港巴34線

Introduction & Background

Global warming is a great crisis, threat that facing by multi-countries, one of the main reason is the behavior of wasting energy by human and bad electric using method case requirement of energy increasing continuous, but also utilize the fuel and technology that not environmental-friendly. Renewable power generate technology are emerging to cater the purse of environmental-friendly power generate technology. Wind power is one of the renewable power generate technology. As the name suggests, wind power will not consume any limited resources, fuel like fossil fuel and produce hazard gas to pollutant ambient air case global warming. For the aspect of cost, wind power is cost-effective, the cost of wind power generate technology spend is highly lower than traditional power generate method, and have a decreasing trend in recent years. So wind power and other renewable energy can increase its competitiveness by virtue of increase the original advantages. According to the annual Wind Technologies Market Report released by U.S. Department of Energy, wind power continue to be one of the lowest cost electricity generation technologies in U.S. Average wind power electricity cost of each consumer is about 12 cents per kilowatt-hour, while this cost is includes electric generation and deliver to consumer, actual power generation cost just 2 to 4 cents per kilowatt-hour, (Robert Fares, 2017)

Now, the tender of our consultant company has been choose by an energy development company to help to select a suitable site to construct a windfarm. It is necessary to utilize GIS to find out all the data and implement environmental modeling which are relevant to the condition of windfarm site selection tender request, then select the possible site location by review by filter and result review procedure. This is the aims of our consultant company to implement this project.

It is suggest that the selection of offshore windfarm should be choose the place that are windy and near the population,. The main reason of choose Wales as the site selection of windfarm construction base on the climate of Wales belongs to Oceanic Climate, usually windy, Wales’s Oceanic Climate are cater the condition of offshore windfarm construction: average windspeed should be 25km/h or above (World Weather Online, ) and geographical, topographical should be empty so let windspeed to be higher and more consistent, to transfer more power for energy production (Haroon, 2015). In recent decade, the average windspeed of Wales were 20-30 km/h in most of the months, and some of the months are above 30 km/h and even over 40 km/h. So it is cater to the windspeed condition of building offshore windfarm.

Study Area

Figure 1. Location of study area

The main study area of windfarm study area of windfarm construction is in Wales of UK, included offshore region like Cardigan Bay base on onshore and offshore windfarm are also consider. The aim of select Wales as study area because the oceanic climate and the wind potential factors are suitable to develop windfarm. 

Objectives

• To find the suitable location of windfarm construction base on the criteria of windfarm site selection 
• To judify the suitable location of windfarm construction according to the GIS application output result. 

Methodology

GIS Application

At this stage, GIS application process is necessary to analysis, calculate the data collected. Some tools in GIS software are utilized in data analysis like “XY to line”, “Join and relates”, ‘Point Distance”, “Kriging” etc. Then cooperate with relevant GIS application skills to getting the answer. No matter which application will be process, the preparation procedure must be implement as follow: First download the raw data from web or collect from baseline survey, then open the table in GIS software by “Add Data” or “Add XY Data” function. The different between “Add Data” and “Add XY Data” is in the number of field data add. 

The main GIS function that will utilize on the analyze process include “Kriging”,“Point Distance”, “XY to line”. “Kriging” is the function that utilize on drawing color ramp map to classify the data by different color. “Point Distance” is the function that analyze the distance between two points, this function will be utilize on calculate the distance between windfarm location proposed to different facilities include airport SSSI, birds migration zones, cities etc. “XY to line” is the function that utilize on drawing line to connect two points to show the distance by graphic format. “Buffer” is a common GIS method, this function will utilize on showing the impact area of facilities by graphic format.  

Spatial Relationship

The following are the spatial relationship will be apply in site selection project, apart from the basic element of plane space: point, line and plane, but also having “Planar Near” to show the differentiation data buffer zones composite with point and plane, like wind speed of different region . (esri, )Table below shows the spatial relationship relevant to windfarm site selection.  

Item	Geometry	Method
Geography of seabed	Point to polygon (plane)	Planar Near
Distance to power demand site	Point to point	Planar Near
Distance to local airport	Point to point	Geodesic Near
Wind speed/Wind potential	Point to polygon (plane)	Geodesic Near
SSSI scope	Polygon to polygon (plane)	Planar Near
Distance to population	Point to point	Geodesic Near

Criteria of Windfarm Site Selection

Windfarm site selection is the multi-criteria project, apart from the wind-power, wind-speed and wind-direction condition, the environment surrounded, geography and humanities conditions are also the criteria of windfarm site selection due to operation and construction stage will be influent by those criteria or those criteria will be influent to the operation and construction stage of windfarm. The specific criteria can be substitute according to the data type (victor or raster), categories of data (environmental, humanities, geography, ecological etc.). The relevant ordinance and the parameter indicated in ordinance will be incorporate into the scope of windfarm site selection criteria. 

