SITE SEARCH REPORT FOR THE

PROPOSED WIND TURBINE INSTALLATION

AT

LAMMA ISLAND

Projects Division

August 2004

Revision 2

The Hongkong Electric Co., Ltd.

香港電燈有限公司

1. INTRODUCTION

The Hongkong Electric Company Limited (HEC) proposes to install a wind turbine system for power generation on Lamma Island. The tentative capacity of the proposed wind turbine is in the range of 600kW to 1MW. The electricity produced by wind turbine will be fed into the existing main power grid for supplying of “green” power to local residents.

Lamma Island is an outlying island providing Hong Kong with valuable assets of non-urban lifestyle and refreshing scenery. HEC has sought to demonstrate the commitment of sustainable development through the application of renewable energy to meet the high environmental standard expected by the community. This Report presents the criteria and findings of the preliminary site search undertaken as part of the feasibility study for the proposed wind turbine installation at Lamma Island.

2. WIND MONITORING AND DATA ANALYSIS

HEC have commenced a feasibility study in April 1999 to collect wind data on Po Toi and Lamma Island to evaluate the wind potential in southern part of the Hong Kong territory. Two wind monitoring stations, one on Po Toi and another on Lamma Island, were set up in April and November 2001 respectively to record one-year wind profile (Fig. 1). Wind vanes and anemometers were installed at regular intervals up to 50m above ground to simulate typical hub height of modern wind turbines. The wind data were logged every second and integrated to a 10-minute average. The collected wind data were stored temporarily in a data logger and periodically downloaded for analysis.

Fig. 1 - Location of Wind Monitoring Stations

The 12-month wind power monitoring at Po Toi and Lamma had been completed in November 2002. The monthly and annual wind speed at Lamma Wind Monitoring Station is summarized in below:-

Month	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec	Avg
Wind Speed (m/s)	6.4	6.2	6.2	5.8	5.8	6.2	6.5	5.5	6.4	6.5	6.1	5.8	6.11

To calculate the variation of wind speed over the area of Lamma Island, the computer wind flow model WAsP and WindPro have been used. The inputs to the models include a digitized map of the topography, surface roughness of the terrain within the area of interest and primary wind data. The WAsP model predicts wind speed at a number of given points in the model domain, specified by Easting, Northing and height. The models are set to predict specific wind power density at intervals of 10m grids over the Lamma Island and at a height of 45m above ground level. This height represents the hub level of a typical modern 600kW wind turbine.

Fig. 2 - Wind Resource Map of Lamma Island

Areas of wind power density over 150W/m², equivalent to the average wind speed of about 5.5m/s, are considered suitable for wind energy utilization and warrant further evaluation ^{(1) (2) (3)}. Modern wind turbines have the cut-in wind speed of approximately 2.5 to 4 m/s and sites with annual wind speed below 5.5m/s are in general not considered economically viable due to low electricity output of the wind turbine. Fig. 2 shows the “isovent” map of Lamma Island, showing lines of equal power density in terms of energy per swept area of wind turbine blades. The areas of favourable potential are shown as blue, light blue, green, yellow and red colours. Areas of high wind potential are in general found at sites of high elevation such as hilltops and ridges of mountain.

3. Proposed Wind Turbine Plant

3.1 Wind Turbine Selection

Wind turbines come in size of 0.5m to over 100m in rotor diameter, in capacity of a few watts to 4 megawatts. Small wind turbines (say <30kW) are usually DC machines and are used to power individual households and remote industrial facilities. Utility scale wind turbines (>500kW) are used for the centralized generation of electricity near load centres. Wind turbines produce energy when the wind blows and for most application variable energy output is not acceptable without an energy buffer. Small wind turbine system uses batteries or diesel engines to supplement the wind power and large wind turbines are ideally suited for the grid-inertia systems.

Diversity of design concept and technical details is evident in present commercial wind turbines. Wind turbine is now becoming a matured technology and the cost is declining. The wind technology is becoming competitive with conventional forms of power generation in the sites of good wind potential. The industry is supported by the volume production worldwide. Until recently the market has been dominated by the concept of “horizontal axis, tubular tower, three bladed, stall or pitch regulated and variable or fixed speed” design for utility scale wind turbines.

