This is a very different process to the mining of natural hydrogen, which contrary to ill informed comments and 'analyses' can and does occur on its own, not in tied in to methane molecules etc, although the extent of the resource is currently being determined.

Cemvita are planning to extract both hydrogen and CO2 to the surface, where the hydrogen will be used and the CO2 pumped back down for sequestration:

https://uploads-ssl.webflow.com/620d223620103dcb187b5fb0/620d223620103d0bfe7b61e6_Cemvita%20Factory%20Gold%20Hydrogen.pdf

The resource base for this is known and vast, as they can tap into umpteen oil and gas wells which are depleted as far as conventional methods are concerned.

There are two major questions:

Is it going to work?

And there must be serious doubts about the effectiveness of the sequestration of CO2, as the geology is going to vary enormously.

I often advocate the use of hydrogen, at least in so far as in my view it is typically sought to be dismissed unreasonably.

But not at any climatic price, so I am very wary of this tech.

Hey JamesDo:

Thanks for the expert input.
As very much a non-expert, I was unsure how to evaluate the somewhat conflicting info out there.
And since I am something of a hydrogen advocate, I prefer to take evaluations against pessimistically, to see if my case still stands up.

So here for instance is the sort of stuff I was looking at:

https://www.frontiersin.org/articles/10.3389/fenrg.2018.00040/full

' Summing up, according to the IPCC (Metz et al., 2005), storage sites are probably reliable and safe, meaning they release very low or practically zero leakages. van der Zwaan and Smekens (2009) suggest a maximum acceptable value for the leakage rate below 0.5% per year, while for Bielicki et al. (2015) lower leakage rates are conceivable. In this study we therefore consider the maximum leakage rate of 0.1% per year, which implies leakage of 9.5% over a century, while a more reasonable leakage rate that we test is 0.01%/year, which leads to a theoretical leakage of 1% of injected CO2 over 100 years4.

As leakage remains uncertain, it is of vital importance to ensure effective and reliable monitoring systems that consistently measure CO2 flows. In recent years, several studies have addressed the issue of monitoring leakage flows to the atmosphere or affecting underground aquifers (Benson and Hepple, 2005; Dethlefsen et al., 2013). '

It would appear from your assessment that the notion that blue hydrogen is just fossil fuels with essentially little reduction in GWH is false, which I rather thought might be the case, but was looking for more definitive grounding prior to making that claim.

This is the near future. I order from car manufacturers , a hydrogen car with an ice engine, i would pay 17 000$ and hydrogen or ammonia at cheaper price than actual gasoline.

We gonna fill-up with hydrogen at existing gas station instead of charging at inconvenient remote place for half to one hour and it's gonna cost few money. With that we can decarbonize transport way before than batteries for less money, no need for subsidies, existing petroleum companies can build the infrastructure and conventional car companies can build the cars that will be cheaper than bevs. Also it is less polluting than mining for batteries.

@JamesDo:

I tend to find more credible analyses which answer, well, it depends!

From the discussion and links it seems clear that CO2 sequestration can be done safely and effectively, and that also that it is possible to screw it up.

So to look at the efficiencies of the hydrogen economy, say for the UK using primarily offshore wind, then Topsoe Haldor hits 90% efficiency in electricity to hydrogen:

https://www.greencarcongress.com/2022/09/topsoe-confirms-fid-to-build-worlds-largest-soec-electrolyzer-plant-companys-biggest-single-investme.html

Pipe that to folk's homes, use a fuel cell, and electrical plus thermal is also around 90%, so total efficiency comes out to 80% or so.

The remaining issue is whether piping it around is practical.
The Dr Martin interviewed in Engineering with Rosie is agin it:

https://www.youtube.com/watch?v=vrKvj2MHLVw

His argument is primarily that the low energy by volume of hydrogen, around a third of that of NG, means that it is impractical, especially through a modified NG pipeline network.

So would, for instance, the UK's network have to transport as much hydrogen as present energy delivered by the NG pipelines?

NG is currently the overwhelming choice for heating property in the UK, as well as cooking and so on.

The notion that we would ever need to move that much hydrogen about seems to me fanciful in the extreme.

Fuel cells can utilise the heat as well as produce electricity, so on the spot production would greatly reduce the need.
Some designs can also run in reverse, so if it is wanted, then electricity could be used to produce hydrogen in the house or office.

Proper insulation of homes should itself reduce demand.

It seems that the assumption is that the measures fancied as in some kind of opposition to hydrogen are assumed to totally fail. so the whole load falls on hydrogen .

But if, for instance, heat pumps take up some market share, then the need to move hydrogen around decreases.

Hydrogen can be made pretty much where it is needed, with the alternative being to run electricity in, or, for instance, site SMR reactors where needed.

The bottom line is that there is no need to move anything like the quantities in terms of energy around using hydrogen as is currently shifted in the NG network, and the 30% of capacity a converted network should be able to easily do looks like a pretty good fit.

And I am eagerly waiting to see how Hydro-Quebec gets on moving Kubas binding for hydrogen storage to commercial scale:

https://www.greencarcongress.com/2021/03/20210320-hq.html

It is works, it will hammer battery electric cars, as well as providing cheap storage for hydrogen wherever it is needed, for instance in homes.

No need for monstrously heavy, massively accelerating Tesla type fake environmental cars as tax breaks for the wealthy, when small, cheap, light and effective transport can be provided.