How Does it Work? System Design Grid Connection Operation & Maintenance
How does it work?
The system is operated in a pumping cycle of two reciprocating phases in order to achieve a net power gain:
PHASE 1: GENERATION (SEE KITE A)
The wing is flown in a circular looping path akin to the tip of a wind turbine blade. By achieving high flight speeds, over 100mph in a 20mph wind, strong aerodynamic lifting forces are developed by the wing and exerted against the tether. This tether tension causes line to be rapidly spooled out from a drum which is connected to a generator. In this way the 100-200m line is drawn from the reel.
PHASE 2: RETRACTION (SEE KITE B)
The wing must be retracted to its start position consuming the minimum amount of energy. The pitch of the wing is actively changed to minimise aerodynamic force and the kite exits the loop to be held static in an overhead position to be glided back towards the starting point. Line tension can easily be reduced by a factor of 10 or more, such that a net energy gain is achieved over the Generation/Retraction reciprocating cycle.
In our system, two kites fly in the same airspace as per the figure such that whilst one is generating power the other is being retracted; energy production is therefore constant and the alternator kept rotating near optimal speed.
By using asymmetric kites (our second patent filed) we are able to produce a very efficient wing that flies the circular path of the generation phase with very little energy required for actuating the wing control mechanism.
The system has been designed with a philosophy where reliability and efficiency are paramount, combined with a solid and conservative design approach.
Key design features of the KPS technology include:
Patented twin kites system that shares one foundation and one power generation/grid connection system
Patented active control surfaces to minimise drag and maximise yield
Ability to control the kite flying height above high ground wind shear to maximise energy yield
Grid compliant electrical generation within the system package with no need for external power conditioning
All serviced components at low height for ease of maintenance
Robust design for easy maintenance in remote locations
Much lower Levelised Cost of Energy (LCoE) than conventional wind and other renewables
Energy capture can be optimised by flying at the height with the the strongest wind
Low operational and maintenance (O&M) cost and high availability
Fully grid compliant
The electrical infrastructure needed to produce grid compliant electricity is contained within the KPS system itself.
Consequently no external power conditioning is needed and several KPS systems can be linked together (daisy-chained), significantly reducing the cabling required.
Operation & Maintenance
Conventional offshore wind turbines are being located further from shore and require specialist intervention vessels for maintenance, meaning that installation and maintenance can be very challenging and expensive.
To avoid this the KPS system can be detached from its mooring in under 1 hour and towed back to a safe haven using a small tug or work boat for the majority of maintenance. This in turn reduces repair time, maximises operational availability, also reduces the need for expensive vessels and reduces risk to personnel.
In an emergency situation, weather extreme or other requirement each KPS system can be shut down from full rated output with the kites docked at a safe height in less than one minute from full power generation.
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