - electric motors are about 2x as efficient in delivering energy to the wheels, which is why EVs can overcome the weight and lower energy density of batteries relative to gasoline or diesel.

So the only possible contender to EVs are H fuel cells. However, they have the same issues with power required to produce H - given the power losses to create H, why not just use that power to charge a battery?

https://www.visualcapitalist.com/vi...difference is that,using a hydrogen fuel cell.

 

[Vanadium 50]

why not just use that power to charge a battery?

This is sensible, but I think the claim is that the grid is overstressed. I would argue the solution is "fix the grid" and not "convince other people to switch to hydrogen", but what do I know?

 

[yungman]

The argument is that if other people drove hydrogen cars as opposed to electric cars, the OPs power bills would be lower. I think this has been exposed as, at best, oversimplifies.

The number that doesn't make sense to me is the $35K for batteries. That buys about 35 kwh of storage, or about a day and a half assuming full electric use during a blackout. That seems excessive, especially as electric use can be throttled during the outage.

I did not say bill would be lower driving H2 car.

It's not the storage of battery that's the limit. It's the max useful current that is the key. for 27KW battery, all are 40A max, you cannot power the whole house. You need at least 60A. AC takes a lot of power. The stupid thing is AC/heat is one unit, in winter, even the AC is not on, you need electricity to run the fan for the heat. If central AC/heat is not backup on battery, you get no heat because no electricity for fan if there is a black out.

So it's max current put the limit during summer, it's NO electricity to power up the fan of heater in winter if there's a black out.

It's a whole lot more complicate than people realize. It's not like you have solar panels and battery, you don't worry about anything.

 

[russ_watters]

It's not the storage of battery that's the limit. It's the max useful current that is the key. for 27KW battery, all are 40A max, you cannot power the whole house. You need at least 60A. AC takes a lot of power. The stupid thing is AC/heat is one unit, in winter, even the AC is not on, you need electricity to run the fan for the heat. If central AC/heat is not backup on battery, you get no heat because no electricity for fan if there is a black out.

So it's max current put the limit during summer, it's NO electricity to power up the fan of heater in winter if there's a black out.

It's a whole lot more complicate than people realize. It's not like you have solar panels and battery, you don't worry about anything.

We're getting deeper into the details here of your specific situation, but....

Is your HVAC a single point power connection? Did you have an electrician or engineer verify the circuiting requirements? If so then what you describe is right, but it is much more common for the indoor and outdoor bits to be on different circuits. Usually you don't have to power the AC to get heat in the winter.

 

[yungman]

We're getting deeper into the details here of your specific situation, but....

Is your HVAC a single point power connection? Did you have an electrician or engineer verify the circuiting requirements? If so then what you describe is right, but it is much more common for the indoor and outdoor bits to be on different circuits. Usually you don't have to power the AC to get heat in the winter.

I have to double check.

My head is literally spinning. There was a deadline in getting into NEM2 where there's a lot of advantages, I was rushing to beat the deadline of 4/14. I didn't even work on battery as that's not part of NEM2. I am just starting to concentrate on battery. It's like open a can of worms, the more you dig, the more complicate it is.

Thanks

 

[Vanadium 50]

My head is literally spinning.

Literally? Oh dear.

 

[gmax137]

It's like open a can of worms, the more you dig, the more complicate it is.

This is why I really liked the old model: "the power company knows what they're doing, so they supply my electricity."

Long off-topic text deleted...

 

[diogenesNY]

There are two mechanisms to use H to power a vehicle - internal combustion engines (ICEs) and fuel cells. I am not aware of any serious attempts to build H ICEs, as they suffer from the inherent inefficiencies of ICEs - electric motors are about 2x as efficient in delivering energy to the wheels, which is why EVs can overcome the weight and lower energy density of batteries relative to gasoline or diesel.

So the only possible contender to EVs are H fuel cells. However, they have the same issues with power required to produce H - given the power losses to create H, why not just use that power to charge a battery?

https://www.visualcapitalist.com/visualized-battery-vs-hydrogen-fuel-cell/#:~:text=The main difference is that,using a hydrogen fuel cell.

While fuel cells have definitely been the leading contender for hydrogen powered vehicles (and there are several methods of generating hydrogen nowadays with a variety of costs and requirements, but that is another topic), there have been some meaningful attempts to build hydrogen burning internal combustion engines.

Now, this is all from memory and goes back over a decade, so I may be a bit lacking in details and direct sourcing, but I beg your indulgence.....

At one point Ford had a small project exploring the possibility of hydrogen burning engines. This was in the 2000s. (Major auto companies have a lot of small and curious research projects ongoing that will never likely see commercialization. Also, other majors may have had their own similar projects, but I am only specifically aware of Ford's). The short version is, they built several prototype engines and put them in cars and did tests, etc. In the end, they concluded that it was an interesting experiment but not of any real commercial value, and closed that lab/shop. I am mostly aware of this because I read a press release from a small company that purchased Ford's portfolio of related IP and several prototype engines and such, and were trying to raise money to continue the project. I never heard anything further about the company that attempted to commercialize the engines, so I think it is safe to conclude that it did not get that far, however there was some nominally commercial pursuit of this idea.

