Location, Location, Location- An investigation into wind farms and noise by The Noise Association

Overall Conclusions

1. Wind Farm noise, in common with noise generally, affects different people in different ways, but the evidence suggests there is rarely a problem for people living more than 1-1.5 miles from a turbine.

2. For many people living relatively close to turbines, the noise does not present a problem. For those who are annoyed by the noise, it is overwhelmingly the “swish, swish, swish” of the turbines which troubles them.

3. For people who are not able to shut out the noise, the problem can be exacerbated by the rotating blades and the dancing shadows of turbines. This can mean that the noise from turbines can be much more intrusive that other noises of a similar decibel level.

4. For some people the impact of turbines can be overwhelming.

5. The noise can be a particular problem in rural areas where background noise levels are low.

6. The infrasound content of wind turbine noise is too low to be heard by most people.

7. At times, low-frequency will form an audible, but not major part, of the “swish” sound of the turbines and can, for people sensitive to low-frequency noise, create additional problems. But the low-frequency content of wind turbine noise is no greater than the low-frequency component found in
several other noise sources and can only usually be heard down wind of a turbine when there is a fair bit of turbulence.

8. However, low-frequency may be underestimated because of the persistent use of ‘A’ weighting in measuring the noise, rather taking ‘C’ weighted measurements.

9. Research by medical doctors has unearthed persistent complaints from people saying they not only hear the noise from wind turbines, but can “feel” disturb

Preface

The old windmill is remembered with fond nostalgia. Today’s wind farms, by contrast, are causing much controversy. For a variety of reasons they are dividing local communities, green pressure groups, politicians and environmental experts. This report aims to map out a constructive way forward with respect to one of the principal areas of controversy – noise. The report assesses noise from onshore wind farms; it is not concerned with offshore wind farms or any other aspect of the wind farm debate.

We discovered that there is some disagreement amongst acousticians on the impact of wind farm noise. This report reviews the latest evidence. But, in many ways, more important than the theory, is what people who are living with wind farms are saying. We sought their views too, but found that they don’t speak with one voice either!

While surveys suggest that wind turbines are not causing a noise problem for the majority of communities, there are people who are suffering badly as a result of the noise generated by neighbouring wind farms. While opponents of wind farms tend to raise noise as an important part of their case against wind power, the wind power industry and its allies can refuse to acknowledge the extent of the suffering that this noise can cause and they sometimes deny its very existence.

Our own conclusion, after reviewing the evidence, is that there is a practical way forward. There are mechanical improvements that can be made to wind turbines, but the key lies in the title of our report – ‘Location, Location, location’. So much depends on the location of the wind farm relative to where people live. In the following pages we explain why we have reached this conclusion and suggest a way in which on-shore wind farms can be built without causing unacceptable noise problems.

I hope you find the report a constructive contribution to the debate.

John Stewart

Introduction
The UK, along with other countries in the world, particularly the rich countries, needs to find ways to cut its ‘greenhouse gas’ emissions. The UK produces about 2.6% of reported global emissions, CO2 being the most significant of those gases and one which most scientists believe to be the principal cause of climate change. Electricity generation currently accounts for 28% of these CO2 emissions and, with a very high proportion of UK electricity sourced from fossil fuels, there appears to be a clear need to develop technologies which do not emit greenhouse gases.

The other factor driving the Government’s desire to find alternatives is the diminishing reserves of oil. Scientists differ on when the world will become seriously short of accessible supplies of oil, but there is no dispute that it will happen. Governments across the world, therefore, are trying to develop alternative sources of energy.

The UK Government has set a target of generating 10% of the country’s electricity from renewable sources by 2010. Wind farms could be part of the answer. Government policy is to encourage industry to invest in wind farms through a system of subsidies financed by the electricity consumer. The ultimate aim is that between 60% and 70% of UK wind power will be generated off-shore but most of the first turbines are being built inland as these are cheaper to build and provide an opportunity to test out the technology before going off-shore.

Over the last few years there has been a huge growth in the number of wind farms. By the middle of last year there were over 100 wind farms in the UK, with a further 19 under construction, another 62 having been given consent, and 150 awaiting planning permission.

This officially-sanctioned growth has delighted the supporters of wind farms, but has lead to the emergence of vocal opposition. Green pressure groups – notably Greenpeace, Friends of the Earth and the World Wildlife Fund (WWF) – have supported the idea of developing wind farms. The Royal Society for the Protection of Birds (RSPB) has given general support, except in cases where birds would be badly affected. The Campaign to Protect Rural England (CPRE) has been much more wary.

Some local opposition groups have been assisted by Country Guardian and, latterly, the Renewable Energy Foundation (REF). Visual intrusion and the impact on the landscape are the reasons most frequently cited by opponents of wind farms. At a policy level, some of the opponents question the viability of wind farms and dispute the amount of electricity they will actually generate.

Wind farms have also divided noise experts. There is an on-going technical debate about the noise and vibration produced by wind farms. The debate has led some acousticians to question whether the Government’s noise guidelines for wind farms are rigorous enough.

It is to noise we now turn