The typical size of wind turbine has grown steadily in term of rotor diameter and rated power output over the past 20 years. Currently the most cost-effective wind turbine size range for grid connection use is 600 to 1500kW with rotor diameter of 45 to 75m. The average unit size of recently installed

(1) Wind Energy – The Facts, European Wind Energy Association, 2004

(2) Wind Force 12, European Wind Energy Association, May 2004

(3) Assessing the World's Wind Resources, Dennis Elliott, IEEE Power Engineering Review, Vol. 22(9), Sept 2002 & NREL National Wind Technology Center Publications 2002

wind turbines is found increasing all over the world. Capacity less than 600kW is being phrasing out of the production line due to economy of scale. Almost all major manufacturers in Europe, USA and Japan have started producing megawatt-scaled turbines, primarily for the European market where windy sites are found. HEC’s wind project focuses on the wind turbines in the range of 600 kW to 1MW as a result of technology maturity, equipment sourcing and site constraints on height clearance.

3.2 Engineering Requirement

The construction and operational criteria upon which the planning of wind turbine system has been proceeded are summarized below.

Site Area

The layout of the wind turbine system will take into account the construction and operational requirements. The proposed wind turbine requires a minimum area of 30m x 20m as laydown area for construction and operation. The foundation, in size of 15m x 15m, will be either piling or footing design. The wind turbine will be ideally located on a piece of flat land to provide direct bearing foundation and to limit civil costs.

The transformer will be installed at the bottom of the wind turbine tower. Switchgear and power conditioning devices will be housed inside a high voltage distribution pillar (HVDP) made of stainless steel (4.6m L x 2.5m W x 2.8 m H). Power cables will be buried underground for connecting the wind turbine, HVDP and the nearby 11kV power grid on the 275kV cable route.

Height Clearance

The site will take into account the height limit imposed by the planning authority. Civil Aviation Department (CAD) has imposed height restriction for all permanent structures in accordance with the Hong Kong Airport Control of Obstructions Ordinance (Fig. 3). Most areas in north Lamma along the cable routes fall between the restricted heights of about 160 to 165m above the Hong Kong Principal Datum (PD).

Typically the 600kW and 1MW wind turbines have rotor diameters of about 45m and 60m respectively. The towers will normally have to cater for approximately half of a rotor diameter of clearance from the ground level. The site shall allow for a clearance of 68m and 90m from ground level to tip height for a 600kW and 1MW wind turbine respectively.

Fig. 3 - Height Restriction Map for Lamma Island

Access

The site will take into account the accessibility of vehicles and mobile equipment required for construction and maintenance of wind turbine system. The permanent road leading to the site shall be paved and have a minimum width of 5m and maximum inclination of not greater than 15% for the passage of heavy trucks and mobile cranes.

3.3 Conceptual Design

The system will consist of a wind turbine of capacity in the range of 600kW to 1MW, a transformer, a switchgear and associated power control devices required for integration to the utility grid.

The output from wind turbine is transmitted to the existing 11kV grid via a step up transformer and a switchgear. The synchronous generators of the grid system supply magnetizing current for the induction generator of wind turbine. The blades of wind turbine will start to move when wind speed is persistently exceeding the cut-in speed (~ 2.5 to 4m/s) of the wind turbine. The electricity generated will be fed to the utility grid if the power output is adequate to cope with the power loss on the transformer and cables. The output voltage of the wind turbine will be automatically adjusted to cater for voltage change across the distribution cables under various loading conditions. An auto-synchronous controller or soft starter will be required to control the operation of a synchronizing breaker with respect to the wind turbine output voltage and frequency (Fig. 4).

Fig. 4 - Schematic Diagram of the Proposed Wind Turbine Installation

4. Preliminary Site Search

4.1 Primary Screening Criteria

Primary screening is largely driven by the non-environmental criteria. In this section, broad environmental screening criteria have applied to focus on the identification of potential sites within the search envelope of Lamma Island. The possible sites resulting from application of both non-environmental and environmental screening criteria have formed the long list of potential sites.