Item	Categories	Parameter	Data Type	Software / Website	Relevant Ordinance
The location of seabed cable	Society	N/A	Raster	Submarine Cable Map 2019	/
Distance to local airport	Traffic impact	2 km	Victor	Magic Map, ArcGIS	Scottish Planning Policy 6
Impact to ecology	Nature conservation	N/A	Raster	Windfarm Development and Nature Conservation	/
Bird migration sites	Nature conservation	10 km	Raster	ArcGIS	Bird Directive Article 4
Wind speed	Environment / Climate	25 km/h	Raster	ArcGIS	/
Geological	Geography	N/A	Raster	ArcGIS	/
SSSI buffer	Nature conservation	10 km	Victor	Designated Sites View, ArcGIS	Renewable Energy Planning Guidance Note 3
Distance to population	Society	2 km	Victor	Digimap, Magic Map, ArcGIS	Scottish Planning Policy

Results

Figure 2. Distribution of birds migration zones, airport and windfarm

Level	Category	Density (per km³)
1	Very Rare	0–26
2	Rare	26–68
3	Moderate	68–120
4	Common	120–180
5	Very Common	180–255

This is the buffer zone of airport and distance to windfarm from airport in Wales existing and the migratory bird migration zones. The aims of investigate the distribute of airport and the seabed cables because this two things are the interference to the windfarm operation and construction, so the windfarm site selection should be avoid to build near airport, migratory birds migration zone and moulting zones. To view the situation of Wales, for the aspect of the airport distribution, the main airport at Wales are concentrate at eastern, northern and southern Wales and some are located at the middle part of Wales with over 90 airports. The distribution of airport is relate to the distribution of windfarm existing because the airplanes will be pass through the sky up to windfarm due to the airlines are overlap with the location of windfarm, this situation can cause risk to windfarm operation. The distribution of windfarm at Wales are mainly locate at the northern and middle part of Wales, some of the windfarm are close to the airport, the take off and landing of airplanes must interference the windfarm. The influent zones of airports to windfarms are represent in red line and 2km buffer zone, the influent zone are cover a large scale of east and middle Wales. So the eastern, middle and southern Wales especially middle part of Wales not suitable to construct windfarm in view of airport.  

For the aspect of migratory birds migration zones and moulting sites, those are relate to the migration direction of migratory birds, the shearwater migration zones are found at the Cardigan Bay and North Sea (offshore region of northwest Germany). The migration zones at the Cardigan Bay are include shearwater like Tadorna tadorna and Oceandroma leucorhoa etc. For now on, there are 12 shearwater species are found in Cardigan and other onshore location of Wales, the number of shearwater found in Cardigan Bay was competitively high with 120-255 found. Thus, the location of proposed windfarm are location inside the shearwater migration zone and very close to the location that shearwater found

Figure 3. Windspeed of Wales on 50m, 100m and 200m 

This is the windspeed existent in 200 m high of Wales with the distribution of on-shore windfarm existing. The lowest and the highest windspeed in Wales are 6.24 km/h and 18.57 km/h respectively. Windspeed of Wales has been divided into 5 levels and categories, from “Low” to “Extremely high”. According to the survey result on Wales windspeed, the middle and northern part of Wales include Gwynedd, Conwy, Powys etc. is competitively low and some locations in the middle part of Wales with windspeed range 6.235290051-10.15404316 km/h. And have a increase trend to southern part of Wales and offshore region of Wales with increase to 11.41191454 - 12.47626723km/h in 200m high. Thus the windspeed at 50m and 100m high is different. A large majority place in Wales have low to moderate in windspeed and some location like offshore have high windspeed level (8.339744414 - 9.547165738 km/h for 50m high and 9.614015326 - 10.42592354 km/h for 100m high) Although the windspeed still not yet reach the criteria 25 km/h to build the windfarm. But the southern part and the offshore region of Wales are the potential locations to develop windfarm. For the aspect of the windspeed of different height the average windspeed of 200m high is competitively high. And consider with the coverage scale of high-speed wind, 200 m high is completely larger than 50m and 100m.  

