3 PROJECT DESCRIPTION

3.1 The Project

The works that are the subject of the EIA Study include the construction and operation phases of the Project. This section describes the key components of the Project.

The Project is the construction and operation of a 600-850 kW wind turbine and associated equipment at Tai Ling Tsuen on Lamma Island. The development and operation of the proposed Project will comprise the following:

i. Erection of a wind turbine (hub height approximately 45m and rotor blade diameter of approximately 52 m, overall height of the wind turbine approximately 71 m);

ii. Excavation and construction of the wind turbine foundation (affected area approximately 15 m by 15 m);

iii. Construction of a site platform and retaining wall (affected area approximately 25 m by 60 m);

iv. Construction of one stainless steel hut as high voltage distribution pillar (HVDP) (size approximately 4.6 m length, 2.5 m width, 2.8 m height) for housing of switchgear and power conditioning devices. Transformer will be installed at the bottom of the wind turbine tower;

v. Laying of underground distribution cables for connecting to the nearby existing cable route (approximately 50 m in length); and

vi. Operation and maintenance of the wind turbine system.

The project site will be located adjacent to the existing 275kV cable road at a ground level of approximately 92 mPD.

3.2 Project Design

The information presented in this section is taken from HEC’s design and may be subject to minor modification.

The proposed wind turbine is a “horizontal axis” machine which consists of three rotor blades turning around a horizontal hub. The hub is connected to a gearbox and a generator which are located inside a nacelle. The nacelle houses the mechanical and electrical components and is mounted on the top of a tubular tower. The mechanism and components of power generation by wind turbine are illustrated in Figure 3.1.

Key:

(1) Wind blowing over the blades causes the blades to rotate

(2) Rotating blades keep the shaft turning

(3) & (4) The gearbox will increase the rotational speed of the shaft and drive the generator to produce electricity

Figure 3.1 Mechanics of Electricity Generation by Wind Turbine

The specification of the wind turbine is summarized in Table 3.1.

Table 3.1 Wind Turbine Specification

Parameters	Specification
Capacity	600 – 850 kW
Cut-in Wind Speed	2.5 – 4 m/s
Rated Wind Speed	13.5 – 15 m/s
Cut-out Wind Speed	25 m/s
Blade Rotating Speed	14 – 31 rpm
Blade Rotating Direction	Clockwise
Average Wind Speed at Tai Ling	5.5 m/s
Annual Production of Electricity	700 MWh
Hub Height	45 m
Rotor Diameter	43 – 52 m
Ground Level of the Project Site	+92 mPD
Tip Height (from sea level)	+159 – 163 mPD

A 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) installed within the site boundary of wind turbine. Power cables will be buried underground for connecting the wind turbine, HVDP and the nearby 11kV power grid on the 275kV cable route. As illustrated in the schematic diagram (Figure 3.2), the output from the wind turbine is transmitted to the existing power grid. The synchronous generators of the grid system supply magnetizing current for the induction generator of the wind turbine. An Auto-synchronous Controller will be required to control the operation of a Synchronizing Breaker with respect to the wind turbine output voltage and frequency.

Figure 3.2 Schematic Diagram of Proposed Wind Turbine Installation

3.3 Wind Turbine Construction & Operation

3.3.1 Construction

The facilities required at the wind turbine site are as described in Section 3.2. Most of the equipment will be delivered to the site via the existing 275kV Cable Route. The wind turbine site covers an area of about 4,400 m² and is situated adjacent to the existing 275kV cable road. All the construction activities will be restricted within the Project Area. A flat area for siting the wind turbine, the associated electrical transformer and access platform will be formed by cutting back the hill slope (Figure 3.3). The site platform will be formed by excavation with minor retaining wall constructed around the perimeter of the site. A circular concrete footing will be constructed for supporting the wind turbine. The construction work on site is minimal and will not result in adverse impacts to the environment.

The main activities and construction sequence are:

· Excavate the site by cutting and filling to form a site platform (affected area is approximately 3,100 m² and excavated materials is approximately 1,300 m³);

· Construct retaining wall around site perimeter;

· Backfill and level site (nearly 95% of the excavated materials could be used for backfilling, the remaining materials will be transported by trucks to the HEC Power Station for offsite disposal);

· Construct circular concrete footing for wind turbine foundation;

· Reinstate ground;

· Erect wind turbine using one heavy duty mobile crane, one light duty mobile crane, and transformer pillars as depicted in Figure 3.4;

· Lay cables;

· Landscaping works including planting of trees and shrubs.


