UK GAS-Prices fall on strong Norway flows, maintenance at Rough

* Gas system near to balanced

* Rough storage stops injecting gas

Sept 3 (Reuters) - Prompt natural gas prices in Britain fell on Thursday morning as strong flows from Norway and maintenance at Britain's biggest gas storage site Rough reduced demand, offsetting lower flows from the UK continental shelf.

Gas for delivery on Friday was trading at 40.50 pence per therm by 0845 GMT, down 0.43 pence from its previous settlement.

The within-day contract eased 0.45 pence to 40.50 pence per therm.

With supply flows at 201.9 million cubic metres (mcm) per day and demand expected at 201.5 mcm, the system was broadly balanced, National Grid (LSE: NG.L - news) data showed.

"More comfortable supplies despite outages on the UK continental shelf have seen prompt prices to soften," one UK gas trader said.

Average temperatures were also predicted to rise towards normal levels by next week, reducing demand.

Injections into Rough storage were reduced to zero on Thursday due to planned maintenance, which is expected to last until Sept. 28. There was also an unplanned outages at Hole House storage.

Supplies from LNG terminals were nominated at 39 mcm on Thursday, while Norwegian gas flows via the Langeled pipeline, Britain's main gas subsea import route, were close to full capacity.

Deliveries to Britain's Barrow and Theddelthorpe gas terminals from the UK continental shelf were shut due to offshore maintenance, with a total volume impact of about 12 mcm/day.

Further along the curve, prices for delivery in October eased by 0.25 pence to 41.35 pence/therm and those for winter delivery were down by 0.20 pence to 44.55 pence/therm.

In the Dutch TTF gas market, prices were also lower. Day-ahead TTF gas was down 0.15 euros at 19.70 euros per megawatt hour.

In Europe's carbon market, benchmark EU Allowances (EUA) were steady at 8.13 euros per tonne. (Reporting by Nerijus Adomaitis, editing by David Evans)