Selective activation of Generators

So I made a CV capable of making planetfall. Or, rather, I'm in the process thereof. Unfortunately, the thing is a power hog. Landing and not overtaxing everything takes three (THREE!) large T1 gens. This isn't a problem on descent or ascent but it blows through my fuel in space, with me never going above 30% capacity.

Is there some way to set up a trigger or something where I can activate and deactivate generators at will?