Utility Week

20 | OCTOBER 2021 | UTILITY WEEK Policy & Regulation Analysis Red flag for blue hydrogen Blue hydrogen should only be used where electrification is impractical or there is not enough green hydrogen to meet demand, says a senior CCC figure. Tom Grimwood reports. D avid Joffe, head of carbon budgets at the Climate Change Committee (CCC), says blue hydrogen should be seen as a transitional fuel while green hydrogen pro- duction is scaled up over the next few dec- ades, eventually becoming a "supply of last resort" and ultimately phased out. Joffe was speaking to Utility Week follow- ing the release of the government's hydrogen strategy, and was also responding to a con- troversial US study published in August that claimed burning blue hydrogen could actu- ally have a greater impact on global warming than burning natural gas. Methane leakage The headline figures from that study, by researchers at Stanford University and Cor- nell University, assumed a methane leakage rate of 3.5 per cent, primarily based on a prior study by one of the authors of natural gas production at fields in the US. However, Joffe is dismissive of the report's conclusions. He says it may be applicable to the US, where gas is sourced by fracking and then "injected into distribution level grids that then leak a lot of gas", but this does not represent the use of natural gas in the UK. He says its quite possible to produce and transport fossil fuel gas with an overall meth- ane leakage level below 1 per cent, although the figure can be higher for liquefied natural gas. This is because the gas industry may not be as well regulated in the countries where liquefied gas is produced, and also because the liquefication, transportation and regasifi- cation of the fuel introduces more opportuni- ties for leakage. Gniewomir Flis, a project manager at the German think-tank Agora Energiewende and formerly a consultant for Aurora Energy Research, agrees that the 3.5 per cent leakage rate used as the baseline assumption in the US study is not representative of the situa- tion in Europe. "The IEA estimates global emissions leakage at around 1.5 per cent," he says. "In the US, the hunt for shale oil leads to many smaller wells, and sometimes to methane venting, since it's a by-product." He says that where gas is extracted for its own sake from fewer, larger wells "there are fewer point sources for leakage, making the process easier to monitor". Joffe says there is room in the UK for regu- lations to be tightened further to reduce the emissions intensity of natural gas, although regulations for imported gas would also have to be stricter to ensure a level playing field. He says: "Regardless of whether we're doing blue hydrogen or not, any natural gas that we import should have as low a green- house gas footprint of production as possi- ble and we should be putting in place policy to drive that down, whether that's a carbon border adjustment-type approach of a tariff or whether that's a standard for the footprint of greenhouse gases in terms of the fossil fuel production." Production Joffe additionally challenges the study's assumptions around the production of blue hydrogen. The paper assumes as a baseline that blue hydrogen will be produced using a process called steam methane reformation rather than autothermal reformation. Using the first method allows 85 per cent of emis- sion to be captured while with the latter this figure rises to 95 per cent. "Steam methane reforming is the domi- nant way of producing hydrogen from methane globally," says Joffe. "But it's not designed for integration with carbon capture and once you think carbon capture is impor- tant you would instantly switch to autother- mal reforming, simply because it produces a pretty pure stream of CO2 directly out of the process." With this possibility in mind, Joffe says the CCC has estimated the reduction in full lifecycle greenhouse gases from burning blue hydrogen when compared with burn- ing natural gas at 60 to 85 per cent – a much greater saving than that suggested by the US study. "There's certainly no case that they've analysed that says this is blue hydrogen done well," he remarks. Joffe says this reduction could "conceiv- ably" reach 90 per cent if the highest carbon capture rates claimed by proponents of auto- thermal reformation are achieved. "We have reasonable confidence, because we have no reason to believe otherwise, that the tech- nology performance will deliver something pretty high, but that needs to be proven," he says. The role of blue hydrogen Even if the top end of the CCC's estimated range can be achieved, Joffe nevertheless urges restraint in the use of blue hydrogen. "You don't want to be using much of a tech- nology option that's only giving you up to an 85 per cent emissions reduction if the overall Gas sourced as a by-product of oil production can leak more methane than dedicated wells

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