Why are Hydrogen cars not popular?

In summary: Are rolling blackouts due to the lack of recharging infrastructure, or the low storage density of hydrogen?The lack of recharging infrastructure.
  • #36
BWV said:
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?
 
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  • #37
Vanadium 50 said:
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.
 
  • #38
yungman said:
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.
 
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  • #39
russ_watters said:
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
 
  • #40
yungman said:
My head is literally spinning.
Literally? Oh dear.
 
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  • #41
yungman said:
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...
 
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  • #42
BWV said:
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.
 
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  • #43
BWV said:
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.
 
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  • #44
Borek said:
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?
 
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  • #46
pinball1970 said:
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.
 
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  • #47
This is interesting. Seems that to get enough batteries together to do any REAL work is completely unfeasible.
 
  • #49
Astronuc said:
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?
 
  • #50
Vanadium 50 said:
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.
 

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