Originally Posted by
Thomar_of_Uointer
These can actually be solved together. As you've probably already figured out, geothermal energy is really easy to work with at the bottom of ocean trenches. It can also be directly harnessed to heat habitats, keeping everyone warm. You may also have major temperature variations across a settlement, with places near the power pipes unbearably hot and the less-inhabited outskirts almost freezing cold. Also note that because of the pressure ice will form at much lower temperatures. Ice may be unheard of.