This is true of every form of energy transfer. There is never, ever 100% energy maintained, and maybe you'll be stunned at how inefficient existing energy sources are.
Methane extraction is absurdly costly, transport and storage are no less absurd BUT we can do it on a needed scale. That's the sole thing that matter. Similar if for hydro: mountain hydro is fantastic, we MUST develop it as much as possible, but it demand mountains and water. For some part of the world it's ok, they are there both in needed quantity essentially all the year, for some other they are not. You can power Norway on hydro with little nuclear backup, you can't power Mongolia even if Mongolia have very little needs compared.
Similarly we can imaging electric commercial trains that only run on p.v. surplus, for all non-perishable goods that might be ok if well designed on scale. We probably can design that on scale in many, many areas of the world. We can't to the same for ships, for plane, for cars. We can't do that for perishable goods of passengers transits.
And, given cheap storage, of course we can run passenger trains on renewables.
Anyway, supposedly around 99% (!) of the net energy of fuels gets lost from the source to your home. This due to energy conversion, loss in transmission lines, transformers, you own electrical installation, battery charging/discharging and other inefficiencies on the grid or the devices you use.
First of all, the green aspect of it is that the source is renewable. That's what makes it green. It's not correct to call it a net loss, because no one wants to produce power from hydrogen in order to harvest more hydrogen. There would always be a renewable input somewhere.
About losses. There are always losses on each energy transformation step. The same thing applies to electricity generated with fossil fuels, or heat generated with electricity generated from heat, or light generated with electricity produced with light.
The fact that the source is renewable means we can probably afford that loss in the long term.
Using green hydrogen as fuel for far-from-grid cases still makes sense.
Electric tractors are not feasible yet, given the required power×autonomy.
Also, consider Iceland, were electricity is cheap and produced via geothermal sources, but exporting it is impossible: producing green hydrogen would make that energy exportable.
And consider also the Haber-Bosch process, where ammonia production requires hydrogen that currently comes from fossil sources (natural gas) which implies carbon emissions. Shifting to green hydrogen would be a game changer in the production of fertilizers. Remember farming is one of the major sources of CO₂ emissions.
If you use all Island electricity you can't even produce enough hydrogen to power a hypothetical nations-wide fleet of cars...
https://www.fch.europa.eu/sites/default/files/FCH%20Docs/202...
So far the very few experimental plants we have made have proven the fact that, yes, the process work on solar, eolic ec, but also the fact that producible volumes are FAR BELOW the demand, not because we do not have enough plants so far on scale, but because we can't have them on scale on Earth at the actual state of tech.
Beside that so far we still completely miss the hydrogen storage issue: we can't store hydrogen in ANY known form. We can fill tanks of it, it will leak out slowly with relevant safety issues, and with the biggest issue that a just filled tank will be essentially empty in few days.
People like to dream, like to deny the reality following dreams pushed by interested parties, but they are just dreams, with good outcome for some scammers for some period of time, disasters for the dreamers.
With this data we can discuss scalability.
I've found this old report https://www.nrel.gov/docs/fy04osti/36734.pdf and I doubt we really have made significant advance since it.
You can buy electrolysers on the open market, cash on the barrel head. Need more hydrogen? Buy more electrolysers. Where does this fail to "scale"?
BTW let's talk about an example: Toyota Mirai, far complex than an EV, complex than an ICE, ~1kg H₂ / 100 km. Now let's say we have spend 67kWh of green electricity to produce that kg of H₂, the process have some loss, again I can't really know how much but some [1] say are around 14%, not bad but still a certain amount of loss. Than the energy need to compress resulting gas to 700 bars. Energy to push it in the car tank. At the end of the game you get what? 33-34kWh out of initial 67?
100 km? A Tesla do 100 km with around 18kWh... Surely and H₂ fuel-cell system have far more power than a lithium one, around five time per similar size/weight, so we can potentially power trucks, even planes with hydrogen, while we practically can't [2] with lithium.
Again trying to imaging a possible hydrogen-based vehicles scenario we end up in far cheaper "energetically speaking" blue/grey hydrogen but what's it's point? We can burn directly hydrocarbons, we already use them. Using them to make hydrogen means just spent a lot for a new supply chain and just shift pollution outside citizens sight. With the benefit of running on 700 bars bombs under our asses...
