India’s pledge to achieve net-zero emissions by 2070, alongside rapidly rising energy demand and large-scale renewable integration, makes long-duration and seasonal energy storage indispensable. While electrochemical batteries and surface pumped hydro systems remain important, their scalability, duration limits, and land footprint, constrain their ability to support a deeply decarbonised energy system. In contrast, Underground Energy Storage (UES), including geological storage of hydrogen, natural gas, compressed air, and carbon dioxide, offers unparalleled capacity, duration, and strategic flexibility. Critically, UES is not a conventional infrastructure problem. It is a geoscientific systems challenge, requiring reliable reservoir containment over decades, cap-rock integrity under cyclic pressure, fault stability, groundwater protection, and continuous monitoring. India’s geological endowment, mature sedimentary basins, extensive basalt provinces, and the abandoned mining infrastructure, could provide a strong foundation, but only if developed through rigorous geophysical science and sustained research investment.
The Government of India’s Union Budget allocation of ₹20,000 crore over five years for Carbon Capture, Utilisation and Storage (CCUS), represents a pivotal recognition of the role of the subsurface in India’s climate and energy strategy. Geological CO₂ storage underpins industrial decarbonisation, but its significance extends well beyond emissions reduction. CCUS establishes the technical, institutional, and regulatory backbone, necessary for all forms of underground energy storage. The scientific principles governing CO₂ storage in geological formations e.g., reservoir characterisation, seal integrity, injection well design, pressure management, plume tracking, and long-term risk mitigation, are fundamentally the same for hydrogen, synthetic gas, or compressed air storage. National assessments indicate that India’s geological CO₂ storage capacity spans across deep saline aquifers, depleted hydrocarbon reservoirs, and continental flood basalts, that would amount to several hundred million tonnes. These formations, subject to appropriate geochemical and geo-mechanical evaluation, can also host other energy vectors, reinforcing the need for an integrated subsurface storage framework rather than siloed projects. Moreover, CCUS deployment accelerates shared infrastructure development like pipelines, compressors, injection wells, monitoring networks, and crucially, regulatory processes for underground injection and long-term liability. International experience demonstrates that these frameworks are largely technology-agnostic and transferable across different gases. India’s emerging CCUS roadmap, therefore, offers a timely opportunity to mainstream underground energy storage within national energy planning.
India’s sedimentary basins contain depleted oil and gas fields and deep saline formations suitable in principle for underground energy storage. Depleted reservoirs are particularly attractive due to their proven trapping mechanisms, known pressure histories, and existing subsurface datasets. In comparison, hydrogen storage, however, introduces additional geoscientific complexity. Hydrogen’s small molecular size, high diffusivity, and potential for geochemical and microbial reactions, demand exceptionally robust cap rocks, careful pressure cycling, and high-resolution fault characterization. Basin-scale studies suggest large theoretical storage potential, but safe deployment hinges on advanced subsurface imaging, rock physics analysis, reactive transport modelling and precise monitoring. Mechanical storage concepts such as, underground pumped hydro and gravity-based systems, further expand India’s UES portfolio. These options reduce surface land conflicts, but rely heavily on geophysical and geotechnical assessment of rock-mass stability, seepage pathways, and long-term deformation behaviour.
{{/usCountry}}India’s sedimentary basins contain depleted oil and gas fields and deep saline formations suitable in principle for underground energy storage. Depleted reservoirs are particularly attractive due to their proven trapping mechanisms, known pressure histories, and existing subsurface datasets. In comparison, hydrogen storage, however, introduces additional geoscientific complexity. Hydrogen’s small molecular size, high diffusivity, and potential for geochemical and microbial reactions, demand exceptionally robust cap rocks, careful pressure cycling, and high-resolution fault characterization. Basin-scale studies suggest large theoretical storage potential, but safe deployment hinges on advanced subsurface imaging, rock physics analysis, reactive transport modelling and precise monitoring. Mechanical storage concepts such as, underground pumped hydro and gravity-based systems, further expand India’s UES portfolio. These options reduce surface land conflicts, but rely heavily on geophysical and geotechnical assessment of rock-mass stability, seepage pathways, and long-term deformation behaviour.
