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Agreed on "green steel".

In general, "green hydrogen" makes the most sense if used as a chemical feedstock that replace natural gas in industrial processes - not to replace fossil fuels or be burned for heat.

On paper, hydrogen has good energy density, but taking advantage of that in truth is notoriously hard. And for things that demand energy dense fuels, there are many less finicky alternatives.

I had to Google what is green hydrogen. It is hydrogen produced by electrolysis.

If you've already got the electricity for electrolysis, would it not be more efficient and mechanically simpler to store it in a battery and power an electric motor?

Before the introduction of 800V charging architectures, long charge-time for EVs was a big con. Hydrogen Cell vehicles were supposed to be EVs with drastically faster fill-up times. The tradeoff was more complex delivery infrastructure.

Yet, most of the world has had 3 phase (400V phase to phase) for ages. At the wall.

I don't know why you prefixed with "Yet" when I clearly spelt out the trade-offs and contrasts in distribution between H2 and electricity.

The Mirai goes from empty to full in 5 minutes or less - which compares very well with fossil-fuel burners. Now that every OEM has abandoned battery-swapping, how fast can EV batteries be safely charged with the said 3 phases? How long were the charging time when the Mirai was debuted? That was the trade-off Toyota was hoping to fall on the good side of, nevermind the Japanese government bet on hydrogen and whatever incentives are available for Toyota.

>with "Yet" when I clearly spelt out the trade-offs

It was with regard that 800V was the driving factor, it'd be possible to have 'fast' charging earlier with existing infrastructure, even home.

>be safely charged with the said 3 phases?

The limiting factor for charging would be charging current in lots of cases. Getting 60% of 75kWh battery, it's 45kWh to charge in 20mins, the output should be ~150kW (90% efficiency) or 325A (on 400v), 4x 12-15mm wires.

Note about 'home' charging - three phase 32A is widely available domestically or around 6-8h to fully charge

North America has 3 phase power for any necessary purpose (factory, DC rapid charging station etc). It's 480V/227V.

The faster fill-up time of hydrogen was mostly a lie. It could fuel a single vehicle at that speed, but then the filling station would need a significant time to build up enough pressure for the next one.

Turns out having to fill vehicles at 350 to 700 bar (5,000 to 10,000 psi) is a massive pain - especially when you can't keep it cryogenically cooled as a liquid in your storage tanks.

I think that is the way it is headed. But you never know. Sometimes when comparing it helps me to reduce these things down to lower levels.

What is a battery? A chemical cell to store hydrogen and oxygen(true, it does not "have" to be hydrogen and oxygen but it usually is) to later get energy out of. For example lead-acid(stores the oxygen in the lead-sulfate plates and the hydrogen the the sulfuric acid liquid) or nickle-metal(charges into separate oxygen and hydrogen compounds, discharges into water) the lithium cell replaces hydrogen with lithium. Consider a pure hydrogen, oxygen fuel-cell, it could be run in reverse(charged) to get the hydrogen and oxygen and run forward(discharged) to get electricity out of it. So it is a sort of battery, a gas battery. Gas batteries are generally a bad idea, mainly because they have to be so big. Much time and effort is spent finding liquids that can undergo the oxidation/reduction reactions at a reasonable temperature. But now consider that there is quite a bit of oxygen in the air, if we did not have to store the oxygen our battery could be much more efficient, This is the theory behind free-air batteries. But what if our battery did not have to run at a reasonable temperature. We could then use a heat engine to get the energy out. And thus the Mirai. They are shipping half of the charged fluid to run in a high temperature reaction with the other half(atmospheric oxygen) to drive a heat engine that provides motive power.

As opposed to having the customer run the full chemical plant to charge and store the charged fluids to run in a fuel cell to turn a electric motor for motive power. Honestly they are both insane in their own way. But shipping high energy fluids tend to have better energy density. Perhaps the greatest problem in this case is that it is in gaseous form(not very dense) so has no real advantage. Unfortunately one of the best ways to retain hydrogen in a liquid form is carbon.

The value proposition of hydrogen is energy density. Batteries have low energy per unit of volume and awful energy density by unit of mass. You will never, ever, fly across the Pacific on a battery powered aircraft. Transoceanic shipping is also not feasible with batteries (current and proposed battery powered shopping lanes are short hops of a couple hundred kilometers or less).

The Toyota Mirai is a passenger vehicle, not an airplane nor a transatlantic container ship.

