Forget solar power, this month check out the only kind of energy sourced from the moon. Tidal power plants have an interesting history, but is there a future for this alternative source of renewable energy? Super durable concrete and floating construction methods have made unusual hydroelectricity plants economically feasible, but a new turbine is poised to carry them into the 21st century. Wave energy converters also capture the motion of the ocean and could boost electricity production at future tidal barrages threefold. And engineers are hard at work just outside of Moscow on a new pumped storage plant that harnesses the natural power of gravity for an environmentally friendly way to balance energy demand.