NE4002 Wind Energy Engineering

Wind farm site visit

Kilgarvan wind farm

Name: Peter Duffy

Student number: 108339252

Lecturer: Dr. Paul Leahy

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Contents 1. Introduction ........................................................................................................................................ 3

2. Site Overview ..................................................................................................................................... 5

3. Environmental aspects/constraints ................................................................................................... 9

4. Planning ............................................................................................................................................. 10

5. Technology ........................................................................................................................................ 11

5.1 Turbines ...................................................................................................................................... 11

5.2 Electrical Infrastructure .............................................................................................................. 14

6. Operations ........................................................................................................................................ 16

7. Maintenance ..................................................................................................................................... 17

8. Conclusion ......................................................................................................................................... 17

9. Appendices ........................................................................................................................................ 18

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1. Introduction

An important part of the continuous assessment for the 4th year NE4002 Wind energy module

involves a site visit to a wind farm. Kilgarvan wind farm was chosen as the destination to carry out

this visit and the report primarily based on what was seen and learned during this site visit, along

with other relevant online data and information.

The Wind farm is located near the border between Cork and Kerry. The route shown in figure 1.1

was taken in order to reach our destination. The wind farm was developed by SWS Energy who

were subsequently purchased by Bord Gáis Energy in 2009.

A large number of wind farms are situated in the area and the visit provided a great opportunity to

observe a range of different turbines types in operation.

The first find farm in the area to be built was Kilgarvan, situated in the townland of Coomagearlahy.

15 Vestas V90 turbines were installed, giving the wind farm an installed capacity of 42.5 MW. This

wind farm was constructed before the present gate system was launched by the national

transmission operator. As a result this Windfarm is said to be “pre-gate”, the notified connection

date to the transmission network was March 2006.

An extension was sought to this wind farm and a further 23 turbines were built. Six Nordex N90

turbines were built in Inchincoosh and seven similar turbines were built in Lettercannon. These are

part of the Eirgrid “Gate 2” group of Windfarms. The combined installed capacity of these

13turbines is 30MW. Ten Vestas V52 turbines were constructed in Sillahertane. The installed

capacity of these turbines is 8.5MW. A summary of this is shown in Figure 1.2 below.

Name No. of turbines Turbine Type MW

Kilgarvan 15 Vestas V90 42.5

Inchincoosh 6 Nordex N90 13.8

Lettercannon 7 Nordex N90 16.2

Sillahertane 10 Vestas V52 8.5 Figure 1.2 Summary of installed turbines.

Figure 1.1 Route taken to wind farm.

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A map depicting all the wind farms in the area which was received prior to the visit is shown below.

The areas which are part of the Kilgarvan site have been highlighted. Although other wind farms are

visible in this map they are not part of the Kilgarvan site and will not be discussed in this report.

Figure 1.3 Map of all wind farms in the area.

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2. Site Overview Site location The Google map below shows the exact location of the Windfarms. Coloured polygons have been created to indicate where each wind farm is situated and give an indication of the size of each area. The nearest main road to the site is the N22. The black line seen in the image below represents the road constructed in order to gain access to the elevated site from the N22. According to Google maps the length of this access road is approximately 8.22km. The construction of this road involved the removal of large quantities of topsoil and the importation

of crushed rock to act as a road base and clause 804 material for the road surface. An important

aspect of building the access road to the site was the need to cater for the large turbine components

which had to be delivered. In order to cater for significant amounts of water which may flow off the

road during heavy periods of rainfall drainage channels were constructed alongside the roadway.

Figure 2.1 Google map representation of wind farm locations.

Site History

The original site was purchased from Coillte by SWS. Once purchased a long and complex planning

process ensued. Planning was granted for 15 turbines in Kilgarvan with a tip height of 120m.

Construction began in 2005 and first generation was achieved in early 2006. The extension to the

development, the developments at Lettercannon, Inchincoosh and Sillahertane, began with an initial

planning application in March of 2003. Construction started in June 2008 and power generation

began in July 2009.

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Wind Resource Winds at the site are primarily originating from the South and South – Westerly direction. According

to the Sustainable Energy Authority of Ireland (SEAI) wind atlas (Figure 2.2) the average annual

wind speed is approximately 9 m/s at a height of 75m above the ground level.

The wind turbines have optimum performance at wind speeds of 10-11 m/s when an output of up to

3MW can be achieved. Thus the turbines are quite well suited to a site with an average annual wind

speed of 9 m/s.

During the site visit the average wind speed was 3m/s

Figure 2.2 SEAI wind atlas for the site.

Areas with the highest average wind speed are represented by the dark orange/red colours, yellow

represents lower wind speeds while the turquoise/light blue areas have the lowest average

speeds.From this wind atlas it is clear that the wind farms have a very good wind resource.

