Unless you have evidence of those calculations (which should be public of course, right? I mean, it's government spending after all) I'd say they haven't, and they have just been pouring money into a fire pit because it won them votes to say they were going green.
What I mean is, I haven't seen those calculations. Have you, or are you just hoping they have done the math? I wouldn't put any faith on any politician doing any hard math on this whatsoever.