UK GAS-Prices fall on high Norwegian flows, low demand

Aug 15 (Reuters) - British wholesale gas prices fell on Tuesday as high Norwegian flows and below-average demand created an oversupplied system. * The within-day gas price fell by 0.90 pence to 41.15 pence per therm at 0800 GMT. * Day-ahead gas was down 0.40 pence at 41.30 p/therm. * "Power demand is forecast lower, plus the system is oversupplied today," said a British gas trader as gas flows from Norway kept Monday's high volumes. * "Prompt has seen (Norwegian) outage issues subside after a period of uncertainty," a second gas trader, adding that this had caused the price to ease. * Britain's gas system was oversupplied by 6 million cubic metres (mcm), with demand forecast at 175.2 mcm and supply at 181.2 mcm/day, National Grid (LSE: NG.L - news) data shows. * Total (LSE: 524773.L - news) gas supply from Norway to Britain was steady at 94 mcm/day. * Tuesday's demand forecast was 17.8 mcm lower than the seasonal norm. * Peak wind power generation is forecast at 3.3 gigawatts (GW) on Tuesday and is expected to grow to 6.9 GW on Wednesday, Elexon data showed. * Average temperatures on Tuesday could reach 23 degrees Celsius in southern Britain and are forecast to fall by 3 degrees by Friday, according to UK Met Office data. * September gas contract edged down by 0.10 pence to 41.75 p/therm. * The day-ahead gas price at the Dutch TTF hub fell by 0.01 euro to 15.82 euros per megawatt hour. * The benchmark Dec (Shanghai: 600875.SS - news) -17 EU carbon contract fell by 0.01 euro to 5.51 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 Edmund Blair)