Identifying materials in tidal energy technology and their effects to human health, ecosystems, and resources: A life cycle assessment perspective

Tidal energy is an abundant and predictable renewable energy source that represents a promising alternative for reducing greenhouse gas (GHG) emissions. To promote the sustainable development of tidal energy technologies (TETs), Life Cycle Assessment (LCA) is a key method for evaluating the environmental impacts associated with materials and technological processes. Although LCA has been widely applied to other renewable technologies, available data for TETs remain limited and scarce. This research conducts a systematic review (PRISMA protocol) and data mining of LCA studies using the ReCiPe method to identify the main impacts generated by TETs and their materials. The results show significant variability among technologies, with tidal stream turbines exhibiting the highest GHG emissions (69.97 g CO 2 /kWh) and bulb turbines the lowest (3.9 g CO 2 /kWh). Copper affects all LCA categories with the highest negative impacts, followed by steel, which is the most widely used material in turbine manufacturing. Therefore, further research on alternative materials is necessary to replace copper and steel or to reduce their primary use in turbine manufacturing. An apparent positive trend since 2015 was observed in the reported GHG emissions of real hydrokinetic turbine LCA projects; this trend is likely influenced by data gaps in LCA databases and by differences in LCA methodologies. Hence, this research calls on academia to unify LCA methodologies and enhance databases to provide more precise and detailed information on the impacts of traditional and emerging materials used in TETs.