The UK geological storage resource is amongst the largest in Europe and is critical to the country achieving net zero by 2030. Funding has been awarded by the Engineering and Physical Sciences Research Council for a two-year project, ‘Maximising the UK geological storage resource’ or MaxStoreUK. The project is led by BGS with collaborators from the Industrial Decarbonisation Research and Innovation Centre (IDRIC) and researchers at Heriot-Watt University and The University of Manchester. The findings will inform investment decisions and policy development and maximise the use of the subsurface in the UK to reach net zero.

MaxStoreUK will build on subsurface hydrogen and carbon storage research investigations previously completed as part of the IDRIC research programme. The objectives of the new project are to:

• share tailored information on regional UK geological carbon dioxide (CO₂)and hydrogen storage opportunities with industry clusters and other key stakeholders
• present a UK hydrogen storage briefing to enable cross-sector policy collaboration
• increase understanding of CO₂ storage in a UK Central North Sea frontier area of extensive strata with multiple prospective storage sites
• advise on solutions to specific risks for UK hydrogen storage with operators and regulators that are addressed by our modelling and experimental data

We are delighted to have been awarded funding and begin the two-year project. We will build on existing engagement with stakeholders to unlock the full potential of the UK subsurface resource to meet the UK net zero targets and drive economic growth.

Dr Maxine Akhurst, principal geologist at BGS and project leader.

This project represents an exciting initiative to build further on the significant impact of IDRIC five-year multi-disciplinary research programme and our strong partnership with BGS. We look forward to continuing this valued collaboration, advancing progress and sharing knowledge in geological storage, which will accelerate the journey of our industrial heartlands towards a sustainable low-carbon future

Prof Mercedes Maroto-Valer, IDRIC Director.

Knapton H2 Storage is a consortium led by gas distributor Northern Gas Networks and partnered with BGS, Centrica Energy Storage, Third Energy Onshore and the University of Edinburgh. The consortium has been awarded ‘Discovery’ funding by Ofgem Strategic Innovation Fund (SIF) to undertake a new study to evaluate geological storage potential in the Knapton area, North Yorkshire. The Ofgem SIF funding is designed to drive innovation in energy networks as part of the ‘Revenue = incentives + innovation + outputs’ (RIIO-2) price control for gas and electricity networks.

Energy storage and backup power will become increasingly important as the UK increases the amount of renewable energy supplying electricity. This study is the first of its kind in the region and will undertake a feasibility assessment of the area geology to host energy storage technologies, allowing for the decarbonisation of adjacent gas-fired peaking power plants (those that only run when there is high demand) such as that at Knapton.

The Knapton, Vale of Pickering and North Yorkshire area hosts a fantastic diversity of geology that may be used for storing hydrogen. The region contains numerous depleted hydrocarbon reservoirs that may have potential for repurposing, alongside other porous rock aquifers, salt deposits and rocks that may support lined rock shafts. The study will generate an understanding of what is possible for hydrogen storage at scale in the local area, supporting the area local economy and the UK energy security.

The natural geology of the area around Knapton will play an important role in supporting the use of hydrogen in the region. Storing hydrogen gives flexibility to the energy system, allowing excess hydrogen to be stored for use during periods when demand exceeds supply. In this project, BGS will build on its extensive laboratory and mapping programmes to help identify areas of the underground geology that may represent future exploration targets for hydrogen storage in bedrock.

Edward Hough, research lead in underground energy storage at BGS.

As more renewables come online, energy storage will be critical to UK energy security and to clean power. Understanding the full potential for storing hydrogen at scale through Knapton H2 Storage will give us key insights into how we can deliver technologies to provide clean resilience on the days where the sun doesn’t shine and the wind doesn’t blow.

Keith Owen, head of energy futures at Northern Gas Networks.

Centrica Knapton site is being redeveloped as a multi-vector energy hub for solar generation, green hydrogen production and battery storage. But without dedicated hydrogen storage, its ability to support seasonal balancing, system resilience and flexible dispatch (H2P) will be fundamentally constrained. This project will advance integration readiness at Knapton and commercial readiness of storage technologies, whilst unlocking a replicable model for medium- to large-scale hydrogen storage to support H2P roll-out and network resilience.

Chris McClane, energy transition interface manager at Centrica.

