For me it has gone beyond if going for some form of Hydrogen Strategy vs decommission the Gas Grid in entirety, and onto the debates within the various aspects of Hydrogen Strategy around some of challenges within those. For example hopes to use deblending Hydrogen from (with over 20% vol) blended mix with Natural Gas at offtakes from National Transmission have not been thought through enough and are a distraction, given the energy losses of deblending and the need then required for storage at offtakes given the cycling of demand downstream, unless deblending will load follow and need to be sized for peak. Instead it better to commit to building a (parallel) Hydrogen Transmission System, and once all conversion complete the existing National Gas Transmission can be fully converted to 100% Hydrogen providing additional Linepack (Diurnal daily) Storage (Salt caverns used for seasonal storage).

The key challenge around 100% hydrogen conversion is switching customers over with being off gas for a period (so can only carried out during the in summer), this period will be massively reduced for those that allready have a Hydrogen Ready boiler, which hopefully will be mandated soon. Hopefully with long lead up along with that Mandate mean many boilers will already be Hydrogen Ready, reducing the amount of work required in people homes. Of course conversion was done before with switch from Towns Gas to Natural Gas but utilization and end user expectations are much higher nowadays. But it is the amount of work in people homes required with associated customer issues that will slow effective scaled up of any electric based alternatives also.
Any advance of one will help the other though, if Hydrogen in homes is not going to be ruled out all together. I think the chance for alternative of very high levels of insulation with Heat Pumps to undermine case for Hydrogen conversion has passed with Zero Carbon new build Homes 2016 being canceled. If Heat Pumps are not being used in new builds at scale now, than we need to crack on with preparing for 100% gas grid conversion.

I was at one point was convinced by books such as Without the Hot Air by the late David Mackay that Heat Pumps were the way to go. But it has not quite gone way expected. There is a lot of inertia tied up with the companies, workforce structures, tenants and home owners around home heating, as well as failure of policy.

I myself tend to see bio-methane injection in gas grid as short term distraction too, given they won’t scale up to be the full solution required. It does provide benefits of a Greenhouse Gas reduction in short term, in same way as up to 20% vol hydrogen blending (preferably generated from off peak surplus Renewables). But at the moment bio-methane suffer poor value at small scale with overheads of injection into Gas Network (monitoring, adding smell, and for now adding Propane to keep energy density (Cv) & associcated Wobbe Index within limits etc), and limited capacity for injection away from peak. Although some of these limitation can be overcome to a certain degree. There have been moves afoot in Germany to have an additional pipeline network to gather Green Gases together from separate generation sites to have economy of scale of injection into higher pressure tiers of Gas Network.

Although I am happy to debate many aspects of energy supply with those interested, I have up till now wished to avoid myself out there to be a full on public advocate of pushing forward with investment in switching to using Hydrogen as energy carrier, and don’t wish promote use of hydrogen taking away from investment being increased for retrofitting homes, especially as I see as all supporting each other and all paying for themselves over time.

In the back and forth argument there are too many strawmen attacked from each side. The Hydrogen advocates often point to winter energy peak in gas being six times electric, and so would require unrealistic expansion of electric grid and storage. The switch to electric based on the use of heat pumps needs to be based on reducing heating requirements massively by full retrofit with high level of insulation but this comes with it own problems, if to be achieved 100% by 2050 or before. Even more limited upgrading of homes under Warmfront, various social housing upgrades to various Standards and recently ECO did not produce results expected, and are lessons being learnt? Often they don’t deliver what originally hoped. I have several personal experiences that inform this view, but that is maybe for another blog post.
Electric advocates point to lower energy density of hydrogen but as far as distribution by pipeline goes the lower viscosity goes a long way to make up for this and reinforcement of network will be small part of switch.
I am convinced at moment that aiming to convert the existing valuable Gas Networks that to 100% Hydrogen is worth pursuing over decommisioning all of them. And will continue to support doing this in most environmental beneficial and cost effective way.

Also see my previous post on this blog at:
https://j12.org/blog/2020/07/18/decarbonise-heat-at-scale/

with links like Gas Goes Green

also listen to the podcast from SGN