By overallocating. In Europe, most homes can do well with 10kwh daily electric energy. Make that 20 to be on the safe side. To fill that reliably you might need

By overallocating. In Europe, most homes can do well with 10kwh daily electric energy. Make that 20 to be on the safe side. To fill that reliably you might need something between 10 and 50kwp solar energy. Everything can be bought once.