Managing subsurface energy as a unified energy resource for the energy transition: a review

The global energy transition requires the subsurface to be managed as a multifunctional geological platform rather than only as a source of hydrocarbons. This review examines how oil and gas, geothermal energy, underground hydrogen storage (UHS), compressed air energy storage (CAES), underground thermal energy storage (UTES) and geological carbon dioxide (CO₂) sequestration can support the transition together. Drawing on 107 sources, it (i) characterizes the energy contributions, storage capacities and transition roles of each system; (ii) compares the systems on technical, economic and environmental criteria using sourced numerical ranges; (iii) synthesizes six shared challenges, reservoir characterization, drilling complexity, wellbore and cement integrity, thermal stress, flow assurance and induced seismicity, that favor cross-sector knowledge transfer; and (iv) examines integration pathways, infrastructure repurposing, regulation and investment, together with the limits of integration, including the permanence of CO₂ storage, irreversible formation alteration and induced seismicity. The review concludes that petroleum engineering knowledge is an underused asset for low-carbon subsurface applications, but that genuine multi-use of a single formation is more constrained than technology transfer or infrastructure reuse.