| Title | Offshore Geothermal: The Size of the Prize |
|---|---|
| Authors | Rebecca Bolton, Rob Crossley, Alex Jones, Mark Williams |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Offshore geothermal energy presents a significant yet untapped opportunity for clean, dispatchable power. Building on decades of offshore exploration knowledge, our recent work focuses on quantifying this potential through geoscientific modelling and regional heat flow analysis. Using basin-scale thermal models and integrating offshore heat flow measurements, we identify areas with favorable geothermal gradients and subsurface conditions. Our approach considers key geological and engineering parameters, including sediment thickness, thermal conductivity, temperature-at-depth, and permeability, to delineate zones of technical and economic interest. Several offshore basins, particularly those associated with actively rifting continental crust and young oceanic crust, show potential for high-enthalpy geothermal resources. Thin crust in these regions enables elevated conductive heat fluxes, often exceeding 500 mW/m², bringing high temperatures closer to the seabed. Hydrothermal convection, combined with increased boiling points due to overlying water pressure, can yield temperatures exceeding 350 °C at relatively shallow depths. Seismic imaging plays a critical role, helping to map subsurface structures, identify fluid pathways, and refine thermal regime characterisation, enhancing the ability to pinpoint viable targets. We also explore operational considerations such as drilling technology constraints, regulatory frameworks, and exploration feasibility. These insights have fed directly into the development of a screening tool, designed to support early-stage site comparisons and prioritisation. The size of the prize is substantial. Offshore geothermal could deliver tens of gigawatts of low-carbon, baseload power. Realising this opportunity will require continued research, investment, and cross-sector collaboration, but the potential rewards are too great to ignore. |