Power systems group Rolls-Royce has confirmed media speculation that it is in talks with German engineer Siemens about the possible sale of its energy gas turbine and compressor division.The unit supplies aero-derivative gas turbines, compressor systems and related services to customers in the oil and gas and power generation sectors.According to press reports, the business could fetch a value of up to £1bn."These talks have not concluded and we will make a further announcement in due course," Rolls-Royce said in a statement.BC