maybe they can just, you know, burn their trash in incinerators for electricity
They do that already, it produces about 1% of the total electricity.
In the end it'll also boil down to proper design. I've seen illustrations of houses that uses water heated by the sun to warm to home, maybe they do that there. I mean, the sun still shines during winter, except if there's a blizzard.
Much easier: windows facing the sun. It helps, but it's not enough.