Terrain The terrain of a site has a large impact on the output that that be achieved from wind turbines. The

type of terrain in the Kilgarvan site would be classed “complex terrain” (Large scale elevations or

depressions- hills,ridges, valleys, etc).

In order to represent the terrain present in the wind farm sites I created models of the turbines and

landscape using Google sketch and Google Earth software packages. Using these software packages

the changes in elevation present in the sites can be accurately displayed. Accurate models were

created for Inchinccosh, Lettercannon and the original Kilgarvan (Coomagearlahy) sites.

Unfortunately an accurate model could not be created for the Sillahertane site as the satellite views

available are not sufficiently clear to accurately locate the positioning of turbines.

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Sillahertane

Figure 2.3 Google Sketch model of Sillahertane Windfarm

Lettercannon

Figure 2.5 Google Sketch model of Lettercannon Windfarm

Figure 2.4 Google Earth model of Sillahertane Windfarm

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Figure 2.6 Google Earth model of Lettercannon Windfarm

Kilgarvan

Figure 2.7 Google Sketch model of Kilgarvan (Coomagearlahy) Windfarm

Figure 2.8 Google Earth model of Kilgarvan (Coomagearlahy) Windfarm

The original Kilgarvan site is the hardest to depict in these snapshots of the software as it is the

largest and has the most turbines. By using these models in the software it is easy to navigate

around the site and get a proper idea of the type of landscape and terrain present.

Originally there was large forestry on the sites, this was initially cleared to make room for the

turbines and then cultivated further in order to increase the output from turbines. Evidence of

forestry and vegetation is visible in the above models.

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3. Environmental aspects/constraints

Wind farms have relatively little impact on the environment in comparison to conventional fossil fuel

power plants; however there are some concerns and constraints which must be taken into account

when developing wind farms. Important factors include the visual impact on the landscape, the

noise produced by rotor blades, shadow flicker from rotating blades and the death of birds that fly

into the rotors. As part of the planning process an Environmental Impact Statements (EIS) had to be

submitted for the wind farms.

In the case of wind farms situated in the Kilgarvan area particular attention had to be paid to the

Roughty River. This river and the tributeries which run into it are very important areas for the

breeding of fish.

Noise and shadow flicker issues were not as large a concern as they usually are in the development

of many other wind farms as the surrounding areas are not heavily populated. Noise from turbines

can be minimised by producing efficient designs which convert more of the wind’s energy into

rotational torque and less into acoustic noise. Noise can be further reduced by insulating the drive

train in the hub. At the design stage of the project a predicted noise modelling survey was carried

out over a two kilometre radius of the site.

Shadow flicker is the casting of shadows from moving turbine blades which could under certain

conditions cause flickering at nearby properties. In order for this to occur the sun would need to be

relatively low in the sky and be behind the tower. The turbine nacelle would need to be facing a

certain direction so that the turbine blades were turning and casting the shadow in the direction of

the property. Shadow flicker can be reduced by using shadow flicker analysis during the design

process. If wind farms are having trouble with shadow flicker becoming a nuisance, a sensor can be

installed which shuts down the wind turbine on the rare occasion the unwanted sun and wind

direction conditions occur. As there are no properties located near the site this is not an issue for

the wind farms.

The dangers turbine blades pose to birds are well documented and many birds are killed due to

collisions with wind turbines worldwide. Newspapers reported recently that a rare white-tailed sea

eagle was found to have died as a result of a collision with a turbine situated in Sillahertane.

(Source: Irish times April 4th2011). The eagle was introduced to Killarney National Park three years

ago and this incident may make it more difficult to built wind farms in the areas in the future. The

effects of wind farms on protected birds are one of the single biggest obstacles to planning in

Europe.

Local residents were wary of possible electromagnetic effects from turbines which may interfere

with signals to televisions in the area. This was accounted for in the designs to insure major

problems wouldn’t arise.

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4. Planning

4.1 Kilgarvan Site In May 2002 a planning application was lodged with Kerry County Council (Planning Ref. 02/1241) for

the construction of 17 wind turbines, an electrical substation and two meteorological masts to be

50m in height. In response to this conditional planning was granted in November 2002. Another

planning application was made in August 2003 (Planning Reference 03/2306) for the construction of

an extension to the planning granted in (Planning Ref. 02/1241), this application was granted in

October 2003. Additional modifications were made for the final constructon of the 15 Vestas V90

turbines. The location of thes site can be seen in Figure 3.1 (Google map representation of wind

farm locations.) and the individual turbine location is visible in Figure 1.3 (Map of all wind farms in

the area.)

