With the rise of usable electric cars in the marketplace, and markets around the world slowly phasing out the sale of fossil fuel cars, you could be forgiven for thinking that the age of the internal combustion engine is coming to an end. History is rarely so cut and dry, however, and new technologies aim to keep the combustion engine alive for some time yet.
One of the most interesting technologies in this area are hydrogen-burning combustion engines. In contrast to fuel cell technologies, which combine hydrogen with oxygen through special membranes in order to create electricity, these engines do it the old fashioned way – in flames. Toyota has recently been exploring the technology, and has announced a racecar sporting a three-cylinder hydrogen-burning engine will compete in this year’s Fuji Super TEC 24 Hour race.
Hydrogen Engines?
The benefit of a hydrogen-burning engine is that unlike burning fossil fuels, the emissions from burning hydrogen are remarkably clean. Burning hydrogen in pure oxygen produces only water as a byproduct. When burned in atmospheric air, the result is much the same, albeit with small amounts of nitrogen oxides produced. Thus, there’s great incentive to explore the substitution of existing transportation fuels with hydrogen. It’s a potential way to reduce pollution output while avoiding the hassles of long recharge times with battery electric technologies.
The basics of a hydrogen-burning combustion engine are largely the same as any gasoline engine out there. In fact, virtually any existing gasoline engine can be converted to run on hydrogen simply by replacing the fuel injectors with parts suitable for injecting hydrogen instead. However, due largely to the fact that a combustible mixture of hydrogen and air takes up more space in a cylinder that would otherwise be for air, power output would be reduced by 20-30% compared to the same engine burning gasoline, assuming the hydrogen is injected prior to intake valve closure.
However, measures can be taken to offset this. By designing engines to burn hydrogen from the outset, things like compression ratio, combustion chamber design, and injection methods can all be optimised to suit hydrogen fuel. For example, by using direct injection technology to squirt hydrogen into the combustion chamber after the intake valve is closed, power of a hydrogen engine can be increased significantly, as demonstrated in the graphic above. This is due to the engine vacuum on the intake stroke pulling in 100% air, rather than 30% of the space being taken up by hydrogen in a stoichiometric mix.
There are still engineering problems that remain to be solved before hydrogen engines can go mainstream. There’s also the same chicken-and-egg distribution problem that affects fuel cell cars; it remains difficult for companies to sell hydrogen-powered vehicles in the absence of filling station infrastructure. There are also issues of crankcase ventilation, where gaseous hydrogen can ignite in the crankcase having slipped past the piston rings, as well as backfire issues in systems that premix the hydrogen gas in the intake. None of these problems are insurmountable, however, and solving them is more a case of routine engineering effort rather than blue-sky research.
It also bears noting that, while hydrogen-burning engines are far cleaner than their fossil-fuelled equivalents, and don’t emit any CO2, trace amounts of lubricant oils still sneak through the combustion process because no piston rings are perfect. Obviously, this is not a problem for hydrogen fuel cells.
Real-World Examples
Toyota’s racing entry will field a three-cylinder engine in a car based on the Toyota Corolla Sport, intending to compete in a 24-hour endurance race. There isn’t a whole lot more to go off, though a YouTube video on the hydrogen engine seems to imply that port injection, rather than direct injection, is being used. This is not surprising, because the racing entry is essentially a technology demonstrator to raise the profile of hydrogen cars, rather than an all-out effort to produce the highest possible power with a hydrogen engine.
Toyota aren’t the only company experimenting with the technology, however. Mazda’s efforts resulted in the RX-8 Hydrogen RE, sporting a duel-fuel Wankel engine capable of burning gasoline or hydrogen as required. A small number of these vehicles were leased out in various locations with suitable filling infrastructure.
BMW went as far as building a version of its 7-series luxury sedan complete with a 6.0 litre dual-fuel V-12 engine. The engine gave up some performance compared to the solely gasoline powered models, however, and was also only released in limited numbers from 2005 to 2007.
Earlier projects such as those from BMW and Mazda raised significant interest, but little genuine demand from the marketplace. High prices combined with rudimentary hydrogen storage technology, along with a near-total lack of infrastructure, meant that such cars weren’t a great proposition for the average driver.
While previous experiments with hydrogen combustion engines have fallen flat, the continual push to develop better hydrogen storage and filling stations, as well as better performing engines, may yet see it have some promise in the future. However, it will be an uphill battle against existing electric cars, which have a huge lead in the infrastructure race, as well as in hearts and minds.
While electric cars have their place, we can’t overlook the Infrastructure problems caused by charging mass amounts of electric vehicles! They all have to get that electricity somewhere, and the grid is already taxed in some areas for various reasons. While It is hugely more efficient to centralize generation, the future of the grid is likely a more distributed solution, and you still have to get that power to the car.
Increasingly, I get the impression that solving the climate change dilemma is going to take more than just a couple solutions, and that its going to take a lot of creative and out of the box thinking by a lot of smart, motivated people.
Its very encouraging to see people working on new solutions and pushing the development of this and other alternative methods for powering vehicles. Whether we like it or not, the need for transportation is not going to go away, and because of varying environments and needs, no one silver bullet will be the answer.
New ideas would be great. Internal combustion of fossil fuel derived hydrogen isn’t new. It is just another gasp of a dying industry.
I love my diesels, but all future vehicles that I purchase will be electric.
Might work for you, won’t work for everyone. At least not until some miracle in miniaturisation makes CAES viable for vehicles, (which is almost impossible with the physics of how they work), the on board water cracker to run the fuel cell or Hydrogen infrastructure spreads (sure there are a few other ways of being electric and not suffering the downsides of batteries I’ve not mentioned that fill one niche or other but you get the idea I hope).
Batteries are perfect or at least adequate for many folks uses, but not everyone’s. Where ICE burning hydrogen is almost a drop in replacement in useability/functionality to petrol, and its not much of a stretch or cost to add Hydrogen to fuel stations, they already handle a variety of fuels including LPG, which is in many ways a similar storage and transport challenge.
