Wind Energy in NSW: Myths and Facts
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Wind Energy in NSW: Myths and Facts 1 INTRODUCTION Wind farms produce clean energy, generate jobs and income in regional areas and have minimal environmental impacts if appropriately located. Wind farms are now increasingly commonplace and accepted by communities in many parts of the world, but they are quite new to NSW. To increase community understanding and involvement in renewable energy, the NSW Government has established six Renewable Energy Precincts in areas of NSW with the best known wind resources. As part of the Renewable Energy Precincts initiative, the NSW Department of Environment, Climate Change and Water (DECCW) has compiled the following information to increase community understanding about wind energy. The technical information has been reviewed by the Centre for Environmental and Energy Markets, University of NSW. The Wind Energy Fact Sheet is a shorter and less technical brochure based on the Wind Energy in NSW: Myths and Facts. The brochure is available for download at www.environment.nsw.gov.au/resources/climatechange/10923windfacts.pdf. For further renewable energy information resources, please visit the Renewable Energy Precincts Resources webpage at http://www.environment.nsw.gov.au/climatechange/reprecinctresources.htm. 2 CONTENTS CONTENTS ...............................................................................................................3 WIND FARM NOISE ..................................................................................................4 WIND TURBINES AND SHADOW FLICKER...........................................................11 WIND TURBINE EFFICIENCY AND COST EFFECTIVENESS ...............................12 WIND POWER AND THE ELECTRICITY GRID.......................................................16 WIND POWER AND GREENHOUSE GAS REDUCTION........................................20 STRENGTH OF WIND RESOURCES IN NSW........................................................25 WIND FARM CONSTRUCTION...............................................................................27 WIND FARMS AND COMMUNITIES .......................................................................29 WIND FARMS AND BIRDS AND BATS...................................................................34 WIND FARMS AND CULTURAL HERITAGE...........................................................35 WIND FARMS AND VISUAL IMPACTS ...................................................................36 WIND FARMS AND LIVESTOCK.............................................................................37 WIND FARMS AND AIRCRAFT...............................................................................38 WIND TURBINES AND ELECTROMAGNETIC INTERFERENCE ...........................39 WIND FARMS AND PROPERTY VALUES ..............................................................40 WIND FARM SAFETY .............................................................................................42 3 WIND FARM NOISE Claim: Wind farms are noisy. Fact: As with most mechanical plant, wind turbines produce noise – but modern turbine designs have reduced the noise levels. Noise at residential locations can be managed to acceptable levels with effective planning and turbine location. Wind turbines produce noise through the interaction of the blades with air and through mechanical noise emitted by the motor and gears. Improvements in modern turbine technology have significantly reduced the noise produced from the blades and the mechanical components, due to better noise insulation of components and turbine blade design. Noise represents lost energy and therefore is something turbine manufacturers are continually working to minimise. The experience of noise is highly subjective and may vary significantly between people. Impacts may relate to the volume, timing and/or character of the noise produced, but the potential impacts can be mitigated through effectively locating and operating turbines. As discussed below, the NSW Government regulates wind farm noise according to strict guidelines to ensure that noise impacts are maintained within acceptable limits. Claim: NSW does not effectively regulate noise impacts from wind farms. Fact: Current noise controls for wind farms in NSW are amongst the strictest in the world.1 The NSW Government assesses potential noise impacts of a wind farm using the South Australian Environmental Protection Authority – Wind Farms Environmental Noise Guidelines (2003) (the ‘SA Guidelines’).2 The SA Guidelines are amongst the strictest in the world, with more stringent requirements than European and North American standards. Noise at the receiver is measured in decibels (dB); this is usually adjusted to approximate the sensitivity of the human ear and presented in A-frequency weighted decibels, or dB(A). Under the SA Guidelines, the predicted equivalent noise level over ten minutes (LAeq,10min) should not exceed: • 35 dB(A) • the background noise (LA90,10min) by more than 5 dB(A) whichever is greater, at all relevant ‘receivers’ (where the noise is heard) for each integer wind speed from cut-in to rated power of the Wind Turbine Generator. 