About electricity, given the nice sun which always shines in RW and the unlimited amount of surface, photovoltaic panels could be more sustainable than in reality and possibly, with a bit of tweaking for the sake of gameplay (but also of 'deep realism', see this post of mines), more efficient and easier to make. It is also rather simple to implement visually (well, VERY simple, as you can't see electricity!); it would 'only' require code to manage energy propagation and conversion to movement and a few (static) meshes for a few devices (the photovoltaic panel, a battery, an outlet, perhaps a cable).
Steam is suggestive, but fuel supply would be hard (and without the need of fuel, it would be too simplistic, wouldn't it?).
