Predicting the noise impact of wind turbines – PIBE

Wind energy is one of the promising energy sources to reach the objective set by the French regulation of increasing renewable energies to about one third of the final energy consumption by 2030. In spite of a strong growth of the wind energy sector these last 10 years, and in spite of a solid potential for development, France has fallen behind on this goal. This may be partly explained by the constraint framework in which wind energy is developing, as well as the opposition of wind farm neighbors who very often mention noise as a potential annoyance. First French collaborative research project on wind turbine noise, the goal of the PIBE project is to improve prediction methods for wind turbines noise and to explore new solutions for noise reduction. The project brings together experts in aeroacoustics, sound propagation, experimental characterization of noise, and wind turbine engineering.
The research program is structured in 3 work packages (WP).
The first WP aims to study the amplitude modulation phenomena, known to be a major source of annoyance when they occur. This axis focuses particularly on characterizing and modeling the dynamic stall of the flow around the blades, as well as the conditions of amplitude modulation generation at the receiver. These phenomena will be studied both in wind tunnels, and near a wind farm managed by one of the project partner. The publication of a detailed database of the wind tunnel characterization of dynamic stall noise will help advance knowledge about a poorly understood phenomenon.
The second WP focuses on quantifying the variability of noise predictions. To achieve this goal, the uncertainties and variabilities of the parameters influencing both the noise emission and the noise propagation will firstly be calculated; secondly, a model of uncertainty propagation (associated with advanced and appropriate statistical methods) will estimate the overall uncertainty. The results will be disseminated through the implementation of an open access online database.
The last WP of the project will study and propose new noise reducing devices, using blades with modified leading and/or trailing edges. The efficiency of the solutions will be characterized in wind tunnels, from both acoustic and aerodynamic points of view. An estimate of their performance potential at scale 1: 1 will also be conducted.
Results of the projects will eventually allow a better control of the risk of wind turbine noise pollution by the wind energy industry from the wind farm design phase, and thus improve the integration of wind power in the territory. It will help to reduce litigation risks by proposing a better response to noise reduction concerns raised by local residents of existing wind farms (efficient noise reduction devices). It will also enable wind farm developers to optimize production of wind turbine energy, thanks to a better prediction of producible energy during the wind farm phase of development. The results for the uncertainties related to the variability of atmospheric phenomena on the emission and propagation of noise will also feed future works of standardization. It will help to improve the practices of noise prediction, even for other environmental noise sources than wind turbines.
In a context in which the reduction of noise pollution remains a major challenge for the authorities, the project will contribute to the limitation of noise emissions and of the possible associated extra auditory effects on health, such as effects on sleep or activities cognitive. Wind farms generating less noise pollution, because designed more optimally, will contribute to a better acceptance of wind power by the citizens. It will thereby support the growth of renewable energy development that guarantee the reduction of greenhouse gases, while respecting the well-being of local populations.