4.2 Lettercannon Site A planning application for the Lettercannon site (reference no. 03/2508) was submitted in August

2003. This application included the construction of four 1 MW wind turbines, service roadways and

control house, a temporary wind monitoring mast to be 40m in height . Further information was

sought and the applicant ion was revised to include seven 3 MW wind turbines with a blade

diameter of 90m and hub height of 80m. Conditional planning was granted in October 2004. An Bord

Pleanala received an appeal however the original decision was upheld, with a few additional

conditions to be adhered to

4.3 Inchincoosh Site A planning application for the Inchincoosh site (Reference No. 07/1605) was made in April 2007 for

the construction of six wind turbines with a hub height of 80m and a blade diameter of 90m, a

meteorological mast to be 80m in height, four borrow pits, construction of internal site tracks and

associated works. This planning application was conditionally granted in August 2007, once further

information had been submitted

4.4 Sillahertane Site A planning application for the Sillahertane site (Reference No. 03/91359) was lodged in March 2008

for the erection of ten 1 MW wind turbines and a temporary wind monitoring mast 40m in height

and control house. Planning was granted in May 2008 and was then revised to allow for the

construction of ten 850 kW turbines.

(Data sourced from www.Kerrycoco.ie)

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5. Technology

5.1 Turbines

Kilgarvan

Kilgarvan wind farm has fifteen Vestas V90 turbines with each turbine having the capacity to

generate 3MW. The hub height of these devices is 85m and the rotor has a diameter of 90m. The

devices have three carbon fibre blades. The device has independent pitch control to each blade.

The tower weighs 210 tonnes while the nassel weighs 60 tonnes. The V90 is advancement from the

previous model, the V80. Improvements from its predecessor include a 27% greater swept area.

The blades are now manufactured carbon fibre as opposed to the fibre glass previously used, this

reduces the weight of the larger blades. The devices also include new features such as automatic

blade-bearing lubrication which reduce the number of preventative maintenance visits needed

annually. A full data sheet for a Vestas V90 turbine has been included in the Appendices of this

report.

Figure 5.1 Vestas V90 turbines at Kilgarvan

Figure 5.2 Vestas V90 Nacelle components Figure 5.3 Vestas V90 power curve

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Sillahertane

Sillahertane wind farm site has ten Vestas V52 850 kW turbines. Although this type of turbine is

smaller than the V90 and has a reduced installed capacity it is very efficient. It is also one of the

most reliable turbines available and is suitable for both high and medium wind speeds. Over 3,400

have installed world-wide. It is known to have very good pitch regulation and incorporates a system

featuring microprocessors that continuously adjust the pitch of the blades to ensure optimal blade

angles in relation to the prevailing wind. The site was not visible on the tour but an example of the

turbines from another wind farm is shown below. A full data sheet for a Vestas V52 has been

included in the appendices of this report.

Figure 5.4 Photograph of Vestas V52

Figure 5.5 Vestas V52 Nacelle components Figure 5.6 Vestas V52 Power curve

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Lettercannon and Inchincoosh

There is a combined total of 13 Nordex N90 turbines installed in Lettercannon and Inchincoosh wind

farms. Seven turbines are located in Lettercannon with the other six being in Inchincoosh. Each

turbine has a maximum power output of 2.3MW, bringing the total installed capacity in these sites

to 30MW. The hub height of these devices is 75m and the have a rotor diameter of 90m. These

turbines are especially suited to inland locations and they are designed for a service life of at least 20

years. The rotor consists of three blades which are made of glass fibre-reinforced polyester. The

generator is a doubly fed asynchronous machine. A full data sheet for a Nordex N90 turbine has

been included in the appendices of this report.

Figure 5.9 Nordex N90 Power curve

0

500

1000

1500

2000

2500

4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Po

we

r (k

W)

Wind Speed (m/s)

Nordex N90 2.3 MW Power Curve

Figure 5.7 Nordex N90 wind turbines Figure 5.8 Nordex N90 Nacelle

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5.2 Electrical Infrastructure

A 110kV substation is situated in Coomagearlahy near the on-site offices. The exact location is shown in the Google map below. A 3D model of the substation was created using the Google sketch and Google Earth software and this further helps to visualise the electrical infrastructure on site. The power generated from each turbine is transferred via a step up transformer to a 20kV collection system which feeds into the substation. Power is then transferred down the mountain to Clonkeen substation which is located beside the N22. Over 6km of 0verhead 110kV transmission lines are used for this process. This substation then supplies the power generated from the wind farms into the national grid. The locations of both substations are shown on the next page, as is a photo of the overhead transmission lines which are used to transfer the power down the mountain.

Figure 5.12 Google sketch model of Coomagearlahy sunstation.

Figure 5.13 Google Earth model of Coomagearlahy substation.

Figure 5.10 Google maps location of Coomagearlahy substation. Figure 5.11 Transformer located in the substation.

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Figure 5.14 Google map of both substations.

The picture below shows the Eirgrid transmission network for the South of the country. Eirgrid is the national transmission operator and is thus responsible for the operation and transmission of electricity above and including 110kV. Voltages lower than 110kV are dealt with by ESB networks.

