Coexistence of meteorological radars and wind farms: successful operational stories

In the last years, the concern on the impacts of wind farms on the measurements of the meteorological radars is on rise. As the wind energy has become more and more a strategic alternative, the number of installed wind farms has also grown and the size of the turbines has increased significantly. Thus the impacts on operational radars and on their measurements have become more relevant, and the interaction between wind farms and radars as well as the mitigation strategies to minimize their impacts on radar QPE and hydrological products have become a hot issue in the radar field.

The main impacts specifically related to wind-farms are essentially, (i) the clutter caused by wind turbines, which usually overpasses the current clutter filters based on the analysis of the Doppler velocity spectrum (the turbine clutter has a speed component due to the rotation of the blades), and that is frequently combined with the orographic clutter caused by the hillslopes in which they are located, and (ii) the areas of under-detection potentially generated by the partial beam blockage they are supposed to cause.

Presently, the effects of existing wind farms are rarely corrected operationally, and the methods to evaluate the impacts of new installations are mainly assessed using theoretical models and laboratory studies.  Very few studies based on operational data have been used to evaluate the real impacts and our capacity to correct them operationally.

This study presents several real cases of wind farms in Galicia (NW of Spain), Catalonia (NE of Spain) and Quebec (Canada). The effects on the radar volume scans and derived products are analysed in a variety of situations (no rain, light rain, heavy rain, anomalous propagationÉ), and a characterization of the impacts based on these observations is proposed. Also the effect of several fully operational correction algorithms are analysed and the results are compared to those obtained with the basic Doppler processing.

Using these success operational stories some simple ideas to minimize the impact when designing new wind farms are provided, as well as a protocol to evaluate the expected impact (that is compared with the one proposed by the Radar Operation Center of the US NWS).

Finally, the results obtained in these case studies are used to show the crucial importance of implementing efficient processing as the main step to operationally correct the effects of wind farms on radar products.

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