 

[snorkack]

There are two mechanisms to use H to power a vehicle - internal combustion engines (ICEs) and fuel cells. I am not aware of any serious attempts to build H ICEs, as they suffer from the inherent inefficiencies of ICEs - electric motors are about 2x as efficient in delivering energy to the wheels, which is why EVs can overcome the weight and lower energy density of batteries relative to gasoline or diesel.

So the only possible contender to EVs are H fuel cells. However, they have the same issues with power required to produce H - given the power losses to create H, why not just use that power to charge a battery?

For battery energy density, see
https://www.epectec.com/batteries/cell-comparison.html
A problem here is that they use Wh. The factor of 3600.
The best batteries, Li-Co ones store 150...190 Wh/kg. That makes 540...680 kJ/kg. It is correct to point out that this is relatively efficient, with low losses in electric motors - but still less than 700 kJ/kg total.
1 kg of benzine stores 46 000 kJ/kg. Note that unlike battery, this does not include oxidant because it is taken up from air. Although this is a total, and infernal combustion engine is much less efficient in converting heating value of fuel into mechanical energy than electric motors with the storage of batteries, 1 kg of benzine still travels much farther than an 1 kg battery.
And 1 kg liquid hydrogen stores 120 000 kJ/kg - even though it takes up more volume than benzine. Note that this does not count weight of thermal insulation.

 

[pinball1970]

As far as I am aware safe storage is the main problem. You don't want to drive with a pressurized tank of a gas waiting to leak and explode.

To the general public (including me) that would be high on the list of cons if I had to guess.
We know what can happen when petrol cars crash, we have experience and the results can be catastrophic.
With pressurized Hydrogen?

 

[hmmm27]

Wikipedia - list of H2 ICE vehicles

 

[256bits]

To the general public (including me) that would be high on the list of cons if I had to guess.
We know what can happen when petrol cars crash, we have experience and the results can be catastrophic.
With pressurized Hydrogen?

Tanks are 'supposed' to be crash and bullet proof.
Maybe not as to the design of carrying radioactive tanks on railroads, but up there more than other pressurized tanks.

Including a site that outlines how hydrogen can be stored.
The material based is what is usually researched for mobile units.
The material storage has the advantage that not all of the hydrogen is released all at once in case of rupture, since it has to seep out of the pores of the material.
https://www.energy.gov/eere/fuelcells/hydrogen-storage

The tanks can be several times as massive as the hydrogen that they store.

 

[Integral]

This is interesting. Seems that to get enough batteries together to do any REAL work is completely unfeasible.

 

[Astronuc]

Headline/Claim: A hydrogen-car can run over 1242 miles on a single tank
https://interestingengineering.com/...-car-can-run-over-1242-miles-on-a-single-tank

the Eco-Runner Team Delft - https://www.ecorunner.nl/car/

 

[Vanadium 50]

A hydrogen-car can run over 1242 miles on a single tank

So can a gasoline car. All depends on the size of the tank, doesn't ot?

 

[Astronuc]

So can a gasoline car. All depends on the size of the tank, doesn't it?

That is true.

The car is small
https://www.eurocircuits.com/blog/the-eco-runner-xii-wins-the-eco-marathon/
In the Eurocircuits blog, it states, "An efficiency of 486 km/m^3 hydrogen, which equals to 5407 km on one kilogram of hydrogen, was more than enough for first place and to break our own previous record."

The Interesting Engineering article and the Eco-Runner website is annoyingly short on details, such as the technical specifications. What they do indicate is not very impressive.

Eco-Runner I, which participated in the Shell Eco-marathon, a worldwide energy efficiency competition in 2005. The car then achieved an efficiency figure of 346m/L (557km/L) of hydrogen in the top-5 entries. In 2022, its Eco-Runner XI attained a figure of 2110 m/L (3396km/L), also setting the world record for the longest distance traveled in a hydrogen vehicle by driving non-stop for 36 hours and covering 743 miles (1196 kilometers).

An average speed of 20.6 mi/hr (33 km/hr), which is fine for around the village, and one is not in a hurry to get very far.

The requirements have led to a unique bubble-car shape which allows it to keep aerodynamic drag and weight as low as possible. The car's curb weight stands at 147 pounds (67 kilograms), and has a top speed of 15.5 mph (25km/h).

I presume, that the previous quote refers to the Eco-Runner XII. I would imagine the car would get blown of the road in a strong cross wind. Definitely not ready for the Autobahn.

A simple Google search does not readily find the tank capacity of the Eco-Runners.

Liquid hydrogen has a specific gravity of 0.0708, or density of 0.0708 kg/l, or specific volume of 14.1 l/kg.

If one assumes 1242 miles (2000 km) with a fuel consumption of 5407 km/kgH2, then 0.37 kg of H2 would be consumed, which would occupy 5.2 l of liquid hydrogen.

On the other hand using the rate of 557km/L of hydrogen, 2000 km/557 km/L = 3.6 L, which indicates a better performance, but one still does not 'know' the capacity of the tank.