Also an Electric car is only as green as its power source, so won’t actually solve the problem at all if the grid you connect it to is dirty.
For myself I can’t see getting an EV being worth it, the embodied energy to create a new vehicle is so high, and I barely do any miles, so while running even something as terrible as old American iron with their marvellous fuel efficiency (I don’t, actually don’t like ’em myself – rather have a 2CV (despite the fact its French…) or something similarly fuel hogging like an old Landrover – practical over flash, so why I didn’t just start with one of those and avoid this sidebar…), as I was saying I’d almost certainly be greener keeping it running (which has very little cost) and burning lots of fuel when I do use it than buying into a new electric and probably not making enough use of it off the relatively green UK grid to pay back its production cost in its lifetime. If an EV ever came my way at a decent price I’d certainly not say no though – we have a solar installation so the EV as an additional house battery hopefully leading to a saving on the ‘leccy bill, while also providing cost free motoring when I need it would be great. Infact as an additional house battery it might actually pay back the environmental debt from when it was built despite the lack of miles it will do…
“Also an Electric car is only as green as its power source, so won’t actually solve the problem at all if the grid you connect it to is dirty.”
This popular meme ignores the huge efficiency differences between a massive power plant, professionally maintained & operating as close to peak efficiency as possible – even burning dirty fuels like coal, and the millions of comparably poorly maintained, less efficient ICE cars, each of which pollutes a bit more until the catalytic converter heats up and at idle. Even if the electric power plant generated electricity with comparatively greenhouse-unfriendly gasoline, the greater efficiency would mean overall cleaner transportation with electric cars.
Sorry, they aren’t. modern coal plant get somewhere around 40-45% efficient. So do modern small diesel engines, that put out a lot less other stuff in the air (look up what the demands are for euro 6 emissions, and see that this is the minimum for engines 7 years old)
yes, natural gas plants are way better, and so are cars on natural gas (although the efficiency of SI ICE engines is not as good as diesel). all of these are still fossil fuels and that needs to go regardless of how much they pollute. but something quite easily forgotten by die-hard BEV promoters, diesel engines are quite happy running on all kinds of vegetable oils, algae oils, or whatever fatty leftovers society produces.
BEV’s are the obvious replacement for what most people use a car for now: below 60km/day commuting. but not everyone fits that profile. road freight doesn’t, large commutes don’t. unpredictable commutes don’t. “the solution” is not one size fits all. i think biofuels, remote work and public transport have a way bigger role to play than we give them now
>60km/day commuting. but not everyone fits that profile.
Almost everyone does occasionally drive further than 60km a day.
If you mean with CAES “compressed air energy storage”, then this is a very low density energy storage that incurs also huge thermodynamic losses. I do not know, who could want that in a car. Multiple times the volume of really high pressure gas storage vessels than for a gaseous fuel like H2 or CH4 that you burn for the energy.
Also an “on board water cracker” is thermodynamically impossible as energy source.
I love my diesel too – a 2012 Citroen. But my wife and I also have a 2014 Nissan LEAF.
We use the LEAF for local journeys, and the diesel for the longer trips.
It’s not an ideal solution, granted, but few of us in the UK can afford a Tesla with a 300 mile range.
It’s more ideal than you think. Having a 300 mile battery would see most of the potential capacity wasted because you will never drive that much – e.g. 3,500 charging cycles at 300 miles = 1 million miles. At usual you would do somewhere around 160k before the battery reaches its shelf life anyways and has to be replaced, or the car becomes too worn out and the battery is scrapped with it.
Either way, there’s a huge embedded energy cost in the battery, expressed as Energy Stored on Energy Invested (ESOEI) which for lithium batteries is presently quoted at 32:1
https://en.wikipedia.org/wiki/Energy_return_on_investment#ESOEI
What that means is, you pay the equivalent of 32,812 miles up-front to have that 300 mile battery, and adding that to your 160k miles, your embodied efficiency becomes 82%. Your mileage may vary, but for the bigger battery, you’d be wasting a lot of energy.
Coincidentally, the average wall-to-wheel efficiency of a Model 3 is somewhere around 82-85% as well, so the combined efficiency of both under-utilizing the battery and charging it is below 70%
Then you can add the grid transmission loss, which comes in at 6-7%. That makes it about 65% and then consider the average power station efficiency… or for “fuel-less” sources, what is their attained EROEI: how much energy you have to spend to make that energy.
…when you look at the big picture, the whole “electric cars are more efficient” starts to look a bit sketchy.
Yeah, because gasoline bubbles up straight from the ground under the gas pump. /s
Gasoline has its own EROEI, and it’s not particularly bad. I think petroleum as a whole was quoted at around 8:1 and it used to be hundreds to one.
A poly-silicon solar panel in southern Germany is quoted by the wikipedia page at 4:1
Of course, the bigger irony would be to build a solar panel to charge another (grid scale) battery to charge your EV battery at night. Calculate the efficiency of that.
Although, for the ESOEI numbers given, the article that Wikipedia points to assumes a 6,000 cycle charging life for the battery, whereas actual EV batteries are in the 3,000 cycle range which means the real ESOEI would be closer to 16:1 and that doubles the embedded cost, so we have to re-do the calculation.
Result is, your embedded efficiency with the same mileage assumptions is just 70.9%.
Worth pointing out that while I don’t think Dude’s maths is quite right, as it doesn’t quite line up with what I got (probably down to different sources), it is in the correct sort of ballpark.
The big take away here is though that with time and investment things really do get much better – as pointed out in the case of energy cost to extract and distribute petrol, so now we are really investing into a carbon neutral future the numbers being used should get significantly better – making Dude mostly wrong for me thinking “”electric cars are more efficient” starts to look a bit sketchy.” – EV right at this moment as a whole might not be more efficient where you are – so many variables it is hard to judge but with all the progress being made it clearly will become so, probably quite soon at least for anybody likely to be reading this… Dude is also missing the point a little – its not just about efficiency but how you source the energy, its the tailpipe gasses that are a clear major win in EV – while the EV may well be powered by fossil fuels the gas emissions from those power plants are much, much lower for energy produced (unless its crappy Chinese coal station which is probably still slightly better but not much for instance), and the Solar, wind etc +EV options allow for the possibility of entirely carbon, Nox, etc free motoring.
