UK GAS-Prices rise as less Norwegian supply tightens system

* First Nigerian LNG delivery since Sept. 2014 scheduled

* Gas market undersupplied, North Morecambe outage extended

March 2 (Reuters) - British wholesale natural gas prices rose on Wednesday as faltering Norwegian supplies left the transmission network struggling to cope with rising demand.

Gas for within-day delivery rose 0.45 pence per therm to 30.95 p/therm at 1011 GMT, while day-ahead gas was 0.30 p/therm higher at 30.95 p/therm.

The gas market was undersupplied by 5.5 million cubic metres/day (mcm) of gas. Demand was pegged at 286.9 mcm/day, seven percent above seasonal average levels.

Flows from Norway fell to around 52 mcm/day from around 60 mcm/day on Tuesday, according to National Grid (LSE: NG.L - news) data, while Centrica (LSE: CNA.L - news) extended an unplanned outage at its North Morecambe gas sub-terminal to 1430 GMT on Wednesday.

Withdrawals from Britain's largest gas storage site Rough were steady at 30 mcm/day, while output from the South Hook liquefied natural gas (LNG) import terminal stayed at similar levels.

Britain is scheduled to receive its first Nigerian LNG cargo in 18 months on March 10, as converging global gas prices reduce incentives for shippers to send Atlantic-produced supply to Asia.

Last year around 40 percent of Nigerian LNG exports went to Asia, with 30 percent bound for Europe, although none of that actually made it to Britain, an industry source said.

"It (Other OTC: ITGL - news) will be interesting to see if new Australian (LNG) production displaces Nigerian volumes out of Asia," he added.

UK temperatures are expected to decrease by three degrees Celsius below average levels on March 7 before becoming milder thereafter, according to Thomson Reuters (Dusseldorf: TOC.DU - news) meterologist Georg Muller.

Further out on the curve, the Winter '16 contract fell 0.05 pence to 33.60 pence per therm.

In the Netherlands, day-ahead gas at the TTF hub rose by 0.10 euros to 12.65 euros per megawatt-hour.

In Europe's carbon market, the front-year EU Allowance price fell 3.20 percent to 4.84 euros a tonne. (Reporting by Oleg Vukmanovic)