At a Glance:

It is true that wind turbines interfere with radar, creating additional navigational complexity that may complicate vessel maneuvering within OSW farms. However, these issues have been known about and investigated for years, and several federal agencies (including BOEM) have worked together to develop mitigation strategies. Every OSW developer works alongside these federal agencies to ensure that the potential impacts to vessel radar are as limited as possible.

A Deeper Dive:

In 2006, the US Department of Defense produced a report for Congress on the impacts of onshore wind farms on military air defense radar systems. This report demonstrated that the turbines’ rotating blades can “impact the ability of a radar to discriminate the wind turbine from an aircraft” and “degrade target tracking capabilities as a result of shadowing and clutter effects.” The report concluded: “Given the expected increase in the U.S. wind energy development, the existing siting processes as well as mitigation approaches need to be reviewed and enhanced in order to provide for continued development of this important renewable energy resource while maintaining vital defense readiness. The Department of Defense strongly supports the development of renewable energy sources and is a recognized leader in the use of wind energy.” For almost 20 years, our military has demonstrated a need and desire to develop methods and technologies that accommodate on and offshore wind.

Since then, BOEM and OSW contractors have worked closely with the Department of Defense and other federal agencies to investigate and implement mitigation strategies. In 2010, the White House asked the Department of Defense, the Department of Energy, the Department of Homeland Security, and the Federal Aviation Administration to participate in a working group to address wind turbine interference with surveillance technologies. This resulted in the establishment of the Interagency Field Test and Evaluation (IFT&E) Program, which conducted a series of flight tests to investigate short- and long-term mitigation strategies. In that same year, Congress created the DoD Siting Clearinghouse, which acts as the voice of the DoD to “assess potential mission compatibility impacts of energy-related projects… and explores mitigation options while preserving military mission readiness and operations.” Later, in 2014, the federal government established the Wind Turbine Radar Interference (WTRI) Mitigation Working Group, which includes the Department of Defense, the Department of Energy, the Federal Aviation Administration, NOAA, and BOEM. Through collaborative efforts with researchers, the Group was able to develop an official mitigation strategy in 2016, with a follow-up strategy established in 2023. 

It is worth noting that, while significant investments have been made by air traffic control and military radar system operators, less attention has historically been paid to marine vessel radar (MVR) systems generally. However, this has changed in recent years, with one example being the mitigation strategies for MVR established in this 2022 report by the National Academy of Sciences, Engineering, and Medicine. Researchers and policy makers have been aware of the complications caused by OSW for quite some time now, and they have implemented (and continue to develop) mitigation strategies to ensure the security of our coasts and the effectiveness of military radar systems.

As a result of this concerted and collaborative effort, various technologies and methods have been implemented to cope with radar interference. Some of the methods highlighted in the WTRI 2023 strategy update include, but are not limited to, radar system software and hardware upgrades and supplementary sensor installation within and around wind farms.

There are also strategies specific to search and rescue (SAR). These include the Rescue 21 system, which improves searching capabilities within wind farms, and the transference of meteorological data from OSW developers to the US Coast Guard to improve Search and Rescue Optimal Planning System (SAROPS) models. A good example that can be recreated in other coastal states is the Rhode Island Navigational Enhancement and Training Program, which provides RI fishermen and for-hire vessels with more advanced navigation equipment and one free training session on navigating wind lease areas. Through continued collaboration, OSW developers and the government can work to ensure the safety of mariners and the readiness of our military.