Airborne Wind Energy Companies Deploy Worldwide

University-sponsored research labs and private industry throughout the world are working toward a common goal -- to launch the airborne wind energy industry. Though each company’s system design, operational height and market deployment goals vary, they all intend to take advantage of the phenomenal energy resource available in high altitude winds.


Aeroix - Berlin, Germany 

The Aeroix Enerkite system is based on a project co-developed by Festo, a worldwide leader in pneumatic and electrical automation technology. Aeroix also provides technical textiles products.

CyberKite, an autonomously controlled kite wing of up to 24 square meters (258 square feet), is operable without any external energy feed-in. The kite uses resilient winches, which are supplemented with battery technology. In the "generator mode" the servo drives are being run periodically by the ropes, which are de-coiled by the traction relayed by the kite. The regained electrical energy is stored in the batteries and reduces the energy demand of the system.




Ampyx Power - Brennels, Netherlands 

Ampyx Power spun-off from TU Delft and its Ladder Mill project 18 years ago. The Ampyx PowerPlane produces electricity at an operating altitudes between 300 and 500 meters. A system prototype has successfully generated 10 kilowatts of power.

Ampyx Power recently obtained second round financing from the Norwegian energy company, Statkraft, (Europe’s biggest producer of renewable energy) and Byte, a Dutch IT company.

The PowerPlane system uses a glider plane to unwind a winch during flight to propel a generator on the ground. Ampyx is currently developing a 100 kW prototype. The Power Plane test rig has a wingspan of 5.5 meters and plans are to design larger systems with 35 meter wingspans capable of 1 MW power generation.

Ampyx received approval to test in Noordoostpolder, Netherlands and plans to demonstrate fully automated power production in late 2010 and produce a commercial 1MW PowerPlane in 2013.


Guangdong High-Altitude Wind Power Technology - Guangdong Province, China 

Dr. Zhang Jianjun began his research on high-altitude wind power generation in the United States and returned to China where he built China’s first high-altitude wind energy research center and wind tunnel lab in Guangdong Province. The company plans to build a 1 MW high-altitude wind power generating system in Foshan City.

The technology consists of a kite/glider pulling cables and driving generators to produce electricity. When the kite ascends to the maximum height, the angle of the wings of the kite will be adjusted by the control system to make it descend with its own weight.


Joby Energy - Santa Cruz, CA USA 

Joby Energy systems are comprised of two-wing airframes supporting an array of turbines. The turbines connect to motor-generators which produce thrust during takeoff and generate power during crosswind flight. Orientation in flight is maintained by an advanced computer system that drives aerodynamic surfaces on the wings and differentially controls rotor speeds.

For launch, the turbines are supplied with power to enable vertical take-off. Upon reaching operating altitude, the system uses the power of the wind to fly cross-wind in a circular path. During occasional periods of low wind the turbines are powered to land the system safely.

The system uses a reinforced composite tether to transmit electricity and moor the system to the ground. The high redundancy of the array configuration can handle multiple points of failure and remain airborne.

The company is currently building and testing 10 - 30 kW system prototypes while simultaneously designing and building 100 and 300 kW systems. Plans are to fly initial commercial systems between 500 and 2,000 feet and to begin manufacturing of commercial systems in 2012.


Joby Energy airborne wind turbine concept


Kitenergy - Torino, Italy 

Kitenergy utilizes autonomously controlled tethered airfoils operating between 500 and 1000 meters. Electricity is generated at ground level by converting the traction acting on the tethers into mechanical and electrical power, using rotating mechanisms and electrical “yoyo” generators. The autonomous controls driving the airfoils pull the lines to direct the wing motion.

The Kite Steering Unit (KSU) is comprised of electric drives, the drums, the on-board sensors and hardware.

kitenergy yoyo configuration

KG--yoyo configuration cycle: traction (solid) and passive (dashed) phases.




Kite Gen Research - Chieri, Italy 

In the simplest configuration of the Kitenergy technology, the KSU is fixed on the ground. The KSU can autonomously perform a two-phase cycle, simply acting on the two lines that connect the airfoil to the fixed steering unit. The lines are connected to two alterno-motors by means of wrapping drums. In the traction phase, the airfoil is driven to fly fast in crosswind direction, with “figure eight” trajectories, and generates high traction forces that unroll the lines. The drums are put in rotation and the alterno-motors produce energy. When the maximal length of the lines is reached, the control enters into the recovery phase, where the wing is driven to a region where the lines can be pulled by the motors until the minimal length is reached, spending a small fraction of the energy generated in the traction phase and a new traction phase is undertaken. The energy balance between the traction and recovery phase is approx. 90% (i.e. only 10% of the energy generated during the traction phase is then spent during the recovery phase). The energy produced is stored in batteries and then directed to the electric grid.