Also highly important to realise that the 70% Dude arrives at is actually not bad overall either. While I have talked down EV’s some, there are clear situations they are massively better right now.
>the 70% Dude arrives at is actually not bad
Well, that was the embedded efficiency corrected. Then count the charging efficiency which brings it down to 60% and transmission efficiency which brings it down to 57%, then the source efficiency – take the solar panel in south Germany – and it goes down to 42%
> the Solar, wind etc +EV options allow for the possibility of entirely carbon, Nox, etc free motoring.
Depends. There are currently no economically viable processes to make silicon without emitting CO2, even before accounting for the fact that 80% of solar panels come from China which doesn’t mind using coal for energy to make them. Same thing for concrete, steel, glass fiber, etc. for wind turbines. Nobody has figured out how to “close the loop” for these technologies.
If you wanted to make the best case for EVs, you would do much better arguing for nuclear power.
But notice: this wasn’t an argument against EVs per se – just pointing out that a long-range EV is not the most optimal, and something small like a Nissan Leaf is actually way better because you get to size and price the battery according to the 95% trip length instead of the 5%. This makes a huge difference – but also assumes that you can afford to keep two cars.
This is a line that the fossil fuel lobby have been trying to push for a while. No, the grid won’t struggle to support all these extra electric cars. This isn’t just me saying this, this is the folks who run the grid. It may even be helped by EVs, as the latest generation can return power to the grid (at a profit to the owner) when it is under strain.
The other thing you fail to consider is how you get your hydrogen to start with. Either you steam-reform natural gas (which produces lots of CO2) or you crack water with electricity, a far less efficient process than just using it to charge batteries.
>how you get your hydrogen to start with
Well, see the case of solar over-production in Australia. It’s one way to turn low-value surplus energy into valuable fuels. For transportation fuels, the difference in input/output prices determines economic viability, not efficiency.
Gasoline is currently valued at something around $1.50 AUD per liter which corresponds to 17 cents a kWh raw and in the ballpark of 50 cents a kWh efficiency adjusted. Electric cars have such a high up-front cost that they still don’t compete with gasoline at 50 cents a kWh which is 10-20 times the bulk producer prices paid on the electric grid.
Obviously, it is profitable and feasible to take cheap surplus energy off the grid and turn it into hydrogen, and this scheme works even if the process is terribly inefficient. The only objection is that CNG/LNG is an order of magnitude cheaper. However, the more renewable energy we build, the more peak surplus we will get, and there’s nowhere else to put it for long term storage and stockpile – the most economical way to deal with it is to turn it into fuels.
The cost of battery storage has dropped to the extent that it becomes practical to use it to soak up excess capacity, which you should know well as an Australian. The 100MW battery bank that Tesla built in Jamestown, South Australia, paid for its self in a couple of years.
Not really. Batteries are expensive enough that they can compete with equally expensive peaking capacity, but they’re far off from competing for base load.
Furthermore, there’s a need for seasonal storage – not just day-over storage – for renewable energy, and this is where batteries make absolutely no sense.
When we’re talking about storing energy for months, let’s say 6 months to shift power output from summer to winter: you will only go through a handful of full charge-discharge cycles within the calendar life of the battery, while the energy cost to manufacture the battery in the first place is worth about couple hundred charge cycles. In other words, the embedded energy efficiency of the battery would be in the low 10-20% range. Even the worst hydrogen generation scheme would beat that.
It’s one way to turn low-value surplus energy into valuable fuels.
Where in the world does that happen.
ITM Power just sold a a 24 MW PEM electrolyser to Linde, Germany, so at least there. One would assume they generate hydrogen when the power is cheap.
These modern units do the electrolysis under high pressure already, so the gas doesn’t need to be put through a compressor – it goes straight to a tank or into the local gas mains. That’s one advantage of P2G: there is already an existing delivery network for natural gas, which can tolerate up to 30% hydrogen and of course 100% synthetic methane, so there’s a very large “battery” already built for you. The whole EU-wide distribution network holds hundreds of TWh worth of gas, and you can easily build more gas bells to add local capacity.
I guess the recent electrical grid problems in Texas and California don’t ring any bells then? Grid problems are not just a tool of the fossil fuel lobby, they are a reality; that said there are other contributing factors in those incidents that bear some blame, which is ultimately part of a separate discussion. The capacity may be there in the grid as a whole, but that electricity still has to come from somewhere, and getting it from somewhere to where it is needed, and even producing it cleanly, still appears to be a continuing problem.
Case in point, as previously mentioned by others here in this thread, the solar over-production issues we are seeing in Australia; While Australia may not need that energy now, there is another place in the world that does, but we don’t have an effective way to get it there, or store it, and it is largely wasted or causes problems because of this. Until these and other problems are solved, we will see more problems when everybody tries to plug in their car at night to charge.
Gasoline doesn’t pop up out of nowhere either. Gas stations need electricity to be able to pump it up to your tank, so even though we’re going to need less of them then the infrastructure isn’t going to be too hard to build out. You are highly unlikely to be able to refuel your gas car each night at home either, and few people can (or should) drive on a highway for four or more hours without taking a break.
EVs are a far more practical alternative than you seem to think, and the difference in running costs are going to be the thing that kills the gasoline engine in the same way that automobiles killed the horse drawn carriage (they will still exist, but will be hobby items rather than daily drivers). There are far fewer things that need to be swapped or maintained (even the brakes last longer as much of the time regenerative braking is used to soak up kinetic energy rather than throw it away as heat).
> for four or more hours without taking a break.
Sure, a pee and a sandwich, stretch your legs a bit, but if you’re stuck at a slow charger for two hours that’s different.
The current state of the art is around an 80% charge in 20 minutes, that sounds like pee and a sandwich territory to me. You only need that kind of infrastructure on long distance routes as most of the time an overnight charge will be fine.
