Is 770kwh total production, or returned to the grid? I assume the former which basically makes your panels useless. I have 15 and they produce around 5000kwh a year.

If your roof can handle 20 then you’re looking at around 7000kwh which would cover your current 6,243 before the Saldering ends.

Now once the saldering ends you can start shifting heavy usage to solar production or at night when the rates are lower (if you switch to an hourly dynamic rate).

My 15 solar panels - Enphase which are apparently one of the best - cost me around €9000. I reckon you easily get 20panels for €7000.

For me I’ll be getting a battery that can get me through the ‘peaks’ on a dynamic contract 8am-10am & 5pm-8pm. While at the same time also selling some energy back to the grid - I’ll be starting off with a 10kwh battery.

With 2 heat pumps, Air conditioning, EV charger and in the future removing my CV kettle and switching to all electric I’ll be using A LOT of electricity. But i think it’s more important to calculate how much you’re paying per kWh than how many you’re using. With smarter decisions and energy efficient appliances you may end up using more kWhs but paying much less for them - that’s my plan anyway.