Business Development Director at enitial Ivor Parry explains how, as wind power becomes an increasingly popular way of generating renewable energy, noise monitoring has become an essential part of the wind turbine planning process.
The Government is committed to increasing the proportion of energy that comes from renewable energy. The 2009 Renewable Energy Directive set a target of 15% by 2020, compared to just 3% in 2009. It’s certainly a challenge for the country which requires both large scale and small scale operations.
As people and businesses become more energy conscious, they are increasingly thinking more about how they can benefit from renewable energy. One option for businesses in rural settings, such as farms, is to build a wind turbine on their land to generate energy – which can be exported to the grid in return for a Government subsidy on their energy bills in the form of feed-in tariffs.
Noise levels
With any planned wind turbine project, the potential impact on the local area needs to be considered along with likely objections from the local community. This often includes issues such as any noise which might be heard outside nearby houses. Enitial recently completed a project monitoring noise levels at several proposed wind turbine sites on farms across Scotland.
The potential noise impact is assessed by predicting the noise which will be produced when the wind is blowing from the turbines towards any houses. It is then compared to the background noise which already exists in the area, without the turbine operating. It’s important to ensure the difference between noise levels isn’t significant enough to cause a nuisance. Recommendations from the Wind Turbine Noise Working Group are that turbine noise levels should be kept to within five decibels of the average existing evening or night time background noise level.
Specialist noise monitoring technicians from enitial typically monitored the sites over a 24-hour period to establish the ambient noise levels, and characterise them for different times of the day. Larger sites where several turbines were proposed were monitored over a period of three weeks.
Technicians made an environmental assessment of the area by setting up noise level monitoring equipment – ‘class 1’ which is the most accurate – and calibrating the readings onto a graph. It shows sound level against time and is used to show how a wind turbine could alter ambient noise levels.
Establishing noise levels at proposed wind turbine sites is essential to ensure any wind turbine would not go against environmental guidelines and affect residents’ quality of life. If a wind turbine is proposed on a busy, noisy industrial site, the wind turbine noise would be inconsequential whereas on a very quiet farm, the difference could potentially appear very loud in comparison and ultimately become a nuisance.
