1. What is the Transmission Cable Tunnel Project? Is this project owned by SP Group?

SP PowerGrid, a member of SP Group, operates Singapore's grid network, with about 1.3 million industrial, commercial and residential customers benefitting from a reliable electricity and gas transmission and distribution system.

With rapid growth and urbanisation of Singapore's economy and society, demand for power supply has increased over the years and there is a need to develop a sustainable solution to upgrade and renew our grid infrastructure for future needs.

We will be building two cable tunnels 60m underground - the 16.5km East-West Tunnel and the 18.5km North-South Tunnel across Singapore to house the main transmission cables. These cables form the backbone for our nation's power supply for the coming decades.

When completed, the tunnels will allow for efficient installation of transmission cables as well as facilitate ease of maintenance and replacement of cables.

A total of 18 utility buildings with shaft access will be constructed along the tunnels' routes. These buildings will be located in relatively less densely populated areas where possible.

2. Who are the consultants and contractors engaged for this project?

The project's consultants are Worley Parsons for the East-West tunnel and Mott MacDonald Singapore for the North-South tunnel. The contractors appointed for this project are:

  • Samsung C&T Corporation
  • SK Engineering & Construction Co. Ltd
  • Hyundai Engineering & Construction Co., Ltd
  • Obayashi Corporation
  • Nishimatsu Construction Co., Ltd - KTC Civil Engineering & Construction Pte Ltd Joint Venture

3. Why has the underground cable tunnel method been chosen for routing electricity transmission cables

The traditional method of laying cables is through direct burial along roads. With continuous digging and burying of cables for many years, the space beneath roads is very congested with gas pipes, water pipes, telecom cables, sewer lines, drainage channels, MRT tunnels, etc. The direct burial method is now less viable and if used, will require substantial diversion of services and create major disruptions to traffic and road use. After evaluating the options, we are of the view that an underground cable tunnel is the best solution going forward. In the long run, this solution will also be the most cost-effective for the country.

4. How long are the tunnels?

The North-South tunnel will be 18.5km long and run from Gambas to May Road while the East-West tunnel will be 16.5km long, from Ayer Rajah to Paya Lebar.

5. When will construction works for the project start and end?

Construction works are scheduled to start in first quarter of 2013. The East-West tunnel is expected to be completed in 2017 while the North-South tunnel, which is longer, is expected to be completed in 2018.

6. What are utility buildings?

They are buildings which house ventilation facilities and equipment, lifts and staircase, electrical and mechanical services as well as the necessary framework to support the power cables which will be connected to the grid network at the cable entry shaft.

7. What will the buildings look like?

The building will be designed to blend with the environment. Careful selection of finishes will be made to ensure pleasant-looking buildings.

8. Where are your shafts and tunnels located?

The shafts will be built in various locations across Singapore. The tunnels will be located under public roads and will not encroach into any private properties. The North-South Cable Tunnel will span 18.5km from Gambas to May Road while the East-West Cable Tunnel will span 16.5km from Ayer Rajah to Paya Lebar.

9. What are temporary shafts? How long will they exist?

Temporary shafts will be built to facilitate the construction of the tunnels and will be backfilled when the tunnels are completed.

10. Is traffic congestion expected? If so, what will be done to address the issue?

Each site had been studied closely and detailed information obtained on the conditions of each building location. Access to the construction sites will be via the minor roads, where possible.

When construction starts, the traffic conditions near the utility building locations will be continuously monitored. Where relatively heavier traffic is anticipated, our contractors will work with the authorities to help minimise congestion. Traffic wardens would be deployed and traffic signs will be installed on site.

11. What will be done about the noise generated?

While most of the construction activities will take place underground, all construction sites will be shielded with noise barriers and all necessary measures to control environmental disturbances will be taken. Additional noise enclosures will be erected over noisy equipment to mitigate noise at source. General construction noise will abide by the strict standards set by the National Environmental Agency (NEA).

For more information on NEA's noise regulations, please refer to their website at http://www.nea.gov.sg/anti-pollution-radiation-protection/noise-pollution-control.

12. What will be done about the dust and dirt?

We will manage the construction sites stringently to ensure we minimise dust and dirt coming out of the site.

Some measures include:

  • Water spray and physical cover at the site to minimise construction dust; 
  • Only construction machinery with low smoke emission will be used;
  • A wash bay to clean the wheels of vehicles before they enter the public roads;
  • Construction waste and debris will be disposed off promptly;and
  • Strict and discilined site housekeeping to keep the premises clean.