there isn't anything out there known by "dark energy" unless your watchign somethign liek star wars or star trek or whatever they make up in them..
the earth spins on its axis, because there is no force in space acting against it to stop it spinnign, its not using any energy to spin, nor is it loosing energy because it is spinning, it moves through space because there is no force acting against it to stop it moving, and it will keep moving at the same speed forever. unless it blows up, or hits another planet or big meterite etc.
doesn't need dark energy or energy when its not using energy at all.