UK government warns of global warming risks related to hydrogen leaks

The UK Department for Business, Energy and Industrial Strategy (BEIS) has published a report describing the possible impacts of an emerging international hydrogen economy on the global climate.

Scientists from the University of Cambridge and the University of Reading explored the atmospheric impacts caused by hydrogen leakage. They calculated the radiative forcing resulting from hydrogen emissions and the global warming potential of hydrogen.

“Any leakage of hydrogen will affect atmospheric composition (with implications for air quality) and have an indirect warming effect on climate, partially offsetting some of the climate benefits of the reduction in carbon dioxide,” the scientists warned, noting that hydrogen leakage also reduces the tropospheric concentration of hydroxyl radicals. “Increases in tropospheric ozone, water vapour and methane, consequent on increases in atmospheric hydrogen, would all tend to increase radiative forcing, partially offsetting the climate benefits of a switch to hydrogen.”

Radiative forcing is a parameter defined by the Intergovernmental Panel on Climate Change (IPCC) that measures influence a given climatic factor has on the amount of downward-directed radiant energy impinging upon Earth’s surface.

The British scientists developed a new way to calculate Global Warming Potentials (GWPs) for gases whose emissions result in indirect radiative forcings. It considers the lifetime of a gas in addition to the lifetimes of the radiatively active gases causing the indirect forcing.

“This allows GWPs arising from indirect forcings to be calculated for gases with intermediate and longer lifetimes, such as hydrogen,” the scientists said. Several scenarios describing the atmospheric response to changes in the emissions of hydrogen were modeled and hydrogen leakage was found to affect the concentration of methane, ozone and water vapor in the atmosphere. 

“The changes in radiative forcing, like the changes in atmospheric composition, indicate that, to maximize the climate and air quality benefit of a transition to a hydrogen-powered economy, minimization of both hydrogen leakage and a reduction of the ancillary emissions of, for example, carbon monoxide, nitric oxide and volatile organic compounds is required,” the scientists concluded.