Rolls-Royce Holdings plc, formerly Rolls-Royce Group plc is a provider of power systems and services for use on land, at sea and in the air. The Company operates in four segments: civil aerospace, defense aerospace, marine and energy. The civil aerospace is engaged in development, manufacture, marketing and sales of commercial aero engines and aftermarket services. The defense aerospace is engaged in development, manufacture, marketing and sales of military aero engines and aftermarket services. The marine segment is engaged in development, manufacture, marketing and sales of marine propulsion systems and aftermarket services. The energy segment is engaged in development, manufacture, marketing and sales of power systems for the offshore oil and gas industry and electrical power generation and aftermarket services. In January 2013, the Company bought PKMJ Technical Services. In January 2013, Alstom SA acquired Tidal Generation Limited from the Company.