The principal location requirements and evaluation criteria for the proposed development are to avoid ecologically sensitive areas on the Lamma Island. The proposed sites should not intrude into any of the following areas:-

§ all potential sites for country parks and special area;

§ all registered sites of special scientific interest (SSSI); and

§ all developed areas.

For the purpose of the site search, the excluded areas shall be supplemented by the consideration of existing land-use and the identification of areas to be excluded due to insurmountable access constraints and height restriction. These consideration forms the basis for the preliminary screening criteria.

4.2 Constraint Mapping

4.2.1 Methodology

Constraint mapping techniques have long been used in site selection studies to bring together environmental and engineering considerations into an overall assessment. This is achieved through the collection of layers of mapping information showing features, constraints and planning proposals, to produce a multi-layered constraints map that forms the basis for the identification of the unconstrained areas. Constraints mapping provides a means of taking into account of potentially damaging environmental effects in a structured and rigorous way.

4.2.2 Constraint Criteria

(a) Country Parks

Country Parks comprise areas designated under the Country Parks Ordinance for the purpose of providing informal outdoor recreation and conserving landscape, wildlife and historical features. No new development can be carried out within country parks without approval of the Country and Marine Parks Authority. No designated country parks on Lamma Island and the potential sites for country parks are shown in Figure 5.

Fig. 5 - Potential Country Parks Fig. 6 - Site of Special Scientific Interest

(b) Site of Special Scientific Interest (SSSI)

The classification of a particular area as an SSSI carries significant weight amongst AFCD, EPD as well as conservation organizations and comes under the statutory protection of the Town Planning Ordinance. As a consequence, SSSI within the search envelope have been identified and shown in Figure 6. The wind turbine installation should not be encroached up the SSSI.

Fig. 7 - Developed Areas Fig. 8 - Areas without Proper Access

(c) Developed Area

Recent land use planning policy in Hong Kong has favoured the separation of industrial activities from the residential, commercial and retail mix of development areas. Developed areas of Lamma Island as shown in Figure 7 are therefore excluded from the area of search.

(d) Access Constraints

In view of the aesthetical impact and visual intrusion, any new permanent access leading to the site is not recommended. Most of the roads on Lamma Island are unable to fulfill the access requirements for erection and maintenance of a 600-850kW wind turbine. Areas accessible by heavy vehicles or marine vessels area limit to those along the existing 275kV Cable Routes and the coastal flatland closed to berthing facilities (Fig. 8).

Fig. 9 - Composite Map of Constrained Area

4.3 Potential Sites

The constraints mapped, and described above, have been brought together to produce a composite map (see Figure 9) showing the unconstrained areas for the search of potential site. The unconstrained areas have been scrutinized to determine potential locations for the 600kW or 1MW class wind turbine depending on height restriction.

Six locations (Figure 10) are identified by applying broad engineering requirements to the unconstrained areas.

Site	Location	Allowable Wind Turbine Capacity
1	Lamma Extension	600kW to 1MW
2	Tai Ling	600kW to 850kW
3	Yung Shue Long	600kW to 850kW
4	Tai Peng	600kW to 1MW
5	Pak Kok Tsui	600kW to 1MW
6	Lamma Quarry	600kW to 1MW

Fig. 10 - Potential Sites Identified for the Proposed Wind Turbine

5. Screening of the Potential Site

5.1 Intermediate Screening Criteria

Having identified sites that meet the broad environmental and technical criteria for a wind turbine installation, the intermediate screening exercise will establish a short list of feasible sites considered appropriate for further detailed investigation. The intermediate screening process includes site-specific engineering considerations in addition to appraisal of environmental and technical requirements. Each site is examined more closely to establish whether is to be retained for a detailed appraisal or excluded from further consideration because of a basic incompatibility with one or more of the highlighted issues.

