Viscounts were turning off two engines for the taxy 25 years ago so it is not a new idea. Last year as I understand it a 767 in the USA has been fitted with electic motors to drive the wheels with the plan that the a/c would taxy to the start-up point just short of the runway. that said I have seen no mention of it since. Has anyone heard or seen any of the results of these trails.
The issue is large as there are vast amounts of fuel burnt off at the major airports. At times at LHR & LGW it is a scandel.