Travis AFB Sustainability Study Report Final Background Report | Page 167
New wind turbines over 100 feet above ground level (AGL) must not be
within a line‐of‐sight of the Travis AFB DASR, as shown on Figures 5.8‐2,
5.8‐3, 5.8‐4, 5.8‐5, and 5.8‐6, with placement reviewed by the ALUC.
Existing wind turbines can be replaced at the same dimensions and material
without review by the ALUC. However, if the replacement wind turbines are
a different dimension and are over 100 feet, they must be reviewed by the
ALUC and must not be within the line‐of‐sight of the Travis DASR.
Radar towers at Travis AFB (Source: http://www.thepapertrailnews.com/)
The LUCP adequately manages wind turbine development in Solano County,
but has no authority outside the county. Future placement of wind turbines
outside Solano County could lead to radar impacts if they are developed
within the field of view of Travis AFB’s DASR radar. Generally, turbines
greater than 30 miles away from the radar would not be a concern. The
30‐mile radius around the radar includes land in the counties of Yolo,
Sacramento, San Joaquin, Contra Costa, Sonoma, and Napa.
Findings
The presence of large wind farms can have negative effects on radar
systems depending on the number and height of turbines, the distance
between the turbines, and the distance from the radar. The two main
impacts of large wind farms are screening or blocking out portions of the
“field of view” so that it cannot see aircraft that fly behind the “screen”; and
causing false readings on the radar that make it appear there are aircraft
flying in the area that are not really there. Travis AFB has addressed this
issue by masking the area impacted by interference from the wind farms.
Masking the wind farms eliminates the detection of the turbines by the
radar, but it also inhibits the radar from accurately identifying aircraft that
are operating in the masked area, leaving a blind spot in the radar’s field of
view.
The development of new or modification of existing wind farms may have a
negative effect on the radar viewshed and create additional interference
issues. To mitigate this impact, the updated 2015 Travis AFB LUCP
establishes policies for future wind turbine placement in Solano County.
TSS Background Report
The presence of large, commercial wind farms presents challenges to
the Travis AFB flying mission by impeding radar tracking of aircraft
near the Base.
The ALUC regulates the placement of new and replacement wind
turbines over 100 feet AGL in Solano County. However, wind turbines
outside of the county may be an issue for aircraft operations, as
Solano County ALUC has no authority outside the county. Generally,
turbines greater than 30 miles away from Travis AFB’s DASR radar
would not be a concern.
Travis AFB has addressed wind turbine impacts by masking portions of
the radar’s field of view, but this reduces the radar’s ability to track
and monitor aircraft in that area.
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