I have just come across this for bulk hydrogen storage as liquid, making it easy to transport as well as store:

https://phys.org/news/2024-08-formatebicarbonate-energy-hydrogen-storage.html

And the open access source paper:

https://www.nature.com/articles/s41467-024-51658-2

Reversible at low temperature, and as the diagram shows, absolutely non toxic, unlike methanol etc.

Actually a formic acid potassium bicarbonate cycle, which although of low energy density would be readily transportable and easily stored.

Unfortunately although as they say the catalyst is commercially available, it is ruthenium, which is basically hen's teeth rare.

So if they can sort out a more abundant catalyst, there are considerable advantages over LOHC , methanol and ammonia cycles for transporting hydrogen

IF.....

Natural gas can be turned to hydrogen with pyrolysis you just heat it, you end up with carbon black and hydrogen we can use carbon black for anodes in lithium ion batteries and carbon fiber body panels.
I believe it's best to create hydrogen at point of use,
transporting it is not necessary.

I don't see why you would transport hydrogen when you don't have to you can't really put more than 10 per cent in natural gas pipes so now you have to build a complete hydrogen pipeline network

There are a few things to consider here. 1) hydrogen has about 1/3 energy content per volume than NG at the same pressure, so dilution is reducing the energy content of the gas. This can be partly or fully compensated by hydrogen's lower viscosity so flow rates can increase. 2) Hydrogen has different combustion properties than NG, so the end-users will have to adapt burners, gas turbines etc. at some point. (This may be the source of SJC's 10% - the amount you can blend without having to change anything else.) 3) Hydrogen affects the fracture mechanics of steels deleteriously, so that most repurposed NG pipes will likely have to operate at a lower pressure. 4) Hydrogen has to be very clean for use in fuel cells, which may imply that green and blue hydrogen will need to be segregated. 5) local gas distribution (as opposed to transmission) typically uses polymer pipes, and hydrogen can diffuse through these more easily than NG, giving a higher leak rate. None of this is insurmountable and technology changes all the time, but I'm far from convinced that hydrogen will be a winner for energy transmission. These guys https://terraformindustries.wordpress.com/2023/06/26/the-terraformer-mark-one/ claim they can produce synthetic methane using solar PV, electrolysis hydrogen and air-captured CO2, at a price lower than shipped LNG , and eventually lower than drilled NG. I calculate efficiency of 28% (joules electricity to joules methane heat of combustion), which gives a terrible round trip efficiency. It's appalling as a solution to the renewables storage problem, BUT since it's a drop-in NG replacement, it means zero gas infrastructure changes, and carbon-free renewables backup. No massive upgrades needed for electrical transmission any more. Going from methane to methanol to run IC engines also means no rush to mass electrification of transport. Apparently they have a working demo unit. Food for thought. (More here https://www.youtube.com/watch?v=wG8P9StpvX8&t=255s)

MattF:

I have split an otherwise very long post in reply.

The assumption is that hydrogen would be used in present equipment, ie massively inefficiently.

There is zero sense in continuing to use hydrogen or gas burning cookers, which are a considerable health hazard, instead of the far more efficient and cleaner induction cooking.

Home heating with fuel cells would largely be a freebie from producing the electricity.

Not only would fuel cells do a great job themselves, but integrate very well with solar on the roof etc.

The notion that we would have to pump around as much hydrogen in energy terms as we currently do natural gas is dependent on the utter failure of everything from better insulation, to solar integration etc

Too expensive? If we don't, we scrap the sunk costs of the NG grid, and impose further strains on providing cabling for renewables.

And hydrogen can be stored in sufficient volume to cover dunkelflaute events, periods of several days, especially in winter when there is low solar incidence, when the wind ain't blowing and there is near zero imput from renewables.

Hi SJC

I try to be pretty specific about which area I am talking about, as the specs of the existing pipelines vary, for a start, and all sorts of regulations.

My comments refer mainly to the UK, where the limit is most certainly way higher, with modifications, but still very do-able, and more peripherally to Europe, where most places are pressing ahead.

