A friend recently told me “I am not interesting in electric cars because I will wait for hydrogen cars”. Are electric cars only an interim step on the path to the ultimate: hydrogen cars? This post looks at the reality of hydrogen as power source, for cars and for other uses.
- Hydrogen Background and Summary.
- Why Are Hydrogen Cars Electric? Why Not Combust The Hydrogen?
- How Hydrogen Cars work.
- ‘Pros’ and ‘Cons’ of Hydrogen Cars
- The ‘Pros’: The Case For Hydrogen Fuel Cells.
- Familiarity Refuelling
- Energy Weight Density: The Hydrogen Advantage
- The ‘Cons’: The Case Against Hydrogen Fuel Cells.
- Poor Efficiency: The Case Against Hydrogen
- Running Costs.
- Fuel Supply Reliability & Flexibility.
- Environmental Risks: Hydrogen vs Battery Electric.
- The ‘Pros’: The Case For Hydrogen Fuel Cells.
- Exposed System vs Closed Loop.
- Pro-Hydrogen Claims Debunked.
Hydrogen Myths and Misconceptions Summary.
I now have a separate exploration of hydrogen facts and myths, but here is a summary of the points relevant to the future with cars.
The abundance of Hydrogen is often misrepresented. While The Universe is around 70% Hydrogen, the Earth is only 0.14% Hydrogen, and bringing Hydrogen from space is not an option.
There is no freely available or ready to mine hydrogen. The hydrogen we have here on Earth is mostly locked up in water, or in fossil fuels. To release Hydrogen from water, ‘green hydrogen‘, electricity is required, but this process can be sustainable if the electricity is from renewable sources.
So far most hydrogen is extracted from fossil fuels (blue or grey hydrogen), as this is less expensive, but produces the same amount of CO2, and more, as running cars directly on fossil fuel.
Hydrogen is neither particularly abundant on Earth, nor exists as a sustainable energy source.
For more see:
- Abundant and Sustainable?
- Sources: Mined Hydrogen vs Blue vs Clean ‘Green’ Renewable, sustainable Hydrogen
- Hydrogen Energy: Nuclear, Chemical or Electrical? All are possible.
Why Are Hydrogen Cars Electric? Why Not Combust/Burn the Hydrogen?
Basic high school physics teaches us how burning hydrogen produces energy + water. Rockets burn hydrogen, why not cars? As explained here, because burning hydrogen is far less efficient than using hydrogen to generate electricity, and powering an electric motor with the electricity. Just as lithium batteries use a chemical reaction to produce electric power, hydrogen cars use a controlled form of the reaction between hydrogen and oxygen to produce electric power. The result is an electric vehicle, powered by electric motors, that uses a hydrogen fuel cell in place of conventional battery technology.
The store the same energy is a gasoline tank, you need a hydrogen tank over 6x larger. However, because using a fuel cell and electric motor combination is so much more efficient than combustion, and thus requires less hydrogen, using a fuel cell can reduce the tank to just 3x larger than with a gasoline engine.
That being said, Toyota is still experimenting with hydrogen combustion engines, with a recent reveal of a special one off race car. An engineering analysis of that race car can be found on Engineering Explained. However, even with Toyota as the main supporter of Hydrogen for cars, their public support is for fuel cell cars, and even that support is just the one model, the Toyota Mirai, compared to the 25 battery electric vehicles they have announced they will have by 2025.
How Hydrogen Cars Work.
The video explains the working of the Toyota Mirai, a latest model state of the art Hydrogen car that is available to consumers in California for around US$50,000. This new model now with a range of 640 km (400 miles), the Mirai offers better range than similarly priced battery/electric competitors (e.g the RWD US$46,000 Telsa Model 3 ‘long range’ has only 600km/373miles of range). A Tesla model S with similar range to the Mirai, costs US$70,000, and battery electric car with 800km/500miles like the Lucid Air costs even more.
It should be noted that the Mirai is a limited production vehicle, only sold in limited numbers in very specific markets, and given the number sold and cost of R&D to produce any new car, there is no way that Mirai sales represent a profit, and therefore the price comparison may be distorted. It is possible that the Mirai price represents the price Toyota estimates would be profitable for a volume production car, but there is considerable uncertainty.