[1] https://mdpi-res.com/d_attachment/materials/materials-12-019...
[2] yes I know eVTOL experiments, they can't scale behind such kind of very expensive personal toys with lithium chemistry for energy source
Hydrogen is stored. The amount that leaks can be as small as you like. Actual loss as a percentage of what you put in is always negligible. The point often made about leaks is just that H2 must not be allowed to accumulate, so needs positive airflow to prevent detonations.
Mirai is just an electric car with an H2 tank, a fuel cell, and a small battery. The fuel cell has no moving parts: H2 and air go in, power, H2O, and N2 come out. Mirai is very light, so takes much less energy to muscle around than a battery car. Its small battery is to use while the fuel cell heats up, and maybe to absorb some kinetic energy braking.
A battery electric car is much more complex. It needs to manage charge and temperature on all its cells, use braking to recover and store kinetic and downhill energy to try to extend range. The battery is expensive.
But energy is fungible. After there is plenty of renewable generation capacity, hydrogen made from renewables has not cost anybody anything tangible. Until there is plenty of renewables, making hydrogen costs NG, so will not happen much.
Cars will have batteries. Trucks will probably run on ammonia. Aircraft will run on LH2. The kWh that goes into a unit of H2 will not matter much, because it is just sunshine and wind. We need to get there by spending on renewable generating capacity, first.
kWh also matter MUCH: personally I can potentially produce just few grams of H₂ in a good sunny day from my p.v. witch happen to be perfectly capable of recharging an EV in a sunny day.
Try this: a classic home is cheap, but demand much energy. A modern one is far more expensive, but demand far less. Now if spending for good insulation, airtightness, relevant windows, VMC, water-heater with heat-pump + solar, a p.v. system and an EV means an initial investment of around 150% more than a classic house with a classic ICE, you can't pay it back much before EV battery is dead but anyway it's doable. If you want to add to the mix H₂ perhaps as a way to pass trough nights and non-sunny days the overall costs climb around 400%. It's essentially unsustainable for single individuals/families AND it's unsustainable for the society on scale. That's is.
Producing, compressing etc enough H₂ to power a personal vehicle means having a 20kWp p.v. at home and using the vehicle only in sunny days from spring to summer. All equipment's would costs twice the house itself. Try to do the math for a truck and even more for a plane. Also try to consider how much fuel-cells we can make on scale, since they ALSO demand rare and precious elements.
The fact is, your numbers are all way off, so do not produce sensible judgments. They make you seem nutters. Get better numbers.
"my numbers" are not mine, but from the current state of research on the field. The current state is simple: we can produce green hydrogen but in too little quantities, that means:
- we can't use it on scale
- there is no point in using it at smaller scale
That's why kWh count, because panels are not "toll free" coming like fruits on some tree branches, they have to be produced and they have a cost. They have a usable life, they need to be decommissioned after that. Actually we can make a single family home hydrogen+p.v. in certain area of the world, such home will cost few MILLIONS, need a variable amount of land from an hectare to few hectares, and last at around 10 years without special maintenance. We can produce few of them for the 1% of the humanity. Unfortunately such humanity can't keep up the species nor can't produce the aforementioned tech in their backyard, that's is. Is it more clear now?
We can do many things in general, some can scale, some can't, some are reasonable some are not. A green hydrogen industry so far is not reasonable and can't work on scale. We can continue researching on it of course, but we need working things, not dream, so we need something else to keep up.
Panels do not, in fact require "decommissioning". They last much longer than 10 years: warranties are 20 years, often more. Output may be degraded by up to 20% after that, but they continue producing. If cooled, they last longer.
You can buy an electrolyser off the shelf today and plug it into any outlet. Efficiency is at least 60%, and rising; recent advances, which will hit market soon, have pushed it over 95%. A hydrogen car is much, much lighter than a battery electric car, so requires less energy to operate, but typical conversion losses today are larger than the difference.
