The role of carbon dioxide in enhancing geothermal energy: A review of current developments and future potential

Abstract

This paper explores the potential of carbon dioxide as a working fluid in geothermal systems, emphasizing its dual role in enhancing energy efficiency and contributing to carbon sequestration. Carbon dioxide -based geothermal systems offer a promising approach to sustainable energy production by combining clean energy generation with environmental benefits. Recent advancements, such as carbon dioxide foam-based stimulation and the integration of enhanced geothermal systems with carbon capture and storage technologies, are reviewed. Field trials, including the GreenLoop™ technology and the Øygarden carbon dioxide storage project, demonstrate significant operational efficiencies. For instance, thermal power extraction in GreenLoop™ systems using supercritical carbon dioxide reached 5 MWth, with minimal surface infrastructure requirements. Additionally, carbon dioxide storage projects like Carbfix have achieved over 95 % mineralization of injected carbon dioxide within two years, highlighting the rapid and permanent storage capabilities. The review identifies key technical challenges, including carbon dioxide leakage prevention, foam stability under high-pressure conditions, and system scalability. Emerging research areas, such as microbial interactions in carbon dioxide sequestration and advanced simulation models, are pivotal for optimizing system performance. Furthermore, geothermal potential in regions like Reykjanes, Iceland, with temperatures exceeding 500 °C at depths of 4500 m, showcases the feasibility of carbon dioxide -based systems in high-temperature environments. This study concludes that carbon dioxide -based geothermal technologies have the potential to significantly advance renewable energy production while mitigating global greenhouse gas emissions. Long-term monitoring, innovative system designs, and collaborative efforts are essential to overcoming current barriers and scaling these technologies for commercial deployment.