Abstract
Offshore wind is a key part of the U.S. clean energy transition, given the powerful winds off our coasts and their ability to generate power when solar sources are offline. Offshore wind will also play an important role in renewable energy portfolios around the world, with several countries in Europe and Asia making significant investments in the technology.
Wind energy is most abundant in areas with water depths greater than 60 meters; this will require floating offshore wind systems to use large cables to anchor to the seabed, as opposed to fixed foundations. These anchoring cables create concerns about the entanglement of marine life, like large whales and sea turtles.
While there have been no documented cases of marine life entanglement in floating offshore wind systems to date, the entanglement risks posed by industrial activities using similar infrastructure suggest that the same risks will apply to floating offshore wind. We have seen marine life entangled in other fixed lines and cables, causing injury and death. Moreover, lost and abandoned fishing gear and other types of ocean debris can get snagged on the ropes and cables used to anchor and stabilize floating offshore wind systems, creating additional entanglement risks. For some protected species— like the endangered North Atlantic right whale or Southern Resident orca—entanglement impacts could have negative consequences for the health of a population. It is therefore essential that all floating offshore wind developments include proactive measures to reduce entanglement risk and protect marine species.
Floating offshore wind is still a new technology—few systems have been installed globally, and none have yet been established in U.S. waters. Now is the time to get ahead of any potential entanglement issues and create monitoring and mitigation measures for future floating offshore wind platforms that protect marine life.
ADDRESSING ENTANGLEMENT RISK HAS TWO ESSENTIAL COMPONENTS: MONITORING AND MITIGATION
Offshore wind cables and lines must be monitored for entangled debris and wildlife. Effective monitoring can detect entangled wildlife and alert response crews in a timely manner. Long-term monitoring can also provide valuable information on how, where, and why entanglements occur and which species of wildlife are most vulnerable.
Mitigation measures are also essential. These include a variety of strategies designed to prevent entanglements from happening (like using rope materials that are less susceptible to entanglement) as well as quick and effective responses when entanglements occur (like following prescribed wildlife rescue protocols).
This report presents an overview of technologies that are currently available for monitoring entanglement risk and identifies additional areas requiring technology research and development. It also recommends best practices for reducing entanglement risk at all stages of floating offshore wind development, from the early phases of designing and planning, through energy generation, to eventual decommissioning of turbines. These recommendations include both monitoring and mitigation measures. While we focus on the U.S. regulatory landscape, our monitoring and mitigation recommendations could be adapted to regulatory regimes in other countries.
Offshore wind development is needed to power the clean energy transition and prevent the worst impacts of climate change, but it cannot come at the expense of wildlife. By integrating monitoring technologies into offshore wind developments and committing to strong mitigation measures, we can ensure the responsible and sustainable development of offshore wind.