* Curve lifted by oil, concern of winter supply squeeze
* Power market eases on higher nuclear availability
LONDON, Aug 10 (Reuters) - Wholesale gas prices in Britain rose on Friday as tight supplies kept pressure on the spot market while the ongoing strength of oil helped push up prices further out on the curve.
Gas prices for next day delivery were up 0.25 pence per therm between Thursday and Friday morning to 53.40 pence a therm at 0830 GMT, while within-day prices were up 0.2 pence to 53.20 pence per therm.
The rise came despite typically lower demand during the last working day of the week.
At 163.1 million cubic metres, Friday's gas demand was over 30 percent below the seasonal norm, according to data from National Grid.
Despite this low demand, the system remained tight, with flows expected to be slightly lower at 162.3 mcm.
Analysts said prices were kept high as there was a risk for lower gas flows through Norway's Langeled pipeline.
"Maintenance at Kollsnes (gas processing plant) is scheduled to start (on Friday), lasting until September 10," Thomson Reuters Point Carbon said, adding they expected day-ahead gas prices ranging from 53.50 to 53.90 pence per therm.
The price upside was limited as a result of high import levels of liquefied natural gas (LNG).
Reuters data showed that over 900,000 cubic metres of LNG are expected to arrive in Britain between now and August 16 via at least four LNG tankers from Qatar.
CURVE
Further out on the curve prices also rose, with contracts for delivery next winter rising above 65 pence per therm.
This means that the contract has gained almost 6 percent since the beginning of the month.
Traders said that the bullish sentiment was a result of strong oil prices, as well as concerns of a supply squeeze in winter.
"Oil is trading well above $110 a barrel, so that's pushing gas up as well, but there is also the fear that Britain could experience a supply squeeze in winter should it get cold or one major source of supplies fall away for some time," one gas trader said.
Despite the unusually low demand in gas over this summer, Britain gas system has been tight and, on many occasions, undersupplied.
POWER
In the power market, sentiment was more bearish as nuclear power supplies have improved during this week.
Power prices for baseload (24 hours) delivery the next day dropped 20 pence per megawatt-hour (MWh) to 40.05 pounds a MWh.
Traders said that the return of EDF Energy's 640 megawatt Torness 2 nuclear power station on Thursday evening had eased the system.
Earlier this week, EDF Energy's 550 megawatt Dungeness B21 nuclear power station had returned to the grid and Magnox's Wylfa 1 nuclear power station was given permission to generate electricity until September 2014, almost four years beyond its original closure date.