Sure, but if the economics of hydrogen motors worked out for planes and shipping, the argument is that it would also economically work out for cars.

Is suspect large trucks may eventually move to hydrogen, but smaller passenger vehicles will stay on batteries. The nature of hydrogen containment favors larger capacity, on account of better volume to surface area ratios.

Hydrogen was marketed as a stopgap until batteries are good enough. Well, batteries are good enough for trucks now:

https://www.electrive.com/2026/01/23/year-end-surge-electric...

Once you go battery electric, you never go back. It's the most efficient way to move vehicles.

>Is suspect large trucks may eventually move to hydrogen [...]

They won't, why would they? The number of hydrogen gas stations is going down and the price is going up. Batteries are good enough already - the Mercedes eActros 600 with its 600 kWh battery has a range of 500 km.

Lol yes lets just casually plug into a 1.2MW charger and not take down the electricity of the nearby town while I charge my truck.

Nuclear trucks and boats are what I envision so maybe I'm the one who needs a reality check.

Well, of course countries would have to modernize their electrical grid. But that's a good outcome.

Around where I live, we have electric car ferries.

To avoid having to upgrade the grid massively, we use large battery banks shoreside which are being charged at a sustainable (to the grid) rate, then the ferry charges rapidly by depleting the battery bank, leaving the grid alone.

Works a charm.

Electrifying all transport in the nation would increase electricity load by 20%.

But even if 100% of all vehicles sold today was electric, it would still take ~20 years before almost 100% of vehicles on the road were electric. And it's not, so we're probably looking at > 30 years to increase electricity load by 20%.

That annual increase is far less than the increase caused by data centers. It's about the same as the annual increase in load caused by increased use of air conditioning.

Life expectancy. A hydrogen tank can be refilled forever. A battery is normally limited to a few thousand cycles. A truck, or airplane, is expected to be fueled/recharged daily for decades. A car is designed to survive the length of a standard lease. Those running fleets of trucks/aircraft will always care more than car owners about long-term ownership costs.

This isn't necessarily true. Most cylinders storing compressed gasses need to be hydrostatically tested in regular intervals to ensure continued safety and will need replacement when they fail. Other kinds of composite cylinders have fixed ages where they should be replaced.

Inspection is expected. In the transport industry, all sorts of parts need regular inspection. Batteries are different. Performance loss over time leading to replacement decisions is unussual. Virtually no other part degrades in performance the moment you use it. Lots of parts have time limits, especially in aerospace, but few degrade. Those running fleets see this as unussual and unpredictable which, at scale, means extra expense. A tank that needs inspection every decade is a known problem. A battery that looses 1% to 5% capacity every year, depending on weather/use factors, is harder math.

> In the transport industry

I'm not in the transport industry, I just want to go to the grocery store.

> Performance loss over time leading to replacement decisions is unussual. Virtually no other part degrades in performance the moment you use it.

Tires? Brake pads? Lubricants? Belts? Springs? Bearings? Bushings? Seals? There's tons of parts on my cars that have expected wear intervals that will need replacing after x number of miles with performance that changes with the wear of the part, there's a whole service manual of when to replace certain parts.

Nope. All those parts work at basically 100% until failure or replacement. Some even improve with a bit of use (tires, brake pads, seals). They wear, they dont degrade. Batteries drop in performance from day one.

So tires with 2/32nds will have better grip in the rain than warmed up fresh ones? They just get better until they pop? That must be the reason why race cars only use heavily worn tires instead of fresh ones when they race. Engine lubricant is better at 5,000mi than 1mi?

You only bother buying heavily used motor oil and tires right? After all they perform so much better.

And springs and shocks are perfect examples of things that start to lose their effectiveness on a curve instead of necessarily just all at once. You can tell the dampening effects get worse and worse, the car might start sagging more, etc. They have a whole range of performance before they need to be replaced.

Even the motor itself will often slowly have reduced compression due to slowly looser fitting parts before actual failure, fuel injectors will slowly get more gummed up over time, valves might get gunked up having reduced airflow, spark plugs are slowly vaporizing themselves and can have worse spark characteristics throughout their life, etc. Its not like everything just continues working 100% until they snap. Everything that's moving or reacting is slowly wearing itself out.

Mold release needs to be rubbed off. And the bead needs a few weeks to harden. That's why the tire people tell you to go easy on new tires. As for other stuff, work on cars for few decades and you will learn which parts are more reliable once proven than when brand new, which need time before being pushed to limits.

