A quantitative analysis of the impact of wind turbines on operational Doppler weather radar data

L Norin

doi:10.5194/amt-8-593-2015

Abstract

Abstract. In many countries wind turbines are rapidly growing in numbers as the demand for energy from renewable sources increases. The continued deployment of wind turbines can, however, be problematic for many radar systems, which are easily disturbed by turbines located in the radar line of sight. Wind turbines situated in the vicinity of Doppler weather radars can lead to erroneous precipitation estimates as well as to inaccurate wind and turbulence measurements. This paper presents a quantitative analysis of the impact of a wind farm, located in southeastern Sweden, on measurements from a nearby Doppler weather radar. The analysis is based on 6 years of operational radar data. In order to evaluate the impact of the wind farm, average values of all three spectral moments (the radar reflectivity factor, absolute radial velocity, and spectrum width) of the nearby Doppler weather radar were calculated, using data before and after the construction of the wind farm. It is shown that all spectral moments, from a large area at and downrange from the wind farm, were impacted by the wind turbines. It was also found that data from radar cells far above the wind farm (near 3 km altitude) were affected by the wind farm. It is shown that this in part can be explained by detection by the radar sidelobes and by scattering off increased levels of dust and turbulence. In a detailed analysis, using data from a single radar cell, frequency distributions of all spectral moments were used to study the competition between the weather signal and wind turbine clutter. It is shown that, when weather echoes give rise to higher reflectivity values than those of the wind farm, the negative impact of the wind turbines is greatly reduced for all spectral moments.

Highlights

As a response to the increasing demand for renewable energy the number of wind turbines is growing rapidly in many countries around the world
Wind turbines located in the vicinity of a Doppler weather radar can have a detrimental impact on the radar’s performance
The objective of this study was to investigate the impact of wind turbines on operational Doppler weather radar data

Summary

Introduction

As a response to the increasing demand for renewable energy the number of wind turbines is growing rapidly in many countries around the world. The worldwide installed cumulative energy capacity of wind turbines has shown a more-than13-fold increase during 2001–2013. In Sweden, the wind power capacity has increased even more, 15 times, during the same period (Global Wind Energy Council, 2014). In the coming years many more wind turbines are expected to be built and existing, older ones are likely to be replaced by larger, next-generation turbines. Modern wind turbines are large structures, many reaching 150 m above the ground. Clusters of densely spaced wind turbines, so-called wind farms, are being built both on- and offshore

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Discussion

Conclusion