Note the Mirai, with a 0-60mph time of 9.2 seconds, does not offer impressive performance, particularly when considering even the long range Tesla model 3 takes less than half that time at 4.4 seconds, never mind the Lucid Air can halve that time again. The Mirai is not fast. This is the general trend at this time. Both Toyota and Hyundai offer Hydrogen vehicles that have around 10% more range than equivalently priced battery electric vehicles, but with substantially lower performance than their battery equivalents. Note also that while battery electric vehicles are in mass production, hydrogen vehicles are for sale in limited numbers only and as such pricing is artificial.
A strong point for the Mirai is that refuelling takes only 5 minutes, compared to 20 minutes to refuel the Lucid Air, or 30 minutes to refuel the Tesla model 3. Note that newer EVs than the Tesla, like the Hyundai Ionic 5, can be refuelled faster.
To achieve the long range, the Mirai has a fuel tank capacity of over 142 litres (over 37 US gallons). A Toyota Prius uses gasoline, but can get a longer range from an 11 US gallon tank.
Pros and Cons for Hydrogen Cars.
The Case For Hydrogen Cars:
An attraction of Hydrogen cars is that experience of refuelling is similar to the familiar experience of refuelling combustion cars. The same gas stations, operated by the same companies, could provide hydrogen refuelling, and the experience of refuelling would be similar to that with gasoline cars.
Low Fuel Weight
The key benefit of hydrogen is that the stored energy is much lighter that any alternative. The video below highlighting the problems of using hydrogen, quotes the difference at over 200x the stored energy per kg compared to batteries. That is a huge difference, and results in hydrogen being a viable option where the difference in the weight of stored energy is suffiently important, the cost of electricity is extremely low, or a combination of these two factors. Clearly, for aviation, that weight difference for the amount of energy required for a flight could easily the cost of the extra energy needed to extract and liquify hydrogen and other inefficiencies.
Conventional EV battery recharging can take hours and even over a day in some cases, and in a more direct comparison, current ‘rapid charge’ technology for EVs still takes around 20 minutes to deliver full range equivalent. A hydrogen vehicle like the Toyota Mirai can achieve full refuelling with 5 minutes. Refuelling times using hydrogen approach times to current refuelling with petroleum, diesel fuel or avgas. Although refuelling may be a little slower, in part due to the large size of the fuel tanks, refuelling times are still very nothing like slower electrical recharging times.
If there is room for a large amount of storage, then hydrogen cars can match the best of current battery technology, and with a far lower weight for a given amount of range. In vehicles such as planes, where wings could house the tanks for lightweight hydrogen, or ships, which can also accommodate large fuel tanks, the range of hydrogen vehicle can greatly exceed that possible with batteries.
Note: 2021-May-31st. Toyota just broke hydrogen range record.
The Case Against Hydrogen Cars.
This video puts the case against Hydrogen simply: the truth about Hydrogen. In summary, it currently costs over 8x the price per kilometre/mile to run a Hydrogen fuelled vehicle in comparison to a battery electric vehicle. While this ratio could reduce there are just too many steps prevent it costs at the very least 2x or twice the energy and thus cost per kilometre. Sustainable use of hydrogen power requires using electricity to produce hydrogen, power to compress or supercooling the hydrogen for liquification, and then conversion of the hydrogen back to electricity inside the car. In summary, you need, in the best imaginable future, at least twice the electricity per kilometre to power a hydrogen car. The best imaginable future for Hydrogen would be where stored hydrogen was the original source of energy. Even then, hydrogen cars are less efficient, because most of the steps with losses still apply to squeezing the hydrogen into a car fuel tank that cannot efficiently be kept cool enough for liquid hydrogen. Without a way to avoid this resulting is double (and in reality, at least triple the cost for the electricity that reaches the engine in most cases).
At least twice as much electricity is required to drive the same distance using Hydrogen power as battery power. Further, infrastructure to convert electricity into Hydrogen, store the Hydrogen, and then refuel a dangerous material that is difficult to contain will all add to the price or operating a Hydrogen vehicle.
While it is a complete change in thinking, the ability to ‘refuel’ or recharge anywhere there is electricity available, can be far more appealing than refuelling with Hydrogen unless a new infrastructure is developed. Cars do spend long periods stationary, and almost any time a car is stationary becomes a potential refuelling time.