51ÁÔÆæ briefing notes aim to communicate the latest scientific research in a succinct format to policymakers, industry and the general public. The latest note, ‘Underground hydrogen storage: insights and actions to support the energy transition’, outlines the current state of play in terms of hydrogen storage research and development, and names underground hydrogen storage as an emerging technology that will be crucial to support the UK’s transition to net zero.

As renewable energy sources like wind and solar increase their market share, the need for reliable, long-duration energy storage solutions become increasingly important for enabling a balance between supply and demand. Hydrogen, produced from renewable sources, can act as an effective energy carrier to store excess power as well as an alternative fuel to decarbonise hard-to-abate sectors like shipping and heavy industry.

Various underground storage technologies, such as salt caverns, lined rock caverns and depleted hydrocarbon fields, provide scalable and long-duration hydrogen storage options. Although they require significant initial investment and specific geological conditions, these technologies offer the potential for large-scale, long-duration storage capacities.

Currently, the UK energy storage system holds some of the lowest levels of gas storage in Europe, at 12 days average. Estimates for the hydrogen storage required by net zero in 2050 are up to five times greater than the current UK gas storage capacity, but there are still considerable knowledge gaps in how and where such large-scale storage can be achieved.

The briefing note provides key recommendations in order to close these knowledge gaps:

• implement more demonstration projects to build in situ technical capability, address market barriers and promote wider hydrogen adoption
• integrate hydrogen storage into the UK energy strategy through comprehensive planning and supportive regulatory frameworks
• invest in research and development to rapidly expand knowledge in the hydrogen storage technologies essential for meeting clean energy targets

The successful integration of hydrogen storage is key to stabilising the grid and ensuring a reliable hydrogen supply to meet the UK climate targets. However, while technology holds great promise, significant investment, research and development are required to address technical and regulatory challenges and the success of large-scale deployment depends on overcoming geological, regulatory and commercial challenges.

Dr Tim Armitage, BGS Geoscientist and author of the briefing note.

More information on BGS energy storage research can be found on the website.

Following a successful bid, the East Midlands Storage (EMStor) consortium has been awarded from Ofgem, building on work delivered during the earlier discovery phase. In this alpha phase, the consortium includes the original partners Cadent (lead partner), BGS, Edinburgh University and Star Energy Group, now joined by Centrica Storage, Uniper and National Gas.

The discovery phase assessed a range of different geological storage options in the East Midlands. Storage in repurposed onshore hydrocarbon fields was identified as the leading hydrogen storage option. The discovery phase also showed that hydrogen storage is a vital component to any future hydrogen system in the East Midlands to ensure energy security, resilience and affordability. The development of hydrogen storage in repurposed hydrocarbon fields must be done in tandem with the development of hydrogen production, such as at Uniper Ratcliffe-on-Soar power station and Cadent hydrogen network.

The EMStor alpha phase will further develop knowledge by advancing understanding of:

• decisions on next steps and future phasing

• public perception of hydrogen storage

• technical aspects of underground hydrogen storage, such as geological feasibility and well-integrity assessment

• approaches to regulatory, permitting and planning for potential demonstration

A dissemination event will be held in spring 2025 to detail findings and outline next steps.

We’re delighted to have secured this funding so that we can continue to break new ground in onshore hydrogen storage. The ultimate aim is to increase the technology readiness level of storage of hydrogen in disused hydrocarbon fields by demonstrating that it works, by 2030. Local geological stores of hydrogen in the East Midlands will allow a much more rapid deployment of our hydrogen pipeline network and mean that more customers can switch away from natural gas and decarbonise more quickly.

Sally Brewis, head of regional development, Cadent.

51ÁÔÆæ will conduct essential tests on how the hydrogen may behave in the subsurface, including how hydrogen interacts with the environment and reservoir rock, so that we can more accurately predict, measure and monitor underground hydrogen storage.

51ÁÔÆæ is excited to be working with our EMStor partners on developing underground hydrogen storage in the East Midlands. Underground hydrogen storage will help provide energy security and ensure the supply of renewable and low-carbon energy to local businesses throughout the energy transition.

Through Project EMStor, we hope that to raise the technology readiness level and prove the scientific case for underground hydrogen storage in porous rocks.

Edward Hough, research lead in underground energy storage, BGS.

