Location

Hong Kong

Client

CLP Power Hong Kong Limited

Contract Value

HK$300 million

Construction Period

2000 Q2 - 2003 Q3

The combined length of the two channel crossings (2,100m) makes this project the world's largest HDD project completed in hard rock. When completed, this undersea cable network not only supplied the growing electricity demand of Sham Tseng and Ma Wan, but it eventually formed part of the supply network backbone for Lantau Island.

HDD technique was selected to avoid the problems of a seabed installation: irregular topography, strong currents, heavy shipping traffic, and damage from the dragging of ships' anchors. HDD also eliminated adverse environmental impacts to the foreshore and seabed, resulting from dredging and underwater blasting.

The HDD method involved drilling of pilot holes, which were reamed and enlarged to the desired size. Steel casings and HDPE cable ducts, were thereafter pulled back into the holes, to form a sustainable support system for cables. This system allows repair/replacement of the cable circuits during their operational lifetime.
Environmental Friendliness:
The environmentally-friendly aspects of this HDD project contributed to CLP Power's winning of the "2001 Hong Kong Award for Industry Environmental Performance".
These aspects included:

Foreshore and seabed were left undisturbed - marine life was preserved since there was no dredging or underwater blasting
Minimal land area was required for working areas - there was no long-term visual impact
Minimal disruption to the public
Use of oil-free XLPE cables - the most environmentally friendly and sustainable cable system currently on the market, as no dielectric fluid was necessary within the system
Mud recycling plant was built and equipped with noise abatement measures