Sustainable Hockerton's Wind Turbine

Alan Simpson MP officially opened our wind turbine on the 21^st March 2010. He presented a fascinating talk which we have captured on video. Rob at Hockerton Housing Project has included it in a blog  OPENING by Alan Simpson MP so you can recapture the experience if you want. We presented Alan with a brochure called “Sustainable Hockerton The story so far” written by Peter Cooke one of our directors. If you would like to read it you can download it by clicking SHOCK The story so far.pdf (730KB pdf file). It was a fantastic afternoon with sun, wind and over sixty people, mostly SHOCK members celebrating together the start of production. Simon Christy provided a venue in his restaurant / conference centre in the village where we could warm up and talk after being on the windy hill with the turbine.

 Wind turbine generation data - Wind turbine generation out put graph

The following notes are extracts from the planning application and explain more about the turbines history:

Location Research

To establish the available sites in Hockerton Parish for a single wind turbine a map was created and distributed. This map showed houses in the area with a 500m radius circle around them. Turbine sites outside these circles are thus very unlikely to cause a disturbance for the residents of the houses. The government guidance for larger wind turbines is 400m separation so an extra allowance of 100m has been made. The high ground with an open aspect to the South West is advisable to catch the wind. This indicated land near the north boundary of the village to be a preferred location.

Once a site had been found this location was also circulated to all parish properties on a leaflet and an open meeting held. This location was agreed as a suitable location and is the one shown in this application’s site location plan, appendix 4.

An Opportunity

An opportunity has arisen. Enthusiasm has been generated by the availability of a second hand wind turbine from Denmark. It is very good value for money and if proven to be viable could fulfil the first step in the vision above. Several communities are taking advantage of them already. One on the Isle of Gigha, Scotland with three relatively small turbines. (Click here for further information). To some extent this reduces the risk of the development here (Note however our wind resource is less than Gigha’s).

This application relates to a single turbine of relatively small scale; which is also good value to buy. This will be community owned and will be used not only to pay back the community investors but also provide some money to support sustainable initiatives in the local community of Hockerton. Thus the people not willing or able to invest in the initial purchase will benefit from the turbine as the community projects are funded.

It is estimated that the proposed turbine will generate enough electricity to cover the electrical needs of all the domestic dwellings in Hockerton.

Resources and help with the details of the proposal have come from Hockerton Housing Project Trading Ltd, Nottingham County Council, EMRA, the CRI and other bodies.

Power Generation

The wind turbine objective is to generate the equivalent amount of clean electricity that the houses in the parish Hockerton use. Details are contained in Appendix 6. In summary it is estimated that the:
• Domestic consumption is 275 MWh per year.
• Turbine production would be 330 MWh per year
• Carbon dioxide equivalent saving of 176 tCO2 per year

In other word all the domestic electricity use would be covered and some of the commercial consumption. Importantly green house gas emissions will be reduced by 176 tCO2 per year.
Please note: This production depends heavily on the wind at the site. The estimated figure comes from the DTI wind speed data base and is 6.0 m/s for the application site at 25m height. The electricity is transported via the “nation grid” which means the electricity will be sold to a power company; Good Energy Ltd is envisaged. The income generated will be distributed to investors who can then use this money to pay their electricity bill from the power company. In other words the output from the turbine will not go directly to the houses, down our own dedicated wires! The rating of the turbine is 225kW – this is the maximum output power. The average generating power will be less depending on the wind speed. This average power has been taken into account in the calculation of the figures above.

As this application does not relate to a commercial development of five or more turbines (Ref: SPG Wind Energy, July 1999, page 3) and is not more than 29m in diameter (Ref: SPG page 5) it is assumed that a formal Environmental Impact Assessment is not required, so the appropriate policies to comply to are taken as W1, W2 and W3 from the SPG on Wind Energy. These are now listed below.

Policy W1 Notes

Policy W1 relates to the environmental impacts of noise generation, shadow flicker, electromagnetic disturbance, visual impact and net environmental gain. It also requires a statement on why the design, height, number, colour, density of turbines and blade diameter are appropriate. These are discussed and stated below.

Noise Generation

This is a relatively small geared turbine so will produce minimal noise; it’s the ford fiesta of the turbine world with many installations around the UK. However as all wind turbines it will emit sound; in this case from the gear box and from the blades. Little noise impact is expected in its location.

