Underground hydrogen storage

The Challenge

We are in a global race to decarbonise, a process in which hydrogen value chains will play a significant role. Australia is well positioned to be an international leader in both hydrogen exports and industry decarbonisation; however, a globally competitive and sustainable hydrogen industry requires safe and affordable large-scale hydrogen storage.

Underground hydrogen storage (UHS) in salt caverns and porous rocks provide such a solution. Underground hydrogen storage in depleted oil and gas reservoirs offers the dual benefit of repurposing existing geological structures and surface facilities while advancing sustainable energy storage in the range of tens to hundreds of TWh. However, to date, no commercial projects exist for UHS in porous rock worldwide. Currently the Technology Readiness Level (TRL) for UHS in porous rock is only 5 for hydrogen-natural gas blends (10-20%), whereas for pure hydrogen storage in depleted gas reservoirs the TRL is only 3 to 4.

The Solution

To improve the TRL for UHS, hence facilitating hydrogen value chain development in Australia, the Future Energy Exports CRC working with Curtin University and Beach Energy, have developed a UHS technical roadmap and associated techno-economic analysis. This includes unique experimental assessment protocols of the integrity of the required caprock through fracture characterisation and associated hydrogen-conditioned rock mechanics experiments. Energy network modelling is also under development to enable integration of UHS in existing energy networks in South Australia.

Outcomes

The assembled team have achieved the following outcomes to date:

  1. Development of a technical screening tool and risk assessment matrix, which enables assessment of H2 conversion and contamination, storage integrity, storage performance and system economics. This tool can be used to assist industry with evaluation of the potential and technical viability of hydrogen storage in their assets.
  2. A technical report describing the screening and risk assessment tool, including the identification of controlling factors in underground hydrogen storage, which can be used to identify available options and the potential technical, economic, commercial, and environmental risks of implementation.
  3. Assessment of six depleted gas fields in the vicinity of the Katnook Gas Processing Facility in South Australia using the screening tool, and selection of potential depleted hydrocarbon reservoirs for UHS feasibility studies.
  4. Completed a techno-economic analysis of this hydrogen storage project including estimated capital and operational expenditures for the lifetime of the project.

Impact

Building on the results of this first project, the research team has expanded to include The University of Western Australia, Department of Department of Energy, Mines, Industry Regulation and Safety, WA, and BP-Australia. This revised team is implementing the technical screening tool/risk assessment matrix to identify the preferred depleted gas reservoirs for underground hydrogen storage in the Perth Basin, WA. The team are investigating various permutations regards the inclusion of UHS in a future hydrogen export and domestic market in both the Perth basin and in Western Victoria. Accompanying experimental work are focussed on hydrogen-conditioned rock mechanics and quantifying hydrogen entrapment and hence the risk of loss due to potential aquifer invasion during hydrogen storage cycling.

Next Steps

The Technical Readiness Level (TRL) of UHS technology is improving thanks to global research efforts and associated strategic partnerships. For example, Europe is actively developing a first of its kind UHS solution (EUH2STARS, led by RAG Austria), helping pave the way for a decarbonized European economy. Building on the results of the FEnEx CRC projects (21.RP2.0091, 23.RP2.0176, and 23.RP2.0193), coupled with learnings from EUH2STARS, the FEnEx CRC team will continue to engage with stakeholders and partners across Australia to establish a consortium equivalent to EUH2STARS with the aim of demonstrating UHS as part of the future Australian energy economy.