Deep geothermal energy extraction, a review on environmental hotspots with focus on geo-technical site conditions. (July 2022)

• Record Type: Journal Article
• Authors: Gkousis, Spiros; Welkenhuysen, Kris; Compernolle, Tine
• Is Part Of: Renewable & sustainable energy reviews. Volume 162(2022)
• Publication Date: 2022-07
• Subjects: Geothermal energy -- Life cycle analysis -- Environmental assessment -- Environmental impacts -- Renewable energy -- Review -- LCA; GHG Greenhouse gases -- RES Renewable energy sources -- CF Capacity factor -- CHP Combined heat and power -- LCA Life cycle analysis -- GW Global warming -- LCI Life cycle inventory -- AC Acidification -- FWEC Freshwater ecotoxicity -- CEDf Cumulative energy demand -- fossil sources GWP -- Global warming potential EU -- European Union HT (HTc/HTnc) -- Human toxicity (cancer/non-cancer effects) AD -- Abiotic resources depletion CED -- Cumulative energy demand EP -- Eutrophication WC -- Water consumption LCIA -- Life cycle impact assessment NCG -- Non condensable gases FU -- Functional unit EGS -- Enhanced geothermal system CEDnr -- Cumulative energy demand non-renewable sources -- LCC Life cycle costing; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.rser.2022.112430
• Languages: English
• ISSNs: 1364-0321

Abstract

Abstract: Knowledge about the environmental impacts of geothermal energy is important for understanding the role this technology could play in the transition towards sustainable energy production systems. In this study 30 life cycle assessment (LCA) studies on geothermal energy plants were reviewed, focusing on the major environmental hotspots and the cause-effect relationships between the geo-technical parameters and these environmental impacts. The variability in the reported environmental impacts is explained, and a more transparent picture of the geological, design and technical factors causing these impacts is provided by triangularly evaluating the reported results based on the plant's geo-technical characteristics (such as, well depth and geofluid temperature), the life cycle inventory, and the hotspot analysis results. The study focuses on six impact indicators that have been identified as high priority for geothermal energy by the GEOENVI project, as well as the water consumption impact. The results indicate that the impacts vary in magnitude and across different life cycle phases. Apart from the type of energy conversion technology used, differences in the geological and design parameters also introduce large variability in the impact results reported in the literature. Furthermore, all the reviewed LCAs adopt a static approach. Therefore, we present a research agenda that highlights the need to perform dynamic LCAs on geothermal energy exploitation plants to consider the changing context in which these technologies are operating. Highlights: Environmental impacts of geothermal energy extraction vary strongly. Factors determining the impacts vary for different energy conversion technologies. Site-specific geo-technical parameters drive the environmental impacts. Dynamic assessment is required to accurately estimate impacts in time.