Figure 5.15 Map of the Eirgrid transmission network for the South of the country

Figure 5.14 Overhead powerlines used to transfer power generated.

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6. Operations

The power generated by the wind farm is operated and managed by Eirgrid. Eirgrid is a state owned

commercial company which is responsible for the provision of transmission and market services.

Eirgrid is Ireland’s Transmission network operator (TSO) and Market operator (MO) in the wholesale

trading system in the country. The wind turbines on site have the ability to vary the power they

produce by adjusting the pitch angle of the blades. This was examined in the technology section of

this report. When wind speeds are greater than 25m/s the wind turbines will stop generating

power. This speed is the cut-out speed for the turbines and ensures that they do not suffer damage.

In certain circumstances Eirgrid may need to curtail the power generated from the wind warm, this

can be done from the National Control Centre (NCC) located in their offices in Dublin 4. They must

ensure that the power supplied to the national grid is sufficient to meet the demand at all times. It is

vital that they balance the supply and demand as efficiently as possible to run the network in the

most economical manner and keep the system running smoothly and safely. The frequency of the

system must be maintained at 50Hz so careful monitoring is needed at all times.

Figure 6.1 NCC located in Eirgrid Offices

The performance of the turbines can also be monitored on-site. A system control and data

acquisition (SCADA) system is located in the site office beside the substation. Unfortunately we

were not allowed into the building during the visit. We were told that they monitor wind speed,

direction, rotor speed, blade pitch and power generation. Maximum performance is achieved from

most of the turbines when there is a wind speed of approximately 10-11 m/s.

Figure 6.2 NCC located in Eirgrid offices

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7. Maintenance

There are four full time people involved in the running of the wind farm. Two of these are Bord Gais

employees, one being the wind farm manager and the other is more involved with on site

environmental issues. Two Vestas maintenance technicians usually deal with faults which can occur

onsite. An automated texting system is used to inform them of any onsite fault or problems when

they are not there. Vestas can also monitor the turbines from their control centres.

The turbines are serviced regularly to ensure a high availability. Vestas are involved in a five year

contract with the operator which guarantees an availability of 97%.

The Vestas V90’s have an annual two day scheduled service. The Vestas V52’s also have a two day

annual service, although these days are split up so as to have one at the beginning and one at the

ned of summer. Although some dirt and moss was visible on the turbine blades they are never

cleaned. There is no evidence to show deterioration in performance as a result of this dirt and so it

would not be economical to clean the blades.

8. Future plans

There are plans for further extensions to Kilgarvan wind farm. At present there is an application in

Gate 3 for the installation of a further 62.2MW of power on the site. There is also an application in

Gate 3 for the development of 10MW of power at Sillahertane and 21.6MW at Lettercannon. All of

these projects are still in the application phase but have been assigned nodes under the “Eirgrid

Gate 3 node assignment” procedure.

9. Conclusion

The site visit to Kilgarvan wind farm gave a great insight into the running and operation of a real life

wind farm. It was great to see the large turbines up close and get the opportunity to go inside the

massive structures. The knowledge and experience of the on-site employees was very interesting

and added greatly to the value of the trip. It was of particular interest to visit a Windfarm such as

Kilgarvan which has a number of different wind farms sites and turbine types in operation and has

been in operation for many years.

Researching and writing the report increased my awareness of the difficulties and level of

organisation associated with designing, constructing and operating a wind farm. The strict planning

controls and environmental constraints to which the wind farm must abide show the level of

planning which is needed to develop such a large scale project. Overall the site visit was very

worthwhile and a great addition to the wind energy lectures received during the course of the term.

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10. Appendices

Vestas V90 datasheet

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Vestas V52

Rotor

Diameter: 52 m

Area swept: 2,124 m2

Nominal revolutions: 26 rpm

Operational interval: 14.0-31.4 rpm

Number of blades: 3

Power regulation: Pitch/Optispeed®

Air brake: Full blade pitch

Tower

Hub height: 44 m, 49 m, 55 m, 65 m, 74 m

Operational data

Cut- in wind speed: 4 m/s

Nominal wind speed: 16 m/s

Cut-out wind speed: 25 m/s

Generator

Type: Asynchronous with Optispeed®

Nominal output: 850 kW

Operational data: 50 Hz/60 Hz 690 V

Gearbox

Type: 1 planet step 2-step, parallel axle gears

Control

Type: Microprocessor-based monitoring of all turbine

functions as well as OptiSpeed® output regulation

regulation and OptiTip® pitch regulation of the blades.

Weight

Nacelle: 22 t

Rotor: 10 t

Towers:

Hub height: IEC IA

44 m 45 t

49 m 50 t

55 m 60 t

65 m 75 t

74 m -

t = metric tonnes

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Nordex N90 datasheet