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 CO 2 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. • SBGSs success requires integrated technical, environmental, social, and policy planning. • SBGSs cut CO 2 emissions and reduce energy use significantly, with hybrid systems offering additional efficiency gains. • Long-term gains offset high costs and adoption needs awareness and accessibility. • Material innovation, system design, and policy support are key to SBGS expansion.