4 things to consider before installing a domestic wind power
Posted by Dave Houston on 14 September 2012 at 9:31 am
Wind turbines are a Marmite technology - you either love them or hate them. Whichever way you feel, they are still a credible source of energy for the home if you have a good site, so the pros and cons deserve serious consideration prior to installation.
1. Visual impact on the landscape
This is generally the major objection to wind-farms and should not be underestimated when thinking of installing your own domestic turbine. Small wind turbines, up to 20kW (around 12m in height) will be visible in the local area so will need planning permission.
To get the best performance out of a wind turbine it should be sited so that it is exposed to the best possible wind resource. This usually means the turbine will be positioned away from any obstructions, which could create turbulence, such as trees or buildings, and mounted on a mast typically ranging from 12-25m, a significant height considering the average UK home stands at around 8.5m.
2. Is flicker a problem?
Your installer will need to take into account flicker, which is the shadow cast by the turbine while it rotates. Flicker is an easily modeled property, a well-positioned turbine will not cast a shadow onto local buildings. Even in the shadow of a turbine, the right conditions for flicker (position of the sun on its zenith, sunlight’s intensity, time of year) only occur around 15 – 30% of the time. So, although it should be a consideration, it isn’t necessarily a barrier to installation.
3. How noisy are wind turbines?
Noise is caused both by the mechanism within and the blades moving through the air. A turbine from 1.5 right up to 50kW will have an MCS acoustics label with its noise rating in decibels. Using this data, an installer will calculate the ‘slant distance’ from the turbine’s hub height, to the nearest habitable window, this includes neighbouring properties as well as your own.
The quieter the turbine, the closer to a property it can be located, so garden size and noise levels could prove to be a restriction when thinking about installing a domestic turbine.
4. Do wind turbines kill birds and bats?
The most widely reported instance of the impact of wind turbines on surrounding wildlife is avian deaths. Early examples of wind farms and domestic turbines in the US did result in a disproportionately large number of deaths in local bird populations. However, improvements in technology and a better understanding of avian behaviour mean that today, wind turbines now account for less than 0.1% of human-related avian mortality (cats, power lines and windows being the major causes).
Where bats are present, a bat survey may be required. The vast majority of UK indigenous species will not fly/hunt any higher than 10m. The most common turbine hub height is 15m, with typical rotor blade length for a 10kW turbine of 3-3.5m, there is little to no impact on bats. Planning departments work to criteria set out by the government in the PP22 guidance document, which states that where possible, turbines should be located away from hedgerows and water sources. If this isn’t possible, the planning authority may require an Environmental Impact Assessment to demonstrate potential effects on the local environment, and how these could be mitigated.
The major driver of the uptake in domestic win turbines in this country has to be the reduction in carbon emissions facilitated by wind power. It’s a free, renewable energy and will increasingly provide for our energy requirements as we move away from non-renewable forms of energy.
About the author: Dave Houston is owner and founder of GenFit, based in Chester, providing Solar PV, Solar Thermal, Biomass and Wind Turbine Installation.
If you have a question about anything in the above blog, please ask it in the comments section below.
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