Wind Farm Subsidies (Abolition) Bill — House of Commons, 2015-03-06
Topic: Energy
Matthew John David Hancock (Conservative, Centre-right): The commitment I gave is absolutely about onshore wind. I know that my hon. Friend has concerns about offshore wind, especially off Christchurch, and I understand that. We have had exchanges in this House and discussions about it. We are bearing down on the offshore wind subsidy, as the cost is reducing and industry is reducing its costs. There are links in respect of why we have chosen to resist this Bill, despite there being so much in it we agree with, because we want to make sure that we adopt a planned and careful approach, sticking to commitments that the Government have given and that this House has given to industry, which is developing already I also wish to discuss the noise produced by wind farms, because I know it is a significant concern to my hon. Friend the Member for Wellingborough, he raised it and it is important to address the point. Again, this is an area where the Government have taken action. The method of assessing the noise impact of a wind farm is described in ETSU-R-97. That requires the likely impact of wind turbines on local residents and those working in the vicinity to be considered in relation to existing background noise levels, taking into account the characteristics of particular locations. Hayes McKenzie reviewed ETSU-R-97, finding that it is fit for purpose but identifying inconsistencies in the way it was being used in practice to measure and predict the impact of noise. In May 2013, the Institute of Acoustics published good practice guidance which addressed the issues Hayes McKenzie identified. The guide, which was endorsed by the Department of Energy and Climate Change, will help to improve the consistency of the application of ETSU-R-97 in the consideration of wind farm projects. I hope my hon. Friend will see that good work is being done by DECC there, and perhaps it will temper his desire to abolish me—it—at the next opportunity with his next private Member’s Bill. As my hon. Friend will doubtless be aware, we also recently announced a review of the available evidence on amplitude modulation—AM—noise produced by wind turbines. The aerodynamic noise—the noise produced by the rotating wind turbine blades—includes a steady component, as well as, in some circumstances, a periodically fluctuating, or amplitude modulated, component. One form of AM, commonly referred to as "blade swish", is an inherent feature of the operation of all wind turbines and can be explained by well-understood mechanisms. It is therefore often called "normal amplitude modulation"—NAM. Some AM, however, exhibits characteristics that fall outside those expected of NAM and can potentially give rise to increased annoyance. Such characteristics include a greater depth of modulation or a changed noise character. For that reason, it is sometimes called excessive amplitude modulation. Research suggests that that form of AM is caused by sudden variations in the direction and speed of the wind, which mean that the wind hits different parts of the turbine blade at different speeds, causing it to stall momentarily. The stalling can then produce a whooshing sound that some people find irritating. The evidence to date indicates that the incidence of AM from wind turbines in the UK is low, but we are committed to increasing our knowledge and understanding of the potential impacts of wind turbines and therefore we keep our evidence base up to date.