*Figure 3.4* *Construction of the Wind Turbine*

3.3.2 Operation

The wind turbine will be designed for fully automatic start up, synchronization to the 11kV power grid, power regulation, disconnection from the grid and shut down. It will produce electricity when the wind speeds are in the range of 2.5 to 25 m/s. The rotor blade will rotate from 14 to 31 rpm approximately under normal circumstances. The wind turbine will cut-off from the grid when wind speeds are below 2.5 m/s or above 25 m/s.

The operation of the wind turbine will be monitored and controlled through a central monitoring system located in a control room of the Lamma Power Station. The wind turbine site will be unmanned and require attendance of operational personnel only during emergency or routine maintenance.

3.3.3 Project Programme

The construction of the Project is scheduled to commence in the first quarter of 2005 and will be completed within about 12 months, 8 months for civil works including site preparation, formation and foundation, and 4 months for electrical and mechanical works (such as installation & erection of the wind turbine).

3.4 Concurrent Projects

At present there are no planned projects to be constructed in sufficient proximity to the Project to cause cumulative effects. Therefore, cumulative impacts are not expected to occur.

3.5 Scoping of Environmental Issues

The impacts associated with the Project are summarised in Table 3.2 and are described in further detail in the following sections. The intention of installing the wind turbine is to demonstrate the ability to utilise wind energy (renewable power) for power generation in order to facilitate sustainable development. From an operational standpoint, the wind turbine is not expected to cause unacceptable adverse effects; operational impacts are principally related to ecology and, landscape and visual issues.

Table 3.2 Potential Sources of Environmental Impacts

Type of Potential Impact	Construction	Operation	Remarks
Noise generation	Ö	Ö	See Section 4
Night time operations	Ö	Ö	See Section 4
Impacts on Ecological Resources	Ö	Ö	See Section 5
Landscape and visual impacts	Ö	Ö	See Section 6
Gaseous emissions	Ö	X	See Section 7
Dust	Ö	X	See Section 7
Liquid effluents	Ö	X	See Section 8
Disposal of spoil material	Ö	X	See Notes
Generation of waste or by-products	Ö	X	below
Disruption of water movement or bottom sediment	X	X
Risk of accidents which would result in pollution or hazard	X	X
Endangerment of cultural heritage resources	X	X
Traffic generation	X	X
Storage, handling, transport, or disposal of hazardous materials or wastes	X	X
Ö = Possible X = Not expected
Notes: The construction works will involve some site formation which will necessitate the removal of small quantities of spoil. Therefore, the number of trucks is expected to be minimal. It is expected that minimal excavated spoil material (approximately 1,300 m³ of excavated materials) will be generated from the construction of the tower foundation, site platform and retaining wall during the construction of the Project. The quantity of waste materials arising from the construction phase is not expected to be high as most of the spoil (95% of the excavated materials) will be used as backfill, but practical measures will be taken to avoid, minimise and recycle wastes. Good construction practices, including limiting activities within the site boundary and avoiding of filling and illegal dumping by site management and audit, are recommended to ensure that adverse environmental impacts are prevented.

The site selection exercise has resulted in a wind turbine location that has avoided impacts to high ecological value habitats and to both the archaeological sites (eg Sham Wan) and areas of heritage interest (such as the Tin Hau temple in Sok Kwu Wan). The small footprint of the wind turbine and the short connection to the nearby 11 kV power grid on the existing 275 kV cable route has minimised direct disturbances to the ecological resources of Lamma Island. Reducing the potential for impacts and maintaining the existing environmental conditions as far as possible has been a major objective of the assessment and selection of the wind turbine location.

The alternatives assessment (Section 2) and the previous components of Section 3 present the most preferable option environmentally as well as in terms of programme and operational aspects. Subsequent sections of this report demonstrate that the Project can be constructed and operated in an environmentally acceptable manner.

3.6 Environmental Conditions in Absence of the Project

The existing environmental conditions, including the general natural habitats and landscape of the Project Area, could be retained in the absence of the Project, however, the demonstration of the potential for wind utilization in generating power as well as the potential reduction in air pollutant emissions would not be materialised without this proposed Project.