Yeah, state of the art. Practical reality is that most of the time the “standard” quick chargers will not give you the full output. There’s one near me that is supposed to do 50 kW but people say it gives anything from 2 – 20 kW depending on the car.
Maybe a 15-20 minute charge time, but I’m 5th in line at a busy station.
>even the brakes last longer as much of the time regenerative braking is used
That’s not strictly true. Brakes break from disuse. Even without regen brakes, when you drive like a granny and always feather the brakes, they get stuck from dirt and rust buildup and you get to take your car to the garage regularly to get them fixed.
Knowing people who own electric cars (they aren’t inside of my personal budget – yet), yes this is strictly and precisely true. I didn’t say that the brakes last forever, I said that they last longer than in gas cars. Significantly longer.
>Gas stations need electricity to be able to pump it up to your tank
In an emergency, you can use a hand crank transfer pump. Otherwise the energy used for pumping fuel is negligible.
The point being that where there’s gas there is also an electrical connection to the grid. You don’t find a gas station without wired power (or at least, not enough to be statistically relevant). The infrastructure is there already.
But does it have the sort of utility connection that allows multiple parking spots with quick charging? Say 120 kW x 10 = 1.2 Megawatts. That’s a whole separate substation worth of power.
Gas stations need very little electricity to pump gas, but plug in the 20 cars at the same time…. Different story.
Until the cost of the EV vehicles come way down and the battery replacement costs are competitive, and charge times are way less… Not practical at all for me (not saying for some with deep pockets). Can you image pulling off the highway into a EV station and all ‘pumps’ are in use (with say a good hour or two to charge). Or sitting on a snowy highway waiting for the plows to clear the road, meanwhile you heater is way up burning through the battery while you wait? Or even stalled in traffic down in Arizona with your A/C all the way up? Not practical at all. If I run off of gas on the road, I can thumb a ride back into town and get a can of gas. Try that with an electric car…. Here comes a tow truck (powered by gas)… Now, for back and forth to the store or even town next door… Fine. But who wants to by a ‘very’ expensive car sitting there just for that use? Not me. My vehicle has to be an almost ‘do it all’ … Which even then I still have to own a truck for some situations and car/SUV to do most everything else.
Taking a break? That’s usually a potty break, pick up some gas and your on the road again…. 10-15 minutes max. Or stop at park to rest and take a walk… Or pick up some food… Not a gas station in sight… Driving back from Virginia was 3 13-15 hour driving days to where we live. Again, not practical for situations that we run into.
I am working in the electric utility business. When I say distribution system, I am thinking of the electricity that is stepped down for home/business use. That distribution system wasn’t meant for ‘high’ usage. Say every one plugs in their car during the night for a charge. And people would want that as a ‘convenience’ factor. It also wasn’t meant for home/business solar/wind producers to push electricity back into the system.
>Can you image pulling off the highway into a EV station and all ‘pumps’ are in use (with say a good hour or two to charge).
Yes I can. Sometimes during public holidays, various Tesla Supercharger stations get backed up with 4+ hour lines just to get to the plug.
https://www.thedrive.com/news/31274/more-teslas-on-the-road-meant-hours-long-supercharger-lines-over-thanksgiving
>”a line measuring roughly a quarter mile in length, consisting of 50-odd Teslas waiting at a Supercharger in Kettleman City, California, just off Interstate 5.”
Here’s the problem:
“the station’s popularity is compounded by its location about halfway between Los Angeles and San Francisco, but even its 40 stalls aren’t enough to accommodate the increased demand, especially when all that simultaneous recharging lowers the speed for everyone.”
It’s not that the cars couldn’t charge any faster. If you had full supercharging for all 40 stalls, you would have power draw of almost 5 Megawatts, which is the average power draw of a whole small town. This is why, even adding faster chargers and more stalls would not increase the throughput at that site – the power utility literally has to build them a dedicated line to add capacity.
What about metal embrittlement due to hydrogen absorption?
I like to say that hydrogen fuel cell cars offer the best selection of the worst downsides – the high up-front cost of an EV, the fossil-sourced fuel of an ICE (since it’s almost entirely produced as a fossil fuel byproduct today), and the fuel storage, (currently) sourcing, and transportation problems hydrogen offers that are unrivalled by any other technology. The only thing they don’t have is the complexity of an ICE. A hydrogen-powered ICE vehicle trades the EV-like up-front cost for ICE complexity and addresses none of the other issues.
I wouldn’t call petrol, diesel and kerosene as a “byproduct”. Since it is the majority of the crude oil itself.
It is more fair to call everything else derived from crude oil as a byproduct.
But yes, dumping hydrogen into an ICE is a crude fix.
Hydrogen embrittlement is one concern. (Only happens at a few hundred C though, but we get that when burning hydrogen.)
But increased NOx values is another. Hydrogen burns a lot warmer than petrol (since it is more rapid), this will lead to more NOx.
Then there is the forces involved, hydrogen burns really quickly.
Though, fuel cells are likely not a good solution either, they have relatively low power densities. So a battery or capacitor bank would be needed for it to perform adequately. Could though be an adequate and reliable range extender in an EV.
Then there is the whole issues of storing hydrogen, it is an expensive endeavor in itself. Either requiring large pressures, or relatively expensive materials that temporarily binds the hydrogen in a more dense fashion.
Personally, I think methane and ethane are better solutions.
Methane is already a byproduct of society, though most methane just gets dumped into the atmosphere, or actively worked on having its production reduced. Sewage treatment plants is one of the main methane producers other than grazing animals.
And methane can be converted to ethane with relatively low losses. And the advantage here is that ethane has a density of 360 kg/m^3 at 4.2 MPa, compared to methane having only 96 kg/m^3 at 12 MPa, a fairly huge difference.
Ethane also has an energy density of 50 MJ/kg, compared to petrol at only about 30 MJ/kg, making up some of the difference. (Hydrogen at 90 MPa though gives some 46.8 Kg/m^3 with 100MJ/kg of energy, ie, a lot less energy than ethane, but at a far higher pressure.)
