Energy group Centrica has bought its own offshore gas storage facility in a £300m deal with struggling US firm Dynegy.

The British Gas group, which supplies 65 per cent of the UK residential market, has bought Dynegy Storage and Dynegy Onshore Processing UK.

The agreement includes the transfer to Centrica of an onshore processing plant in Easington, North Yorkshire, which employs 70 staff.

The firm said last night that the move would not affect jobs.

The two Dynegy businesses operate the Rough offshore gas storage facility in the North Sea and the associated pipeline, the onshore processing site in Easington as well as an office in Richmond, Surrey.

The Rough asset is the largest storage facility in the UK, with a capacity of around 100 billion cubic feet of stored gas.

Centrica will pay a net cash consideration of £304m plus £11.8m in respect of net working capital for the businesses.

Storage facilities are required by gas suppliers because of fluctuations in residential demand between summer and winter.

However, Centrica said it would continue to offer the bulk of the storage facility to the open market.

It uses between 25 per cent and 30 per cent of the facility and said this would not change now it had taken on ownership.

Shares in the group rose 4.25p to 170p.