there are two ROI points, one ecological/energy wise and the other economical. the former has been roundabout 1.5 years of production a decade ago. I assume thi

there are two ROI points, one ecological/energy wise and the other economical. the former has been roundabout 1.5 years of production a decade ago. I assume this has gotten better through more efficient production. the latter depends very much on the price of electricity. but since the kWh production price for photovoltaics recently fell below that of coal shows that solar totally makes sense.