In short, retrofitting a sewage treatment plant to collect methane and produce more of it, and then convert some of the methane to ethane is a worth while thing for the transport industry. (The vast majority of sewage works currently pump air into their ponds to aid aerobic digestion, this greatly reduces methane production, most works don’t produce much methane currently, but they can if adapted. And it isn’t like these facilities will disappear in the future.)
Methane can also be used as a grid backup when solar and wind isn’t sufficient.
Another thing with methane and ethane is that there is fuel cells that can use them as fuel as well. So I am not against fuel cells, but rather the idea of hydrogen as a viable fuel for the future when there is other better alternatives already on the table.
Not sure I agree on ‘crude fix’ – its an effective use of many decades of material science and development in ICE – a good engineering solution, functional and well understood. Even Hydrogen in ICE has been researched for many decades (I know I’ve seen mention of Hydrogen powered largely ceramic ICE engines from the 70s) and there are many well understood adaptations. I don’t think it should be a long term solution, but it functions now rather well.
Fuel cells are great but have many problems, a key one being they can be poisoned by impurities, and then its basically recycle the fuel cell, no easy fixes. I’m sure fuel cell will really develop and those problems can be worked around creating a simple maintenance setup for good lifespans in the end – but that work has already be done for ICE, so its the expedient choice.
I agree that Methane and its many relatively easily tapped sources is a travesty that can and should be addressed, but in the end doesn’t really matter what the vehicles burn, you can convert methane to Hydrogen if you want (plus there are so many other consumers of heat/energy so it could all be put to other uses as is instead). Either way as a well designed ICE should be able to burn either with pretty good efficiency there isn’t really a need to force one choice or other.
This is true.
But I still regard using pure hydrogen as a fuel as a bit flawed, it doesn’t have the energy density of other fuels, and has a slew of other issues associated with it. The whole hydrogen economy idea is a fair bit overhyped.
I think that the underutilized methane in the world could help solve a lot of the energy problems of moving to more renewable energy sources.
Though, methane/biogas has a big thing against it, and that is all the people going, “But burring [ANY] fuel is bad for the environment!” So a lot of investments aren’t being done, since it isn’t seen as the cleanest source of energy. Even if burning hydrogen has the same issue.
Even if methane burns a lot cleaner than a fair few other fuels, is fairly trivial to purify, and has good energy density. Not to mention will always be a byproduct in our societies regardless if we want it or not. So lets use what we do get, be it for home heating, electricity generation when wind/solar isn’t enough, or fuel in the transport industry.
Though, the best advantage of biogas is the relative ease of storing it, it doesn’t go bad over time like diesel and petrol does.
But migrating biogas vehicles over to ethane would have fairly large advantages, since it is even more energy dense than methane thanks to it being a liquid at 4.2 MPa, so some of the range issues of current biogas cars could be fixed by such a switch. Though, personally I think it could be a decent fuel for a range extended EV.
The hydrogen economy is a distraction and a pipe dream. It’s just another drag-feet-gimme-subsidies scheme.
Power to gas technologies already exist to turn electricity and CO2+H20 directly to methane and other heavier hydrocarbons.
Power to gas is a bit unnecessary other than for some quicker carbon capture.
Using existing methane sources should be sufficient for the future.
Considering how for an example waste water treatment plants currently pump air through their pools to reduce methane production by a lot. IIRC it is somewhere above 80% reduction for a crude setup having a large fork just casually swirling about in the water. Pumping actual air into the water and making it a bubble bath likely sends the reduction above 95% if not more.
So putting a lid on the pool and skipping the aeration part, then methane production should drastically increase. (Some treatment plants already do this.)
Where I live (Stockholm, Sweden) the local waste water plant does produce biogas in sufficient quantities to run a lot of the city’s buses on it, and also have excess biogas for export.
It surely isn’t going to be the primary energy source in society, but it surly can compliment other renewable energy sources thanks to the ease of storing large quantities of biogas for later.
>Using existing methane sources should be sufficient for the future.
There isn’t actually all that much potential for methane production in waste water. I once saw a quote that all the toilet waste in Sweden would power about 10,000 LNG cars, which is far fewer than there are cars in Sweden.
Yes, but far from all vehicles needs to be powered by methane alone. A large portion of all journeys can be done with batteries. A lot of commutes are less than 1-2 hours long, where a fair portion of the time is spent in a traffic jam. This is true for most countries in general.
Methane only starts being useful when the commute gets longer, primarily in the transport section. Though, a lot of transport should honestly be done by far more efficient rail transport, but that has its own huge sets of downsides.
And there is also a risk that those numbers are based on suppressed methane production levels, ie, when the treatment plant strives to produce as little methane as it can. (as is currently the case in most such facilities.)
I have seen publications just take the current average methane production in treatment plants and go with that figure, and that is fairly incorrect.
>A large portion of all journeys can be done with batteries
Yes, but even with a 100:1 ratio, assuming the previous number is still correct, you’d only have enough toilet-waste methane for 1 million cars, which is still far fewer than there are cars in Sweden (6.28 million).
I first off don’t think that a country with 10 million inhabitants can only produce enough biogas to drive 10 thousand cars in active use. Especially if this is based on normal driving habits of Joe average.
Sweden has 2900 gas driven buses. These are for public transit, ie drive all day long. And consume more fuel than the typical car. (though, less fuel per passenger.)
Then there is 54 thousand gas driven cars. (2021 stats for this and the buses from Trafikverket. (The national transport authority.))
There is though some natural gas use as well, but in 2020, 95% of all gas used for vehicles were biogas. (According to the industry association Energigas Sverige.)
In 2016 Sweden only imported 10% of its biogas needs. While in 2018 imports were 48% but most biogas sources are still unused. (Numbers from a field study called “Mer biogas! För ett hållbart Sverige, SOU 2019” made by the public inquiries branch of the Swedish government.)