East Midlands Storage (EMstor), a consortium led by Cadent and partnered with BGS, Star Energy Group, Net Zero Strategy and the University of Edinburgh, has been awarded discovery funding by Ofgem Strategic Innovation Fund to undertake a new study to evaluate geological storage potential in the East Midlands.

The EMstor study is the first of its kind in the region. It will undertake a feasibility assessment of the East Midlands’ geology to evaluate its potential to host storage technologies, allowing expansion of Cadent proposed 100 per cent hydrogen pipeline.

The East Midlands has numerous depleted oil reservoirs, which may have potential to store hydrogen. The study will characterise the potential geological reservoir to establish if it is suitable for hydrogen storage at scale in the local area.

It such exciting news that this funding bid for our EMstor study has been a success. This evaluation could potentially lay the foundations for a hydrogen storage demonstration project in the area through subsequent funding rounds, which could be game changing for the hydrogen economy in the region and will enable a more rapid decarbonisation of industry and power generators that want to switch to hydrogen. Consideration of using disused oil reservoirs for storing hydrogen is a new frontier for the industry and could have far-reaching benefits if it shown to be possible through this work.

Sally Brewis, head of regional development at Cadent.

The natural geology of the East Midlands will play an important role in supporting the use of hydrogen in the region. Storing hydrogen gives flexibility to the energy system, allowing excess hydrogen to be stored for use during periods when demand exceeds supply. In this project, BGS will build on its extensive laboratory and mapping programmes to help identify areas of the underground geology that may represent future exploration targets for hydrogen storage in bedrock.

Edward Hough, research lead in underground energy storage at BGS.

The UK Government recently pledged to cut carbon emissions by 78 per cent by 2035 as part of a commitment for the country to be net zero in terms of carbon emissions by 2050 (with Scotland aiming to reach this target five years earlier in 2045).

The UK has made significant progress already. The share of electricity generated by renewables (principally wind and solar) now stands at 43 per cent, a threefold increase from a decade ago, and coal typically provides less than two per cent of electricity generation: in 2020 there were over 5000 coal-free hours of generation. There is an argument, however, that the hard work starts now, with the difficult-to-decarbonise areas of industry, domestic heating and transport to be addressed. These users of energy will require major changes to their ‘business as usual’ and new technologies that utilise the natural underground asset to store energy will be required to support further decarbonisation efforts.

A well-known issue with some renewable energy sources, including tidal, wind and solar, is that they are intermittent: turbines don’t turn on calm days and solar farms need the sun to generate electricity. Additionally, excess energy produced can be extremely difficult to store for later use. Geology can provide novel ways to store this energy, helping to increase the share of renewable energy sources in the energy market.

Cavern storage

The UK is fortunate in that there are naturally occurring beds of halite (rock-salt) — for example, under parts of Cheshire, Teesside, Lancashire and in the North and Irish seas.

Halite is an extremely useful substance. It is soluble and has an extremely low permeability that can contain gas. Large cavities can be developed in beds of halite with an established technique known as solution mining, with the resultant voids used having been used for the storage of natural gas since the 1960s and, on a much smaller scale, the storage of hydrogen since 1972.

Solution-mined caverns can be used to store excess wind and solar energy through the compression of air in them; this is known as compressed air energy storage (CAES). Energy can be stored in this way for longer periods than in traditional batteries. The technology for CAES has been demonstrated at several locations worldwide and we think the geology is suitable in several areas of the UK to support schemes in the UK. When air is compressed, the heat of compression can be stored and used later to heat the air that is released from the cavern to drive turbines to generate electricity.

A particular research area that BGS is working on is the integrity of halite, where gas in caverns may be filled and emptied at faster rates and with greater pressure variations than current natural gas storage operations. This would allow for increased volumes of hydrogen to be stored and used. In particular, the properties of bedded halites, where mudstone and other insoluble material is interbedded with the halite successions, are being investigated.

Hydrogen

Hydrogen has the potential to be manufactured without a carbon footprint from a wide range of materials such as natural gas, biomass and some types of waste. Whether produced by electrolysis or steam methane reformation (where the associated carbon dioxide that is produced can be captured and stored), hydrogen can be blended into the existing natural gas network for domestic use, electricity generation, or as a fuel cell in cars and lorries.

