UK GAS-Prices rise on lower Norwegian flows

June 27 (Reuters) - British wholesale gas prices rose on Wednesday, as a decrease in Norwegian flows created an undersupplied system, with low wind power output failing to bridge the demand gap.

* Within-day contract was up 1.25 pence at 54.25 pence/therm at 0807 GMT.

* Day-ahead gas rose by 1.50 pence to 54.50 pence per therm.

* "Weather is more or less normal ... at this point I can see only the lower Norwegian flows," said a British gas trader explaining the price hike.

* Gas supply from Norway to Britain fell to 45 million cubic metres (mcm) per day, from 49 mcm on Tuesday, driven by a 6 mcm decrease in flows through the Nordic country's biggest pipeline Langeled.

* Peak wind power generation is forecast at 2.0 gigawatt (GW) on Wednesday and is expected on similar levels on Thursday, National Grid (LSE: NG.L - news) data showed. The output is low versus the total capacity of Britain's wind turbines, which is 11.8 GW.

* The British gas market was undersupplied, with demand forecast at 146.0 million cubic metres and flows at 138.7 mcm/day, National Grid data showed.

* Average daily temperatures in Britain are seen at about 18.0 degrees Celsius on Wednesday, and are expected to rise to 18.7 C on Thursday, Thomson Reuters Eikon data showed.

* Britain was not expecting any liquefied natural gas (LNG) vessel to arrive as of Wednesday

* The July contract was up 0.75 pence at 53.50 pence/therm.

* Day-ahead gas at the Dutch TTF hub rose by 0.17 euro to 21.80 euros per megawatt-hour.

* The benchmark Dec (Shanghai: 600875.SS - news) -18 EU carbon contract was up 0.18 euros at 15.21 euros a tonne. (Reporting by Lefteris Karagiannopoulos in Oslo, editing by Louise Heavens)