I did however find a rough estimate for the total gas market in Sweden, including industry use and energy production for the grid, electricity and heating. And there biogas accounted for about a third of all gas use in 2019, where about half of that biogas were nationally produced. (Acceding to the National Energy Authority (energimyndigheten) numbers in their yearly summation on the gas market for 2019.)
So Sweden only being able to support 10 000 cars during optimal biogas production is not correct.
Currently we do have the means to support about half of what we already have in the vehicle fleet if we don’t include industry and power generation use.
Though, water treatment plants are only accounting for about 1 third of all biogas production in Sweden, so if we only look at that, and then forget about all the treatment plants that aren’t collecting biogas, then yes, 10 000 cars seems like a reasonable figure for what can currently be supported.
But yes, Sweden does have a net import of biogas, and natural gas.
Though, I do suspect that further utilization of biogas sources and improvements in public transport can lead to a net decrease in biogas needs for the transport industry.
>So Sweden only being able to support 10 000 cars during optimal biogas production is not correct.
Note that biogas involves all waste streams, whereas the quote I’m remembering related to toilet wastes – not the same comparison. There is biogas production out of waste streams in paper production, agricultural output, solid waste digestion….
> I do suspect that further utilization of biogas sources and improvements in public transport can lead to a net decrease in biogas needs for the transport industry.
What fraction of the transport industry is actually powered by methane? I think it’s a very small fraction. The amount of gas you need to transform transportation to biomethane can only go up.
>Hydrogen at 90 MPa though gives some 46.8 Kg/m^3
Yeah, but it’s at 90 MPa! Please calculate the hoop stresses for a typical steel tank for that. For welded structures, you want to keep the stresses below 60 MPa to have enough of a safety margin against fatigue, and even that requires expert welding (=not cheap).
Yup, that is an issue of hydrogen storage and why I think hydrogen in the transport industry is overhyped.
Considering how methane powered busses makes for a fairly sizable explosion when their tanks burst, and they are only down at 12 MPa, not 90.
Another reason why I think that ethane is the better option for gas powered vehicles, it only needs to go to about 4.2 MPa for keeping ethane liquid at room temperature. But one would likely build it to handle elevated temperatures too for obvious reasons.
And it also neglects the fact that we have no way to actually get that hydrogen. Right now most hydrogen is obtained, surprise, from fossil fuels. There is a lot of hydrogen in water but getting it from there using electrolysis is an enormously expensive (and dangerous!) job, requiring gobs of electricity.
And if we have to build a power station + electrolysis plant + deal with the leftover oxygen and chlorine (if sea water is used) which cannot be just vented, transport and storage of all that highly volatile hydrogen, the low efficiency of the internal combustion engines … it is just easier and much more efficient to charge batteries using that electricity instead, especially for cars (buses, trucks and trains – there the economy could be different).
Hydrogen makes little sense for cars. Its only advantage is that existing engine designs can be adapted more or less easily and it is faster to fill up a tank than to recharge a battery. Nothing else, really.
Butane is even better at 0.35 MPa to liquid at room temperature.
>deal with the leftover oxygen and chlorine (if sea water is used)
Just react it with the sodium, and it’s sea salt again. Pump it back.
Dude.
Yes, butane is even easier to liquefy.
But converting the easily sourced methane into butane is less efficient than just going to ethane.
Though, most processes doing this technically also produces propane, butane and so forth, all though in greatly decreasing amounts and with reduced efficiency for each additional step.
But the other gases are a byproduct that can be used in areas where it is applicable, the main reason I think stopping at ethane for vehicle fule is advantageous is mainly for the overall efficiency still being fairly good while still having taken a major step down in tank pressure requirements compared to methane.
Going to propane might still be worth while, but the returns are diminishing.
There are even more interesting fuels than methane if you think outside of the box:
https://en.wikipedia.org/wiki/Butanol_fuel#Ralstonia_eutropha
>”Ralstonia eutropha is a gram-negative soil bacterium of the betaproteobacteria class. Ralstonia eutropha is capable of converting electrical energy into isobutanol.”
Isobutanol is basically a drop-in replacement for gasoline. You just need to adjust the AF ratio a bit, but otherwise it’s equivalent.
What kind of combustion byproducts would you get from an ethane engine? Methane is a worse greenhouse gas than C02. A quick skim of wiki says that ethane combustion has water and CO2 as byproducts, so similar to gasoline. That kind of makes it a non-starter as a replacement since a hard requirement for any alternative fuel would require no or negligible greenhouse gas production.
Methane is only a greenhouse gas if it is released.
Something that currently is the case in most waste water treatment plants.
This is why I say that it should be collected, and used as a fuel instead.
Converting the methane to ethane is only making it more practical as a vehicle fuel. For grid based power, burning the methane as is, is sufficient.
That the combustion products are CO2 isn’t a major issue to be fair, since the source of the methane to start with is from waste water from society itself. And last I checked, most humans do not eat crude oil and other fossil energy sources.
In the end.
The process doesn’t add any additional CO2 to the environment and provides a usage for what is otherwise a far more potent greenhouse gas if left to its own devices.
Very insightful comments. I think that leveraging that sinergy between greenhouse gas reduction and reusing it as energy source by a mostly straightforward fuel like ethane could be very efficient, if the numbers really add up. Thanks for posting. (sorry the non-native english errors if any)
To add to that, it’s not actually terribly costly to pull CO2 from air and produce methane, ethane, butane, etc. synthetically. It’s not particularly efficient (40-60%) but the processes have already been piloted and the practical value of these fuels is far greater than the loss of energy.
What about metal embrittlement due to hydrogen absorption?
NASA was able to accidentally address that issue on their hydrogen car. They found out that trace amounts of CO on the hydrogen seemed to reduce it.
Can’t be too much of a problem, there are ceramic coated car parts being made
Would that involve a car having two tanks – one for hydrogen, and a much smaller one for CO?
Funny, I seem to remember adding CO to hydrogen tanks leads to rapid corrosion of the steel.
