Shear genius solves windy issue

Turbine-noise assessment could lead to more wind-farm approvals

Energy consultancy TNEI Services has developed a way of modelling and assessing turbine noise, a development that could mean more wind-farm approvals.

With many applications for wind farms being opposed on the grounds of noise, calculating how loud turbines may be and altering their design or position to minimise this is vital.

Failure to consider wind shear – the relationship between wind speed at different heights above the ground and, in particular, between the ground and hub height of a wind turbine – can, on certain sites, lead to under prediction of levels of wind-turbine noise. The amount of wind shear experienced can vary depending on the surrounding terrain, time of day and season.

TNEI Services’ method takes account of wind shear at individual wind-farm sites. The method is founded on software designed by TNEI’s noise experts in conjunction with TNEI’s Wind Resource Assessment team.

The modelling should improve the accuracy of wind-turbine noise assessment, providing developers, local planning authorities and wind-farm neighbours with confidence that wind-turbine noise has been properly considered. ‘The model can be used for wind-turbine developments of all sizes, ranging from private sites with a single installation to medium developments with up to 10 turbines,’ said James MacKay, senior technical consultant at TNEI. ‘The issue is of most concern for taller turbines as the amount of wind shear experienced increases with size. We have incorporated data from the model in some planning applications that are currently under consideration.’

As well as recent industry guidance, TNEI’s model includes the effects of local geography, as well as daily and nightly variations and seasonal effects on wind shear. The data is gathered using an on-site wind mast.