When facing a 12 hour power cut, a 'trick' (it's science really but I try to avoid that word so as not to irritate drei dopplegangers) is to ensure your freezer is full. If there are gaps then put bottles of frozen water in there (can use ice packs, of course (to save anyone telling me), but bottles of water will do for this purpose). As the ice thaws it requires heat and it takes the heat from inside the freezer - thus keeping it cooler. A mostly-empty freezer will cause the contents to thaw rapidly.
Or, Buy a couple of deep cycle batteries and an inverter, plug that in, it should last a few hours depending on the amp hours of your batteries.
My TV is the old type - it runs on water. Btw (if you are a fan of Harry Hill) > If there is a dispute about water v battery: FIGHT!