Study warns offshore turbines may disrupt coastal radar coverage

Offshore wind farms can reduce the effectiveness of shore-based radar and create false target signals, according to a study by researchers in China. The research, published online in the peer-reviewed journal Radio Engineering, was conducted by Professor Liu Zunnian’s team from Qingdao Technological University and the Yantai Communication Centre of the Beihai Navigation Security Centre under China’s Ministry of Transport. Using a model of an X-band surveillance radar, the researchers found that at a distance of 5km, effective radar coverage fell by 6.9 per cent while blind areas increased by 14.9 per cent after a wind farm was introduced.

The model also showed that reflected signals could create “ghost” targets, making vessels harder to identify. The simulation was based in Shandong, a major port region. It examined turbines represented by 120-metre towers with blades about 100 metres long.

The researchers attributed the effects to obstruction, diffraction loss and multiple reflections. At one existing radar site 5km from a wind farm, coverage fell by 3.3 per cent and the undetectable area rose by 0.4 per cent. Increasing distance did not consistently eliminate interference.

At a 90-degree angle, ghost interference reached 4.5 per cent at 20km in the model. An unnamed military equipment expert, who was not involved in the research, told the South China Morning Post that turbine interference was an international issue. The expert said projects should take radar coverage into account during planning and could be kept away from restricted areas.

Liu recommended careful site selection, avoiding long turbine rows along a radar’s main line of sight, improving algorithms and adding radar systems where necessary. The researchers acknowledged that their model did not include complex weather, changing sea conditions or different turbine designs.