Airborne Wind EnergyPowerWeb webinar lecture

Roland Schmehl

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Presenter

• Associate Professor at Delft University of Technology • Co-founder of Kitepower BV• Coordinator of 2 H2020 projects (AWESCO & REACH)• AWE-responsible PI in Dutch NWO project NEON• Co-organizer of AWEC 2015, 2017 and 2019• Co-editor and editor of 2 Springer textbooks on AWE

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2013 2018

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Outline

• Fundamental working principles• Classification of concepts• Implemented technology demonstrators• Development challenges• Research challenges• Development of the sector

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Drag power:● Flying wing shaft power⇝● Shaft power electricity (ω )⇝ ↑● Electricity conductive tether⇝

Lift power:● Flying wing traction force⇝● Traction force shaft power (ω )⇝ ↓● Shaft power electricity⇝

Fundamental concepts Miles L. Loyd (1980)

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Key aspects +–

● Consumes significantly less material● Highly adjustable to wind resource● Access to high altitude wind● Increased mobility

● More complex than turbines● Requires reliable & robust control

● Depends on high-performance materials● Need to revise current regulatory framework

Image source: Skysails

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Aerospace Engineering – Open Days – 6 March 2020

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Introduction

Kitepower Enerkíte Ampyx Power Kitemill Twingtec

KPSSkysails Skypull Windswept eWindSolutions

Technology demonstrators

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Man-lifting kite train (1930)AWES classification

Adapted from: Watson et al. “Future emerging technologies in the wind power sector: a European perspective”, Renewable and Sustainable Energy Reviews, 2019.

Elelectricity generation

Flight operation

crosswind

rotational someAWE Vertical take-off and landing (VTOL)Horizontal take-off and landing (HTOL)Multi-drone conceptsLigther-than-air concepts

~ Flexible wing concepts

Kitemill Skypull TwingTec E-Kite

EnerKíte Ampyx KPS Kiteswarms

Kitepower Kitenergy eWind Solutions

~~ KiteGen stem

SkySails Power~~

Laddermill Guangdong HAWP

tether-aligned Omnidea

Windswept

AWEsystem

with fixed GS➡

➡

➡

crosswind X-Wind loop track KiteGen carousel

~~ with moving GS➡ ➡

crosswind

rotational

Makani KiteKraft

Windlift KiteX

Bladetips Brainwhere

Altaeros Magenn

Sky WindPower on flying device➡

➡

➡

Kitewinder

➡

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Man-lifting kite train (1930)AWES classification

Adapted from: Watson et al. “Future emerging technologies in the wind power sector: a European perspective”, Renewable and Sustainable Energy Reviews, 2019.

Elelectricity generation

Flight operation

crosswind

rotational Vertical take-off and landing (VTOL)Horizontal take-off and landing (HTOL)Multi-drone conceptsLigther-than-air concepts

~ Flexible wing concepts

Kitemill Skypull TwingTec E-Kite

EnerKíte Ampyx KPS Kiteswarms

Kitepower Kitenergy eWind Solutions

~~ KiteGen stem

SkySails Power~~

Laddermill Guangdong HAWP

tether-aligned Omnidea

someAWEWindswept

Kitewinder

AWEsystem

with fixed GS➡

➡

➡

crosswind with moving GS➡ ➡

crosswind

rotational

Makani KiteKraft

Windlift KiteX

Bladetips Brainwhere

Altaeros Magenn

Sky WindPower on flying device➡

➡

➡

X-Wind loop track KiteGen carousel

~~

➡

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Man-lifting kite train (1930)Further reading: awesco.eu/awe-explained

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Technology demonstrators

• Makani• Ampyx• Twingtec• Kitepower

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Wing7 (30 kW)California 2013

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M600 (600 kW)California 2017

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Norway 2019

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AP-2 (50 kW)Noordoostpolder 2013

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AP-3 (250 kW)Marin 2018

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19

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2019

WIND ENERGY 2.0

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TwingTec pilot next to turbine with same power

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25 kW kite power system2012

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2012

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System components

26 TU Delft V3 25 m2 Genetrix Hydra 14 m2 TU Delft V3 25 m2

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Genetrix Hydra 14 m2 TU Delft V3 25 m2TU Delft V3 25 m2

2.55 m

2.03 m

0.974 m

0.876 m

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Automatic pumping cycles at Maasvlakte II of Rotterdam Harbor

2012

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Launch from upside-down position

• The following three videos show the same launch attempt on 2 August 2012

• The videos are taken from three different positions– GoPro video camera on the ground next to mast– GoPro video camera taped to the leading edge– Photo camera on the ground

• Weak link ruptures as result of sudden tether disengagement from mast head

https://doi.org/10.5446/46849

https://doi.org/10.5446/46844

https://doi.org/10.5446/46845

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40 m2 kite2017

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100 kW ground station

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42

43

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Kite park power output

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Kite development: 25 – 40 – 60 m2

