The Straits Times understands that the disruption, which has now been confirmed by the Energy Market Authority (EMA), was the first major disruption to the gas supply here since December 2006.

The November disruption has not been disclosed publicly before this.

Market analysts say that although the shutdown was brief, and households were not affected by the price hike, the high prices reached highlight the vulnerability of Singapore's energy supply.

It is believed that some commercial power customers were affected.

On Nov 4 at about 3.10pm, an onshore receiving facility operated by ConocoPhillips on Jurong Island was affected by the storm - causing a gas supply shutdown.

Supply was back to normal by 11.30pm but not before spot prices for electricity - which change every half hour, based on market supply and demand - shot up from around $100 per megawatt hour to about $400 per megawatt hour for about an hour the same day.

Households in Singapore were not affected, however, as electricity tariffs for this group of consumers is pre-determined by a formula pegged to fuel oil prices - reviewed every three months.

This means, for example, that electricity prices for the January to March quarter, are determined by the average daily trading price of oil futures for the month of the previous October.

Business users, which use more electricity, are free to negotiate their contracts with power retailers.

The Straits Times understands that about 90 per cent of such users choose fixed price contracts, which minimise the volatility of electricity prices.

Read the full report in Tuesday's edition of The Straits Times.