From April 28 to May 2, 2025, the European Geosciences Union General Assembly (EGU25) brought together thousands of researchers in Vienna to tackle the pressing environmental and technological challenges facing our planet. Our team was proud to contribute to this dialogue within the session “ERE2.5 EDI – Shallow and Deep Geothermal Energy”, held on Monday, April 28th.

This interdisciplinary session welcomed contributions exploring geoscientific and engineering perspectives on geothermal energy—from shallow systems and energy geo-structures to aquifer thermal storage and deep reservoirs. Our three poster presentations highlighted how geothermal energy systems can be made more efficient, accessible, and environmentally sustainable through smart design, urban collaboration, and novel infrastructure integration.

Here’s a recap of what we shared:

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🌍 Environmental Benefits of GSHPs vs. ASHPs Across Building Insulation Levels

Authors: Lazaros Aresti, Grigoris Panayiotou, Bartlomiej Ciapala, Paul Christodoulides

Summary:
We used Life Cycle Analysis via openLCA and the ReCipe method to assess the environmental impact of Ground Source Heat Pumps (GSHPs) compared to Air Source Heat Pumps (ASHPs).
Key findings:

• GSHPs have a clear environmental edge in poorly insulated buildings and colder climates, thanks to higher heating efficiency.
• In well-insulated buildings, ASHPs can be the more sustainable choice.

This highlights the importance of context-specific design in renewable heating and cooling systems, especially under policies like nZEB.

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🌞 Evaluating Shared-Loop GSHP Systems in Cyprus

Authors: Paul Christodoulides, Gregoris Panayiotou, Christiana Filippou, Lazaros Aresti

Summary:
In this work, we explored shared-loop GSHP systems on the Mediterranean island of Cyprus, where high cooling demand and limited urban space make decentralized systems challenging.
Using TRNSYS and GLD, we modeled system capacity, user heating loads, and ground thermal response. Results showed that:

• Shared-loops help reduce infrastructure costs.
• Balancing thermal loads among users remains a challenge, especially in mixed-use or uncoordinated scenarios.

Nevertheless, the scalability and urban fit of shared-loop systems make them promising for future smart city infrastructure.

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🏗️ Energy Geo-Structures in Residential Foundations

Authors: Lazaros Aresti, Georgios Florides, Paul Christodoulides

Summary:
Can retaining walls and foundation slabs become part of the energy system? This study explored the use of Energy Geo-Structures (EGs) in a residential nZEB building in Cyprus.

• COMSOL Multiphysics was used to simulate ground-coupled thermal behavior.
• Results showed variable performance among different foundation elements, with potential for partial thermal loading strategies.

Our findings support EGs as a viable option in space-limited or retrofit scenarios, aligning structural function with sustainable energy goals.

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Looking Ahead

EGU25 was a vibrant platform for exchanging ideas, building collaborations, and advancing geothermal technologies at all scales—from household-level retrofits to regional resource management. Our team is committed to continuing this work through applied research, cross-sector partnerships, and real-world demonstration projects.

If you’re working in geothermal energy, sustainable buildings, or district heating/cooling networks, we’d love to connect and explore synergies. Let’s keep the conversation going.

📩 For collaborations or more information on our work, feel free to reach out.