The energy transition needs subsurface geoscience

The switch to a low-carbon economy is heavily reliant on mining, geothermal energy and geological storage. Subsurface geoscientists are critically needed to responsibly source, manage and refine these operations while minimizing environmental and social impacts.

Progress towards the decarbonization of energy systems — the so-called energy transition — requires subsurface geoscience, including disciplines such as geology, geophysics and geoengineering, areas historically linked more closely to the fossil fuel industry. With this newly launched Collection, Nature Reviews Earth & Environment explores the importance of the subsurface in the energy transition, including advances and barriers to implementation, and providing a space to identify and mitigate the associated societal and environmental risks.

For instance, the switch to a low-carbon economy will be material-intensive, requiring the extraction of huge volumes of materials from Earth’s subsurface to build technologies and infrastructure. These materials include critical metals, such as cobalt, lithium, rare Earth elements, aluminium, copper, nickel, lead and zinc. Deposits rich in these critical metals include porphyry copper, ion adsorption-type, iron-oxide apatite, bauxite, placer, and even deep-ocean polymetallic nodules, among others. Detailed understanding of the geology and ore formation mechanisms is necessary to discover and map these deposits. However, production of these materials (from mining to manufacturing) often incurs severe environmental costs and societal impacts, not limited to intensive water use, destruction of ecosystems, mining-related pollution, human exploitation, and mine tailings disasters. As demand for metals increases and mining companies exploit larger and lower-grade deposits, the threats from these impacts will only increase without responsible management.

Geoscientists must urgently apply adaptive management practices to continually refine operations with the goal of environmental protection and disaster risk reduction. For example, applying an integrated life cycle assessment and geometallurgical approach to mining operations can optimize the technical performance and reduce the environmental impact of raw material extraction. But ultimately, recycling materials in a circular economy must always take precedent over the extraction of new resources, and appropriate policies must be put in place to financially incentivize reuse over extraction.

Non-electrical energy sources will also be necessary to provide a diverse array of decarbonized energy options. Geothermal resources have the potential to provide up to 150 GWe of sustainable energy by 2050, which will require increased deployment of engineered geothermal systems and supercritical, low-temperature and offshore geothermal resources. The key to locating, drilling and safely and profitably utilizing geothermal wells lies in understanding the heterogeneous structure of the subsurface and how it controls exploitable fluid reservoirs.

Gigatonne-scale geological storage of green energy (such as hydrogen) will be required at scales of 10s–100s TWh yr^–1 for regions like the UK, USA and EU to enable grid balancing, price arbitrage, and energy security while avoiding energy wastage from curtailment. UHS technologies are the most cost-effective option for large-scale energy storage, and the technical readiness of UHS is nearing commercial viability. Yet, perceived risks around efficiency, affordability and potential conflicts with other technologies are hindering wider implementation. Geoscientists need to demonstrate the flexibility UHS can offer and highlight how it will complement a diverse array of supporting technologies.

Furthermore, limiting anthropogenic warming to 1.5–2 °C requires a reduction in the net flow of CO₂ into the atmosphere, with one of the key emissions reduction technologies being CO₂ capture and storage (CCS) in geological formations (including in porous rocks and through mineral carbonation). Geological storage of CO₂ is already technically and commercially successful at the megatonne scale, but scaling up to the necessary levels of megaton storage by 2050 is limited by a lack of market-based policy support that allows CCS projects to become viable businesses. Politicians and climate policies have relied on promises of CCS and other carbon removal technologies to make their emissions reduction targets seem achievable, but without providing the necessary financial resourcing to fund projects through to commercialization, CCS projects and other urgent emissions reduction efforts get delayed. The primary priority must be the immediate and sustained limitation of current CO₂ emissions by fossil fuel phaseout, supported by financial resourcing of carbon reduction and removal technologies, including geological CCS.

The Collection will be updated continually, with upcoming planned topics including global metal mining, shallow geothermal energy, and geological hydrogen accumulation. We’d be interested to hear from you if you have timely, complementary and important ideas on the theme of this Collection — such as geological energy storage technologies, nuclear waste storage, and related hazard assessment and policy implications — but of course, we can only take on a limited number of proposals. Stay tuned!