Operational and construction noise assessment for wind farms incl. vibrations
Wind farm noise assessment: standard-compliant rating levels for operation and construction as the basis for the noise permit.
Noise is among the most critical factors in wind farm planning. It decides the acceptance by residents and the permit. The operational noise report assesses the noise of the wind turbines in regular operation, the construction noise report that of the construction phase. Statements on vibrations are added. We calculate the rating levels with modern calculation software, assess them to standard and give recommendations on how to minimise noise exposure.
In Austria, levels are calculated under ÖNORM ISO 9613-2 on sound propagation outdoors, whose prediction uncertainty depends on the input parameters and the site conditions. They are compared with the guide values relevant in the procedure, for example the planning guide values for land-use zoning under ÖNORM S 5021. The assessment considers the most unfavourable situation and sets the additional noise from the new turbines against the existing background noise. The total noise exposure results from the actual situation, minus decommissioning, plus new construction and approved plants. The study area is the area in which the additional noise is no longer clearly below the existing noise or exceeds the guide values. Day, evening and night are considered separately, and there are separate assessment criteria for low-frequency noise and infrasound. Approved plants are also taken into account in the existing noise, and subjective perception should also be considered.
In Germany, the forecast is based on DIN ISO 9613-2 with the interim procedure. It calculates with the loudest operating mode and takes account of the existing noise from other plants. Assessment is based on the guide values of TA Lärm, which depend on the type of area and lie at night between 35 dB(A) in purely residential areas and 50 dB(A) in commercial areas depending on the area, and at 70 dB(A) in industrial areas. Short-term peaks may exceed them by no more than 30 dB(A) by day and 20 dB(A) at night. In the construction phase, construction traffic, road building, logistics areas, the cable route and the erection of the turbines have an effect. The construction noise report places these sources in time and shows where measures are needed. Vibrations have their own sets of rules, for example ÖNORM S 9012 (vibrations and secondary airborne noise from land transport, 2016 edition) as well as rules on vibrations in structures; which one applies in the procedure is determined project by project. In the procedure, the same questions usually arise: what levels do the nearest dwellings reach? How does the construction phase affect them? Our reports answer them traceably, so that authorities, experts and residents can check the results.
Our experience with complex terrain helps in the acoustic optimisation of your wind farm. We supply measured baseline levels with sound immission measurement, and we additionally assess the shadow impact of your turbines. Construction traffic and excavation also affect the waste management concept. We coordinate closely with permitting authorities, experts, host municipalities and residents, and accompany you in the procedure and in contract negotiations with the wind turbine manufacturer. After approval, noise emission measurement and frequency analysis checks whether the forecast noise situation is met.
