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Monday, 08 January 2018 01:00

Singapore's deepest transmission cable tunnel system is almost ready

Singapore's deepest transmission cable tunnel system is almost ready Credits: The Straits Times

A network of giant tunnels which will protect Singapore's electricity supply for the future has been completed.

The multibillion-dollar Underground Transmission Cable Tunnel Project will house 1,200km of extra-high voltage cables - more than thrice the distance between Singapore and Kuala Lumpur. It is one of the world's deepest electricity supply projects.

According to the energy utility company SP Group, the first cables will go online by the end of 2018. The laying of cables is projected to be completed by 2022. About 500 km of cables will be laid, which is less than half the capacity of the tunnels. They will supply about 20% of Singapore's peak demand, which in 2016 was 7.149MW, according to Energy Market Authority (EMA) data.

Given the depth of the tunnels, it will be easier to monitor and replace the cables in the tunnels, compared to those that currently run under roads and need traffic to be disrupted as engineers dig up and cover the streets.

Most tunnels will be about 60m beneath the earth - the height of a 20-storey Housing Board building - but some will be at 80m, the deepest of any tunnel in Singapore. "We had to build 60m deep because Singapore lacks space. We had no choice," said Mr Michael Chin, SP Group's managing director of infrastructure and projects.

The three tunnels are named the North-South, East-West and Jurong Island-Pioneer Tunnels, and work on the $2.4 billion project started in 2012. For most of their distance, the tunnels are 6m in diameter, about two storeys high, but at junctions, they swell to 11m.

SP Group said the high-voltage cables in the tunnels will mainly replace eight circuits running north and south or east and west across the country. These eight circuits, built in the 1980s, are the oldest transmission cables still in use in Singapore.

The tunnels are built to last 120 years, while the cables' lifespan is 30 years, meaning they can be replaced up to four times inside the tunnels.

Mr. Teo, who is a council member of The Institution of Engineers, Singapore, said: "It is very difficult to monitor cables when they're under the road. Now, you can just go inside the tunnels with your equipment." He said one way SP Group could make the tunnels even better was through leasing space inside to telecommunications companies. "They could lay optic fibre cables inside to allow massive kinds of infrastructure for other services," said Mr. Teo.

Source: The Straits Times

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