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Kite development: 100 m2

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2016 Q2 Q3 Q4 2017 Q2 Q3 Q4 2018 Q2 Q3 Q4 2019 Q2 Q3 Q4

Quarter

0

20

40

60

80

100

120

140

160

Days

Actual flight days per quarter

Cumulative flight days

Flight days

R&D landscape2018

 

 

 

Stanford University

AirLoom Energy 

Skypoint-e

EnerKíte

SkySails Power

WindLiftUNC Charlotte

Worchester Polytechnic InstituteUniversity of Delaware

Fraunhofer IWES

AnuracChalmers University

RMIT University

Guangdong HAWP Technology

 

DTU-Wind

  

 

  

 

KitenergyKiteGen

Politecnico Milano

EPFLETH Zurich

TwingTec

ABB Corporate Research

TU Munich

University of Freiburg

 

 

 

UF Santa Catarina

 

  

University of VictoriaeWind Solutions

Makani / X

Oregon State University

University of Trento

Altaeros Energies

 

University of Zagreb

 

OmnideaUC3 Madrid

Beyond the Sea®Kitewinder

ENSTA Bretagne

University of Limerick

Kite Power Systems

Grenoble INP

KU LeuvenTU DelftKitepower

Ampyx Power

TU Berlin

Altitude Energy

KitemillECN

NLR

 Skypull

KiteX

University of Applied

XsensAenarete

Sciences of Northwest Switzerland

E-Kite

Upwind

Sky WindPower

Kyushu UniversityTMIT

University of Strathclyde Windswept & Interesting

AirSeas / Airbus

KiteSwarms

academiaindustry

University of Stuttgart

University of Bonn

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Challenges

• Reliability & Safety– None of the projects has proven more than a few days of operation– Operation in kite parks

• Durability of materials– Tether and kite are critical components

• Regulations– Interference with air traffic and ground use

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VLM simulation

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CFD analysis

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Oehler & Schmehl. "Aerodynamic characterization of a soft kite by in situ flow measurement". Wind Energy Science, 2019

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CFD simulation with OpenFOAM Streamlines around the kite colored With the spanwise velocity component, computed for Re=3x106 and 12° AoA

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Relative flow measurement setup

TU Delft V3 kite

Oehler & Schmehl. "Aerodynamic characterization of a soft kite by in situ flow measurement". Wind Energy Science, 2019

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Norway 2019

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g

Effect of power

● Changes chordwise force distribution

● Powering up the wing makes wing pitch backwards

depowered

powered

Oehler & Schmehl. "Aerodynamic characterization of a soft kite by in situ flow measurement". Wind Energy Science, 2019

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Effect of power

● Wing flattens● Force increase also by area

increase

powered

depowered

Oehler & Schmehl. "Aerodynamic characterization of a soft kite by in situ flow measurement". Wind Energy Science, 2019

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Aerodynamics

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Aerodynamics

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Aerodynamics

Fluid-Structure Interaction simulation of a ram air wing section

Aeroelastic bending and torsion of a half wing supported by a bridle line

Wijnja, Schmehl, De Breuker, Jensen and Vander Lind: "Aeroelastic Analysis of a Large Airborne Wind Turbine". Journal of Guidance, Control and Dynamics, 2018

Aeroelastic model of an AWT and the tensile support system connecting it to the ground

Wijnja, Schmehl, De Breuker, Jensen and Vander Lind: "Aeroelastic Analysis of a Large Airborne Wind Turbine". Journal of Guidance, Control and Dynamics, 2018

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Kite park layout

row

wind

colu

mn

wind

column

row

Faggiani & Schmehl. “Design and Economics of a Pumping Kite Wind Park". In: Schmehl (ed.) "Airborne Wind Energy - Advances in Technology Development and Research", Springer, 2018

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Kite park power output

 

 

1 kite

4 x 4 kites

8 x 8 kites

-500

0

500

1000

1500

2000

6004002000 800 1000Time [s]

Pow

er [k

W]

Faggiani & Schmehl. “Design and Economics of a Pumping Kite Wind Park". In: Schmehl (ed.) "Airborne Wind Energy - Advances in Technology Development and Research", Springer, 2018

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Safety & reliability

400 m

70 m

2 m

20 m

Ground station

300 m

Safety zone

Ground station

50 m

Danger zone

65 m

Operational zoneOperational zone

Flight zone

Danger zone

50 m

KITEPOWERairborne wind energy

KITEPOWERairborne wind energy

Salma, Friedl & Schmehl: "Improving Reliability and Safety of Airborne Wind Energy Systems", Wind Energy, 2019

(C) (A)

(B)

(D)

(E)

2012/08/02 Salma, Friedl & Schmehl: "Improving Reliability and Safety of Airborne Wind Energy Systems", Wind Energy, 2019

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Kite park power output

r.schmehl@tudelft.nl twitter.com/kite_power awesco.eu

Questions?