Sustainability challenges and opportunities of shallow borehole geothermal systems

Shallow Borehole Geothermal Systems (SBGSs) are gaining recognition as a low-carbon solution for sustainable heating and cooling, yet their widespread adoption remains limited by fragmented assessments and implementation barriers. This study presents a structured, multi-stage review of SBGS sustainability, integrating environmental, economic, social, technical, and policy dimensions. The methodology combines a broad exploratory scan of over 160 publications with a targeted analysis of 31 peer-reviewed articles published between 2010 and 2024, supported by more than 100 references to provide contextual data where direct metrics were unavailable. Litterature applications reveal that SBGSs can reduce CO2 emissions by 65–85 % compared to fossil fuel systems and yield energy savings of 26–50 % through ground source heat pumps. However, cost-effectiveness remains highly site-dependent, with initial investment and drilling expenses posing major barriers, particularly in dense urban areas. Social acceptance, legal clarity, and permitting delays further hinder deployment. To validate and apply the findings, a scenario-based case study of a hypothetical 10 MW community-scale SBGS project was developed. The case study integrates quantified indicators from all five sustainability dimensions and demonstrates the system's potential benefits and trade-offs under real-world constraints. This work offers a holistic and data-informed synthesis of SBGS sustainability and highlights the need for long-term performance monitoring, regulatory harmonization, and deeper engagement with social and economic contexts to support broader adoption and policy alignment across diverse geographical regions.