Integrated Methodology for Distributed Geothermal Co-Heat and -Power Production and Its Application – A Case Study from the Pannonian Basin

Abstract

Geothermal energy represents a reliable and low-carbon resource with significant potential for both heat and electricity generation, particularly in regions characterized by medium-temperature reservoirs such as the Pannonian Basin. However, the efficient utilization of these resources requires an integrated approach that simultaneously considers subsurface geological conditions and surface-level constraints. This study presents a comprehensive methodology for the first-order evaluation of geothermal resources for combined heat and power production. The approach integrates geological risk assessment, based on Common Risk Segment (CRS) and Composite Common Risk Segment (CCRS) mapping, with a GIS-based multi-criteria analysis of environmental, technical, and socio-economic factors. The methodology is applied to a case study in southwestern Hungary (Bóly region), where potential locations for new geothermal doublets are identified and evaluated. Preliminary reservoir simulations indicate that the selected doublets can provide up to 4.2 MW_th thermal capacity over several decades. The integration of geothermal heat into district heating systems, combined with electricity generation using Organic Rankine Cycle (ORC) technology, enables efficient cascading utilization of the resource. Under representative conditions, the system can supply a substantial share of local heat demand while producing several GWh of electricity annually. Another case study of an existing well near Szarvas (southeastern Hungary) was also presented. The results demonstrate that medium-temperature geothermal resources can support decentralized energy systems and contribute to improved energy security, resource efficiency, and decarbonization.