It's effectively free if you have no other opportunistic use for it. For example it's free if you don't have a smart electrolyzer attached to it. If you do have

It's effectively free if you have no other opportunistic use for it. For example it's free if you don't have a smart electrolyzer attached to it. If you do have one, then it's not free. (Likewise it's not free either if you have no wasted overgeneration.)