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Comment by natch | Hacker News Reader

Is hydrogen cheap to transport, cheap to store, and cheap to use though? I thought making it was only a small part of the problems with hydrogen.

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No, too many losses. Same problem with storage.

Use isn't that expensive, fuel cells do exist.

The problem with green hydrogen (made with electricity) is the inefficiency.

It's only good for storage when you have already filled every battery and pumped hydro storage you have and are still making an excess. Electricity -> hydrogen -> electricity conversion is so hilariously inefficient that even petrol engines can beat it.

I don’t understand that comparison. You can’t use electricity to make petrol, right?

Synthetic fuels can be created with electricity. But, again, the efficiency is laughable. The amount of energy lost in the conversion is so huge that it's not viable unless you've got crazy levels of overproduction.

But my comparison was about the fact that petrol engines convert only 20-30% of the energy in the fuel to actual motion - everything else is lost in friction and output as heat.

Toyota had a prototype engine that went up all the way to 35-37% efficiency, but it didn't make it to production.

Modern electric engines are 90-95% efficient.

Fuel cell vehicles also use electric motors. They will not lose to combustion engines on efficiency. You seem to contradict yourself on how you think hydrogen vehicles work.

Fuel cell vehicles sill need hydrogen to generate the electricity.

Hyrdogen has about 80% losses from electricity to wheels. When 55kWh of electricity is used to generate hydrogen and that is used in a Toyota Mirai to move the car, only 11kWh ends up at the wheels.

If you do that same with a Hyundai Ioniq 5, all 55kWh (minus some transfer losses) get to the wheels.

Those are purely made up numbers. A fuel cell will easily be more efficient than an internal combustion powered car. Also, a battery is not 100% efficient, nor is charging an EV 100% efficient.

No petrol engine can match a fuel cell on efficiency. Especially once you realize the existence of refining losses.

I never understand why people are so obsessed with the problems of using hydrogen for transport. We use millions of tons of it for making fertilizer and other industrial processes. We could potentially expand industrial uses to include steel and replacing methane in high heat applications.

I mean, this doesn’t have to go into cars / be distributed widely… it could just used to time-shift solar energy to night time by burning it on-site. Which means you only need to solve the storage problem.

Which is already solved: salt caverns work well.

I checked and: "Salt caverns are artificial cavities in underground salt formations, which are created by the controlled dissolution of rock salt by injection of water during the solution mining process."

Yeah, I don't have one of those in the garage unfortunately. I do have space for one of these though https://newatlas.com/energy/lavo-home-hydrogen-battery-stora...

Hydrogen is not the storage solution for your garage. A normal battery is better suited. Hydrogen is for storing weeks worth of energy at grid scale.

I doubt even 15% efficiency would be there; along with massive maintenance/size issues. Solar is cheap and easy when it comes to maintenance, effectively no moving parts. Internal combustion (or a gas turbine) is a whole new development... and there is the storage.

The best bet are still batteries, albeit the current incarnation of LiXXX (e.g. LiFePO4) are still not there. Even storing energy in batteries poses multiple conversions of electricity that goes to 92-95% efficiency.

Hydrogen is a small slippery hard to contain gas molecule.

Ammonia transport and storage is far more likely.

Hydrogen is not at all hard to contain. Just put it in a gas bottle. The real issue is the very low density which makes the tanks rather large.

Then why do the actual people who work with hydrogen worry about transport losses if you just need a thick enough tank?

In Michael Liebreich’s Keynote Speech at World Hydrogen Congress 2022[0] he speaks about the problems of shipping hydrogen. you get around 1% of loss PER DAY (0.1% for LNG). And because of the huge tanks the energy capacity is 1/4 of a comparable LNG carrier. The economics just don't make sense.

[0] Michael Liebreich’s Keynote Speech at World Hydrogen Congress 2022 (16:00 mark about)

The talk is about liquefied gas. Bottled gas has way too low density to put it on a tanker. The losses are due to boil-off, not due to leakage.

In gas form, hydrogen is much worse. You need about 18 truckloads of hydrogen stored at 200 bar to match a single truck load of diesel in terms of energy.

You can also use certain oils to absorb (not sure if that is the technical correct term here) the hydrogen for transport. Renders it inert, no losses and it doesn't even count as dangerous goods for land and sea freight. Seems to be pretty easy to get the H2 out of the oil for use or transfer.

The man in the keynote I linked was "Michael Liebreich, Chairman and CEO of Liebreich Associates, through which he provides advisory services and speaks on clean energy and transportation, smart infrastructure, technology, climate finance and sustainable development. In September 2020, he became an official adviser to the UK’s Board of Trade".

...and he didn't know of any better ways of transporting H2 than liquid form.

