Power in the world

In Ergar the main power source comes from energized crystals from the great crystal ravine.
In Argo the main power source is the mist surrounding the world, it is fuel for "Mithril Engines" a secret technology that creates rotary motion with tons of torque or lateral motion with immense force
In Ravia they use a type of oil found beneath bodies of water then refine it to fuel their engines similar to fossil fuels on Earth.
In Fiirtha they use a special form of obsidian only found in Mount Leer that produces enough heat to create a nuclear style power source where the fuel stones heat up water or other liquids around it creating steam