An on-line interactive spreadsheet should be visible. This spreadsheet was written using Excel, and can only be viewed using Microsoft Internet Explorer rather than Mozilla Firefox. If you can't see the program you need to install the Microsoft Office excel web interactive add-in; please click on the link to the Microsoft Office Website, or directly run the program owc11.exe. This will install the add-in, allowing use of the spreadsheet when you next access this page.
Turbine Noise Prediction
When designing a wind farm, impact upon neighbours is one of the most important considerations. There are three issues to consider - the view of the turbines, shadow effects and noise impact. This excel spreadsheet is a much simplified version of the tool we use for assessing sites for noise impact, and has been limited to three turbines.
Thisinteractive spreadsheet calculates the way sound levels diminish with distance, and also allows for the way air density helps reduce sound levels. The noise levels from individual machines are combined using a logarithmic formula, giving an overall total. The program does not take into account ground conditions, or any barrier effects from land, houses or vegetation.
You can change any of the variables in the green box, such as turbine noise level, height and distance to the windfarm. The end result is an indication of sound power level, which has to be less than 45dB(A) to avoid being intrusive. Note that some councils are suggesting that windfarm noise should be limited to 35dB(A), equivalent to rural background noise levels, however national guidelines do allow for sound levels up to the 45dB(A) limit for project owners.
This tool only provides an indication of sound levels and more detailed work is normally required for actual site assessment. We hope you find this useful, and please get in touch if you need more detailed information. Please note that this tool has been made available under a creative commons licence.
The spreadsheet was written using Excel 2003, and Microsoft offer a patch to allow online interactivity. This patch also works with Excel 2000, and the spreadsheet has been tested on Office 2007.