> As for other stuff, work on cars for few decades

That's the experience I'm drawing from when I point out that "virtually no other part degrades in performance the moment you use it" isn't based in reality. Everything is constantly wearing out. Anything rubbing on another thing, any fluid being pushed through a hole, anything that might be reacting with another thing, its all slowly getting more and more out of spec. And when it gets more and more out of spec, its performance gets worse. You might not immediately notice it, that performance might not be in the go go kind of performance, but it isn't working as well as it used to.

Are you really going to tell me a car with a couple hundred thousand miles on it running all original parts (assuming they didn't literally break apart yet) is likely to be anywhere near the same performance as when the car had 200 miles on it? Its not. Its almost like there's a reason why mileage is considered when people price cars. The suspension isn't going to keep the wheels as well planted, the cylinders likely don't have the same compression, those fuel injectors are likely tired and aren't spraying optimally, that coolant pump is worn down and barely able to pump coolant anymore, your timings are likely not optimal anymore due to slack in the timing chain or belt, your spark plugs aren't making as full or reliable of spark, etc.

If your response is "well you would have replaced those by now"...well, why would you have to do that? Because they...had their performance reduce over the life of the part?

And even then, a part of that break-in period of those parts is the part's performance actively changing over the life of the part with pieces of the part literally degrading, just pretty quickly and positively for performance as opposed to negatively. That positive slope of performance change is a pretty early hump though, otherwise as I mentioned you'd be taking me up for ensuring all your tires are near-bald (but not quite, they haven't actually failed yet!) all the time and you'd be dumpster diving for the good stuff out behind your auto parts store.

There is something called hydrogen embrittlement. Where hydrogen causes cracks in metal. https://en.wikipedia.org/wiki/Hydrogen_embrittlement

Yeah, Li-ion batteries already have comparable life cycles to hydrogen tanks 1-2k fills/recharges, _but_ batteries are improving rapidly and tanks are already a mature technology.

I worked in one of the top 5 logistics companies in the world and I can recall them investing in electric trucks and charging infrastructure. Idea was to have strategically placed overhead lines that could recharge trucks without need for them to stop. Can't recall any mentions of hydrogen.

I have seen at least one stretch of highway in Germany that has overhead power lines for trucks. I think it's a very interesting concept: the big downside of batteries is slow charging (compared to diesel) and limited range. Charging while driving on highways would largely solve these downsides.

Cargo trolleybuses? An interesting idea.

Many jurisdictions require that commercial drivers take a 30 minute break every 4 hours. Those that don't should. Those stops make battery trucking feasible.

And if you want to stop for 5 minutes instead of 30 you can use battery swapping solutions like the one Janus uses.

Batteries are feasible for long distance trucking today.

Green Hydrogen trucking uses 3X as much electricity as using it directly. Trucking's biggest expense is fuel, so that will be the killer factor ensuring battery will beat hydrogen for long distance trucking.

Using mandated breaks for recharging heavy trucks isn't actually helpful in much of the world. Maybe it is in parts of Western Europe.

The problem is that those mandated breaks are mandated and happen (with a small amount of wiggle room) wherever the truck happens to be at that moment. Rolling out enough charging infrastructure to make that work is an even more immense challenge than the already massive challenge of adding sufficient charging infrastructure to places like existing truck stops.

Imagine the cost of installing 1MW chargers on, say, half the wide spots on every highway.

Imagine the cost of installing massive diesel depots at half the wide spots on every highway. And yet, there they are. And we already have car chargers every few dozen miles on the highways. A larger number of smaller chargers adding up to likely a larger wattage than what the trucks need.

  > Imagine the cost of installing 1MW chargers on, say, half the wide spots on every highway.

Do those spots have lighting? If so, a significant portion of the work has already been done. Even if the electrical wiring must be supplemented or replaced, just having already the subinfrastructure to snake high voltage wiring up there is the major hurdle.

Perhaps, but the larger question is whether the price of hydrogen itself can be sufficiently reduced. $36/kg is not justifiable for distance trucking or planes. If the price of hydrogen dropped sufficiently, then there's more demand to build hydrogen infrastructure, which increases demand for hydrogen in smaller vehicles, etc. in a positive feedback loop.

That theory didn't play out, mostly because the price of electrics kept dropping year after year, undercutting any appeal in early investment in hydrogen.

