Well, I've seen designs for flying wind turbines before (check out Sky WindPower's design, for example) but a new design from Magenn Power Inc might be a bit more practical and has been generating some excitement from readers over at Treehugger. Unlike Sky WindPower's gyrocopter-based design, Magenn's design seems much simpler, is designed to operate at lower alititudes, and is based on well-developed airship technology.
The Magenn Power Air Rotor System (MARS), is an innovative lighter-than-air tethered device that rotates about a horizontal axis in response to wind. A helium (or hydrogen) filled airship-like bouyant turbine, the 'Air Rotor', is tethered to the ground by an insulated conductive tether and rises to a height of 400 to 1000 feet to take advantage of more constant and higher wind speeds at higher altitudes. There, the body of the Air Rotor spins in the wind generating electricity which is transferred down the tether to a transformer at a ground station and then transferred to the electricity power grid. The body of the Air Rotor is constructed of Vectran, a high tenacity, bulletproof, composite woven material (similar to Kevlar) that is stronger than steel of the same thickness.
The MARS turbine gets both bouyancy from it's lighter-than-air contents as well lift from the 'Magnus effect.' Named for the Magnus airship designed by MARS designer, Fred Ferguson, the Magnus effect refers to the behavior of a rotating airship wherein as wind speed increases, the rotation of the airship increases, which in turn generates lift, increases stability and minimizes air drag because of reduced leaning. It also keeps the MARS turbine positioned within a very controlled and restricted location, and causes it to pull up overhead rather than drift downwind on its tether.
According to Magenn, their MARS design offers several distinct advantages over traditional blade-like horizontal-axis wind turbines mounted on towers:
Conventional wind generators are only operable in wind speeds between 3 meters/sec and 28 meters/sec. Magenn Air Rotors are operable between 1 meter/sec and in excess of 28 meters/sec.
Magenn claims that these qualities combine to make their MARS turbines "the most cost-effective wind electrical generation system."
Magenn claims that the MARS design is very scalable and allows them "to produce wind rotors from very small to very large sizes at a fraction of the cost of current wind generators." This would allow the MARS design to be used in a number of different applications. As Magenn's website writes:
"The Magenn system concept is deployment-flexible. Large MARS units may be deployed to supplement established grid systems supporting the electrical requirements of large urban areas. Small MARS units would be deployed in emergency, as-needed, and/or mobile applications (e.g., pack version deployed by a hiker, motorist, boater, or for military and emergency response applications). Various in-between sizes would be ideal for farms, houses and cottages located where grid power is nonexistent. Small to medium sized systems could also be air-dropped into disaster areas for emergency electrical power for medical and all other uses."
According to Magenn, the company "will start manufacturing its Air Rotors in Fall of 2006 and will start taking product orders in April of 2006 for ... 4.0 kW MARS units." These "cottage or home sized" units will be 39 feet long with a 14-foot diameter and are designed to operate at a height of 150-400 feet. Target price at release will be $9,999 (USD). According to their products page, Magenn also plans to release both larger and smaller sized units between 2007 and 2009 starting with a camper or boater sized 1 kW unit (6.5' diameter, 19.5' long, operating height of 50-150') that they plan to sell for $1,999 (USD) beginning in 2007. The largest planned turbines would be released in 2009 and include two units suitable for commercial power applications and rated at 800 kW and 1.6 MW. Both units supposedly would have a 67' diameter, be 200' long, and operate at heights of 400-925'. I'm confused about how they could get double the output from the same-sized unit though. The price of these units is still to be determined.
Obviously, Magenn's design raises concerns about tethered wind turbines interfereing with air traffic. However, Magenn is keenly aware of this issue and has paid particularl attention to ensuring that their systems comply with altitude guidelines as directed by FAA regulations. According to Magenn, "the five points below represent a summary of Magenn planning to satisfy these guidelines:
I think the most significant problem that Magenn's flying turbines will have to overcome will be issues with visual pollution. I'm pretty certain that NIMBY (Not In My BackYard) opposition would be substantial to having a few dozen flying turbines tethered above urban areas with blinking lights every 50 feet along each tether. These might meet a more warm reception from farmers or other people living in rural areas where the small population density might make NIMBY opposition smaller. Small MARS turbines may find a niche in disaster relief applications as well where the dire situation would presumably outweigh any NIMBY issues that might arise.
In the end though, this is a very smart design and offers some substantial advantages over normal turbines. Being able to deploy the turbines at much higher heights than traditional turbines where they can utilize more constant wind speeds could seriously decrease the levelized cost of wind power. Additionally, being able to delpoy these turbines closer to urban areas - where wind speeds are not high enough at lower elevations to support traditional wind turbines but might be high enough at altitudes of 1,000 ft - would avoid infrastructure issues that plague traditional wind developments. Such traditional developments are often sited in remote locations where the costs of building new infrastructure to connect to the grid can become a substantial portion of overall project costs. Citing generation near demand centers also reduces transmission losses. Also, eliminating the need for the large steel towers that support traditional turbines means that the MARS design could likely deployed at a lower cost than traditional turbines.
It will be interesting to see if this design can overcome NIMBY opposition to visual pollution issues. If it can, Magenn's MARS flying turbines could become another useful addition to our renewable energy 'toolbox'.