If you’re in a cloudy, rainy, cold climate, and your utility rates are low, don’t install a PV system, no matter how much you want to jump on the bandwagon.
You can use your money to save the world in many other planet-friendly, more efficient ways. Install a geothermal system for heating and cooling. Put in a pellet stove and figure out how to work it perfectly. Give to Greenpeace.