If PV installations using tax rebates are such a good idea, then everyone should do it. If everyone did it, then we are simply paying taxes out of one of our collective pockets, funneling the money through a government bureaucracy, with the attendant costs, and then putting the remaining money back into another one of our collective pockets. So the "ideal" outcome of tax subsidized PV - 100% saturation - actually results in an increase in their cost to society as a whole, not a decrease. The same holds true of utility subsidies and other similar misguided schemes. PV holds great promise, but there are better ways to do it than through these end user subsidies.