Even in a northerly place like Minnesota, our existing panels provide a decent bit of electricity. However, they were put in when this house was not fully occupied, and because of rules – that you can only put up 120% of your current use worth of generation capability, the array size was too small to cover electric use with full occupancy.
Why add more? Well, in some ways the consideration was more – why not? They pay for themselves, albeit not very quickly. This installation was relatively cheap, I believe around $9,000 total using the roof of the existing chicken coop. The size here is running at about 4 kW (the existing is somewhere around 7kW).
The hope is in the future to add a setup of Tesla Powerwalls or similar to provide a backup microgrid, but at $25,000 for the proper size and installation, those would probably not pay for themselves ever. Another concern with those is that construction and disposal of the batteries – it doesn’t seem particularly renewable given all I’ve heard about rare earth metals. Hopefully in a few years better energy storage systems are available, then we would have a more apocalypse ready energy system.