(WASHINGTON) — Offshore wind farms can interfere with navigational radar used by ships and smaller vessels to avoid collisions, posing challenges for safe maritime navigation, says a new report from the National Academies of Sciences, Engineering and Medicine.
The maritime community has expressed concern that wind turbine generators could interfere with radar, complicating navigation for both large vessels passing through shipping channels near offshore wind farms, and smaller vessels navigating through or adjacent to the structures. Previous studies that examined this question relied on data from European wind farms — however, wind turbines in offshore wind farms located in or planned for the U.S. Outer Continental Shelf are larger, and spaced farther apart than those included in past studies.
The report concludes that wind turbine generators have significant electromagnetic reflectivity, and therefore can interfere with radar systems operating nearby. The rotating blades can also create reflections in Doppler radar systems. In particular, these forms of interference could obfuscate smaller vessels and stationary objects such as buoys on radar, complicating navigation decisions and increasing the risk of collision with larger vessels. Maritime search and rescue teams also rely on radar to find smaller boats — their primary targets — and interference could therefore also complicate rescue operations near wind farms.
Conducted at the request of the Bureau of Ocean Energy Management, the report identifies and characterizes the impacts of wind turbine generators on the efficacy of marine vessel radar on vessels operating within or near existing and planned offshore wind facilities on the U.S. Outer Continental Shelf. The report recommends pursuing two courses of action to reduce impacts by:
• Filling knowledge gaps through data collection, modeling and analysis, and focused research on wind turbine generator characteristics;
• Pursuing practicable options to reduce interference on marine vessel radar such as enhanced operator training, use of radar reflectors on small vessels, use of reference buoys, evaluation of radar mounting procedures, new radar designs, and the development of wind turbine generators with reduced radar signatures.
– National Academies of Sciences, Engineering and Medicine