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Presentation on Kite Energy Systems
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Kite Energy Systems
By Christoff Muller
High Altitude Wind Power
What is Kite Energy Systems?
High Altitude Wind Potential
Optimal wind power density (left) and optimal height (right) that was exceeded 50%, 68%, and 95% of the time during years 1979-2006.Taken from "Global Assessment of High-Altitude Wind Power" by Cristina L. Archer and Ken Caldeira
Typical wind turbine: Rated power at 12m/s at sea level need about 1 kW/m2
Optimal wind power density (left) and optimal height (right) that was exceeded 50%, 68%, and 95% of the time during years 1979-2006. Taken from "Global Assessment of High-Altitude Wind Power" by Cristina L. Archer and Ken Caldeira
High Altitude Wind Potential
High Altitude Wind Potential
Optimal wind power density (left) and optimal height (right) that was exceeded 50%, 68%, and 95% of the time during years 1979-2006.Taken from "Global Assessment of High-Altitude Wind Power" by Cristina L. Archer and Ken Caldeira
Typical wind turbine: Rated power at 12m/s at sea level need about 1 kW/m2
68% of the time most of South Africa has more than 1kW/m2 wind at between 8 and 10km high95% of time, southern tip has more than 0.5kW/m2 at a meagre 2 to 4 km high!
Much higher average wind speeds Much more consistent (greater utilisation factor)Potentially capable of supplying base load!Wind might be too strong too often?Wind speed control by controlling operating height
Crosswind Kite PowerConcept of sweeping large area of wind by flying a high L/D wing was described by Miles Loyd in 1980
Identified two method of crosswind power extraction: Drag based (eg generators on wing) Lift based (eg wing pulling on the tether line)
Much smaller airfoil can capture much more powerTether angle cannot be very vertical- limited altitude, but can still reach heights 500m+
Safety
Air traffic:
need dedicated airspace zones
airband radio warning
make use of locations far from air traffic
(eg. Karoo/offshore)
Danger in case of failure (heavy parts falling from the sky)
Environment
Must automatically survive:
Very high winds (storms)No wind (auto land & launch system)Big systems could have humans in the loopLightning!
Lighter than air systems
Flies in no wind
Big & expensive per kWh
MAGENN AIR ROTOR SYSTEM (M.A.R.S.)Claims under US$0.20 per kWh Plans initial commercial units of 100kWRated power from 10 up to 23m/s wind
from http://www.magenn.com/index.php
Reel-in/Reel-out Systems: Crosswind- lift type
Not Continuous power generation- use multiple out-of-phase unitsLoss of autopilot is catastrophicDesigned for crosswind operation- limited altitude
Small size /kWLightweight, low cost kiteSimple kiteline
Flying Generator: Crosswind drag type
Heavier system (not good for light wind)Loss of autopilot is catastrophicDesigned for crosswind operation- limited altitude
Small size /kWOnboard generators act as motors for launching/landingDurable materials
Jobi Energy
Continuous Loop Systems
Generator on ground, powered by a long continous loop of kiteline turning it
Continuous Loop Systems
Continuous Loop Systems
Continuous power generation from each unitCan easily scale up to use high altitude windsDifficult to adjust height/ retrieve autonomously
Generator on ground, powered by a long continous loop of kiteline turning it
Super Turbine
More smaller turbines gives higher rpm (smaller gear ratio or direct drive)
Mass-produce turbines
Easily mounted on unique structures held up by kite/blimp (offshore) or between mountains/ buildings
Thank you