"The "green" taxiing system will be offered as an option on the Airbus A320neo, a version of the Airbus A320 with more fuel-efficient engines that Airbus plans to bring to market in 2015. Fuel is a major portion of an airline's operating costs, and with the price of fuel on the rise carriers are struggling to reduce consumption wherever possible.
The system consists of electric motors inside the wheels of an aircraft's main landing gear that will be powered by the aircraft's auxiliary power unit while taxiing, Safran Chairman and Chief Executive Jean-Paul Hertemann said. As the planes will be able to move around autonomously, it will eliminate the need for airport tugs to maneuver planes. The system will allow planes to move backwards as well as forwards, for example, when leaving their boarding gate."
Looks to me like Honeywell are already well on the way to having it developed...