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This looks like a solution in search of a problem. Hydrogen combustion will never reach the efficiency of current off-the-shelf fuel cells, let alone potential

This looks like a solution in search of a problem. Hydrogen combustion will never reach the efficiency of current off-the-shelf fuel cells, let alone potential future improvements on fuel cells; battery-level efficiency is completely out of the question. There is no use case for choosing combustion instead of fuel cells, period. Hydrogen combustion introduces additional problems like NOx emissions that simply don't exist for fuel cells. Aside from maybe material science, there are no further insights to be gained here that would be applicable in any real-world scenario/product. > But using a hydrogen engine rather than fuel cells would have certain advantages. Such vehicles would employ conventional engine technology and provide a driving experience similar to gasoline cars. And "it's easy to generate torque at low rpms, making it ideal for trucks," a Toyota executive said. None of these are advantages, it's rather the opposite of an advantage. Electric motors provide consistent torque from zero to maximum RPM and don't need sophisticated transmissions. On top of that, hydrogen engines don't work particularly well with variable loads (the same goes for fuel cells, but this can be mitigated by a buffer battery). Fun fact: Toyota's car isn't even the first hydrogen-powered car to complete a 24h race. In 2013, a modified Aston Martin Rapide S equipped with a dual-fuel petrol/hydrogen system completed the 24 Hours of Nürburgring.

Hypx_ 5y ago
It has the advantage of allowing us to avoid investing in any new manufacturing facilities or new production lines. For some cases, it makes sense.
- perl4ever 5y ago
  I'd like to know what the advantage is of burning hydrogen compared to just making synthetic hydrocarbon fuel. I believe it usually uses fossil fuel feedstock but doesn't have to.
  - femto 5y ago
    Lower pollutants [1]. I can't see how burning hydrogen in an engine will compete though, as an electric car is mechanically simpler than a car with an internal combustion engine. As economies of scale build, cars powered by electric motors will undercut internal combustion engines in price and reliability. [1] https://afdc.energy.gov/fuels/hydrogen_benefits.html https://afdc.energy.gov/fuels/hydrogen_benefits.html
    - perl4ever 5y ago
      Hybrids are the future; convince me I'm wrong. No matter how refined the manufacture of electric cars gets, a hybrid will always reduce the battery capacity needed to a fraction of what it would be otherwise. I believe the typical difference between a plug-in hybrid and full electric is around an order of magnitude. It is just as irrational to have a battery with a 300 mile capacity as it is to have a gas engine with 300 hp. In either case, you are allowing for the greatest possible need which happens rarely if at all. A hybrid allows you to build both the engine and the battery for the average case which is on the order of 10% of the worst case. This is a huge inherent benefit.
- bobthepanda 5y ago
  Where are we currently producing any hydrogen fuel in large enough quantities? Or hydrogen fuel tanks? The engines are not the hard part of the hydrogen car.
  - Hypx_ 5y ago
    Electrolysis of water. We'll have more than enough.
mateo1 5y ago
Electric motors might produce consistent torque but that torque isn't as high as you need for a truck. Certainly not without a transmission. Fuel cells might be more efficient than ICEs but you ignore power to weight ratios, performance degradation and total useful life. Also there's the total cost of the vehicle to consider. Personally I dislike both hydrogen and electric vehicles on the grounds of safety. 50kg of hydrogen will produce a pretty devastating explosion in seconds. You've seen teslas burn so you know that side too. At this moment the only thing we gain by converting conventional vehicles to electric or hydrogen is less local NOx and particulate emissions and offsetting them with more emissions elsewhere. These technologies would make a lot more sense if we could source cheap electricity from renewable sources, and we don't. Wind and solar make up an impressive 11% of total electricity production in the US but if you account for storage requirements we're still decades away from anything resembling the dreams of a low carbon economy. It's consumers and pop-sci that's driving this change, and that's not necessarily a good thing.
- pelorat 5y ago
  > Electric motors might produce consistent torque but that torque isn't as high as you need for a truck Sounds like that could be solved by having additional motors that can be switched on by demand, plus a gearbox.
- DarmokJalad1701 5y ago
  > You've seen teslas burn so you know that side too. How often do Teslas burn compared to ICE cars? > At this moment the only thing we gain by converting conventional vehicles to electric or hydrogen is less local NOx and particulate emissions and offsetting them with more emissions elsewhere. Using an EV with today's grid is still significantly more efficient in terms of energy use and CO2 emissions even with some fossil fuels being used to power the grid. Source: https://www.fueleconomy.gov/feg/Find.do?year=2020&vehicleId=42275&zipCode=90001&action=bt3 https://www.fueleconomy.gov/feg/Find.do?year=2020&vehicleId=... A few large heat engines (power plants) running at a constant peak-efficiency load is much more efficient than thousands of smaller heat engines running at variable loads.
  - 5y ago

