Over the last decade there has been keen interest in developing marine hydrokinetic systems, especially underwater kites, for use as utility-scale renewable energy sources.  

That interest might seem unexpected, as kites are commonly thought of as airborne playthings. But in this instance, kites are generically lifting bodies moving through flowing fluids and tethered to base stations. A kite moving in cyclic patterns perpendicular to the prevailing flow can travel much faster than the flow itself. If a turbine is attached to the kite, it can capture much more power than a stationary turbine of the same size.