The Wood Green Animal Shelter’s V29 Turbine in Godmanchester, Cambridgeshire is the same type and size of turbine and can be listened to gain an appreciation of the noise levels emitted. However if this is not possible reference to the noise analysis made by the manufactures can be made, see appendix 1.

Two distinct areas are covered, tonal noise and “general” noise. Analysis of the tonal noise is made first. It states that when measured, at a distance of 56m no audible tones can be heard. The nearest dwelling is over 500m from the turbine. The nearest footpath is 337m away.

The report also contains information on general noise levels. In summary at 56m from the hub the A-weighted noise level was 56.7 dB(A) was measured. The following translates this into a more meaningful figure for the application site.

In a rural location with “soft” surrounding surfaces e.g. not Tarmac, if you double the distance from a noise source you can reduce the noise level by 6dB(A). (The inverse square law states that each time the distance from the source is doubled the sound pressure level reduces by 6dB(A)). So at a distance of 448m (Double 56 three times) you would expect a noise level of 38.7 dB(A). This compares to a car travelling 100 km/hr passing 15 m away 80 dB (A), normal conversation 60 dB(A), moderate rainfall 50 dB(A), Bird singing 50 dB(A), quiet living room 40 dB(A), whispered speech 40 dB(A), average rural sound level at night 35 dB(A). As background noise levels increase significantly as wind speed increases it is very unlikely the effect of the turbine noise will be measurable at 500m. In other words the 38.7 dB(A) is created with a wind speed of 8m/s. At this wind speed the background noise level is above the average because of leaves rustling etc and will be much higher than the 35 dB(A) figure, thus the turbine noise will be masked by the “wind noise” .

An estimation of noise impact illustrating the above phenomenon can also be made by listening to the two turbines currently sited in Hockerton 200m from the A617. No complaints have been received about the noise these make, one has been up for about 6 years.

Shadow Flicker

Analysis of shadow flicker has been made. This shows that there is no possibility of shadow flicker for Wyton Lodge Farm, Sunnybank Farm, The A 617, Roewood Farm, Winkburn and other dwellings in Hockerton. The view from a small section of the minor road to the west of the site has a theoretical chance of receiving shadow flicker for a short time. Shadow flicker is not relevant to this application.

Civil Aviation and Ministry of Defence

A notification proforma (Civil Aviation & Ministry of Defence Safeguarding) has been completed, returned and a response received from the Civil Aviation Authority and MOD. No objection was made. See request form and letter in appendix 8. Further enquiries have been made to the aeronautical sites as recommended by the Civil Aviation Authority and no aviation objections were raised. See letter to from Gamston aviation also appendix 8.

Electromagnetic Disturbance

Several organisations have been contact to assess the impact on telecommunications and TV reception. OFCOM was used as the first point of contact, with subsequent communication with civil fixed links operator Vodafone Limited, CSS Spectrum Management Services and the Joint Radio Company (JRC). The BBC Windfarm analysis tool was used as recommended by OFCOM for TV reception and an on site survey was carried out to clarify the uncertainties highlighted in the in this report. Summary of responses:

Organisation Summary of response
Vodafone Limited Do not foresee any potential problems
CSS Spectrum Management Services Do not foresee any potential problems
JRC Do not foresee any potential problems

BBC Windfarm analysis tool and Onsite survey

An assessment has been made of the potential effects of interference with household reception of TV signals using the BBC tool. A survey was carried out of local transmitters and households using them to clarify the report. Based on this survey an analysis of the potential effects of the turbine was made, it is predicted that there will be no significant negative effects on reception.

Visual Impact on the Environment

The visual impact on the environment has been assessed. The wind turbine is a three bladed, up-wind machine mounted on a 29m free standing tower. Locally; its impact could best be determined by comparing it to the current turbines sited at Hockerton Housing Project (HHP). Those turbines are of similar height 26m so give a good idea of the visual impact the tower will make. The blades are longer than the HHP turbines; here comparison can be made by looking further-a-field at the Wood Green Animal Shelter; Godmanchester turbine. This is a very similar turbine to the one proposed for Hockerton. 29m tower with 27m diameter blades.

Net Environmental Gain

The environmental gain can be considered in a wide context to establish the net gain, to do this we can consider sustainable development as a whole. Sustainable development is best analysed in three areas: environmental, social and economic. Taking each in turn:

Environmental
A wind turbine produces clean renewable energy. Electricity from the grid has associated greenhouse gas emissions and in particular emissions caused when it is produced. So the energy produced from the wind turbine will reduce pollution and help to combat global warming.

