UK GAS-Prompt prices rise as outage tightens nearby supply

LONDON, March 31 (Reuters) - Prompt natural gas prices in Britain were higher on Tuesday, as an outage at Centrica (LSE: CNA.L - news) 's North Morecambe Barrow terminal cut Continental Shelf gas flows, tightening an undersupplied system.

Gas prices for within-day delivery were up 1.8 percent at 48.20 pence per therm at 0955 GMT.

Gas flows at Britain's North Morecambe gas terminal were cut to zero in an unplanned outage on Monday, operator Centrica said.

National Grid (LSE: NG.L - news) data showed the system was expected to be around 18 million cubic metres (mcm) short, with supply flows at around 241 mcm and demand forecast at around 259 mcm.

"For the UK, temperatures are likely to remain above normal until 3 April and then drop to just below normal for the following week," consultancy Energy Aspects said in a note.

"Our short-term residential and commercial demand forecast model indicates gas demand in the UK, France, Italy, the Netherlands and Belgium will continue to be higher than last year over the coming two weeks."

Centrica Storage Ltd (CSL (Other OTC: CMXHF - news) ) said plans to limit the maximum stock level at Rough, Britain's largest gas storage site, for "testing and verification works" would last up to six months but possibly longer.

Energy Aspects said that the reduction in storage capacity could reduce the average winter withdrawal rate by 4 to 6 mcm/d.

Prices for summer delivery were down 1.1 percent at 45.85 pence per therm.

In the Netherlands, the day-ahead gas price at the TTF hub was up 0.1 percent at 22.02 euros per megawatt-hour.

The benchmark European Union carbon price was down 0.9 percent to 6.87 euros per tonne on ICE Futures Europe. (Reporting by Sarah McFarlane; editing by Jason Neely)