Scottish & Southern Energy plans to buy almost 80% of the North Sea gas and infrastructure assets of Hess for $324m.

The utility, which in April agreed an outline deal with Hess, said it had expected the partners to take some of the original 383 billion cubic feet of gas and liquid resources available.

The remaining gas would provide about 6% of the amount the company needed to supply its customers and fuel power stations, the energy company said.