CAN NATURAL HYDROGEN PLAY A ROLE IN THE ENERGY TRANSITION? (Invited Presentation)

The development of civilization is closely associated with the exploitation of Earth-based energy resources, the evolution of which is broadly characterized by changes in the relative dependence on biomass, coal, petroleum, and renewable sources. However, the contribution of CO₂ to the atmosphere from anthropogenic energy production is profoundly altering the planet’s climate. To mitigate the potential negative consequences of climate change, there is a need to transition away from carbon-intensive energy resources toward increased reliance on low-carbon renewable sources, such as wind and solar. While renewable electricity can potentially meet most of society’s energy needs in the future, the intermittent nature of these supplies means that energy storage will be required to ensure a reliable energy supply. Moreover, some sectors of energy demand will be difficult or impossible to electrify (e.g., long distance aviation) and will require alternative solutions.

Hydrogen (H₂) is expected to play an important role in energy storage and the decarbonization of processes that cannot economically be electrified. Currently, global H₂ production is ~100 million metric tons (Mt) per year, and this is expected to grow to >500 Mt/yr by the year 2050. At present, nearly all H₂ is produced from natural gas and coal, which contributes more than 900 Mt/yr of CO₂ to the atmosphere. Future demand for H₂ is projected to be met by a combination of generation from electrolysis of water using renewable electricity (green H₂) and fossil-fuel derived hydrogen coupled with carbon capture (blue H₂). Meeting these projections with current technologies will be both costly and mineral resource intensive.

The existence of natural H₂ on Earth is well documented in many types of geologic environments; however, it is rarely observed above trace levels in association with petroleum. Thus, many geoscientists have concluded that economic accumulations of H₂ in the subsurface are non-existent. The high diffusivity and reactivity of H₂ are cited as limits to its geologic residence time, but this reasoning is not supported by the available evidence. This presentation will explain why natural H₂ has been overlooked as a potential primary energy resource and discuss the potential for natural H₂ to be a low-carbon primary energy resource in the future.