The hydrogen industry will need to address the potential environmental impacts from leakage, as well as how it interacts with other atmospheric gases, before it is adopted as a long-term alternative energy source, a new study has found.
According to the study, led by researchers at Auburn University and Stanford University, embracing a ‘hydrogen economy’ will require better understanding of the global hydrogen cycle, to determine if hydrogen can be considered a climate-safe alternative.
Indirect warming
While hydrogen has been held up as a viable means of decarbonising the global energy system, and does not trap heat in Earth’s atmosphere like carbon dioxide and methane, it interacts with other gases in ways that may negate its benefits, indirectly heating the atmosphere at a faster rate than carbon dioxide.
“This indirect warming raises concerns about the climate consequences of potential hydrogen leakage, and highlights that the climate benefits of a future hydrogen economy will depend on minimising leakage through the hydrogen value chain and reducing natural gas (methane) emissions,” commented Zutao Ouyang, lead author of the study and assistant professor of ecosystem modeling in Auburn’s College of Forestry, Wildlife and Environment (CFWE).
Ouyang, together with an international consortium of scientists known as the Global Carbon Project, developed the first ‘global hydrogen budget’, a comprehensive accounting of global hydrogen sources and sinks to assess changes in atmospheric hydrogen and its climate consequences.
“The team collected direct measurements of hydrogen in the atmosphere, along with the most comprehensive ever data collection and modelling to estimate the major sources and sinks of hydrogen and produce a first-of-its-kind global picture,” added Pep Canadell, executive director of Global Carbon Project, and chief research scientist at CSIRO Environment, Australia.
As the researchers note, atmospheric hydrogen levels increased by around 70% from pre-industrial times through to 2003, followed by a brief stabilisation period, before increasing again in 2010. This increase, they determined, was due to leakage from increased hydrogen production, as well as hydrogen being formed by the oxidation of increasing methane emissions.
Methane controls
As they note, this feedback loop suggests that for hydrogen to become more established as an energy alternative, strong controls on methane emissions need to be put in place.
“By quantifying the previously unaccounted warming feedback between hydrogen and methane that are missing in current climate projections, we hope to improve future climate scenarios and support decision-makers in minimising both economic losses and climate risks associated with hydrogen leakage,” Ouyang added.
The research study was funded by the Gordon and Betty Moore Foundation, Stanford Doerr School of Sustainability, Stanford’s Global Methane Office and Auburn’s CFWE. Read more here.
Main photo: Researchers at Stanford University test the Aerodyne Tildas hydrogen analyser, the world’s first commercialised H2 analyser, used in the lab to measure hydrogen concentrations. Photo by Rob Jackson, Stanford University.