For the US, here is Office of Energy Efficiency and Renewables:

' One possibility for rapidly expanding the hydrogen delivery infrastructure is to adapt part of the natural gas delivery infrastructure to accommodate hydrogen. Converting natural gas pipelines to carry a blend of natural gas and hydrogen (up to about 15% hydrogen) may require only modest modifications to the pipeline.3 Converting existing natural gas pipelines to deliver pure hydrogen may require more substantial modifications. Current research and analyses are examining both approaches.'

https://www.energy.gov/eere/fuelcells/hydrogen-pipelines

I don't want to get too far into the weeds of comparing the specifics of different areas and suitability for conversion, as it is way above anything I could manage, and have simply used the judgements of the authorities in those countries.

Googling has not turned up much specific to the US in any case, but many studies which in fact refer to the US don't bother to mention the where, and assume some kind of universality

But on the off chance that this analysis from 2022 by the KNF group is focussed primarily on the US, what they say may be of interest:
https://knf.com/en/uk/stories-events/blog/knowledge/article/hydrogen-natural-gas-pipelines

' Using pure hydrogen in conventional gas pipelines is a relatively new process. Initially, concerns arose that the H2 might damage metal pipelines due to hydrogen embrittlement. This has proven not to be the case.

With conventional gas pipelines, only components like pumps, compressors, measuring and control units need to be replaced when switching to a blend of 25 % hydrogen or higher. Inner lining of pipelines or other large-scale modifications are not necessary.6

Hydrogen in natural gas pipelines: comparable capacities

Hydrogen and natural gas differ tremendously in their energy density by volume. H2 offers roughly 1/3 of the energy fossil gas carries in the same volume. This seems problematic at first glance, as this would mean that a pipeline previously transporting natural gas would deliver only a third of the energy when turned into a hydrogen pipeline.

However, this is not the case as hydrogen is far less dense than fossil gas, allowing for higher flow rates. A natural gas pipeline repurposed for hydrogen can still deliver 80 to 90 % of the original energy transport capacity under otherwise identical conditions.7;'

As far as I can see the limit for the US is going to be at least 15%, but the discussion in the US as to the costs and practicalities of higher amounts up to 100% are still a matter for debate, whereas in Europe ( And China etc? I haven't looked into it for eastern countries) they are happy that they can manage conversion, by and large.

Hi Davemart

As with everything, the devil is in the details!

"The assumption is that hydrogen would be used in present equipment, ie massively inefficiently." Short term, that's a reasonable assumption. Changing everything takes time, and doing it all at once isn't practical.

"There is zero sense in continuing to use hydrogen or gas burning cookers, which are a considerable health hazard, instead of the far more efficient and cleaner induction cooking." Agree, although I'll miss the instant control of the pretty blue flames...

"Home heating with fuel cells would largely be a freebie from producing the electricity." Would it though? First thing on a winter morning, house is freezing, you turn a few LED lights on and the TV, but the waste heat from the fuel cell generating power for these isn't much. Maybe you're also generating power for a heat pump? Or maybe the house is toasty from the fuel cell charging your EV all night? Fuel cells have a cost, heat pumps have a cost. This is a job for modelling, and the models are going to be sensitive to assumptions.

"Not only would fuel cells do a great job themselves, but integrate very well with solar on the roof etc." Sure. Do we throw a battery into the system to capture excess solar on those long sunny days?

"The notion that we would have to pump around as much hydrogen in energy terms as we currently do natural gas is dependent on the utter failure of everything from better insulation, to solar integration etc." Long term, agree, but that's an AWFUL lot of work has to happen to reach that point.

"Too expensive? If we don't, we scrap the sunk costs of the NG grid, and impose further strains on providing cabling for renewables." Possibly. Or possibly we find storage solutions way better than what's on offer right now and co-locate it with the renewables so they can function as (hated words) baseload and peaking supplies.

"And hydrogen can be stored in sufficient volume to cover dunkelflaute events, periods of several days, especially in winter when there is low solar incidence, when the wind ain't blowing and there is near zero imput from renewables." In very large geological stores, possibly. More stuff to do to make this work.

Sometimes when I squint a bit, I can almost see all this change happening as described, and even working, but technology, politics and fashion have a tendency to surprise those in the crystal business. I'm betting (hoping?) we'll transition to a low carbon economy eventually, without breaking the world, but it'll look quite different from what we (or anyone else) are imagining.