The approach adopted is qualitative and sough to identify potential conflicts with the development of a wind turbine system. The criteria employed are as follows:-

(a) Engineering

· Wind Potential – favourable specific wind energy, reasonable energy output and utilization factor (average specific power more than 100W/m² or wind speed more than 5.0m/s)

· Geological Considerations – availability of adequate lay-down area, reasonable site platform

· Electrical Connection – proximity to existing 11kV power grid

(b) Environmental & Planning

· Noise – proximity to sensitive receivers

· Visual – proximity to dwellings and recreational areas/facilities

· Ecology – implication to site of conservation significance

· Land Use – potential confliction with area designated in the Outline Zoning Plan (OZP)

· Cultural & Historic Site – proximity to cemeteries, monastery ground and archaeological sites

Each of the long listed sites identified in Section 4.3 has been evaluated with respect to the intermediate screening criteria described above and the outcome is summarized below:

Long-listed Sites	Conflicts of Long-listed Sites against Intermediate Screening Criteria
	Engineering	Environmental & Planning
Site 1 – Lamma Extension	Very low wind potential (~ 60W/m^2). Excluded on this ground.	Encroach onto Lamma Extension site and limit future development of the power plant.
Site 2 – Tai Ling	No conflict identified.	Ground level 90mPD, maximum tip height of wind turbine limited to about 75m.
Site 3 – Yung Shue Long	Limited flat area and high back-slope, extensive excavation and slope reinforcement required. Excluded on this ground.	Ground level 88mPD, maximum tip height of wind turbine limited to about 77m.
Site 4 – Tai Peng	A slope of about 3m between site and cable route.	No conflict identified.
Site 5 – Pak Kok Tsui	Unfavourable wind potential (< 100W/m^2).	Located on the landing point of 275kV cable linking up Lamma Power Station to HK Island. Excluded on this ground.
Site 6 – Lamma Quarry	Very low wind potential (~ 60W/m^2). Excluded on this ground.	Limit future restoration of Lamma Quarry. A visual intrusion to Sok Kwu Wan. Excluded on these grounds.

5.2 Short-listed Sites

Of the 6 potential sites for wind turbine within the areas of least constraints established, four sites have been excluded due to principal engineering, environmental and planning conflicts summarized above, leaving the following two sties to be included in the comparative assessment (Figure 11) :-

(a) Site 2 – Tai Ling

(b) Site 4 – Tai Peng

Photos of Site 2 and Site 4 are attached in the Appendix 1.

6. Comparison of Short-listed Sites

The section provides an overall comparison and rankings of short-listed sites across all technical and environmental areas. At the end of this section, comparisons of each specialist area are then combined to provide the overall rankings of the short-listed sites. From the comparison assessment, the more preferred site is identified.

Fig. 11 – Short-listed Sites for the Proposed Wind Turbine

6.1 Wind Potential

Wind resource map (Fig. 2) reveals that both Site 2 – Tai Ling and Site 4 – Tai Peng have specific wind energy of about 150W/m². This wind potential is equivalent to an average wind speed of about 5.5m/s and suitable for utilization. Both sites have a clear exposure to the prevailing wind direction of easterly without topographic and man-made obstructions.

With a wind potential of 150W/m², the 600kW and 1MW wind turbines are able to generate about 700MWh and 1,150MWh electricity per annum respectively. These amount of electricity produced correspond to a utilization factor of 13%. Site 2 and Site 4 are considered to have same ranking in wind potential assessment.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Wind Potential	1	1

6.2 Height Restriction

The ground level elevations of Site 2 – Tai Ling and Site 4 – Tai Peng are 90m and 72m PD respectively. The height allowance for wind turbine at Site 2 will be 75m which is suitable for a machine in the range of 600kW to 850kW depending on manufacturer’s specification. Site 4, being lower in ground level, has a height clearance of 93m and is able to accommodate wind turbine up to 1MW. Site 4 is considered to have less restriction on height limitations and selection of wind turbine capacity.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Height Restriction	2	1

