Database-Driven Analysis of Energy Geostructures using a Global Dataset: Diffusion, Efficiency, and Environmental Performance

Energy Geostructures (EGs) are multifunctional systems that combine structural support with thermal energy exchange using low-enthalpy geothermal energy. This study presents a comprehensive analysis based on a global database of 972 case studies from 27 countries, primarily in Europe, including real world installations, test sites, and simulations. It focuses on the development and performance of various EG types – particularly energy piles (789 cases), energy walls (79), and energy tunnels (27) – making it the most extensive EG database to date. Geographically, Austria, Switzerland, Germany, and the UK lead in EG adoption, with Italy and France also contributing significantly. The analysis highlights both established technologies and emerging types, such as energy quay walls and barrettes, which show promising potential despite limited representation. The study reveals consistent geometric and design features: energy piles are used in small to medium-scale projects, energy walls offer large, activated surfaces, and tunnels are installed at intermediate depths. Thermal performance is linked to pipe configuration, diameter, spacing, materials, and environmental conditions – most systems are in stratified, moist soils in cool-temperate climates. EGs also offer environmental benefits, notably CO2 emissions reduction, reinforcing their value in sustainable infrastructure and heating and cooling network development.