Here in Ireland it's a bit of a heart-stopping dinner and is quite similar to Christmas in the USA due to various traditions crossing the atlantic in both directions but also quite similar to Xmas in the UK.
Multi-course dinner including:
Turkey or Goose
Sometimes Spiced Beef (particularly around Cork area)
(typically patatoes, turnips, sprouts, carrots, onions, peas etc etc.. it varies from house to house)
The compulsary Christmas fruit cake (very very dark rich cake laced with Cognac and dried fruit)
Christmas pudding.. served flaming.. you pour brandy over and light it with a match.
Mince pies (strange pies full of "minced meat" which is actually a mix of spices, alcohol and preserved fruit. Very victorian dish.
Vast amounts of food and drink basically.
It's also traditional to completely over estimate how much food you need and to use at least 2 shopping trollies (carts) in the supermarket and to buy a turkey that so bit it barely fits in the oven.
In terms of electricity consumption Xmas dinner cooking period is one of the annual peaks as 1 million ovens all go online simultaniously along with every hob, light, heater and cooking applience known to man.
The grid is still intact! so I think we can safely say the power system is able to deal with demand