Fuel efficiency is the key characteristic of A350 XWB to be real success between Airlines.
Airbus marketing team repeat constantly that the A350 XWB has 25% lower operating costs;
“Airbus brings together the very latest in aerodynamics, design and advanced technologies in the A350 XWB to provide a 25% step-change in fuel efficiency compared to its current long-range competitor. Contributing to this performance are the Rolls-Royce Trent XWB engines that power the A350 XWB family.
Over 70 per cent of the A350 XWB’s weight-efficient airframe is made from advanced materials, combining 53 per cent of composite structures with titanium and advanced aluminum alloys. The aircraft’s innovative all-new Carbon Fibre Reinforced Plastic (CFRP) fuselage results in lower fuel consumption, as well as easier maintenance.”
And behind that there are data regarding the consumption versus the discovery of new reserves of fuel. (see above chart)
Average oil prices have rebounded to 2008 values and the forecast is to have oil prices growing and growing.