How ‘Blue’ Is ‘Green’ Energy?

• Published in: Trends in ecology & evolution (Amsterdam) 2020-03, Vol.35 (3), p.235-244
• Main Authors: Wright, Andrew J., Araújo-Wang, Claryana, Wang, John Y., Ross, Peter S., Tougaard, Jakob, Winkler, Robin, Márquez, Melissa C., Robertson, Frances C., Williams, Kayleigh Fawcett, Reeves, Randall R.
• Format: Article
• Language: English
• Subjects: ecological impacts; marine renewable energy devices; offshore wind farm; Sousa chinensis taiwanensis; Taiwanese white dolphin; tidal turbines
• ISSN: 0169-5347; 1872-8383
• DOI: 10.1016/j.tree.2019.11.002

Often perceived as environmentally benign, ‘green’ renewable energy technologies have ecological costs that are often overlooked, especially those occurring below the waterline. After briefly discussing the impacts of hydropower on freshwater and marine organisms, we focus this review on the impacts of marine renewable energy devices (MREDs) on underwater marine organisms, particularly offshore wind farms and marine energy converters (e.g., tidal turbines). We consider both cumulative impacts and synergistic interactions with other anthropogenic pressures, using offshore wind farms and the Taiwanese white dolphin (Sousa chinensis taiwanensis) as an example. While MREDs undoubtedly can help mitigate climate change, variability in the sensitivity of different species and ecosystems means that rigorous case-by-case assessments are needed to fully comprehend the consequences of MRED use. Global offshore wind capacity has been increasing at 15–30% annually, aided partly by the establishment of the industry in China.There are over 90 tidal energy technology developers globally, with about half focusing on horizontal axis turbines that rotate in a plane perpendicular to the flow of the current.Over 200 companies are pursuing wave energy converter development, most commonly point absorber devices that convert the vertical motion of floats into electricity.Construction noise impacts are relatively well understood, but those from the operation of marine renewable energy devices remain largely unknown. Monitoring at demonstration sites and full commercial projects is needed to address this knowledge gap for future installations.Direct and indirect effects of installations on marine life depend on relative scales and interactions with impacts from other existing industries.