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The idea that because 'town gas' contained a high level of hydrogen (H₂) means that converting the gas grid to 100% hydrogen will be easy is clearly wrong (yet it's pushed repeatedly as relevant) (thread)
Indeed town gas did contain plenty of H₂, perhaps around 50% volume https://semspub.epa.gov/work/01/458914.pdf. Worth noting that even with 50% H₂ and 25% methane (CH₄) as in this example, the majority of the energy is coming from methane. CH₄ is a more energy dense molecule.
The only relevant similarity is that hydrogen can be transported in pipes, and burns. Facts that are hardly surprising! Questions do remain over the suitability of the gas network and internal pipework (potential biggy) for 100% H₂, things currently under investigation.
Any potential conversion from CH₄ to H₂, like the previous conversion from town gas to 'natural' gas would need new appliances because of how the gas burns-H₂ burns fast. This *could* possibly be only elements of appliances (if 'H₂ ready'). http://dx.doi.org/10.1016/j.apenergy.2017.09.049
Certain companies are pushing for H₂ ready appliances to be standardised https://www.h2-view.com/story/exclusive-worcester-bosch-wants-only-hydrogen-ready-boilers-on-the-market-by-2025/https://www.baxi.co.uk/about-us/news/baxi-calls-on-government-to-mandate-hydrogen-ready-boilers-by-2025 (why might that be?)
But, because physical changes to appliances would be needed, you can't just clean up the energy source (like with electricity) and leave it. A geographical programme of some sort would be needed whereby whole areas were turned off, all homes visited, checked and made suitable.
Three visits may be needed. Visit:
1. Check appliances.
2. Gas turned off before meter- Replace, remove or make suitable existing appliances in whole area
3. Following gas mains being converted to H₂ - re-visit and turn gas supply back on and commission appliances
1. Check appliances.
2. Gas turned off before meter- Replace, remove or make suitable existing appliances in whole area
3. Following gas mains being converted to H₂ - re-visit and turn gas supply back on and commission appliances
Step 3 could be done by households but it comes at a risk, currently in GB this should only be performed by a gas engineer (there is an emergency plan which could be used but yes, comes with a ummm...risk).
Overall the point I'm making is that there's nothing simple about an H₂ switchover. And we haven't even talked about how the H₂ is produced and how much it will cost.
And for the record, I'm not saying that electrifying everything would be easy. But smart electrification can have major carbon benefits and minimal system impacts now. And we know it works! http://raponline.org/knowledge-center/heating-without-hot-air-principles-smart-heat-electrification/
So, yes do the hydrogen trials but it can't be relied upon meaning we need to crack on with what we know does work before we know more and we need to realise we will never know everything. Timescales are very very tight!
For more details on that final point, my recent article on policy maker's perceptions on heat decarbonisation has some suggestions for policy makers: https://www.sciencedirect.com/science/article/pii/S0301421520302408
1. Reduce uncertainty
2. Focus on low regrets initially
3. Accept uncertainty (ENDS)
1. Reduce uncertainty
2. Focus on low regrets initially
3. Accept uncertainty (ENDS)
