UK GAS-Prices rise on undersupply, low temperatures forecast

Sept 21 (Reuters) - Wholesale gas prices rose on Thursday due to undersupply caused by reduced Norwegian flows and a forecast for low temperatures, traders said. * British within-day gas price up by 1.30 pence at 46.80 pence/therm at 0831 GMT. * Day-ahead gas edged up 0.85 pence to 46.20 pence per therm. * The October gas contract grew by 0.48 pence at 44.98 pence per therm. * Lower day to day Norwegian gas flows and low temperatures forecast drove gas prices up, said a British gas trader. * Gas supply from Norway to Britain fell to 67 million cubic meters per day (mcm/day) on Thursday from 76 mcm/day, as flows through the Langeled pipeline fell to 28 mcm/day from 40 mcm/day the previous day. * Britain's gas system was undersupplied by 16.2 mcm on Thursday, with demand forecast at 195.1 mcm/day and supply at 178.9 mcm/day, National Grid (LSE: NG.L - news) data showed. * Peak wind power generation is forecast at 4.4 gigawatts (GW) on Thursday and is expected to rise to 5.0 GW on Friday, Elexon data showed. * Average temperatures on Thursday could reach 18 degrees Celsius in southern Britain and are forecast to remain stable the next day, UK Met Office forecasts showed. * The day-ahead gas price at the Dutch TTF hub fell by 0.30 euro to 17.20 euros per megawatt hour (MWh). * The benchmark Dec (Shanghai: 600875.SS - news) -17 EU carbon contract fell by 0.18 euro to 6.73 euros a tonne.

Thomson Reuters (Dusseldorf: TOC.DU - news) analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Lefteris Karagiannopoulos in Oslo; editing by Jason Neely)