Agree if that power is truly sustainable.

OTOH, if you have solar panels and drive power to the grid, you can sell "credits" to large power users who will use them to "offset" their less-green power sources to appear to get their power in sustainable ways / be carbon-neutral. Kind of an "I'm using dirtier power, but I teamed up with someone who's using fully sustainable power, so it all comes out in the wash!"