Radar Interference

The U.S. government also performs research and identifies standards or support to understand and limit radar interference of wind farms.

A 2011 National Oceanic and Atmospheric Administration (NOAA) report discusses efforts to improve estimates of wind farm impacts and develop options for mitigating wind farm interference issues with U.S. Doppler weather radars, known as the Next Generation Weather Radar system.

In a 2017 DOE study, researchers evaluated the potential impacts to first order of existing and currently planned offshore wind facilities on ground-based coastal air surveillance radar. Mitigation measures, including radar network fusion, radar upgrades, and infill systems, are also discussed. The analysis for existing facilities focused on Block Island Wind Farm, the first commercial offshore wind farm in the United States.

The Bureau of Ocean Energy Management (BOEM) released a report on their 2019 effort to study, using a literature review and expert interviews, how proposed and hypothetical future offshore wind energy installations on the Atlantic coast may impact land-based radar systems, potential mitigations for these impacts, and how an atmospheric phenomenon, known as “ducting,” influences these impacts.

A 2021 BOEM report details a research effort to develop a scalable simulation tool and wind turbine interference mitigation software for SeaSonde radars. The overall result of using the mitigation strategies outlined in the report led to an estimated reduction of 86% of wind turbine interference in the SeaSonde radar spectra at Block Island.

In 2022 by The National Academy of Science, Engineering, and Medicine detailed the potential interference of offshore wind turbine generators with the performance of ship-based radar systems. The authors recommend practicable options to mitigate the interference of wind farms, such as by implementing enhanced training and using reference buoys, among other options.

The federal government established an extensive review process for wind energy project proposals to review the potential and mitigate radar interference, which is discussed in detail below.

If potential interference issues are identified during the wind farm radar review process, a variety of mitigation approaches can help minimize potential radar inference, including the following wind farm siting practices:

• Designing the wind farm layout to minimize the impacted area of radar coverage or to allow for maximum radar coverage within the project, such as by increasing the spacing between turbines within the project.
• Terrain masking, which means placing turbines on the opposite side of elevated terrain in relation to the radar so they will be blocked from view.
• Relocating proposed turbines or reducing their height so that they fall outside the radar line of sight.
• Eliminating proposed turbines from wind farm site plans if the proposed turbine location may result in radar interference.

The above siting practices may not be sufficient to eliminate radar interference or reduce it to an acceptable level. In these cases, other mitigation techniques, including the deployment of new radar-related software upgrades and/or hardware, can also reduce potential wind energy impacts on radar operations. Examples include:

• Modifying the existing radar system software’s constant false alarm rates, clutter maps, or other filtering and/or preliminary tracking routines.
• Upgrading the hardware or software of the affected radar to implement advanced filtering techniques that can remove interference from turbines.
• Installing supplementary sensors within and around wind farms and sending their readings to radar operators to increase the data available for analysis by the upgraded software.