UK GAS-Prices decline on higher supply, lower exports

LONDON, May 17 (Reuters) - British wholesale gas prices declined on Wednesday due to higher supply and lower exports. * British day-ahead gas price down 0.15 pence to 40.00 pence per therm at 0818 GMT. * Within-day contract falls by 0.65 pence to 40.35 pence per therm. * UK Continental Shelf flows are higher and supply through the Langeled pipeline from Norway are slightly up due to the partial return of the Ormen Lange field from maintenance. * Langeled flows are expected to increase further on Thursday after Ormen Lange fully restarts. * Exports through the InterconnectorUK to continental Europe are down at around 21 mcm/day. This should rise back towards 45 mcm/day next week due to lower demand, Thomson Reuters (Dusseldorf: TOC.DU - news) analysts said. * The UK gas system was largely balanced with demand forecast at 189 million cubic metres (mcm) and flows at 187 mcm, National Grid data shows. * British day-ahead baseload power fell by nearly 15 percent to 44 pounds per megawatt hour. * Day-ahead gas price at the Dutch TTF hub was down 0.17 euro at 15.40 euros per megawatt hour. * Benchmark Dec-17 EU carbon contract inched down by 0.05 euro to 4.49 euros a tonne. * Thomson Reuters analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Nina Chestney)