Colin Holmes

The Case for Wind Energy Generation in Rockmarshall, Cooley Pensinsula, Co. Louth

Abstract

This work is an assessment of the case for a wind farm located in Rockmarshall. An assessment of the location is completed with details on its predicted environmental impact and how local issues are addressed.

Introduction

I chose this subject as it is a point of current heated discussions in my local area. I wanted to use this oppertunity to delve into the key issues and reasonings for chosing an area for a wind farm which so many people disagree on.

Proposed Location

The Cooley Pensinula is the only area in Countly Louth with any significant elevation. The proposed location for the wind farm is within a forestry north of Jenkinstown village approximately 7km from Dundalk.

The SEAI wind atlas highlights the onshore windspeed at a height of 75m of the Pensinula. Rockmarshall does show average windspeeds of 8.75m/s but that windspeed is exceeded by three other areas on the Pensinula. The Carlingford mountains running parallel to the north east coast has the widest and strongest area with an average speed of 11m/s. The other two areas are located in the Black mountains north of Rockmarshall with average speeds of 9.5m/s.

See the attachment 'Rockmarshall Windfarm Location and Windspeed Map and Special Area of Conservation for the Cooley Peninsula'.

The most suitable location for any wind farm is on the Carlingford mountains however as the final map on the document shows it is a 'Special Area of Conservation' along also with the two locations on the Black mountains. As Rockmarshall is not a protected area it becomes the only remaining viable location.

Key Factors in Deciding where to Locate a Wind Farm

Wind resource available

Proximity to a grid connection

Site not restricted by environment designations

Land availability and access

Planning Permission

The initial application for this wind farm was for eight wind generators. After public consultation / two open days and assessment of environmental concerns the number of generators was scaled back to five generators and all were located within the forestry area. [1]

Capacity

The Rockmarshall Wind Farm will have a capacity of 11.5 to 12.5 megawatts. This will provide enough energy for at least 7,000 homes which equates to 18% of households in County Louth. The five wind turbines are of the three bladed type each having a hub height of up to 80 meters. The rotor blades will be up to 41.2 meters making the overall the overall height of the turbines 121.2 meters. Each turbine will have a capacity of 2.5 megawatts. [1]

Environmental Concerns

The electricity produced by the Rockmarshall Wind Farm will displace approximately 20,300 tonnes of carbon dioxide every year. [1]

An Environmental Impact Assessment was carried out as it is required for all proposed wind farms exceeding 5 megawatts. The assessment process took 18 months to complete. The process involved six stages, Scoping, Baseline Studies, Impact Assessment, Assessment of Significant Impacts, Mitigation Measures and Residual Impacts. [1]

1. Landscape and Visual Effects

Wind turbines are unavoidable large structures and their visual impact on the surrounding landscape must be assessed. The Cooley Peninsula is made up of three mountainous regions, surrounding lowlands and large coastal area. The visual impact of the proposed turbines were assessed on 23 reference points within an appoximate 20km visual range. The reference points were chosen from designated scenic routes, local community views, population centres and major transport routes. The key issue highlighted by the report was the visual impact of the turbines on the tallest and most iconic peak in the peninsula which is Slieve Foy when viewed from the south / southeast. The report deemed it it to have a 'moderate visual impact' and also that the impact was temporary as it is fully reversable when the wind farms 25 year lifespan expires. [1]

2. Ecology and Ornithology

Rockmarshall is situated outside the designated protected area of the peninsula. An assessment of the range of birds which would be affected by the turbines was carried out. It was confirmed that no species of high conservation which would be affected by the turbines visited the area over a period of 12 months. The majority of high conservation species are located in the protected bay area.[1]

3. Noise

Noise from wind turbines are generated from the blades themselves turning in the wind and the mechanical noise of the gearbox. The noise is charactarised by a swishing sound but this noise reduces and fades into the background the further away the observer. The turbines will operate at a cut in speed of 3.5m/s (at hub height). The noise and power output then gradually increases with increasing wind speed until the rated power is reached. Above this the power levels flatten off and there is little or no increase in noise with wind speed as the turbine blades are pitched to shed energy and maintain constant electric power. The turbines are shut down with a mechanical brake at windpeeds above 25m/s to prevent damage. [1] pg 211.