The current hydrogen storage option in the subsurface is solution-mined caverns. However, this is limited to regions with halite deposits of suitable depths and thicknesses within which caverns can be developed. As part of the Industrial Decarbonisation Research and Innovation Centre (IDRIC), BGS is researching whether hydrogen storage in porous rocks, such as sandstone, could be viable and under what conditions the natural geology may present a barrier to this type of storage. If storage in porous rocks is a possibility, without loss of quality or amount of the stored gas, then many more regions in the UK without currently obvious subsurface storage options could become potential sites for the hydrogen storage of bedrock, including London, South Wales and central Scotland.

Thermal storage

Porous rocks also have the potential to act as a store for heat via so-called aquifer thermal energy storage (ATES). Such thermal stores, where heat is stored in pore fluids, have the potential to capture excess heat produced from industrial processes or homes, which can then be used at locations or times where and when heat is required.

The efficiency of ATES schemes is influenced by the composition of bedrock, structural elements and properties of confining layers. These aspects will be researched by BGS scientists at the UK Geoenergy Observatory in Cheshire as part of an EPSRC-funded research programme.

About the author

The scale of carbon reduction, required for net zero, will require the implementation of swift and large-scale changes to how we generate and transport energy. One route to broad decarbonisation is to increase the amount of renewable energy that generates clean electricity. This pathway to clean energy will also require a transition from natural gas to hydrogen and to store heat/cool in rocks.

New collaborative research by BGS highlights the scientific challenges of hydrogen storage in porous rocks for safe and efficient large-scale energy storage. sets out the key global challenges and knowledge gaps in hydrogen storage. The study also highlights the urgent need for multidisciplinary research to address these gaps.

As part of the UK Government , £100 million will be provided for energy storage and flexibility innovation challenges. The expectations for energy storage are high, but large-scale underground hydrogen storage in porous rocks remains largely untested. For comparison, similar research into carbon dioxide storage capacity estimation has been ongoing since the 1990s, but carbon capture and storage (CCS) has yet to reach commercial scale in the UK.

To accelerate hydrogen supply on the scale required for net zero, it must be stored underground. BGS is addressing some of the technical challenges of storing hydrogen in porous rock formations by investing in an energy storage research programme.

Michelle Bentham, head of BGS Partnerships and Innovation

Background: underground energy storage

Energy can be stored in the subsurface at many locations in the UK, including offshore, in the following ways: :

• solution-mined caverns developed in halite (rock-salt) can be used to store:
  • primary energy in the form of methane (a lower-carbon fossil fuel)
  • hydrogen (which can supplement or replace existing natural gas as a feedstock to industry, or be used for domestic heating) can be produced by low-carbon/carbon-neutral methods
  • compressed air, capturing and storing energy from wind and solar plants
• natural gas and possibly hydrogen can be stored in depleted hydrocarbon reservoirs
• heat/cool can be stored in aquifers and re-used as seasonal demand fluctuates throughout the year

Targeted BGS research programmes

To support greater uptake of these energy storage technologies, BGS is undertaking experiments designed to replicate repeated cycling of storage caverns to quantify deformation of bedded halite and to examine the response of sandstone properties to the presence of hydrogen. We will also use a borehole array, which has been specially designed to quantify the thermal response of different depositional facies of Permo-Triassic sandstone, at the to understand the thermal response of the sandstone and determine its suitability as a subsurface thermal store. Collectively, this work will:

• inform the development and behaviour of solution-mined caverns to act as storage facilities for methane, hydrogen and compressed air
• give a better understanding of the behaviour of hydrogen in the subsurface, especially changes to microbial populations and reservoir performance
• help us to quantify the thermal response and capacity of the Sherwood Sandstone, which is a major potential subsurface heat store that underlies many parts of the UK

The resulting work will indicate the potential and scale for subsurface energy storage across the UK and give important information to those interested in implementing new schemes to support the transition to a lower carbon world.

Addressing the UN Sustainable Development Goals (SDGs)

Project partners

This was written as part of a GEO.8 collaboration.

• 51ÁÔÆæ
• (GFZ), Germany
• The Polish Geoscientific Network, Poland
• (IPGP), France
• (formerly Institute of Earth Sciences Jaume Almera), Spain
• (INGV), Italy
• (ETH Zürich), Switzerland
• (UU), Netherlands

Contact

Contact Michelle Bentham or visit Energy storage for more information.