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NETWORK / 15 / NOVEMBER 2019 always taken the view that if I don't know exactly where it is, I don't mark it on the diagrams. But Wilson said that changes are underway. "We've had to try and break through that and say, 'actually I need to show the best of my knowledge what my network looks like'." Split views on hydrogen Producing enough energy to meet demand is a much bigger concern when it comes to the decarbonisation of heat, espe- cially if much of that demand is met by hydrogen networks. It was partly for this reason – cost being the other – that Northern Gas Network's (NGN) plans for a £22.7 billion hydro - gen gas grid across the north of England envision the fuel being extracted from methane, with the resulting emissions captured and stored. Anthony Green, head of en - gineering at National Grid Gas Transmission and another con- ference speaker, acknowledged the logic of that argument. "If we need to transition to net zero by 2050, we've got an awful lot of gas we've got to be producing very quickly. And we've got to start that in the 2030s." However, he did not neces - sarily share NGN's scepticism towards electrolysis and focus on prioritising methane-based production, arguing that the latter should only be seen as a stop-gap measure and kept to a minimum. Meanwhile, scaling up hydrogen production using electrolysis powered by renewa - bles should be supported. "I just have this concern that it's storing up problems for a later generation if we're captur - ing the carbon. I would prefer to go green completely," he said, adding that a hydrogen network fuelled by renewables was the "green future we want to get to". In contrast to NGN's findings, Green said that he expected the plummeting cost of renewables to make electrolysis cost- competitive with the methane alternative by 2030. In the short term, however, one option to minimise costs would be to produce hydrogen in Africa using electrolysis pow - ered by solar farms, and then liquefy the gas and ship it to the UK. "There are already LNG ves- sels being developed in Japan to pick up hydrogen produced through electrolysis in the Aus- tralian deserts and carry that hydrogen up to Japan. Could we do that from the African nations that have lots and lots of sun?" Blended learning Green also suggested that blend- ing and then de-blending gases on the transmission network could help to smooth the transi- tion to hydrogen. "Leeds is the city that is looking like it will be first to a hydrogen future. They're going to need 100 per cent hydrogen. "If we can carry 20 per cent hydrogen on the NTS [national transmission system] and then we de-blend it and pull off that 100 per cent hydrogen stream, it allows us to convert to hydrogen very quickly and very easily, whilst sustaining the rest of the country." This process could even be used to supply multiple gases to a particular user. "Take methane on, take LNG on, take biogas on, take hydrogen on, mix it all up and then de-blend it and issue to whatever asset needs it the mix of gas they want. "So if you're 100 per cent hydrogen, you can have that. If you're 20 per cent hydrogen and 80 per cent methane because you haven't converted all of the boilers in your town at that point, you can have that." Green added: "The good news is that there is capability out there in the industrial world to do this already. Now it's a case of could we scale that at the right quality and the right cost to make it feasible to roll that capability out?" Two birds in the bush Green said blending and then de-blending could additionally provide a temporary solution to the issue of embrittlement, whereby steel pipes become weaker as hydrogen molecules are absorbed into the metal. In such a scenario, methane would be used as a medium to transport hydrogen around the transmission network. However, he also said that the embrittlement problem could also be almost entirely mitigated by injecting small amounts of oxygen into the net - work: "By small amount, I mean 500 parts per million." In the meantime, Green told- delegates that National Grid's aim for the upcoming RIIO T-2 price control period would be to ensure that the gas grid operator has "no regrets" and so avoids making any "big investment in any assets that will not be needed in the future". "We want to make sure that any money we're spending, which is consumers' money, is really well focused," Green explained. "Our investment will focus first of all on maintaining the health of our assets." Change is definitely coming for gas networks, but what and when remains uncertain. National Grid's Anthony Green: worried about carbon capture In association with SSEN's Richard Hartshorn: con- sumers in the EV driving seat, not networks