3
Project Description
Hei Ling Chau is an
outlying island to the east of
The proposed Project Site is located on relatively level ground at an
approximate elevation of +70mPD in the southern part of Hei
Ling Chau.
Considering the potential height of the wind turbine (see Table 3.2a), the elevation of the wind
turbine is expected to be about +160mPD.
The dimensions of the Project Site, including the construction lay down
areas for the various components of the wind turbine system, are approximately
54m x 100m (see Figure
3.1b).
According to information provided by CSD and site observations, the
Project Site is currently used for the temporary storage of construction
materials and equipment.
The two helipads on the island are regularly used by the Government
Flying Service (GFS) to support the operation of the CSD facilities. The nearest helipad is located over 170m
from the planned location for the wind turbine (see Figure 3.1b). The helipad is used once a day on
average. The centre of the wind
turbine tower will be located at least 150m away from the approach path and
exit zone of the helipad. The
building height limit associated with the safe operation of the
The proposed wind turbine will be a three-bladed horizontal axis machine
(Figure 3.2a illustrates a typical
three-bladed horizontal axis wind turbine). The main electrical and mechanical
parts, including the gearbox, the generator with a rated capacity of between
800 kW to 1.3 MW and the yaw mechanism, will be housed in the nacelle,
which is located on top of a tower.
The tower will likely be a tubular steel structure, but may be
fabricated from other materials such as concrete ([1]).
The tower will stand upon a concrete base with approximate dimensions of
9 m x 9 m.
Figure 3.2a A Typical 3-bladed Wind Turbine
The rotor blades capture the wind and transfer its power to the rotor
hub, which is connected to the electrical generator via the gearbox. The electrical power generated is transmitted
via a step-up transformer to a substation, from where the power is fed into the
nearest existing 11 kV power grid through overhead or underground transmission
cables (see Figure
3.1b). A
summary of the general wind turbine specification is presented in Table 3.2a.
Table 3.2a A
Summary of the General Wind Turbine Specification
|
Parameter |
General Specification |
|
Type |
3-bladed
horizontal axis machine |
|
Rated
Capacity |
800kW
– 1.3 MW, 50 Hz, 690 V |
|
Grid
Connection |
11
kV |
|
Power
Regulation |
Stall
or pitch control |
|
Design
Lifetime |
20
years |
|
Size
of Rotor Blade |
Up
to 30m length, 5 tonnes weight (assembled 3-bladed rotor weighs up to 21.5
tonnes) |
|
Blade
Rotating Speed |
14
– 31 rpm |
|
Size
of Nacelle |
Up
to 12m (l) x 4.5m (h) x 3.6m (w), 43 tonnes in weight |
|
Size
of Tower |
Up
to 60m height (in 3 sections, vary from about 17m to 23m each) and up to 42
tonnes each in weight) |
|
Overall
Size of Wind Turbine |
Up
to about 90m tip height |
|
Ground
Level of the Base of the Tower |
About
+ 70 mPD |
|
Hub
Height |
About
+130 mPD |
|
Tip
Blade Height |
About
+160 mPD |
3.3
Construction
of the Project
The major construction activities for the Project will include upgrading
some sections of existing roads and creation of temporary access for the
delivery of construction materials and equipment, formation of the platform for
the erection of the tower, construction of the tower foundation, erection of
the tower, installation of the nacelle and rotor and installation of the
control and transmission systems.
Two access routes have been identified for the delivery of construction
materials and equipment to the Project Site (see Figure 3.3a). The first route, the long access route,
makes use of the existing heavy load berthing facilities and road system. The route will take the northern part of
the existing loop route and follow the existing alignment to the Project
Site. Minor enabling works including
utility diversions, removal of structures blocking the transport route, signs
and street furniture, and minor road widening, and minor slope works will be
required at a few locations to facilitate vehicle passage (see Figures 3.3b to 3.3e). The long access route will be used for
the delivery of the following major plant items and construction materials to
the Project Site.
·
Self-propelled
transporter (1 unit, for transportation of the crawler
crane from the existing pier to the Project Site and temporary bridge of the
short access route);
·
Crawler
crane (1 to 2 unit(s), to be disassembled into smaller components and
transported by the self-propelled transporter and
assembled on site using a 55-tonne mobile crane);
·
55-tonne
mobile crane (2 units, for assemble of the crawler crane);
·
Flat-bed
truck (1 to 2 unit(s));
·
Concrete
pump truck (1 unit);
·
Piling
plant (1 unit) and pile casing (to be transported by flat bed truck);
·
Concrete
wagons;
·
Dump
truck (1 unit);
·
Site
cabins (to be transported by flat bed truck);
·
Compactor
(1 unit, to be transported by flat bed truck);
·
Excavator
(1 unit, to be transported by flat bed truck); and
·
Soil-nailing
plant (1 unit, to be transported by flat bed truck).
