The logic here might be that payback in the form of $1 of generated electricity is better than a regular $1 payback via, say, tax credit, because it comes with

The logic here might be that payback in the form of $1 of generated electricity is better than a regular $1 payback via, say, tax credit, because it comes with additional benefits like reduced carbon emissions (not priced into utility bills) or more reliability / having electricity during blackouts.