You decouple power supply from concentrated sources, this reduces the need for centralised base load power generation. There are also gains in the community by

You decouple power supply from concentrated sources, this reduces the need for centralised base load power generation. There are also gains in the community by establishing buy in from home owners, The concepts of sustainability are easier to grasp if its on your roof and you get a return on your investment. And why not spend the tax money on this!