A GIS-based multi-criteria decision analysis for identifying optimal geothermal power plant sites: a case study of the Gulf of Suez, Egypt

The Gulf of Suez is a geologically significant rift basin, characterized by Miocene-age formations that formed through extensional tectonics during the Tertiary period, ultimately facilitating the divergence of the Arabian Peninsula from the African continent. This region has considerable geothermal potential, making it a strategically valuable asset for developing clean, sustainable energy infrastructure. The present study proposes an integrated spatial suitability framework employing Geographic Information Systems (GIS) coupled with Multi-Criteria Decision Analysis (MCDA) to delineate optimal sites for geothermal power plant development within the study area. In the context of escalating global energy demands, geothermal energy, defined as terrestrial heat extracted from the Earth’s crust through deep drilling and surface fluid transport, represents a viable pathway toward energy transition. The analytical framework was constructed from subsurface thermal data derived from 52 hydrocarbon wells, enabling the computation of geothermal gradients at varying depths and heat flow assessments. The Analytic Hierarchy Process (AHP) was applied to nine (geothermal gradient, heat flow, fault density, geology, seismic activity, proximity to the electricity grid, proximity to roads, land use, and slope) spatially explicit criteria encompassing thermal, geological, topographic, environmental, and infrastructural parameters, each assigned relative weights commensurate with its significance. A robust correlation ( R = 0.975) was established between subsurface temperature and depth, yielding a mean geothermal gradient of 48.5 °C/km (R² = 0.9509) and affirming the reliability of the thermal model. The resulting suitability analysis demonstrates that the Gulf of Suez region possesses favorable conditions for the deployment of both Flash Steam and Binary Cycle power plant technologies. Along the eastern coastal corridor, localities including Hammam Faraun, Ras Sudr, and Abu Zenima were identified as suitable for Flash Steam systems at drilling depths of 3,000–4,000 m, corresponding to reservoir temperatures of 140–210 °C, while Binary Cycle systems are applicable at depths of 2,000–3,000 m with temperatures ranging from 100 to 160 °C. On the western coast, sites encompassing Ras Gharib, Ras Shukeir, Jabal al-Zeit, and Jabal Ataqa are technically viable for Flash Steam technology at depths of 3,000–4,000 m and temperatures of 140–210 °C, with supplementary Binary Cycle suitability observed at depths of 2,000–3,000 m and temperatures of 100–180 °C. Zones exclusively suited for Binary Cycle applications include Ayoun Moussa, Wadi Baaba, Wadi Feiran, and Wadi El-Tor to the east, and Zaafarana, Wadi Dara, and Wadi Araba to the west, at depths of 3,000–4,000 m with temperatures ranging between 100 and 160 °C and 100–155 °C, respectively. Northern portions of the study area, characterized by comparatively subdued geothermal gradients, are deemed appropriate for direct-use applications, including space heating, light industrial operations, and residential thermal supply.