1 Acoustic Consulting Report (Prepared for the Ontario Ministry for the Environment) Wind Turbine Facilities Noise Issues 2007, See pg 26, Table 3.1 Comparison of Noise Regulations, [https://ospace.scholarsportal.info/bitstream/1873/13073/1/283287.pdf]. 2 South Australian Environment Protection Authority 2003, Environmental Noise Guidelines: Wind Farms. 4 Background noise is relevant because high ambient noise levels tend to mask noise from a particular source; the same level of noise from a particular source, say a passing truck, is likely to cause greater annoyance in a quiet environment than in a busy noisy environment. A unique characteristic of wind farms is that the noise level from each wind turbine generally increases with increasing wind speed, but the background noise will also often rise with increasing wind speed. Figure 1 illustrates the noise level of common sounds relative to the baseline NSW noise limit for wind farm noise. Figure 1: The level of common sounds3 In effect, this means that in quiet rural environments [i.e. with a background noise below 30 dB(A)], the guidelines require that wind turbine noise should not exceed 35 dB(A) at a position outside neighbouring residences. In cases where there is higher background noise [i.e. above 30 dB(A)], wind turbine noise should not increase existing background noise levels by more than 5 dB(A). Different criteria may apply at different wind speeds because the background noise may vary with changing wind speed. In the case of cumulative or staged wind farm development, the SA Guidelines state that noise generated by an existing wind farm should not be considered as part of the background noise in determining criteria for subsequent development. 3 NSW Department of Environment, Climate Change and Water 2010, Noise Guide for Local Government. 5 Figure 2 provides an example of noise limits at residences/receivers in the vicinity of the Capital Wind Farm, which commenced operating in 2009. The noise limits increase slightly at higher wind speed levels, as the background noise levels are greater at higher wind speeds. Figure 2: Example of Wind Farm Noise Limits from Capital Wind Farm Project Approval Claim: NSW does not monitor wind farms to ensure compliance with noise limits. Fact: NSW has processes in place to ensure wind farms are complying with noise limits in the development approval. In the event a proposed wind farm project is granted planning approval, wind farm operators must carry out noise compliance monitoring as a Condition of Approval. This usually occurs within three months of the commissioning of the wind turbines. The results must be provided to the NSW Department of Planning (DoP), which may request further monitoring. DoP requires noise compliance monitoring and assessment to be undertaken in accordance with procedures in the SA Guidelines. DoP also employs a compliance team to undertake independent noise monitoring at wind farms. If the noise limits are being exceeded, the operator must submit a proposal to manage or mitigate noise. Solutions to exceeded noise limits may include sector management (i.e. strategic shutting down of particular turbines) or double glazing affected residents’ windows. Complaints about noise should be made to DoP (by phoning 02 9228 6333) or contacting the relevant local council, if the wind farm was approved by local council. DoP may require further monitoring by the wind farm operator or carry out independent noise monitoring. 6 Claim: Conventional noise measurement of wind turbines underestimates actual noise (the ‘Van den Berg’ effect). Fact: Various factors (e.g. atmospheric stability, local topographic conditions and land use) make wind farm noise assessment complex, but they are addressed by the SA guidelines or Draft National Wind Farm Guidelines. Traditional wind farm assessment approaches measure all wind speeds at 10m above ground level. The corresponding hub height wind speed is determined using a standard equation. Studies by Van den Berg in an area of Germany found that this empirical relationship did not apply well in stable atmospheric conditions, where the near-ground wind speed and hub height wind speed differed significantly to the wind speed measured at 10m above ground level. The result was that under stable atmospheric conditions, the near-ground wind speed and background noise was lower than predicted but the hub height wind speed and turbine