On road trips, there are already many electric recharge points, and while 20 minutes rapid charging an EV like new model Hyundai Ionic 5 is around 4x longer than the equivalent refuelling time for hydrogen, the refuelling is far less dangerous, which means you can go for a walk and have a coffee or a rest while refuelling. Refuelling Hydrogen requires full attention.
In practice, many electric cars typically have a longer immediate range than gasoline cars, because the behaviour of most people is to delay refuelling gasoline cars until the tank is nearly empty, while electric cars are kept charged. If regularly charged overnight as would be expected, each day an electric vehicle starts with a ‘full tank’.
There are now several Solar EVs on the market, and even the Tesla Cybertruck with optional solar wings can enable normal use of the truck from solar power. People can use home solar to generate the power for their cars. How do you compete with that using hydrogen?
Fuel Supply Security & Flexibility.
Battery cars need energy, while fuel cell cars need a specific type of fuel in order to produce energy. Solar, wind, and even a hand crank can produced electricity. A solar mat will gradually refuel a battery vehicle in the middle of nowhere, but a fuel cell car specifically requires pressurised hydrogen.
Environmental Risks: Hydrogen vs Battery Electric.
There is one sustainability threat: loss of hydrogen!
Hydrogen is not without sustainability risks. Remember how the Earth has insufficient mass to have retained free Hydrogen when the Earth formed? Well, the Earth still loses Hydrogen every year, and separating Hydrogen accelerates that process, so any leaks of Hydrogen can be the ultimate in unsustainability, as the material not just in waste form, it is gone forever. When burning fossil fuels, at least all the atoms are still here on Earth. Although Hydrogen is the most abundant element in the Universe, here on Earth, Oxygen (47%), Silicon (28%) , Aluminium (8%) and Iron (5%) are the most commonly available elements, with Hydrogen down at 0.14%. Water is Hydrogen and Oxygen, so simply put, the less Hydrogen, the less water. And we would miss the water if we lose too much Hydrogen.
Battery production damages the environment. However, so does producing internal combustion engines. In some countries, production of electric cars does produce almost double the pollution of production of internal combustion engines. However, according to Forbes, but in western countries companies like Tesla and Mercedes produce electric cars
As such, the pollution created through the extraction process and production of batteries remains on par or slightly higher than the manufacturing process of petrol or diesel-based engines.
Exposed System vs Closed Loop.
Every motor vehicle so far has been powered by chemical reactions, either inside batteries, or some form of combustion. There are two ways to have the ingredients for these chemical reactions:
- Keep adding the chemicals for the reaction by refuelling the vehicle.
- From steam to gasoline, diesel, LGP and even hydrogen fuel cell, this is how it has been done
- Requires an infrastructure distributing the chemicals needed, and the infrastructure and vehicles all change if the chemicals change.
- Recycle the chemicals for the reaction inside the vehicle.
- This is how battery EVs work.
- The chemicals are kept inside the battery, and when connected to energy source, the battery recycles the chemicals.
- As only energy is needed, the chemicals used can even change from car to car with no need for any new infrastructure.
The rapid progress with battery vehicles has been enabled by the closed loop, moving to another infrastructure that locks into energy from one specific chemical reaction is far more restrictive.
The appeal or hydrogen is that if you do desire an open loop, not recycled in the vehicle, give that the waste with hydrogen is water, this is the best open loop ‘dump the waste’ possible. However, that still doesn’t make the system competitive with closed loop systems. You can make a closed loop with hydrogen, but at this time, it is neither the most efficient, safe, economical, or environmentally sound choice for such a system.
Pro-Hydrogen Claims Debunked.
Various claims are made by hydrogen car supporters. I think all of these can now be debunked.
- Zero tailpipe emissions.
- Great in comparison with gasoline or diesel, but no improvement over any other electric car. Note that hydrogen combustion vehicles not only have half the range of hydrogen fuel cell vehicles, they also do produce nitrous oxide emissions.
- Familiar refuelling.
- In fact putting hydrogen into tanks is problematic and takes a lot of space, and no equivalent system has so far been practical for mainstream usage, which is why there are many LPG cars but only a few hybrid CNG cars that have very limited range on CNG. Hydrogen takes the compressed gas problem to the next level.
- Existing Infrastructure.
- The same companies that sell gasoline and diesel can easily sell ‘blue hydrogen’, but is it so essential that we support those companies? The rest of the infrastructure changes.
- Fast Refuelling.
