Define profit, that can come in various ways as lower power bills or even credits but how long before other costs involved rise and are rising eat away those saving in power usage. Then what other costs the end user may get charged that hasn't been put forward yet, which is likely to come.
Then at some point that system will fail and need to be replaced again.
So to me to get a profit is like, spending money to save money then what you have saved you will have to spend money again to save money again.
You need to follow some serious solar forums to see the overall picture here as they cut the political BS out and work on numbers alone.
