Bane can defend against lightning, that much we already know. Sidious would have to catch Bane off guard or overwhelm him with lightning, which MAY happen, but I doubt it.
Thing is, Bane had been caught off guard by his own lightning reflecting back at him. Plus, (I know its been done to death, but for the sake of argument) my reading of the book implied 1 million volts of electricity to take down the orbalisks. That would require a ridiculous amount of dark side power in a short time. And frankly, as of ROTS I'm not sure Sidious can deliver those goods. In DE he could, clearly, and probably even by ANH, but at this point I am of the opinion he is not powerful enough yet, at least not without some concentration on it. When he delivered the lightning at Windu he had had a moment to gather up his strength (as in, a moment where he was not embroiled in a saber fight to the death)