High Altitude Wind Turbines using a Hybrid System of Bernoulli and Buoyant Lift

37 Nykolai Bilaniuk LTA Windpower 1834 Asphodel 4th Line Hastings ON K0L 1Y0 Canada ltawindpower@gmail.com www.ltawind.com

High Altitude Wind Turbines using a Hybrid System of

Bernoulli and Buoyant Lift

Nykolai Bilaniuk and Karl von Bloedau LTA Windpower, Canada

This paper examines the technology and economics of the dual lift high altitude wind turbine (HAWT) design by LTA Windpower.

In the technology domain, this hybrid approach aims to low-er technology risk by harnessing proven subsystems, albeit in a novel way. It aims to mitigate the risks unpredictable wind conditions present for active kites dependent on automated flight control systems, while avoiding the high cost of heli-um based buoyant lift. A conscious effort is made to minimize ground crew requirements and avoid the need for a winch. The result is a neutrally buoyant design.

The design begins with a conventional blimp, that is, a non-rigid airship. Instead of a gondola, the blimp has airplane-like wings. There are two generator nacelles with downwind pro-pellers (one on the trailing edge of each wing). The combina-tion might be compared to an airplane with a wide-bodied inflatable fuselage, stubby wings and oversized push propel-lers. The distinguishing feature in an operational sense is the combined use of both buoyant and Bernoulli lift. The buoyant lift allows gently managed takeoffs and landings under all

conditions even in the absence of wind and with no ground crew, while the Bernoulli lift is used to reduce the downwind lean of the lifting body as winds increase. The design allows for the use of hydrogen as a lifting gas in view of the high cost and poor supply of helium. Steps to mitigate the risks of work-ing with H2 are considered.

In the economic domain, compared to terrestrial wind HAW-Ts’ prospects in general are difficult to quantify because of the complete lack of commercial operating experience with HAWTs. HAWTs in general will probably not be scalable to the same sizes as terrestrial wind turbines, nor will they be competitive in locations with strong steady surface winds and low construction costs. HAWT is shown to have advan-tages when these conditions are not met.

The dual-lift HAWT technology here proposed has higher build costs per unit output than active kites, but is believed to offset this with lower risk of catastrophic failure and great-er scalability. It should be highly competitive with othgreat-er tech-niques using buoyant lift. Meaningful quantitative compari-sons to answer these unknowns are not yet possible