If it would be "pretty easy" to absorb it to oils, I'm sure that would've been tried already.

the industry's goal seems to be hydrogen->ammonia - transport - ammonia->hydrogen, because ammonia is orders of magnitude easier to transport.

Just before Covid I did consulting for a green hydrogen product, on logistics, supply chain and all that. And, in the low to mid volumes, the easiest way, which included distribution to smaller sites, was using carrier oil and standard oil tank containers. I would have to look the exact oil up again.

Also true, as soon as one hits high volumes nothing beats liquified gas or pipelines.

> Just put it in a gas bottle.

is a bit of an understatement.

Consider that a household LNG gas cyclinder (propane if you're central north american I guess) is typically built to contain between 100 and 200 psi whereas hydrogen requires high pressure tanks to contain between 5,000–10,000 psi.

That's a factor of 50 difference in required containment pressure capability.

Standard industrial gas bottles are 200 or 300 bar (2900 or 4350 psi for the metrically challenged). They work just fine for storing hydrogen [1].

[1] https://www.lindedirect.com/resources/gases/hydrogen

That's indeed how hydrogen is transported around today. The thing is, the volumetric density of hydrogen is quite bad. About 3x less energy than methane in gas form, which is similar to the difference in energy density in liquid form too.

And the hydrogen will still diffuse into the steel. And make it brittle so all bottles, pipelines etc have a limited lifespan compared to infrastructure for methane. And you always need pumps to get it from one containment into another because it stays gaseous all the time. Don‘t get me wrong, all these problems are technically manageable. But from the economic perspective the H2-hype is not reasonable at all. H2-application will stay niche application. Getting iron ore reduction away from coal would be a huge accomplishment given the economics of H2.

This is yet another misconception. Hydrogen embrittlement is due to atomic hydrogen being created in chemical reactions. Gaseous hydrogen consists of H2 molecules which do not lead to embrittlement [1].

[1] https://en.wikipedia.org/wiki/Hydrogen_embrittlement

Maybe embrittlement is the wrong terminus but nevertheless molecular hydrogen poses risks to steel-made components of methane infrastructure. See for example [1]. There is also funded research at Fraunhofer [2].

[1] https://www.twi-global.com/technical-knowledge/published-pap...

[2] https://www.lbf.fraunhofer.de/en/projects/hydrogen-cyclic-st...

You can add hydrogen to natural gas (using existing pipelines and storage), and so slowly replace that. No changes to existing infrastructure needed up to maybe 20% I think.

You can but there are concerns about hydrogen being a smaller molecule so we’d get increased leakage (with knock on effects)

No one really knows how our existing natural gas infrastructure will cope with hydrogen

Trials of grid distribution for up to 20% H2 blended gas have been undertaken successfully in the UK:

https://hydeploy.co.uk/app/uploads/2018/02/HYDEPLOY-FOURTH-O...

https://hydeploy.co.uk/app/uploads/2018/02/21935_CADENT_HYDE...

https://academic.oup.com/ce/article/3/2/114/5487479

Natural gas infrastructure already deals with hydrogen: 2% of natural gas is hydrogen. For town gas which was used before (made from coal), hydrogen content was around 50%, so this isn't entirely new. Of course you can't re-use the existing infrastructure and use 100% hydrogen.

This isn't black-and-white. Leakage is a disadvantage, as it is for fossil fuels (natural gas, oil, coal,...). Other technologies have other problems: windmills kill birds and bats! Pumped storage kills fish! Dams cause methane leaks! It is important to quantify how much of a problem those disadvantages really are.

hydrogen worsens the impact of methane in the atmosphere and as such simply pumping hydrogen through existing infrastructure sounds pretty dangerous.

https://theconversation.com/dont-rush-into-a-hydrogen-econom...

https://agage.mit.edu/publications/global-environmental-impa...

more skeptically, given that green hydrogen remains a pipe dream, it's both a useful delaying tactic for switching to electricity and furthering investment in fossil fuels, which must stay in the ground if we are to have any hope of staying below 1.5c.

https://www.carbonbrief.org/new-fossil-fuels-incompatible-wi...

Natural gas already contains hydrogen. Up to 20% of hydrogen in natural gas doesn't sound all that dangerous. The article you linked says "if a hydrogen economy replaced the fossil fuel-based energy system and had a leakage rate of 1%, its climate impact would be 0.6% of the fossil fuel system.". So the climate impact would be 100 times smaller(?)

Yes there are many delaying tactic for switching to electricity (the promise of "synthetic fuel" for example, to power existing gas cars). But using hydrogen to replace fossil fuels is needed anyway, for example for ammonia production and steel manufacturing. So I don't understand why you think hydrogen will delay the switch to electricity.

I refer you to the current documentary on Netflix called _Glass Onion_ that examines this problem.

While I really like the movie, the hydrogen technology part and its dangers are entirely fictional.

I was very disappointed by my it

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