Table 4. Level of windspeed on 50m, 100m and 200m 

GBR Windspeed at 200m – Wales

Level	Category	Range (km/h)	Location (County)
1	Low	6.24 – 10.15	Powys, Neath Port Talbot etc.
2	Moderate	10.15 – 10.83	Ceredigion etc.
3	High	10.83 – 11.41	Offshore
4	Very High	11.41 – 12.48	/
5	Extremely High	12.48 – 18.57	Offshore

GBR Windspeed at 100m – Wales

Level	Category	Range (km/h)	Location (County)
1	Low	3.99 – 8.51	Powys, Neath Port Talbot etc.
2	Moderate	8.51 – 9.61	Ceredigion etc.
3	High	9.61 – 10.43	Offshore
4	Very High	10.43 – 11.88	/
5	Extremely High	11.88 – 18.78	Offshore

GBR Windspeed at 50m – Wales

Level	Category	Range (km/h)	Location (County)
1	Low	2.44 – 6.99	/
2	Moderate	6.99 – 8.34	Powys, Ceredigion etc.
3	High	8.34 – 9.55	Pembrokeshire
4	Very High	9.55 – 11.22	Offshore
5	Extremely High	11.22 – 19.54	/

Figure 4. Geography and humanities information of Wales 

This is the geography, cities and SSSI distribution in Wales. The buffer of SSSI has been shown in the figure above to represent the place that unsuitable to construct windfarm in 10km buffer zone. According to the result, the SSSI existing are concentrate in the eastern inland and southern ocean of Wales. Almost all the location in Wales are not influent by the SSSI, just some boundary part are cover by the buffer zone of SSSI in England like eastern part of Powys and Wrexham. Thus, the site selection of windfarm can be still consider in the middle inland and western ocean because the SSSI are competitively rare to compare with adjacent district of Wales.  

For the aspect of population distribution, the high population density city in Wales are not common, the population of cities in Wales discovered are at the range of 25-805 per km3. There are some of the coastal town that are face to the Cardigan Bay like Aberaeron, Cilgerran etc. because the distance from the proposed windfarm to coastal towns are quite short, around 10-30km, it is roughly fulfil to the requirement of site selection: the distance of windfarm need to close to the population.  

For the aspect of geography, the large scale of Wales are belongs to Metamorphic Rocks. The distribution of Metamorphic Rocks are covered the eastern and middle Wales. The ground that is belongs to Metamorphic Rocks may not a good location to set up a windfarm base on the shear force and intensity of Metamorphic Rocks is low and weak in bearing. The geography of Wales’s offshore region belongs to Sedimentary Rock Limstone, the composition of limestone is form in shadow marine and pertify into limestone from the bone of dead animals.  

Discussion 

 Possible site selection location 

Figure 5. Site selection of proposed windfarm 

Base on the restriction mention above, the possible site selection should be in the offshore western of Wales ( Cardigan Bay near St. George Channel) The possible site selection location of windfarm are in the offshore of western Wales near St. George’s Channel. In view of the total install capacity of windfarm, 100 MW is suggested to construct.  

. Following is the main factor to consider:  

5.1.1.Distance to the airport and SSSI 

Windfarm must be avoid to build near the airport and SSSI because the reason of interference to each other, this means the operation of airport will influent to operation of windfarm and the operation of windfarm will influent to SSSI. The take off and landing of airplane will crash to the wind turbine if the airport runway is too close to windfarm. According to the analyze result, there are about 90 airports in Wales, and some of the existing windfarms are have the short distance to airport with .Exclude all the not suitable location, For the aspect of SSSI, SSSI is mention above that eastern and western of Wales may not suitable to windfarm construction because there are SSSI or inside the buffer zone of SSSI. The site selection of windfarm should consider SSSI as a factor because the operation of wind turbines will cause endanger birds species die by roll birds into wind turbine with airflow, this risk will exist if the mitigation pathway of endanger bird species are very close or even overlap with the location of windfarm.  

5.1.2. Windspeed 

The windspeed of 3 different level has been shown above. Result has discovered that the windspeed in 200m is the best base on the highest average windspeed between 50m, 100m and 200m high with about 11.5km/h. Compare to the different location, offshore of western Wales near St. George’s Channel is the location with highest windspeed with 11.41191454 - 12.47626723km/h, this location have wind potential, offshore of western Wales is competitively suitable than other location of Wales like middle Wales.  Thus base on the aviation and mitigation bird safety, the height of wind turbines are suggest as 100m-200m above horizontal line.  

5.1.3. Geography  

For the aspect of geography, a large scale of Wales are belongs to Metamorphic Rocks. The intensity of Metamorphic Rocks are low, the shear strength force of Metamprphic Rocks are also low. If the rocks are stress, destroy are easy to occur, weathering resistance ability are competitively low. It is estimate that collapse risk may be occur when windfarm is being construct or after construct due to the fact that foliation will be destroy when the foundation and piling procedure will shock the rocks, in addition Metamprphic Rocks are weak in stress bearing. Sedimentary Rocks are concentrate under the ocean of Wales, mainly limestone and sandstone, the hardness of this two types of stone are generally high (The University of Auckland, 2005). Sedimentary rocks like limestone and sandstone are more suitable to be the foundation of offshore windfarm because sedimentary rocks may be possible to load the weight of wind turbines. In addition, the hardness of sedimentary rocks are variety especially limestone (The University of Auckland, 2005). It’s ensure that the difficulty of rock blasting process to construct wind turbine foundations will be reduce. 

