[belorn]

People looked at how the cost of wind and solar went down and made a assumption that green hydrogen would follow. The reasoning was that the cost of green hydrogen was energy, and thus at some point green hydrogen would be too cheap to meter.

The whole energy plan of central/northen Europe, especially Germany, was built for the last several decades on the idea that they would combine wind, solar and cheap natural gas and then replace the natural gas part with green hydrogen. In Sweden there were even several municipalities that spear headed this by switching mass transportation and heating towards hydrogen, initially with hydrogen produced through natural gas, as a way to get ahead on this plan.

The more sensible project were the green steel project. As experts in green hydrogen said consistently said through those decades, is that green steel would be the real test to make green hydrogen economical. The economics of burning it for energy or transportation would come several decades later, if ever. The green steel project however has not ended up as planned and gotten severely delayed and has seen a cost increase by an estimated 10x. municipalities are now giving up the hydrogen infrastructure and giving it an early retirement, as maintenance costs was significantly underestimated. There is very little talk now about replacing natural gas with green hydrogen, and the new plan is instead to replace the natural gas with bio fuels, hinted at carbon capture, at some unspecified time.

[ACCount37]

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.

[dotancohen]

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?

[Manuel_D]

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).

[ben_w]

> 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.

[somat]

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.

[overfeed]

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.

[rswail]

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.

[graemep]

> 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.

[throwaway473825]

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.

[belorn]

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...

[jacquesm]

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.

[panick21]

> , 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.

[scraptor]

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.

[pfdietz]

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.

[aunty_helen]

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.