An extensive noise assessment was carried out and detailed in the Environment Impact Statement from page 211 to 230. Various factors were considered and used to gauge the noise impact of the turbines on those dwellings closest. The noise levels of the proposed construction was also assessed. A lower fixed limit of 45dB(A) with a maximum increase of 5dB(A) at nearby sensitive locations was considered appropriate. A sample of three houses spaced out evenly along the line of turbines were highlighted throught the report but all houses within a certain range were also assessed. Over 90 dwellings were assessed in total ranging in distance from 600 meters to 1,100 meters from the turbines. Noise sampling was taken during various times of the day with most attention on quiet daytime periods and the nightime. Quiet daytime periods were defined as all evenings from 6pm to 11pm, Saturday afternoon from 1pm to 6pm and all day Sunday 7am to 6pm.[1]

See the attachment 'Noise Assessment Summary from Environmental Impact Statement'.

Various turbines were considered based on their noise levels. At location H42 it was discovered that some turbines would be heard above the normal background noise. As the Vesta's V80 turbine is one of the noisiest as seen on the table it was recommended the Enercon E82 2.3MW turbine be used.

The attachment also shows the locations of the three dwellings / noise monitoring locations. The locations are spread evenly across the range of turbines.

The noise contour map was created based on the worst case wind direction scenario however most properties are upwind of the prevailing south westerly winds.

Logistics / Economic Viability

The energy produced will be exported to the National Grid through a 'secured gate 3 connection' to a substation near Dundalk. The Gate 3 connection makes the grid connection economically viable and minimises transmission losses. [1]

Various other locations were accessed. See the attachment on 'Considered Alternative Site Location'.

Rockmarshalls location which is relatively close to the Dundalk substation was a key factor in the decision making process. Many alternate locations were dismissed due to their distance from the substation or their lack of viable wind potential.

Local Economic Benefits

Approximately 25% of the total construction and servicing contracts will be tendered to local businesses. The local community will also receive a annual fund which will total 212,500 Euro over 25 years. Louth County Council will accrue business rates and Coillte will benefit also as the landowner of the Rockmarshall site. [1]

Conclusion

Rockmarshall is not the ideal location for a wind farm in County Louth. After reviewing the wind atlas for the County it is obvious that while located further three other locations on the Carlingford and Black mountains offer a greater source of wind potential and in the case of the Carlingford mountains the potential for multiple more turbines. However these locations cannot be considered due to its designation of 'Special Area of Conservation'.

A thorough and fair environmental assessment of the area was carried out and the impact of the wind farm in my view is minimal. The visual impact to Slieve Foy is moderate and only when viewed from one aspect. The visual impact of the proposed turbines were assessed on 23 reference points within an appoximate 20km visual range which far exceeded my personal expectations. The ecological impact is also minimal as the wind farms footprint would only affect 1% of the forestry habitat area and houses few bird species none of which are protected. The impact of the wind farms noise was assessed in great detail and while some recommendations were made none are substantial enough to change the viability of the site.

Local objections: See the attachment on 'Objection to Rockmarshall Windfarm From Mountaineering Ireland'. This document offers a concise point by point objection to the development by the mountaineering association of Ireland and contains the main issues all locals are concerned about. After reading the environmental impact statement I believe the issues raised have all been considered and minimised as fairely as possible.

An important issue raised in the environmental impact statement was how the wind farm would detract from the visual impact of the landscape. I disagree that wind farms automatically detract from the landscape. I believe that if properly planned and laid out a wind farm can enhance the landscape. In my view the computer generated images of the predicted wind farm shows an enhanced landscape.

I believe that it is important that renewable energy is kept in the forefront of everyones mind. If all wind farms were located on the west coast or offshore it would be a case of out of site out of mind? I believe there is no better way to maintain everyones attention on renewable energy and usage than to have a windfarm in visual range. It gives everyone in visual range a vested interest in renewable energy and serves as a constant reminder to all that we must use our energy conservatively.

Reference

[1]. Environmental Impact Statement: http://www.rockmarshallwindfarm.com/EIS.pdf