Potential environmental impact  

The possible site selection location suggested above is just a preliminary suggestion, means the location suggested is a competitively suitable, but not represent that no environmental impact generate. The potential environmental impact following mansion are still exist. 

5.2.1. Visual Impact 

It is expect that the wind turbines with over 100m will impact to the sea visual of coastal cities. In general, the topography of coastal cities are very low. At the same time, refer to the general offshore windfarm, the location of offshore windfarm are set at continental shelf that is the land that cover by the seawater, the location of continental shelf is close to some of the coastal cities in Wales for example Aberaeron, Cilgerran etc.. Like the wind turbines suggested to utilize on windfarm, each windfarm height 100-200m, and the distance from location of windfarm proposed to coastal cities of Wales are about 30km and the distance to some of the cities in northern Cardigan Bay like Aberaeron just about 10km, the distance is quite short. So, the visual block of wind turbines to coastal cities can’t be avoid.  

5.2.2.Water pollution 

Water pollution of windfarm can be view by two stages: construction stage and operation stage. The main factor of elevate the water quality is water pollution generate by wind turbines will impact to sensitive receiver of sea water. Risk to water quality are exist during construction stage and operation stage. The process of wind turbines installation that influent to water quality include piling hole drilling lead sediment diffusion, sediment diffusion caused by buried cables and sediment diffusion caused by excavation of cable landing point.(The Hongkong Electric Co., Ltd., 2006), base on the drilling and excavation process will flip out the sediment on seabed. In the operation process, fuel and oil that provide wind turbines to operation will be spill out or leak to the sea due to the transformer failure.(Basic Concepts, 2018) Because the wind turbines are install on the seabed, it is sure that the leak oil will spill out and contaminate the water than increase the turbidity, suspend solid and dissolve oxygen. To avoid the hazard of water pollution generate by wind turbines to sea water sensitive receivers, avoid the project's failure to sensitive receivers of water quality possible impacts, including: the construction of wind farms and submarine cables is far away is suggested to consider in planning stage.(香港環境資源管理顧問有限公司, 2010) 

5.2.3.Impact to nature ecology 

The nature ecology of windfarm project concern is the migration pathway of birds. The potential impact to bird migration will be temporary nuisance and change the bird flight route include Petrels and Shearwater. The coastal area of western Wales have the migration zones of Todorna tadoma and the moulting sites are locate at the south and east side of Wales. The migration pathway of Shearwater like Todorna tadoma were predicted migration from the direction of North Ireland to Wales then to Scotland finally to the east of Germany and Denmark base on another moulting site of Todorna todama was found at Helgoland. The location of offshore windfarm proposed is locate inside the migration zone of Todorna tadoma at the western coastal area of Wales, the migration pathway have high potential to overlap with the proposed offshore windfarm. The risk of windfarm operation to migration birds will be occur. Although the main migration zones of Todorna todama is surround to whole UK, but the arrangement of wind turbines arrangement is suggested to maintain a certain distance to reply the “Bird Directive” Article 4: to minimize the potential for adverse effects on birds.(English Nature, et al., 2001) 

Conclusion 

This is the project to help a customer to find a suitable location to set up a windfarm, onshore and offshore are considered. The criteria of windfarm setting include: distance to facilities like airport, SSSI, the location of migratory birds migration sites, windspeed, geographic etc.  

The method of data analyze in this project will be utilize GIS method to analyze and display the data found. GIS application function include “XY to line”, “Point distance”, “Kriging” have been utilize in the project.  

The offshore region at Cardigan Bay may be the possible location of setting windfarm base on the windspeed is competitively higher than onshore location with 11.41191454 - 12.47626723km/h, and having increase trend following to the season change. In addition, the location of proposed windfarm is far to the SSSI, the influent of windfarm will be drop significant than at the location that western Wales. Thus some of the factor that are necessary to caution. First, the visual impact, then, water pollution problem and the impact to migratory bird. For the aspect of visual impact, the location of windfarm proposed is close to the coastal cities, within 10-30km, the visual will be block after the windfarm constructed. In addition, the location of proposed windfarm is locate inside the scope of migratory bird’s mitigation zone, that means the operation of windfarm that locate at the Cardigan Bay may have opportunity to impact to migratory birds, so the site selection should avoid to locate too close to the migration pathway of migratory birds. For the aspect of water pollution, the main reason of setting offshore windfarm to impact water quality will be oil leak 

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