Nobody needs a hectare of panels for personal transportation use, whether for charging a battery electric car or synthesizing hydrogen for a hydrogen-electric car. A typical rooftop is plenty, at least in summer, depending on latitude. A private system sufficient to produce hydrogen for a car is in low tens of $thousands, not $millions.
None of the above has anything to do with "scalability", which is a utility concern. Utilities can make hydrogen at whatever rate they have bought electrolysers for. The only thing stopping utilities is that if they had money for electrolysers, it would be far better used to buy more panels.
Making shit up gives you bad numbers and false conclusions.
Exactly. And that also means that eventual losses, arising from intrinsic inefficiency, won't have an impact on the environment, which is the main point.
The amount of tolerable losses depends on how cheap the power is, if the power supply is intermittent, some time they'd be greatly in excess of standard loads, in which case you could run hydrogen cracking at 10% efficiency and it might still be useful just as grid ballast.
https://www.linkedin.com/pulse/clean-hydrogen-ladder-v40-mic...
But once we have got renewable overbuilt, all the math changes. Until then, unquestionably the right place to spend capital is building out renewables. Building up hydrogen infrastructure, in the meantime, and even fueling it with gray hydrogen, is OK provided it doesn't cost money that could have gone to renewable generating capacity instead.
Often capital has strings attached, and can't go for renewables. Then, spending on readiness to use the coming, cheap hydrogen or ammonia (and burning gray fuel for now), or generally on energy storage, is better than most choices.
Thing is, money is fungible. Each dollar goes to one place and therefore not another. Energy is too, albeit with conversion losses. So, green hydrogen and NG electric is no better or worse than gray NG hydrogen and renewables. Anywhere we can displace NG entirely is good. Moving use of it around, much less so.
Electricity storage in a lithium-ion battery is on the order of 98% efficient, and electric motors are around 90% efficient (if you take into account the whole drivetrain).
[0]: https://newatlas.com/energy/hysata-efficient-hydrogen-electr...
What always matters most is cost. Inefficiency will get cheaper and cheaper as generation cost falls. Switching from gold & platinum catalyzing electrolysers to something not dependent on those and less efficient is still a win if you get a lot more electrolysers for your money.
Source: https://www.weforum.org/agenda/2021/08/hydrogen-carbon-inten...
What wasn't obvious to me from the parent comment was why it is apparently completely impractical. No energy conversion has an efficiency of 100% so the answer couldn't just have been "because thermodynamics" but as other comments have since revealed, it is because _current_ hydrolyzers only operate on an efficiency scale of 60-80%.
What do you imagine is the raw efficiency of making hydrogen from. NG, vs the enthalpy of the input gas?
BTW, "electrolysers". Hydrolysis is a thing plants do.
Green hydrogen - hydrogen derived from water electrolysis, ostensibly from renewable electrical sources so no greenhouse gases are produced
Blue hydrogen - hydrogen derived from hydrocarbons, produces greenhouse gases as waste
Pink hydrogen - hydrogen from water electrolysis from nuclear electrical sources, no greenhouse gases produced
The description of "green" hydrogen is only tangentially related to the colloquial use of "green". So long as no greenhouse gases are produced the hydrogen is labeled green.
The use for hydrogen isn't an energy source but as an energy transport and storage. So "green" hydrogen is still "green" in the colloquial sense despite its inefficiency if it doesn't produce any greenhouse gases in the pipeline.
All that being said, I personally think hydrogen is stupid as a transport and storage medium for electricity. Electrical transmission lines will always be more efficient than a theoretical hydrogen pipeline. A chemical battery has a lot less that can go wrong than compressed hydrogen storage. About the only place it even starts to make any sense is grid-scale storage and even then I don't think it can practically beat other storage systems.
Blue hydrogen is grey hydrogen but the carbons are captured and stored. So nominally it's carbon-neutral but in practice the capture is never perfect.
The math for blue hydrogen might work out in commercial and residential installations in regions with existing natural gas and siting that makes solar impractical. A fuel cell with a catalytic cracker could feed a building with hot water and electricity vs a combusting water heater that only provided hot water. For similar GHG output it might be an efficiency win. But I see that as a weak maybe all things considered.