| Title | Shallow geothermal energy as an enabler of system flexibility: comparative modelling of 4GDHC and 5GDHC networks in the Catalan Pyrenees within the FlexGeo project |
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| Authors | Jordi García-Céspedes, Hèloïse Chapelle, Ignasi Herms, Guilllem Piris, Georgina Arnó, Víctor Camps, Montse Colomer, Sandra Armengol, José Juan de Felipe |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | Decarbonising heating and cooling systems in remote mountain regions presents both challenges and opportunities. Accessibility in such regions is often limited, both for the transport of goods and for the deployment of energy vectors such as electricity and piped natural gas. As a result, the adoption of local renewable energy sources is further encouraged, not only for decarbonisation purposes but also to enhance energy autonomy and system resilience. These aspects converge in the case study presented in this work, located in Vielha (Catalan Pyrenees, north-east Spain). Within the EU-funded FlexGeo project, a comparative study was conducted to assess two alternative district energy configurations based on shallow geothermal energy: a one-pipe fifth-generation district heating and cooling (5GDHC) network, and a four-pipe fourth-generation (4GDHC) network. Both configurations were dynamically modelled in OpenModelica using open-source libraries, and considered the potential integration of solar photovoltaic systems and locally available biomass, along with a borehole thermal energy storage (BTES) system. The models were fed with hydrogeological data obtained through on-site fieldwork and with demand data based on the actual energy use of several public buildings. The results revealed trade-offs in terms of simplicity, modularity, energy efficiency, and integration potential. These findings provide valuable insights for energy planning in similarly constrained rural and alpine contexts and highlight shallow geothermal energy as a key enabler of flexibility in future energy systems. |