Yes it isn't an easy calculation. With our first FIT scheme the FIT was 45p / kWh but the installed cost £14,500. Our second £5,200 for a bigger array but 4p per kWh. We did it because it seemed the right approach. I would like the govt to demand all new buildings have solar & batteries.

JohnV6
2022 CX Plus Four
2025 Renault Scenic Alpine etech "Yvette"