True, but it is a good first step. Start small, increment to larger solutions.

Green hydrogen is a way to ship solar power elsewhere that doesn't have it, similar to a battery, but with the advantage of being able to be piped/pumped/liquified etc.

Liquid hydrogen loses 1% of its volume per day due to boil-off. Hydrogen is incredibly difficult to move without huge energy losses.

It would be moved by pipeline as a compressed gas, not as LH2. The US already has > 1000 miles of H2 pipelines.

All between co-located industrial generators and consumers. H2 pipelines are DOA due to the absurd compression costs.

A BTU of hydrogen requires more energy to compress to a given pressure than a BTU of natural gas, but hydrogen also has lower viscosity, so less recompression is needed. The point you raise does not rule out hydrogen pipelines.

It does, definitively.

If it does, then it also rules out long distance transmission of electrical power, as that is even more expensive. And the hydrogen advantage is even greater when one considers one can piggyback storage onto this system, as is done in natural gas pipelines. The electrical system would need additional batteries which are much more expensive per unit of storage capacity.

You are simply wrong on this. HVDC losses total ~5% for 1,000km, including step up and step down losses.

H2 will experience 20-30% over the same distance of natural gas line including compression and friction losses. DOA.

I said expensive. Total cost is the relevant metric, not efficiency.

https://docs.nrel.gov/docs/fy22osti/81662.pdf

It's a common mistake to think efficiency dominates all other metrics. It's never just efficiency.

Capex for H2 pipelines is higher than new HVDC, and opex is 5-10x HVDC per MWh-km so you're just wrong on this.

H2 makes sense for feedstocks but not energy distribution.

The reference I gave you completely disagrees with your statement. So, present a link justifying it or I will just go with the link I have.

The PDF you shared actually agrees with my point if you care you to read it. It models the cost for a specific HVDC implementation, but the HVDC line selected is more expensive when transporting just 3% of the energy of the pipeline.

The same capex and opex can support 100x more Wh-km via HVDC, making HVDC at least an order of magnitude cheaper then the H2 pipeline.

What's interesting to me is that this is completely uncontroversial and incontrovertible, so I wonder where your insistence otherwise is?

I'm sorry but you appear to be completely deranged. The paper says nothing of the sort. Let me give the abstract:

"This paper compares the relative cost of long-distance, large-scale energy transmission by electricity, gaseous, and liquid carriers (e-fuels). The results indicate that the cost of electrical transmission per delivered MWh can be up to eight times higher than for hydrogen pipelines, about eleven times higher than for natural gas pipelines, and twenty to fifty times higher than for liquid fuels pipelines. These differences generally hold for shorter distances as well. The higher cost of electrical transmission is primarily because of lower carrying capacity (MW per line) of electrical transmission lines compared to the energy carrying capacity of the pipelines for gaseous and liquid fuels. The differences in the cost of transmission are important but often unrecognized and should be considered as a significant cost component in the analysis of various renewable energy production, distribution, and utilization scenarios."

I'm to read this as supporting your assertion that electrical transmission is several times cheaper??

For that purpose and for long-term storage of energy and for aircraft/spacecraft, synthetic hydrocarbons are much better.

Making synthetic hydrocarbons was already done at large scale during WWII, but it was later abandoned due to the availability of very cheap extracted oil.

So when oil was not available, the economy could still be based on synthetic hydrocarbons even with the inefficient methods of that time (it is true however that at that time they captured CO2 from burning coal or wood, not directly from the air, where it is diluted).

Today one could develop much more efficient methods for synthesizing hydrocarbons from CO2 and water, but the level of investment for such technologies has been negligible in comparison with the money wasted for research in non-viable technologies, like using hydrogen instead of hydrocarbons, or with the money spent in things like AI datacenters.

> If you've already got the electricity for electrolysis, would it not be more efficient and mechanically simpler to store it in a battery and power an electric motor?

Yes, if you actually have the batteries.

Between around 2014-2024, the common talking point was "we're not making enough batteries", and the way the discussions went it felt like the internal models of people saying this had the same future projections of batteries as the IEA has infamously produced for what they think future PV will be: https://maartensteinbuch.com/2017/06/12/photovoltaic-growth-...

I've not noticed people making this claim recently. Presumably the scale of battery production has become sufficient to change the mood music on this meme.

