UPDATE 2-Centrica restarts two idled gas plants during summer

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LONDON, July 18 (Reuters) - British utility Centrica will make 230 megawatts (MW) of capacity available from two idled gas-fired power plants this summer to help manage disruption to power distribution caused by network maintenance, grid operator National Grid said.

"In order to economically and efficiently manage forecast constraint costs and volumes due to planned maintenance on the electricity transmission system, we are contracting Centrica to provide 230 MW of constraint volume from either or both of its Peterborough and Kings Lynn power stations," he added.

Centrica will start making extra capacity available on July 25 and the contract will end on Sept. 2, National Grid said.

The two companies did not provide any details of how much National Grid agreed to pay Centrica for providing extra capacity.

Maximum export limit at the Peterborough plant stood at 155 MW on Monday afternoon, while it was still at zero at Kings Lynn, National Grid data showed. [0#UKBM-GAS]

The two gas-fired plants, which have a combined capacity of around 745 megawatts (MW) and are located within around 40 miles of each other, were idled earlier this year due to low profitability on the back of high gas prices.

Profits from burning gas for power generation have been low since early this year as gas prices have gained on the back of civil unrest in North Africa and the Middle East and additonal gas demand in Japan.

UK generators burning coal instead of gas for power production this winter will earn around 10 pounds ($16.1) more per megawatt-hour produced, latest data showed on Monday. ($1 = 0.620 British Pounds) (Reporting by Karolin Schaps; Editing by Anthony Barker)