The large construction plant will be
delivered to the existing heavy load berthing facility at the northern part of
the island by flat top barge with a large capacity derrick crane. The small construction materials and
plant items will be delivered to the pier using a derrick lighter. A clear water depth at high tide of
around 2.5 to 3m will be required.
A hydrographical survey has been carried out at the existing berthing
facility and has confirmed that there is sufficient water depth and hence no
dredging of the approach channel and the berthing area will be required (see Figures 2.4a
and 2.4c).
Due to the size and weight of the wind
turbine components (including the blades, nacelle and steel tower sections),
the transportation of these components using the long access route will require
significant road upgrading works (including major slope works) at many
locations. An alternative route,
the short access route, will therefore be used to transport these components to
the Project Site. The turbine
components will be delivered by a flat bed barge with an attendant crane and
moored off-shore, adjacent to the existing pier at the southern part of the
island within the typhoon shelter.
The barge will require a clear water depth of 2m. A hydrographical survey has been carried
out in the area and confirmed that there is sufficient water depth and hence no
dredging will be required (see Figures 2.4b and 2.4c).
The short access route (see Figure 3.3a)
will involve the construction of a temporary steel platform at the existing
jetty in the south-western part of the island and temporary steel bridge
structure (see Figure
3.3f).
The temporary platform will be constructed above the high tide level and
no marine works will be required.
The wind turbine components (including the blades, nacelle, and steel
tower sections) will be lifted from the barge to the temporary steel platform
using a floating crane. The
components will be lifted to the deck of the temporary bridge by the crawler
crane and then transported by the self-propelled transporter
to the Project Site along the existing road. Minor widening or slope trimming may be
required at certain locations of the short access route for the passage of long
vehicles delivering the wind turbine components (see Figures 3.3a and 3.3g).
The Project Site (see Figure 3.1b) will occupy an
approximate area of 54m x 100m, including the lay down areas for construction materials
and wind turbine components. It is
currently anticipated that only minor site clearance and formation will be
required. The engineering design
indicates that the materials underneath the Project Site comprise poor quality
fill overlying rock. A reinforced
concrete foundation with pre-bored H-piles will be required for supporting the
wind turbine.
The main construction activities at the Project Site are:
·
site
clearance and formation;
·
pre-bored
H-piling and construction of reinforced concrete foundation (about 9m x 9m x
2m) for the wind turbine;
·
erection
of wind turbine tower by assembling pre-fabricated steel tower sections;
·
installation
of nacelle and rotor blades using the cranes;
·
installation
of step up transformer and substation;
·
installation
of transmission cables between the substation and the 11 kV supply grid; and
·
testing
and commissioning of the wind turbine system.
3.3.1
Operation of the Project
The operation of the wind turbine, including start-up and shut-down,
will be automatic. It will produce
electricity when the wind speeds are in the range of 3 to 25 m s-1. The wind turbine brakes by full
feathering of the blades. The
blades of the wind turbine will be locked automatically when the wind speed is
above 25 m s-1 to avoid damage.
The wind turbine will be unmanned and attendance by operational
personnel will only be required during emergencies or routine maintenance. All functions of the wind turbine will
be monitored and controlled remotely at the control room of one of CAPCO’s power stations or CLP’s
sub-stations. Users with
appropriate access rights can send a Stop, Pause, Start or Reset command to the
turbine using the remote control system.
3.4
Planning and
Implementation Programme
The Project will be planned and implemented by CAPCO together with
consultants and contractors.
Subject to the review of the wind turbine feasibility assessment results
and ongoing regulatory discussions with the HKSAR government (**), the current envisaged
key stages of the Project are presented in Table
3.4a.
Table 3.4a Proposed
Project Programme
|
Key
Stage of the Project |
Indicative
Date |
|
EIA and Permitting |
Q2-Q4, 2006 |
|
Project construction ** |
2007 |
|
Operation of the wind turbine ** |
2008 |
At present there are no planned projects to be
constructed in sufficient proximity to the Project Sites to cause cumulative
environmental impacts.