Lets suppose we have a charge and we want to accelerate it from a point A to B and back. Does the energy requirement increases if we move the charge quicker? I can make an analogy with mass. To accelerate an object over a distance d requires energy. The objects resist to change in velocity. The faster the acceleration the greater the force hence more energy is required over the same distance. When accelerating a charge, a magnetic field is also created. I suppose the effect is that the charge will resist to the change in velocity.