While I don't actually celebrate Christmas, I do enjoy the lights and all the festive decorations around my neighborhood. It has been some time since virtually all Christmas lights phased to LED bulbs, but even with the massive reduction in power consumption, when a couple million people decide to string out hundreds if not thousands of lights a piece, you have to get more energy from somewhere.
With the short days, solar isn't really an option. Fortunately, the winter season coincides with the harsh winter winds that give the wind turbines in the area a little extra juice to run the lights. Especially considering that the run at night when base load is lower and the winds even stronger, we've managed to get dazzling displays every year that don't emit a gram of CO2.
As for me, I've got some beeswax sustainable candles to light ;-)