My biggest issue with Derek's illustration is that he ignores the density of the fields. All his poynting vectors are the same magnitude and therefore the viewer is led to believe that the energy flowing through the air is just as big a contributor as around the wires. In reality, voltage applied to a wire induces an electrical pressure wave (E field) to the electronics spreading out at essentially the speed of light. As each electron reacts to this pressure wave, they are pushed or pulled. As each electron is accelerated, it induces what we refer to as a magnetic field, which is a model that shows the effect that the movement of that electron has on all the surrounding electrons. What frustrates me about Derek's explanation is that he seems to imply that the wire is inconsequential. This is absolutely not true as the wire houses all the electrons in a very mobile state that allows the E field to get them moving to allow the creation of a B field. In addition, field theory shows that the density of the B field is highest right at the electron moving and drops very quickly as you move away, therefore the pointing vectors should be very "thick" right on the wires and get much much less consequential as you move away from the wires. As Derek setup the problem, he is correct, the light will flicker 1m/c s after you close the switch, but only due to the capacitive and then inductive coupling of the wires, full power will take much, much, much, much longer due to the transmission line Dave discusses taking a very long time to settle out.