Pigouvian subsidy?

The Copenhagen confab on climate change may have "failed", and we can only speculate on what "success" would have meant. The November 2009 HUD Research Works includes "Powered by the Sun". Look at Table 1. Place a $50,625 solar panel system on a New Jersey home and your outlay is $6,049 (just less than 12%).

Is this a Pigouvian subsidy? But Pigouvians (as well as Keynesians and many others) have given statists a club (and a gift). But public choice analysis does not get equal billing in the textbooks, nor anywhere else. Governments with rare exception grow. What does it take for Pigouvian and Keynesian study to be tempered by a discussion of how these are used to to grow the state? This is not a trivial matter.