I was thinking about the Australian problem of too much solar power ( https://hackaday.com/2021/05/10/south-australia-vs-too-much-home-solar/ ) and wondering “what if” you had two very high pressure vessels and with excess power directly generated pressurised hydrogen fuel using electrolysis (and pressurised oxygen as a useful byproduct). And looks like it is being worked on, in the US and Germany (ref: https://en.wikipedia.org/wiki/High-pressure_electrolysis ).
Seems like they would be better off just investing in massive batteries.
With platinum electrodes, under ideal conditions, you could probably generate hydrogen for good few decades, with minimal maintenance. The problem with batteries is that each charge is never as good as the last, after a relatively low number of recharges their maximum capacity will have dropped by a noticeable amount. And then new batteries which take additional energy to manufacture need to be added to compensate. Yes in the short term hydrogen would be less efficient, but in the very long term, I think hydrogen might win on efficiency.
Very little about Motorsport can be considered “Green”.
Any vehicle, driven hard will produce clouds of particulates from its tyres and its brake linings.
Any internal combustion engine will require lubrication, and produce exhaust that contains a small percentage of burnt engine lubricant emissions.
Hydrogen is not a wonder fuel – and it’s not a particulary efficient intermediate energy storage medium. Most hydrogen today is produced bt cracking natural gas. Electrolysis is possible, but has a lousy (~50%) efficiency, only to be further constrained by a 20% efficient internal combustion engine.
Metallic embrittlement has been known about for decades, and is unlikely to be solved anytime soon.
Instead of cracking the natural gas for hydrogen … just burn the natural gas :) . It’s there, its a natural resource. Use it.
I’ve been making monatomic hydrogen for 6 years using wind and solar ! We need all the green energy we can make. I like the concept of hydrogen cars, NO Carbon Emissions.
Zeplins on the road. What could possibly go wrong?
TL;DR all the comments
I get the impression most people in favor of EV come from those states (in the USA) that are generally small or work/live in highly dense areas. If you live in some of the larger states away from the metropolitan areas found commonly in California, Texas and even smaller states like Oklahoma, then 300 mile trips are nothing and is accomplished multiple times a week. Most people I know are not going to wait in line for a charging station when gas stations right now are so plentiful.
Well, most EVs are owned by rich people, boomers basically, who are now retired and don’t need to travel for life, or when they do travel they aren’t going anywhere in a hurry.
Although what you say might be true in that most EVs are owned by rich people (simply because of how much they cost), I would say the VAST majority of rich people do not own EVs.
Rich people drive Ferraris, Koenigseggs, or if they think they are rich, Porschs.
If you are rich, you wouldn’t be seen in anything as low-brow as an EV.
I commute 1.5hrs / day in a Tesla model 3. I don’t wait at all to change from my roof and powerwall.
So what you’re saying is, you paid the price of an entire house for a car and charger, for the same convenience as any $1000 piece of junk off the trade-in lot.
Comments like that suggest you are very anti-EV, but other comments you have written suggest you are not.
People buy new cars all the time, and most new cars are cheaper than EVs. Some are also considerably more.
However, when people buy an ICE for commuting in the city for the same price as an EV which will do exactly the same job, I do wonder how long humanity has got.
Hydrogen used as a fuel for a vehicle is just a dumb idea. If any of you have ever played with Hydrogen you know how volatile it is. If you have a hydrogen container on a vehicle that gets into an accident THERE WILL BE NO SURVIVORS if this tank ruptures.
Pure H2 as a fuel has always been great in theory. But even in aerospace, every team who have ever tried to use it as a practical fuel have given up on it.
It’s just terrible for practical reasons.
Like being nearly effortless to ignite in almost any mixture with air, and then tending to detonate with quite a lot of brisance.
Or for ‘boiling itself’ after being liquifyed, just because of the ortho- and para- hydrogen molecular spin alignment relaxation thing. (which kinda feels like Murphy saying “Because f**k you, that’s why”).
Or for just plain leaking straight through most metals, and making them brittle and failure-prone whilst doing so.
And if the world ever starts handling it in very large quantities, we’ll also have to worry about upper atmosphere damage due to rogue H2 leaks messing with the concentration of oxy-hydride there.
OH radicals from water getting ionised occasionally is all that makes methane, for instance, *only* 30x worse than CO2 as a greenhouse gas. Leak enough extra H up there, and that will suppress natural OH levels, which could suddenly make methane (amongst other pollutants) much more long-lived.
Did I mention H2 leaks slowly through most metals like they’re just sponges? If there is a lot of new production and direct storage of H2, there will be a lot more ‘rogue’ emission from it leaking out. Since we already have globally increasing rates of methane emission from melting tundra as the temperature creeps up…
Otoh, NH3 is much safer to the atmosphere. Sure, it turns into white smog when it meets up with and neutralizes the pH of what would otherwise be acid rain, but it turns into fertilizer by doing so. Hell, NH3 is what plants mostly want as nitrogen anyway. Acid rain is mostly a problem because it kills plants.
As to whether it’s better or worse in the upper atomosphere, I don’t know. It would be nice if some publically-funded research would look into that, especially before we go globally gung-ho into the hydrogen economy.
Hydrogen isn’t retained in the atmosphere, its too light, so long term any of it that manages to get through its container, and miles of atmosphere without oxidising into plain ol’ water will just be lost to space rapidly – as you pointed out yourself its really easy to get it to react, so most of it won’t make it that far…
Acid rain is mostly a product of sulphur impurities in fuels, with how much oxygen there is in the air, the relatively low energy required to combine to water I can’t see hydrogen making any difference to acid rain at all. Certainly not to the level you seem to be implying, almost all the hydrogen that doesn’t escape to space will turn to water as far as I can tell.
Ammonia isn’t exactly safe to be around, not saying its not viable, just that it has got its own set of risks – not magic. For me Hydrogen has clear future for good reasons, but it shouldn’t be the only game in town.
The point is, as it goes up it prefers to react with -OH radicals rather than the more stable O2 molecules, which reduces the amount of reactive oxygen species in the atmosphere and makes other molecules just as CH4 slower to break down, which increases their concentration and amplifies the greenhouse effect.