{{/usCountry}}The success of underground energy storage in India would depend highly on the capabilities of the geophysical community across academia, national laboratories, industry, and professional bodies such as the Indian Geophysical Union (IGU). Geophysicists have a decisive role in:
- Basin-scale screening and site selection, using seismic, gravity, magnetic, and other geophysical data for integrated basin modelling to rank candidate formations.
- Reservoir, basement, overburden and seal characterisation, including assessment of heterogeneity, fracture networks, and cap-rock integrity in entire storage complex through advanced imaging techniques and rock physics.
- Monitoring, verification and risk mitigation, employing time-lapse geophysical data, micro-seismicity, and surface deformation measurements.
- Induced seismicity and geomechanics, defining safe operating pressure envelopes and informing regulatory thresholds.
- Integrated modelling and uncertainty analysis, combining geophysical, geological, geochemical, and engineering datasets.
Without sustained leadership from the geophysical community, UES projects risk being under-characterised, over-engineered, or socially contested.
The ultimate impact of underground energy storage should not depend on imported solutions, but on indigenous innovations and sustained research. Experts have argued that India’s industrial ecosystem has too often prioritised importing deep technology over building it, stunting domestic R&D capability. A cautionary example cited was shelving of lithium-battery initiatives by a major Indian firm due to unavailable foreign technology, while a small Finland-US start up, successfully demonstrated solid-state batteries through close academia-industry collaboration and patient investment.
UES research will demand the same ingredients: Long-horizon funding, tolerance for early failure, and deep integration between universities, national laboratories, and industry. Research on injected gas (hydrogen)-rock interactions, cap-rock integrity, multiphase flow, and monitoring technologies will inevitably encounter setbacks at laboratory or pilot scale, but these must be treated as learning milestones, not failures. India must cultivate the belief that real research can happen here, by us.
Academia should be central to building India’s UES capability. Earth scientists and engineers must lead curriculum development and research programs, covering subsurface energy storage, reservoir simulation, geochemical monitoring, induced seismicity, and risk assessment. Recent Indian experience underscores this need. The NTPC-IIT Bombay CO₂ storage initiative, involving India’s first CO₂ injection test well, required detailed mapping of coal-bed reservoirs, high-pressure well design, seismic monitoring, and stress-testing of the injection protocols. Experts associated with the project, emphasise indigenous technology development, careful monitoring of underground conditions, injection pressures, well integrity, and seismic response are essential for success of such a project. It is required to have a national storage atlas and structured feasibility and risk assessments, which can provide a blueprint for future UES initiatives in India. As a first step extending such collaborations by linking NTPC, GAIL, ONGC, Oil India, Coal India and other public-sector entities with universities, national laboratories, and consulting firms with strong technical and managerial capabilities, will be vital for building both technical expertise and managerial capacity in underground storage.
Regulation must evolve in parallel with technology. Clear, transparent rules for siting, permitting, monitoring, and long-term liability are essential to avoid project delays and public opposition. Experience from CCUS globally, shows that uncertainty in permitting and liability, can stall even well-designed projects. India’s CCUS roadmap and emerging regulatory frameworks, should explicitly accommodate multiple gases and storage modes. Therefore, geoscientific survey agencies, groundwater authorities, mining regulators and other stakeholders, must be engaged early. Geoscientists must be integral to these discussions, ensuring that geohazard risks like seismicity, aquifer connectivity, and material compatibility are addressed proactively rather than retrofitted.
Underground energy storage is a scientific and strategic imperative for India’s clean-energy future. It directly links climate mitigation with energy security. Realising this potential, however, requires far more than hardware deployment.
It demands sustained investment in subsurface R&D, geophysical capacity-building, and regulatory frameworks grounded in Indian geology. The geophysical community has a pivotal role to play in mapping storage resources, quantifying uncertainty, monitoring performance, and shaping evidence-based regulation. By leading multidisciplinary efforts across science, industry, and policy, Indian geoscience can ensure that energy is stored where it belongs, “underground”, and that India’s energy transition is secure, resilient, and self-reliant.
This article is authored by Pradeep Singhvi, executive director, Energy and Climate Practice, Grant Thornton Bharat LLP and Nimisha Vedanti, chief scientist, CSIR, National Geophysical Research Institute.