To be fair, there are still plenty of people on HN talking about lack of battery capacity as a reason to delay solar/wind rollout; I suspect it'll take a bit more time for the new reality to sink in fully.

The fossil industry was always suspiciously keen on green hydrogen - partly because the path to green hydrogen would likely have involved a long detour through grey and blue hydrogen, and partly because it gave them an excuse to lobby against phasing out natural gas for domestic heating/cooking ("we need to retain that infrastructure to enable the hydrogen economy!").

You can see the same thing happening in their support for Carbon Capture and Storage - "we're going to need the oil producers to enable carbon sequestration, so we might as well keep drilling new wells to keep their skills fresh!"...

> If you've already got the electricity for electrolysis, would it not be more efficient and mechanically simpler to store it in a battery and power an electric motor?

The Mirai uses the hydrogen in a fuel cell so it is an EV: https://en.wikipedia.org/wiki/Toyota_Mirai

It looks like a reasonable idea, but it needs infrastructure.

Sweden has very little natural gas in its energy mix:

https://ourworldindata.org/grapher/energy-consumption-by-sou...

I highly doubt that hydrogen heating was ever considered. It's usually pushed by the gas lobby (since most hydrogen comes from gas), and Sweden doesn't have a strong gas lobby.

Most of the current energy production in Sweden was built starting 50 years ago, which can be seen in the graph. Since the early 1990s the combination of hydro power and nuclear has had an almost static production rate, and hydro power in particular has been maxed out. Oil was and is still used as the reserve energy, through new plants currently being built are based on natural gas rather than oil. The political statement is that the goal is that bio fuels should be used, but that the mix will be based on the market and the economical viability of different compatible fuels.

The green party has been pushing the green hydrogen goals for decades. Use google translate on https://www.mp.se/politik/energi/ or look at archive.org for historical goals. https://www.mp.se/just-nu/mer-el-och-gron-baskraft/ is more of the same.

If you want something more official, here is a discussion within the Swedish government and by the largest political party: https://www.riksdagen.se/sv/webb-tv/video/interpellationsdeb...

That was extremely stupid of them then. Hydrogen has been very good at one thing: subsidy extraction. But I don't think it was or ever will be a viable fuel for planetary transportation.

> , and thus at some point green hydrogen would be too cheap to meter.

Even if you assume that is true. It will always be more expensive then straight electricity.

> The more sensible project were the green steel project.

Not sure I agree. I think Boston Metal solution is better long term carbon free steel solution.

> natural gas with bio fuels

There was a huge 'bio' fuels hype around like 15-20 years ago if I remember correctly. Huge amount of controversy and false claims with politicians support.

Funny how this now comes back again and nothing was learned.

The idea was to transition from coal to natural gas while using solar and wind to reduce fuel consumption, thereby significantly reducing CO2 emissions. Any claims of hydrogen being burned were either lies to the public to get the gas plants built despite the non-green optics or lies to investors as part of a fraud scheme.

Hydrogen burning could have a place in an all-renewable grid: it could be much more economical for very long duration storage than using batteries. The last 5-10% of the grid becomes much cheaper to do with renewables if something like hydrogen (or other e-fuels) is available.

A competitor that might be even better is very long duration high temperature thermal storage, if capex minimization is the priority.

> it could be much more economical for very long duration storage than using batteries

Yes, but that's not the only option you have. With the absolutely awful efficiency of burning hydrogen you'd need to be building a massive amount of additional wind and solar - which in turn means you'll also have additional capacity available during cloudy wind-calm days, which means you'll need to burn substantially less hydrogen to generate power.

This leads to the irony that building the power-generation infrastructure for generating enough hydrogen means you won't even need to bother with the hydrogen part: you're basically just building enough solar that their overcast supply is enough to meet the average demand. As a bonus, you've now got a massive oversupply during sunny winter days and even more during summer days, so most of the year electricity will essentially be free.

Efficiency is not very important for very long duration storage. What's important is minimizing cost, which is dominated by capex, not by the cost of the energy used to charge the storage system. Paying more to charge it can make sense if that greatly reduces capex.

So, yes, more input energy is needed. So what?

Good context. It's a shame none of these people did high school chemistry.

I do remember there being some news about the steel manf.

I wonder if further advancements in rocketry are adding H2 tech that could help us manage the difficulties of dealing with the stuff. It still only makes sense in very specific circumstances. Like when you need energy in tank form.

But I think battery / biofuel is the future.