Hydrogen & Climate

CleanTechnica: "Hydrogen isn't the answer: 0.7-1.5 billion tons of CO2e [equivalent] would make it a climate liability." I have long beaten the drum for hydrogen as a clean-energy solution helping decarbonize the trickiest sectors such as 'heavy industry, aviation, maritime shipping, and long-haul trucking.' But Michael Barnard's analysis gives me pause, as the leaks in the supply chain with hydrogen—used at scale—could result in up to 1.5 gigatons of CO2 equivalent each yr. Long appreciated is that equivalent leaks of methane in the gas supply chain of about 3% would result in as much heat-trapping effect as burning coal. And diatomic hydrogen [H2] is a much smaller molecule than methane [CH4], hence harder to corral at every stage of production, transport, storage, + use. The reason hydrogen leakage is so consequential lies in its indirect greenhouse gas effect. Enter the hydroxyl radical [-OH], a short-lived + reactive oxygen species that serves as a scavenger of pollutants such as methane + ozone in the atmosphere. But if hydroxyl is scrubbed from the air by hydrogen, then methane persists longer. Hydrogen also increases concentrations of tropospheric ozone + stratospheric water vapor, each with additional heat-trapping consequences. "The most recent GWP study estimates hydrogen’s GWP20 at around 33, meaning one ton of leaked hydrogen has the short-term warming effect of 33 tons of CO2." And electrolysis, 'usually marketed as the cleanest production route, may actually introduce greater climate risks due to its higher leakage rates' compared to conventional steam methane reforming (SMR). Ain't atmospheric chemistry grand?