The tethered wind turbine uses an aerodynamic, flow-concentrating shape and lighter-than-air construction utilizing a lifting gas and an electrically conductive tether fixed to ground to reap energy from the wind at low or high altitude. The design has no need for the large, expensive, bulky and unsightly tower structures, pivoting nacelles, or gearboxes presently used in conventional horizontal axis windmills. The tethered wind turbine easily and passively floats aloft downwind to a direction and position that is aligned with the wind. The invention uses sensors and control modules to fly gracefully at an optimal altitude in most wind regimes and also to ascend/descend when appropriate to seek shelter from extreme weather conditions. Ideally, the tethered wind turbine would utilize carbon nanotube materials in its tether for both structural and conductive purposes. Its ring-wing section profile optimally would have a very low coefficient of drag. A major benefit of this invention is potentially much lower cost per installed kilowatt capacity and a lower operating cost per kilowatt hour delivered to the end user.