I am currently working in a project to calculate the potential of your solar panels installations.
Me and my client/partner are working with the Google Solar API, Google Maps API, my own AddOn for Gravity Forms and a lot of trigonometry functions :).
Here a demo of the WIP.
Solar API
This is the form, ready for testing. It is work in progress. Move forward in the wizard to select your roof and set up the rectangle where your solar panels will be installed