Overhill Wind Farm

Site Name

Overhill

Site Location

6.6 km north-east of Dalmellington and 7.9km south of Ochiltree, East Ayrshire

Proposed Turbine Height

180m to tip

Proposed No. of Turbines

10

Approximate Installed Capacity

Up to 49.9 MW

Planning Authority

East Ayrshire Council

Predicted Community Benefit Fund

In line with good practice

Status

Pre-application

Project Description

East Ayrshire Council granted planning permission in May 2020 for the Overhill Wind Farm (Planning application reference: 17/0395/PP). The “Consented” development comprises ten turbines with tip heights of 149.9m and associated infrastructure. The planning application was accompanied by an Environmental Impact Assessment Report (EIAR) dated May 2017 and Further Environmental Information (FEI) submissions dated March and August 2018. These submissions make up the consented project.

Planning Application

Energiekontor is currently consulting on its proposals to seek a new planning consent on the Site which would increase the tip heights to 180m to tip. The turbines are proposed in the same location as those that were consented. The downloadable documents on this page include 11 visualisations or ‘photomontages’ for the proposal project. These indicate how the 180m tall turbines would look from different ‘viewpoints’ and these viewpoint locations are annotated on the two ‘Comparative ZTV CONSENTED (150m) and Proposed (180m)’ boards.

We have also included the corresponding 11 photomontages that were used for the Consented project (150m to tip) to illustrate the difference in appearance between the Consented project and the new proposal. The new proposed turbine photomontages are annotated with an ‘a’ prefix and the consented turbine photomontages are annotated with a ‘b’ prefix on the boards to the right.  E.g. the view from Skares is shown for the proposed (180m turbines) as ‘9a’ and the consented (150m turbines) as ‘9b’. 

The key changes to Overhill Wind Farm compared to the consented project introduced by the new Proposal are:

Characteristic Consented Development Proposed Development
Number of turbines 10 10
Tip height 149.9m 180m
Blades 3 3
Turbine colour Light grey Light grey
Turbine foundations Approximately 18m diameter on a hexagonal base Approximately 18m diameter on a hexagonal base
Aviation lighting required No Yes

Given that the turbine heights proposed would be over 150m, UK aviation policy requires that the turbines should be lit during night-time conditions. The following measures are proposed to mitigate the effects of lighting:

  • The lights would be fitted with directional intensity mitigation shielding to focus the hub lighting in the horizontal plane (+ or – a few degrees);
  • The lights would automatically dim to a nominal intensity of 200 candela during periods of meteorological visibility in excess of 5km; and
  • Radar-based proximity activated lighting could be included to switch the lights on and off based on the presence or otherwise of aircraft.

Based on an average annual UK domestic electricity consumption figure of 3.889KWh (as set out in the BEIS publication “Energy Consumption in the UK” (2017)) and on BEIS’s standard carbon dioxide savings figure of 430g/KWh, we predict (expected generation) that the consented wind farm using 10x turbine Nordex N117 machines with tip heights of 149.9m could generate a net 102 GWh of energy, which could:

  • Power 26,227 homes
  • Saves 43,860 tonnes of CO2 per year

Based on a 10x turbine Nordex machine with tip heights at 180m we predict that the wind farm could generate a net 146 GWh of energy, which could:

  • Power 37,542 homes
  • Save 62,780 tonnes of CO2 per year.

Why are we seeking a new planning consent for Overhill Wind Farm?

Since Overhill was first designed in early 2017, more than 3 years ago, there have been a number of changes which have affected our ability to deliver the scheme as a subsidy-free wind farm. These include:

Power prices

At the time Overhill was initially designed the general expectation was that power prices would steadily rise over time. In the intervening period however power prices have actually fallen for a range of reasons (e.g. Brexit, covid-19) and are currently around 25% lower than they were in 2017, which is a significant drop. Given what’s currently happening on the UK and world stages with covid-19 and a looming global recession, power prices are unlikely to significantly increase in the short to medium term. That is not necessarily a bad thing as low power prices are obviously good news for consumers and manufacturers, but if new wind generation is to contribute at these lower price levels then schemes need to be able to perform better.

Grid charging review

In December 2019, Ofgem significantly changed the way that generators are charged transmission use of system charges (TNUoS). They removed what is called the ‘residual’, this is to be implemented from 2024 onwards. This impacts both existing and new generating stations of all technologies. However, the impact of this change is greatest for generators in Scotland as these are further away from demand. It also has a greater impact on intermittent generation such as wind and solar as the loss cannot be offset by larger capacity market payments – as is possible for coal, gas and nuclear. The effective impact is a doubling in transmission charges from 2024 onwards, leading to a significant economic impact.

Wind resource

Our initial site design and viability work was undertaken using large scale climatic modelling data, which is not site-specific and carries a margin of error of +/- 10%. We have since installed a met mast on the site for a couple of years to monitor the actual wind resource at Overhill, and unfortunately the measured data is at the lower end of this error margin. This is reflective of a trend we are seeing on a number of sites in southern Scotland at lower-medium altitudes, often influenced by forestry, where the measured wind data is frequently lower than predicted using climatic modelling. A 10% reduction in wind speed equates to a 20% reduction in energy generation, so the wind reduction has serious implications for the viability of the wind farm.

Taken together these factors have a considerable influence on the viability of Overhill, such that without a tip height enhancement achieving viability will be challenging. Depending on the turbine chosen, the tip height increase proposal has the potential to increase the energy generation of the project by 50%, from approximately 100 GWh per annum to around 150 GWh per annum. This increase is transformative for the project’s viability.

Public Engagement

We understand and recognise the value of the feedback provided by members of the public during all engagements and consultations. Due to current restrictions on public gatherings due to the COVID-19 crisis we are conducting this public consultation through other means, including online. The downloadable documents on this page contain the consultation material that we would have presented at a public exhibition for the proposal. We are keen to receive your views and comments to the project and would be grateful for any comments or questions on our proposals, and these can be sent directly to the project manager Justin Reid at This email address is being protected from spambots. You need JavaScript enabled to view it. by August 16th. We will aim to respond within 48 hours of receiving the question.

We will also be holding interactive individual Question & Answer sessions on the 12th and 13th August between 5pm and 7pm where members of the public can discuss the project with members of the Energiekontor team.  Please get in touch with us (This email address is being protected from spambots. You need JavaScript enabled to view it.) and we will allocate a 10-minute telephone conversation slot, on these dates, where we can discuss the project with you.  We would also be happy to discuss any aspects of the proposal up until the submission of the planning application.

Click here to complete a questionnaire on the new proposal.