UK GAS-Day-ahead falls as Norwegian imports oversupply system

Oct 21 (Reuters) - The British day-ahead gas price fell on Monday as a rise in imports from Norway, caused by a boost in flows via Langeled, the largest pipeline between the two countries, oversupplied the system.

* Day-ahead gas fell by 1.35 pence to 26.65 pence/therm by 0800 GMT

* The day-ahead price fell as increased Norwegian gas exports to Britain pushed prices lower, a gas trader said

* Norwegian gas flows rose to 85 million cubic metres (mcm) per day from 54 mcm on Friday, with flows through the Langeled pipeline nearly doubling to 64 mcm/day

* The gas system was oversupplied by 19.4 mcm, with demand forecast at 235.2 mcm and supply at 254.6 mcm/day, National Grid data showed

* Demand was lower than the seasonal average of 253.4 mcm/day

* Wind power generation is expected to reach 5.9 gigawatts (GW) on Monday and rise to 6.4 GW on Tuesday, Elexon data showed

* High power output from wind turbines typically reduces gas-for-power demand

* Average daily temperatures are forecast at 9.6 degrees Celsius on Monday and expected to fall to 8.3C on Tuesday, Refinitiv Eikon data showed

* One liquefied natural gas (LNG) cargo arrived in Britain on Monday, with six more vessels expected by November 6

* The November gas contract was up by 0.90 pence at 42.25 p/therm

* Day-ahead gas at the Dutch TTF hub fell by 0.10 euro to 10.50 euros per megawatt hour (MWh)

* The Dutch month-ahead gas contract, a benchmark for LNG prices as well as European gas, was up by 0.35 euros at 16.23 euros/MWh

* The benchmark Dec-19 EU carbon contract rose by 0.30 euro to 26.18 euros a tonne (Reporting by Lefteris Karagiannopoulos in Oslo; editing by Jason Neely)