Regulation isn’t a good moat. Solar panels are a commodity- it’s a race to the bottom. Solar looks like (and has been) the storybook case of a positive trend that makes for a poor investment.
I think that many of the most visible parts of the solar value chain (the panels and the installers) are very competitive industries that are going to be poor investments. However, there's always some segment of the value chain that is condensed into a few technologically-advanced and capital-intensive companies. I think we'll see this with solar as well, and there will be trillion-dollar companies that come out of it.
https://www.google.com/finance/quote/ENPH:NASDAQ?sa=X&window...