Wind turbines have a good energy balance. The comparison of energy used in manufacture with the energy produced by a power station is known as the 'energy balance'. It can be expressed in terms of energy 'pay back' time, i.e. as the time needed to generate the equivalent amount of energy used in manufacturing a wind turbine or power station.

“The energy produced by a wind turbine throughout a 20-year lifetime (in an average location) is eighty times larger than the amount of energy used to build, maintain, operate, dismantle, and scrapping it again. In other words, on average it takes only two to three months for a wind turbine to recover all the energy required to build and operate it.”
Source Danish Wind Turbine Manufacturers at www.windpower.dk

Wind turbines also use very little land compared to other energy generation sources and even then the land under a turbine can be used for other uses e.g. grazing sheep or growing plants.

Turbines can also be easily decommissioned at the end of its life returning the land to its original state.

Social
With this turbine, we will be able to demonstrate the supply of renewably generated electricity to meet the needs of a small village community is realistic. It will show that ordinary families and individuals can make a significant contribution to reducing the production of gases that contribute to global warming. A community owned business will be set up to manage the turbine and use any profits to further the community’s aims of making Hockerton Parish a more sustainable place to live. These aims are outlined on page 3.

Advice has been taken from Notts County Council of appropriate organisation types to facilitate a community owned turbine.

This will be a ground breaking scheme in England and will thus attract media and community interest from around the country raising the profile of the district. It will also give other groups a practical example to copy hopefully catalysing our fight against climate change in this area.

The government has initiated a program requiring all new homes to be built to a zero carbon standard within 10 years. One of the implications of this will be that these homes will have to have all their energy supplied from renewable sources. A community owned turbine in Hockerton should go along way to achieving this target for our older houses well before the 10 year dead-line.

Economic
This turbine will demonstration the financial viability of a community owned renewable energy generator. Initially the majority of the funding is planned to come from the local community; some funds will come from the wider community as agreed by residence of Hockerton. It planned for this investment to be paid back over time, with interest, as the turbine generates and sells electricity; costs will be paid first. Any profit will go towards funding the other aims of the community organisation – creating a more sustainable Hockerton.
Why the design, height, number of turbines, colour, density of turbines and blade diameter is appropriate is now stated.

Design
A Vesta V29 turbine is envisaged for this site. However the group intends to buy a second hand turbine from Denmark so the final manufacturer can not be defiantly stated. However the Vestas V29 is the most likely design as these are the “Ford Fiesta” of the turbine world and fit the needs of the community at this time. Manufactures details of the Vesta V29 are included in appendix 5.

Height
The hub height of 31.5m is necessary for the turbine blades to be out of the turbulence of the ground and any surrounding trees etc. This is also a standard tower height for this type of turbine.

Number of turbines
Only one turbine is applied for. This is the most cost effective size that will generate enough energy to cover the equivalent electrical requirements of the domestic houses in the village. This will help us meet our aim of being a Zero Carbon, sustainable village.

Colour
The colour of the turbine and tower will be white.

Density
Only one turbine if proposed so this is calculation is irrelevant.

Blade diameter
The blade diameter is 29m. This is appropriate for a wind turbine of rated capacity 225kW in our wind regime and optimised for maximum yearly energy production.

Impact on Wildlife

As a general point there are two other wind turbine in Hockerton on the Hockerton Housing Project site. These are of similar scale; the height of the towers is slightly less, 26m as apposed to 29m, while the blades are shorter 2.6m as apposed to 13.5m. Biodiversity on this site has expanded remarkably, including the period since the first wind turbine there was erected. In resent years rare species including the Hobby and water-vole have been recorded. The impact on wildlife from theses turbines has if anything been positive with birds resting on the guy wires. No birds have been killed, and horses and sheep graze nearby without any detrimental effect. By inference another turbine will not be detrimental to wildlife in the area.

Employment development

Employment will be generated in Hockerton if this turbine is erected. Initially employment will be created in the community owned business managing the turbine electricity sales etc. As profits are generated, these will be used to instigate the other sustainable schemes in the village thus creating more local employment. This may be for example supporting the creation of a cycle path to Southwell; local labour will be employed or loft insulation could be purchased and installed again using local labour.