UK GAS-Prompt prices edge higher as Norwegian imports dip

LONDON, Aug 16 (Reuters) - Prompt British wholesale gas prices edged higher in early trading on Wednesday, as maintenance curbed imports from Norway. * British within-day gas price up by 0.40 pence to 42.00 pence/therm at 0855 GMT. * Day-ahead gas price up by 0.27 pence to 42.25 p/therm. * Traders said lower Norwegian supplies pushed prices higher but weak demand from gas-fired power stations, due to expectations of strong output from Britain's wind farms, limited gains. * Imports from Norway through the Langeled pipeline were about 40 million cubic metres (mcm), down from about 46 mcm the previous day. * Planned maintenance began at Norway's Gullfaks gas field, operator Gassco said. An ongoing outage also cut supply from the Sleipner gas field. * British gas system almost balanced, with demand forecast at 171.8 mcm and flows at 175.1 mcm/day, National Grid (LSE: NG.L - news) data showed. * Peak wind power generation is forecast at 7 gigawatts (GW) on Wednesday, falling to 5.8 GW on Thursday, National Grid data showed. * September gas contract up by 0.20 pence at 42.45 p/therm. * Day-ahead gas price at the Dutch TTF hub up by 0.10 euro to 15.90 euros per megawatt hour. * Benchmark Dec-17 EU carbon contract up by 0.03 euro at 5.56 euros per tonne. * Thomson Reuters (Dusseldorf: TOC.DU - news) analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting By Susanna Twidale; Editing by Edmund Blair)