6.3 Electrical Connection

The wind turbine will be connected to the existing power grid supplying electricity to Lamma residents. Lamma Island has an extensive network of 11kV cables allowing for integration of wind turbine to the grid. Both Site 2 and Site 4 are within a distance of 50m to the Cable Route where the 11kV transmission cables are laid. Site 2 and Site 4 are therefore considered to have identical ranking in electrical connection.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Electrical Connection	1	1

6.4 Site Access

Site 2 – Tai Ling is located closed a Joint Bay on the Cable Route and can be accessed directly by mobile equipment required for construction and O&M of wind turbine. Site 4 – Tai Peng is on a piece of elevated platform close to a Joint Bay. It is not directly accessible by vehicles and special provisions are necessary for equipment delivery. The construction materials and equipment are able to be lifted up to the site from the Joint Bay by a heavy-duty crane. The slope between cable route and proposed site will however require reinforcement. The slope has a size of 3m x 20m and the mitigations associated with the provisions are uncertain at this stage. Site 2 is considered to have a better ranking in assessment for site access.

Sites away from the existing Cable Route are not considered suitable due to technical and environmental constraints. As the new access road meeting the criteria of wind turbine construction and operation stated in above item 3.2 will require extensive excavation and slope reinforcement works, it is considered technically and environmental unattractive for a demonstration project for utilizing the renewable wind energy.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Site Access	1	2 (-)

(-) denotes special provisions are required and a degree of uncertainty is associated with the provisions.

6.5 Land Use

Land use along the Lamma cable route is of mainly agricultural / farmland and green belt area. Both Site 2 - Tai Ling and Site 4 – Tai Peng are on the government land with abandoned farmland and village houses nearby. Consideration is given to the landowners involved in the development and their current and future options for land-use with reference to the latest Lamma Island Outline Zoning Plan. Both sites and their adjoining allotments are all found falling within the green belt areas zoned “Green Belt”. An application for change of land-use under Town Planning Ordinance will be required. Site 2 and Site 4 are considered to have same ranking in land use.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Land Use	1	1

6.6 Ground Conditions

Site 2 – Tai Ling and Site 4 – Tai Peng have a similar site platform made of bare rocks and thin soil. Depending on the result of site investigation and availability of adequate rock beneath soil, it is expected that both sites are suitable for piling or footing type foundation. Site 4 however has the disadvantage of requiring reinforcement of a 3m height slope between the site and adjacent cable route. The extent of work is uncertain without a detailed site investigation for soil conditions. Site 4 is therefore considered inferior than Site 2 in term of ground conditions.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Ground Conditions	1	2 (--)

(--) denotes site conditions unacceptable without mitigation and even with mitigation the impacts are likely to be of a major concern

6.7 Ecology

The proposed sites are typical low-shrub habitats with thin plant coverage. Vegetation at both sites is dominated by grasses, climbers and low trees. The species of natural habitat found at Site 2 and Site 4 are unknown but can be easily avoided if protected or rare species are identified. The construction period will be short and the site works will mainly involve building up of tower foundation and assembly of pre-fabricated components. Construction method will be carefully designed to minimize the potential impact to ground vegetation.

Documented evidences show that the impacts during operational phase will be confined to birds and bats. Overseas experiences of wild birds collision with wind turbines are site and species specific and associated with a dense array of wind turbines in wind farm. It is expected that wind turbine siting at both Site 2 – Tai Ling and Site 4 – Tai Peng with one single wind turbine will have insignificant impact to birds. Site 2 and Site 4 are considered to have similar ranking in ecological assessment.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Ecology	1	1

6.8 Noise

Site 2 – Tai Ling and Site 4 – Tai Peng are approximately 270m and 100m away from the noise sensitive receivers (NSR) at Tai Ling Village and Tai Peng Village respectively. Most farmland and houses have been abandoned in Tai Ling Village and only few permanent households are found having human activities. Tai Peng Village, on the contrary, has over 50 village houses and is one of the major residential spot at North Lamma.

Limited powered mechanical equipment will be used during a short construction period. During operational phase, wind turbine produces low level noise when turbine blades pass through the air. Typically a 600kW wind turbine produces sound pressure level around 40dBA at a 300m distance from the machine.