- There is an advantage here, but given what is happening with batteries, it will be an advantage for at most another 10 years, and that timeframe does not justify an interim system.
- Long Range.
- Possible, but only with special vehicles with huge tanks, which is why the longest range battery vehicles have longer range than the longest range hydrogen vehicles.
- We can never make enough batteries for everyone to have an EV.
- Not with current facilities, but we are closer than we are to being able to provide enough hydrogen. Neither problem is difficult to solve.
- Battery production damages the environment.
- It theory battery production does not need to harm the environment, but in practice it can. In practice, hydrogen production so far has been even more damaging to the environment.
Industry Initiatives: What Funds Hydrogen cars?
While Toyota, Honda and Hyundai all still have hydrogen cars, they are now all also committed, and even more committed with the possible exception of Toyota, to battery electric cars. Other manufacturers such as Volkswagen (which is approximately equal in size to Toyota) have long rejected hydrogen cars as having no future, and Cambridge university reached the same conclusion in their study.
There are vested interests, such as oil and gas companies, that could be expected to lobby for (blue) hydrogen as it could protect their interests, but it is difficult to see any push being successful for passenger cars. The main impact of hydrogen fuel cell passenger cars seems to be targeted at creating uncertainty on the future of electric cars, in order to slow the introduction of electric cars. Clearly oil and gas companies and most existing car manufacturers will lose revenue as a result of any move to electric cars. For car companies, the loss can be minimised by buying time to better prepare, but for the oil companies, there is even more incentive to mimic the behaviour of big tobacco when cigarette consumption smoking was threatened.
Hydrogen Hybrids: PHFCEV?
At one time it occurred to me that hydrogen hybrids might be a great idea, and it is discussed in detail here. The huge power to weight advantage of hydrogen for range, combined with the efficiency of electric for the daily commute. Far less weight carrying around the confidence giving extra range than using a large battery. Could it be the best of both worlds?
Hydrogen Cars If There Is Already Hydrogen For Energy Storage?
Hydrogen does have significant potential as a form of stored energy. One big potential use of hydrogen is hydrogen for stored energy. I hydrogen is already being stored, wouldn’t that change the equation in favour of hydrogen cars? In short, no. Not even then.
Imagine a world where renewables are used to produce huge reserves of stored hydrogen. You might think, in such a future, putting some of that hydrogen into cars would be compelling. However, upon further analysis, even in that case powering the grid though hydrogen will still be the best way to get energy to cars.
In theory, if there is green hydrogen as stored energy, there could one day be ‘town gas’ using hydrogen through an urban gas network. In practice there are many challenges and if this did happen it would be many years from now and even then, would not provide hydrogen to locations on the highway that currently do not have such a gas network. For a long time, and perhaps forever, getting hydrogen to filling points would require tanker trucks. Filling tanker trucks with hydrogen, then driving the trucks and transferring that hydrogen into tanks are the filling stations, all adds cost and requires mechanisms to recompress gas, while the electricity grid is still needed at filling stations and transporting electricity is significantly less expensive and using a network that is already in place.
In summary, even if the power station is storing hydrogen, it is more efficient to send the energy from the hydrogen to recharging points than to transport hydrogen.
The case for hydrogen cars is frail at best.
Hydrogen cars use more electricity, even if the hydrogen is the source of electricity.
Hydrogen could make sense for planes, shipping, and perhaps even some specialist automotive vehicles, but not for mainstream cars as things stand.
Right now, the best choice for most people would be a battery electric vehicle. Whether the arguments for hydrogen will at some point change this, depends on perspective. If you believe that there is all this oil and gas that would otherwise go to waste, then the case for Hydrogen is compelling. On the other hand if you believe that using sustainable energy is best, then the inefficiency of hydrogen limits its use to cases where recharging or range/weight ratio disqualify other electric vehicles.
There did appear to be a case for hydrogen as a transition technology, while recharging was put into place, but at this time recharging networks for electric vehicles are far more established, and we are a long way from having hydrogen refuelling available on any significant scale.
Hybrids, niches, and aviation appear as the best uses for Hydrogen power, whey hydrogen could be used together with battery electric in future, but given the established recharging network, even that is going to require a big step.
Perhaps there is hydrogen in the future, but it does happen, it will not make battery electric cars redundant. Perhaps the best hope is the make an efficient hydrogen battery, to keep it closed loop.
Fully Charged: The future is not hydrogen.