Bono quotes him at the end of this short YouTube video.
I think, but I'm not sure, that he used the line first in a NY Times column in December 2007, excerpted below
People often ask: I want to get greener, what should I do? New light bulbs? A hybrid? A solar roof? Well, all of those things are helpful. But actually, the greenest thing you can do is this: Choose the right leaders. It is so much more important to change your leaders than change your light bulbs.
... when leaders change the rules, you get scale change across the whole marketplace. And the energy-climate challenge we face today is a huge scale problem. Without scale, all you have is a green hobby.
Have no illusions, everything George Bush wouldn’t do on energy after 9/11 — his resisting improved mileage for cars and actually trying to weaken air-conditioner standards — swamped any good works you did.