When falling asleep, relaxing or undertaking recreational activities, nearly a third of residents living near a wind farm are not at all annoyed or only slightly annoyed by the noise of wind turbines. One in ten people experience symptoms of stress, such as irritability or difficulty falling asleep. However, noise is not the only problem for those affected, according to psychologists at Martin Luther University Halle-Wittenberg (MLU) in the current issue of the journal Energy Policy. In particular, a critical attitude towards a wind farm stimulates the experience of stress. According to the study, a better information policy during the planning phase could help alleviate problems for residents.
In their study, the environmental psychologists working with Prof Gundula Hübner and Dr Johannes Pohl from MLU investigated a wind farm in northern Germany from 2012 to 2014. They conducted surveys of residents, and their project partner UL DEWI (UL International GmbH) analysed sound recordings of wind turbines. The psychologists even took weather into account. This allowed researchers to discover, for example, that the noise from wind turbines is perceived more when humidity is high and when there is frost.
Another result: Symptoms of stress were experienced at least once a month by the nearly 10 per cent of participants surveyed who said they felt annoyed by the wind turbines. "Symptoms include problems falling asleep, disturbed sleep in general, a negative mood, and strong irritability," explains Pohl. By comparison, 16 per cent of the participants surveyed said that they suffer from such symptoms at least once a month as a result of traffic noise.
When the psychologists re-surveyed the residents two years later, the proportion of people suffering from at least one concrete symptom had fallen to 6.8 per cent. "Many residents get used to the noise from the wind farm or they have resigned themselves to it. A good one fourth of those affected close their windows at night so that they are no longer disturbed by the noise," says Pohl. It is notable that the people who continued to have the biggest problem with wind turbines were those who were already very critical of the wind farm. This group showed little interest in learning ways to cope with the stress, says the researcher. This shows how difficult it is to change established attitudes. The environmental psychologists at the University of Halle therefore recommend proactively addressing the residents' problems and concerns during the planning phase. "The way the residents experience the planning and construction phase is a decisive indicator of how strongly or weakly they will be impaired in the long run by the wind farm." Pohl concludes. Therefore, it is important to create the most positive experience possible. This could happen, for example, through early information campaigns and community meetings. Furthermore, residents should be included in the planning wherever possible.
Several residents had also prepared recordings of annoying noise at night. These were analysed by the researchers at DEWI. "The wind and the movement of the rotor blades can cause amplitude modulation, in other words an irregular pulsating of the volume. These irregularities are what annoy some of the residents, something which they perceive to be irregular humming or swooshing," says Dr Johannes Pohl from the Institute of Psychology at MLU. A quiet, steady background noise is easier to ignore, says the researcher. Most of the complaints occurred in the night or in the early morning hours when there are fewer other noises. According to the study, however, the proximity of the resident's home to the wind farm had little significant influence on their annoyance.
The psychologists from Halle will incorporate their study's findings into the project "TremAc", which is being funded by the Federal Ministry for Economic Affairs and Energy. As part of the project, ten university and commercial research institutes are working on a new concept for predicting noise and vibrations caused by wind farms. This model should allow the interplay between these two factors to be understood and predicted better, with one of the aims being to make the noise emitted by wind turbines more pleasant for those affected. To this end, acoustic and seismic measurements, as well as surveys covering aspects of environmental psychology and medicine are being conducted at two wind farms.