SINGAPORE-- A warren of giant tunnels which will safeguard Singapore's electricity supply for the next 120 years has been completed, the Straits Times reported.

The report said the multibillion-dollar effort to house 1,200km of extra-high voltage cables - more than thrice the distance between Singapore and Kuala Lumpur - is one of the world's deepest electricity supply projects.

Singaporeans will begin tapping into this electrical source from next year, said the report quoting the republic's energy utility company, SP Group.

"We had to build 60-metre (m) deep because Singapore lacks space. We had no choice," SP Group Managing Director of Infrastructure and Projects, Michael Chin, was quoted as saying.

"If you look at the profile of Singapore, we have the MRT, which is 30m to 40m deep, then you have your deep tunnel sewerage system, which is between 40m and 70m, so we 'choped' (saved) our space at 60m," he said.

The three tunnels are named the North-South, East-West and Jurong Island-Pioneer Tunnels, and work on the S$2.4 billion (S$1=RM3.03) project started in 2012.

SP Group said the high-voltage cables in the tunnels would 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 here.

The laying of cables, which will begin early next year, is projected to be completed by 2022.

The first cables will go online by the end of next year.

About 500km of cables will be laid, which is less than half the capacity of the tunnels.

They will supply about 20 per cent of Singapore's peak demand, which in 2016 was 7,194 megawatts, said the Straits Times, citing Energy Market Authority (EMA) data.

EMA also projected electricity demand to rise by about 2.0 per cent a year.

The impact of the project on electricity prices is expected to be minimal.

"The immediate goal of the cable tunnels is to replace our ageing cables," said Chin.

But, referring to the extra cable distance they can provide, Chin added: "We are also meeting Singapore's future needs."

For most of their distance, the tunnels are 6m in diameter, about two-storeys high, but at junctions, they swell to 11m - about three-storeys.

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

Crucially, they will be much easier to replace than cables that currently run under roads and need traffic to be disrupted as engineers dig up and cover the streets.

Chin said that because all land under 30m belongs to the state, the cables no longer need to follow the road and can run in straight lines deep beneath private property.

Source: NAM NEWS NETWORK