Site 2 has the advantages of longer distance from NSR. The direct sight from Tai Ling Village to Site 2 is largely blocked by topography and landscape. Wind turbine at Site 2 is comparatively less prone to noise impact. Site 2 is therefore considered to have higher ranking than Site 4 on noise impact assessment.

Relocation of wind turbine at either Site 2 or 4 to increase setback between the machine and the NSR is an alternative way to reduce potential noise impact. As explained in above item 6.4, the access road will introduce additional environmental impacts and be not cost effective for a demonstration project.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Noise Impact	1	2

6.9 Visual

The visually significant elements of the proposed wind turbine are a tower up to 60m and rotor swept area of about 2,550m². Key visual receiver groups within the zone of visual influence that are sensitive to the proposed development as identified as:-

(a) residential receivers sensitive on daily outlook and

(b) recreational users sensitive to visual intrusion of natural landscape.

The proposed wind turbine will have tip height up to about 160mPD and is unavoidably conspicuous and visible from part of the hiking paths and residential areas at Lamma and South District.

The visual intrusion on landscape from wind turbines is highly subjective. Many people see them as a welcome symbol of clean energy whereas as some find them unpleasant additions to the landscape. Objective prediction of appearance will be carried out during detailed design for a careful integration of development into the surrounding landscape.

As Site 4 would have a direct exposure to residential receivers at Tai Peng, it is therefore considered to have a lower ranking in visual impact assessment.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Assessment for Visual Impact	1	2

6.10 Overall Rankings

In the sub-sections presented above, the short-listed sites have been assessed and comparatively evaluated according to the potential impacts likely to arise as a consequence of construction and operation of a new wind turbine installation. Bring together the results of technical and environmental evaluation, the preferred site is identified. The categorization and ranking of the sites utilize the system described above are summarized as follows:

Site 2 – Tai Ling

The Tai Ling site is adjacent to a Joint Bay on the Cable Route. The site is directly accessible by vehicle and mobile equipment and has a reasonable laydown area for construction and O&M. The ground level is about 90mPD and can accommodate a 600-850kW wind turbine due to height restriction. The wind potential is about 150W/m² and annual energy production is estimated as 700MWh.

Site 2 has disadvantages of more stringent height restriction and in turn the selection for wind turbine capacity. Site 2 has however credited ranking in assessment for access, ground condition, noise and visual impact against Site 4.

Site 4 – Tai Peng

Site 4 – Tai Peng is on a piece of elevated site platform close to a Joint Bay and not directly accessible by vehicles. The construction materials and equipment would have to be lifted to the site from the Joint Bay by a heavy-duty crane. The ground level is about 72mPD and can accommodate a 1MW wind turbine. The wind potential is about 150W/m² and annual energy production is estimated as 1,1500MWh.

Site 4 has disadvantages of difficult access, uncertain ground conditions and shorter setback distance to the sensitive receivers of noise and visual impact. The ranking of assessment for electrical connection, land use and ecology for both sites are identical.

Site / Rankings	Site 2 – Tai Ling	Site 4 – Tai Peng
Wind Potential	1	1
Height Restriction	2	1
Electrical Connection	1	1
Site Access	1	2 (-)
Land Use	1	1
Ground Conditions	1	2 (--)
Ecology	1	1
Noise	1	2
Visual	1	2
Overall Ranking	1	2

Preferred Site

As a result of the above, Tai Ling is thus the preferred site overall. The proposed site layout is illustrated in Figure 12. The typical plant layout of a 600kW class wind turbine is shown in Figure 13.

7. Program

Making reference to the similar project, a 9-month program for land application is required. The project will fall within the category of designated project under the EIAO due to power generation by a public utility and the environmental concerns identified in previous studies (e.g. visual and ecological impacts). Assuming the statutory EIA process and system design to proceed in parallel with the land application, the program of equipment manufacturing, delivery and site erection will require another 12 months. Adding up, the total lead-time for the wind turbine project will be about 18 months.

APPENDIX 1 – PHOTOS OF SITE 2 AND SITE 4

Site 2 – Tai Ling

Site 4 – Tai Peng