Might I gently suggest this thread has gone rather off-topic, and that rather than have a hundred threads all talking about similar general issues about hydrogen, it would be better to concentrate discussion on the main hydrogen thread linked above?
And rather than speculate about possible hydrogen blends etc, I suggest those interested read
HMG's official hydrogen strategy, which will take a decision on hydrogen blends in 2023 and 100% hydrogen in 2026. Methane/hydrogen blends are nothing new, they've been kicking around for 10+ years in - gasp - other countries.
As an aside,
the current gas network :
There are about 91,000km of remaining iron mains within 30m of buildings (’at risk’ mains) which may give rise to a risk to people. The majority of these - some 78,000km - are cast iron mains, the remaining 13,000km being low pressure ductile iron mains...Iron pipes make up slightly less than 50% of the Transco network, the remainder being made of polyethylene or steel. Most of the iron pipes are over 40 years old; some are more than 100 years old...Since 1977 there has been a targeted programme of replacing these ’at risk’ mains. Over this period 61,000 km have been replaced with a highest annual rate of replacement of 3,300 km/year. Over the past 5 years the average rate of replacement necessary to achieve the agreed safety outputs was 1,840 km/year and at this rate it would take a further 51 years to replace all of the ’at risk’ metal mains.Dodds & McDowal were sketching out the future of UK gas networks back in 2013 :
The UK Climate Change Act 2008 requires the UK government to reduce UK greenhouse gas emissions in 2050 by 80% relative to 1990 levels (HM Parliament, 2008). Studies of UK decarbonisation pathways to meet this target, underpinned by the UK MARKAL energy systems model, have invariably suggested that the low-pressure gas pipeline network should be mostly decommissioned by 2050, with heating provided by either electric heat pumps or biomass boilers (e.g. Hawkes et al., 2011, Kesicki, 2012). Since the gas network currently supplies around 22.9 million customers (DECC, 2011b), including 84% of homes, this represents a profound change to the UK energy system.One of the big problems is what happens to the gas network should it no longer be needed - a lot of it is 45-year regulated assets, does the government buy out those assets?
The other big one that has been touched on is where does the hydrogen come from. There are some industries such as the chemical industry where hydrogen is their only route to decarbonisation, and as such they will consume all the hydrogen available for at least a decade. Home heating has other options, albeit things like heat pump technology ain't great at the moment.
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