Hypx_ 5y ago

It has the advantage of allowing us to avoid investing in any new manufacturing facilities or new production lines. For some cases, it makes sense.

perl4ever 5y ago
I'd like to know what the advantage is of burning hydrogen compared to just making synthetic hydrocarbon fuel. I believe it usually uses fossil fuel feedstock but doesn't have to.
- femto 5y ago
  Lower pollutants [1]. I can't see how burning hydrogen in an engine will compete though, as an electric car is mechanically simpler than a car with an internal combustion engine. As economies of scale build, cars powered by electric motors will undercut internal combustion engines in price and reliability. [1] https://afdc.energy.gov/fuels/hydrogen_benefits.html https://afdc.energy.gov/fuels/hydrogen_benefits.html
  - perl4ever 5y ago
    Hybrids are the future; convince me I'm wrong. No matter how refined the manufacture of electric cars gets, a hybrid will always reduce the battery capacity needed to a fraction of what it would be otherwise. I believe the typical difference between a plug-in hybrid and full electric is around an order of magnitude. It is just as irrational to have a battery with a 300 mile capacity as it is to have a gas engine with 300 hp. In either case, you are allowing for the greatest possible need which happens rarely if at all. A hybrid allows you to build both the engine and the battery for the average case which is on the order of 10% of the worst case. This is a huge inherent benefit.
bobthepanda 5y ago
Where are we currently producing any hydrogen fuel in large enough quantities? Or hydrogen fuel tanks? The engines are not the hard part of the hydrogen car.
- Hypx_ 5y ago
  Electrolysis of water. We'll have more than enough.

mateo1 5y ago

Electric motors might produce consistent torque but that torque isn't as high as you need for a truck. Certainly not without a transmission. Fuel cells might be more efficient than ICEs but you ignore power to weight ratios, performance degradation and total useful life. Also there's the total cost of the vehicle to consider. Personally I dislike both hydrogen and electric vehicles on the grounds of safety. 50kg of hydrogen will produce a pretty devastating explosion in seconds. You've seen teslas burn so you know that side too. At this moment the only thing we gain by converting conventional vehicles to electric or hydrogen is less local NOx and particulate emissions and offsetting them with more emissions elsewhere. These technologies would make a lot more sense if we could source cheap electricity from renewable sources, and we don't. Wind and solar make up an impressive 11% of total electricity production in the US but if you account for storage requirements we're still decades away from anything resembling the dreams of a low carbon economy. It's consumers and pop-sci that's driving this change, and that's not necessarily a good thing.

pelorat 5y ago
> Electric motors might produce consistent torque but that torque isn't as high as you need for a truck Sounds like that could be solved by having additional motors that can be switched on by demand, plus a gearbox.
DarmokJalad1701 5y ago
> You've seen teslas burn so you know that side too. How often do Teslas burn compared to ICE cars? > At this moment the only thing we gain by converting conventional vehicles to electric or hydrogen is less local NOx and particulate emissions and offsetting them with more emissions elsewhere. Using an EV with today's grid is still significantly more efficient in terms of energy use and CO2 emissions even with some fossil fuels being used to power the grid. Source: https://www.fueleconomy.gov/feg/Find.do?year=2020&vehicleId=42275&zipCode=90001&action=bt3 https://www.fueleconomy.gov/feg/Find.do?year=2020&vehicleId=... A few large heat engines (power plants) running at a constant peak-efficiency load is much more efficient than thousands of smaller heat engines running at variable loads.
- 5y ago