Prototype systems that were tested near Asti, Italy (where wind conditions are generally considered inadequate for convention wind turbines) produced 5kW average and 30kW peak, with a ground speed of 4.5 m/s.


Animated rendering of prototype of a Kitegen 3.0 MW System.


Laddermill - Delft, Netherlands 

The TU Delft University Laddermill project is developing the Kiteplane, a cross between a kite and a airplane. The systems will initially be deployed up to 1000 ft and plans are to eventually reach the jet stream. The Kiteplane will be comprised of a number of kites flying in a large loop and ascending and descending to create a rotation that is coupled to an on-ground generator that creates energy.


Laddermill system test at Valkenburg Airport, April 2010.
Peak power reached was 20kW.


Makani Power - Alameda, CA USA 

Google-funded Makani Power’s most recent design utilizes an autonomously- controlled, rigid, single wing airframe with multiple on-board generators. A bi-directional tether powers the system to operating altitude and when generating power tranfers it via an aerodynamic tether to a power substation on the ground. The Makani system will fly at altitudes between 200 and 1,000 meters.

Makani Power boasts a relatively light-weight system that uses only a fraction of the materials a similarly-rated conventional turbine would use, resulting in energy that is cost-competitive with coal.

The company recently conducted a successful test of autonomous controls in continuous cross-wind flight -- simulating the desired flight pattern of its future systems.


Makani prototype testing and company video


Magenn Power - Mountain View, CA USA 

The Magenn Power airborne wind energy system, MARS, is a helium-filled tethered wind turbine that rotates on a horizontal axis at altitudes from 600 to 1000 feet.

MARS rotation also generates the "Magnus effect" which provides additional lift, keeps the MARS stabilized, which means it will operate in a very controlled and restricted location.

Reaching winds at 1,000 feet above ground level allow MARS to be installed closer to the grid. MARS is mobile and can be rapidly deployed, deflated, and redeployed without the need for towers or heavy cranes. MARS is bird and bat friendly with low noise emissions. The system is capable of operating in a wide range of wind speeds - from 4 mph to greater than 50 mph.


Sky Windpower - Oroville, CA USA 

Sky WindPower intends to deploy a 1 MW Flying Electric Generator (FEG) in the jet stream. The FEGs utilize existing rotorcraft technology to capture and convert high altitude wind energy to electricity.

FEGs will operate at altitudes between 6,000 and 30,000 feet. A 12 kW prototype is undergoing testing and is expected to be flown in the fall of 2010. The goal is to produce power at altitude in the winter of 2010-2011.

As with most airborne wind systems, FEG systems may be economically feasible at lower wind sites where conventional wind turbines are impractical and could be located closer to existing transmission than new terrestrial wind farms. Sky WindPower predicts that FEGs will have capacity factors of up to 80% to deliver massive amount of clean power.


Swiss KitePower - Various research institutions in Switzerland 

Swiss KitePower is an academic coalition of researchers at The University of Applied Sciences Northwestern Switzerland, FHNW, Swiss Federal Institute of Technology Zurich, EMPA and the Swiss Federal Laboratories for Materials Testing and Research, ETH. The coalition is sponsored by industry partner Alstom Switzerland AG -- the Swiss branch of a multinational power and transportation company.


Systems testing of "Kite Control Unit" prototype (KCU1) in August 2009

Research and testing projects by research institution include:

FHNW

  • Force measurements on a 4-line power kite
  • Airborne Kite Control Unit
  • 10 kW 'Pumping' kite power plant

EMPA:

  • Tensairity kite design, construction and testing
  • Kite dynamics simulation
  • Flying wing actuator design and testing

ETH:

  • Kite control simulation
  • Instrumented kite
  • Automated kite control software


Windlift - North Carolina, USA 

Currently Windlift is building a 12 kW mobile wind power system mounted on a 6 meter long trailer. The machine generates power by reeling a tether on and off of a winch drum. The airfoils are custom para-wings, similar to kiteboarding kites, but reinforced to handle net loads up to 5000 lbs.

The company has abandoned direct mechanical applications like pumping or compressing air for now, tying it's winch system into a Azure Dynamics AC55 electrical motor/generator. The system’s optimal operations will be below 500 ft. in altitude to avoid any potential conflicts with air traffic. The company plans on completing a build of this system in early July 2010.


NTS - Germany 

NTS Energy & Transports won the recent European Union-hosted Knowledge Intensive Services Innovation Platform (KIS-IP) showcase of renewable energies and satellite downstream applications entrepreneurs.

According to the KIS-P contest website, the German company plans to present its unique and patented concept which will harness wind at high altitude and produce electricity for lesser costs than fossil fuels.