I would give serious consideration to a SOLAR system as well as a good generator. NO it does not need to be a portable.
Most houses (Absent air conditioner) can get by on 5,000 watts of power for Furnace, lights, electronics and kitchen (The services you need) You might consider having an "Whole house" emergence generator Generac or Onan installed in the say 10,000 watt range (this will run most A/C's too)
then when the house is wired you put in two breaker panels. One is "Mains only" and the other.. is the "E" panel (Emergency) that way when (not if) the power company lets you down the back up kicks in