Yes, it also reacts with Ozone and makes the hole bigger.
I wonder If there’ll be an article about Anhydrous Ammonia as a ICE fuel?
Advantages: Requires a HCCI engine with a static compression ratio of at minimum about 35:1.
Or maybe I should say ‘enables’… No other fuel will let you run that high a CR without making NOx just too hard to deal with… but NH3 cancels NOx, so just what happens to not burn will likely allow your cat convertor to reform, or you can just inject a little into the exhaust to do that if you need to. (high NOx before good cat convertors was what killed research into high CR super-high efficiency ICE).
Also an advantage: Such engines will not run on any hydrocarbon fuel (without damage), much the same as how gasolene in a diesel engine’s tank is very bad for it. Gas tends to a thing called ‘premixed combustion’, which results in very massive knock and engine damage very quickly. This is an advantage if you want to keep owners from going back to possibly cheaper fossil fuels.
Biggest advantage is in storage and handling. LNH3 handles just like LPG (except you need to be more careful about it leaking).
By comparison, to compress H2 to a liquid, you need 600 bar of pressure. Ammonia? only 15 or so, temperature depending.
At 600 bar, if the H2 pipe leaks, it self-ignites with an invisible and UV-hot flame, which will easily melt flesh and can cut through metal. And if it doesn’t? That’s even worse- with H2 being explosive in mixture with air, from about 0.5% v/v all the way up to about 98.5% v/v. And when it goes – which it will ( takes nearly no energy to ignite – measured in the microjoules) – it’ll detonate creating a shockwave and turning your car into a bomb complete with shattered-metal schrapnel.
Oh, and BTW, 600 bar? comparable to the peak pressure behind a handgun bullet, so mechanical failure of a tank, in a crash say, would be very bad even before the hydrogen inevitably ignites.
Ammonia on the other hand, burns so slowly in air, that even if you happened to have a large cloud, perfectly on stoich, it will still burn with a maximum flame speed comparable to human running speed! Oh, and it takes hundreds of times more energy to ignite than hydrogen, so it’s not likely to anyway.
BUT, a cloud of NH3 is still quite a deadly thing, and the weaker tank requirements will mean that, sooner or later, there will be a big leak from a crash. In big volumes like that, since it’s just such a damn good refrigerant (it’s most typical bulk use, after directly as fertilizer), it will hang about as a -33 C puddle, and you really don’t want to be caught in a cloud of that down wind. It is only about 60% the weight of air, though – so it will go away as soon as it warms up, and clouds can be intercepted with water curtains, since it really wants to stick to water (exothermic, one of the reasons it burns you).
So long as you had eye-sealed goggles, and can hold your breath and run cross-wind far enough, you’d have a good chance of getting out of it without permanent damage. It’s mainly the eyes and lungs (and their inability to keep functioning with scar tissue) which makes NH3 deadly in big cold clouds like that.
Practical reasons probably mean that LNH3 will substitute for Diesel, whereas H2 might substitute directly for Petrol – but would likely have its market share eaten at the top end by electric, and at the bottom end by LNH3 carbon-displacement refits – simultaneous dual-fuel bolt-on setups where the gasolene allows the NH3 to be fully burnt up, because the engine was originally designed as a petrol engine, and doesn’t have the crazy CR required to get all the NH3 to burn. Maybe with a new catalytic convertor also, to prevent NH3 emissions at hazardous levels.
Actually an interesting point: Any Diesel or Gasolene engine could have up to about half it’s CO2 emissions easliy eliminated by bolting-on such an aftermarket ‘dual fuel’ system.
Just requires cheaper NH3 – most likely due to be the ‘default’ way to ship H2, especially that made from stranded renewable resources. And best estimates put that at a technoeconomic cost per J somewhere around 1/5th or so of DF.
Toyota interestingly had a 86 test car with a NH3 dual-fuel system – but had it cut out the ammonia whenever engine revs were above about 2500 IIRC (may have been lower), probably because the slip (fraction making it through the engine without burning) went too high. Also interesting: Toyota have a patent on a ‘plasma’ plug ignition system for igniting ammonia.
Very probably, if you ever do fill up a H2 car, there will likely be a large LNH3 tank somewhere nearby. If not then it’s an even larger tank of Methylcyclohexane (MCH), which is how Japan currently gets their H2 via ships. And MCH just doesn’t hold much H2 per kg or per L compared to LNH3 – which is 1.5x the H2 content per L than actual Liquid H2, for obvious reasons.
you can not liquefy hydrogen, nor helium in room temperature by compression alone, which is why there is a steep increase in price of liquid hydrogen and helium compared to liquid nitrogen. Diesel engines with SCR have been using urea for decades to limit the NOx emissions. In theory SCR systems could use NH3 too, but for obvious reasons that is not the case as urea is so much easier to handle.
Ok. Deliver the hydrogen to the ‘gas station’ and use it to generate electricity locally to recharge EVs.
I think a lot of people are missing the “humans make stuff for fun” aspect here. The fact that “sport” cars still exists proves that there is a market for less practical things, and while EV seem like a great solution from an efficiency and “greenness” standpoint (if they solve the problem with used batteries), H2 ICE are a great way to keep that enthusiast segment of the market, while still being green.
I’m not looking to buy a RWD coupe because its more practical or efficient, I’m looking for that just because I like it, and if you give me a green option like that it’s a closed deal for me.
Tell that to people and countries planning to ban ICE vehicles by the 2030-35 time frame.
I think the hydrogen car is the longest con I know about. I saw an AMC Gremlin modified to run on hydrogen in 1972 at the UCLA Engineering Fair. The only real problem them was storing the stuff, and nothing has changed. It’s really simple, doing hydrogen as large-scale power source requires a huge manufacturing/distribution effort that simply doesn’t exist, and there’s not the interest/money/exclusive ownership required to do it. Electric cars piggy-back on our existing electrical grid, so there’s minimal investment required for new distribution, and plenty of reasons to increase grid capacity even without cars. That hasn’t changed since 1972 either.