Wind Power – A Sustainable Solution for Rural Electrification? · CEDECAP for demonstration & training . Multiple centres for demonstration & training . Innovative Learning Week

Wind Power – A Sustainable Solution for Rural Electrification?

Jon Leary – [email protected]

Innovative Learning Week 2012 Edinburgh University


Jon Leary The University of Sheffield

Jon Leary




Wind power for sustainable rural electrification.

• 10.00-10.50: Wind power theory and application

• 10.50-11.00: Break

• 11.00-12.00: Building model turbines




Key questions.

• How does a wind turbine work? • How can a wind turbine provide electricity

access to a remote community? • How can you build a wind turbine suitable

for rural electrification? • How can we make sure this is a

sustainable solution?

Introduction




Why electrify rural areas?

• No. without electricity access: – 1.4 billion – 85% in rural areas

• Electric light – Kerosene lamps?

• Electricity generation – Grid extension? – Diesel generators?

0

0.2

0.4

0.6

0.8

1

0 5000 10000 15000 20000 25000H

uman

Dev

elop

men

t Ind

ex (H

DI)

Per capita annual electricity consumption (kWh/person/yr)

Niger

Pakistan

South Africa

Poland

Brazil Russia

Japan, UK, Israel, Korea

USA

Zambia

Norway




Renewable power generation




Renewable power generation

$0.00

$0.20

$0.40

$0.60

$0.80

10 100 1000 10000 100000 100000010000000100000000 1E+09

Leve

lised

Cos

t of E

nerg

y (U

S$/k

Wh)

Capacity (W)

PV

Wind

PV-Wind Hybrid

Hydro

Diesel

Grid (500MW Coal)

How can a wind turbine provide electricity access to a remote community?




Typical off-grid wind power system




Import or manufacture locally?




Import or manufacture locally?

• DISCUSSION: What factors influence the decision of where to acquire equipment? – Supply chain - resilience – Cost – Impact on local economy – Reliability – Knowledge transfer to end users – Flexibility – Impact on local capacity




Case studies of local manufacture





Technology

demonstration

Demonstration models

in Bluefields

CEDECAP for demonstration

& training

Multiple centres for

demonstration & training





Capital

provided by International donors International donors End users

External

environment

Tropical, coastal, frequent

lightning strikes &

hurricanes

Mountainous, inland Desert, inland





Knowledge

transfer to

end users

Printed instructions,

formal training, demo.

centre, participation in

installation ( and

construction in Cuajinicuil)



centre, participation in

installation



centres, installation

performed by end-users





Resilience Operators perform simple

repairs only

Operators perform most

repairs, regional office for

serious problems

End-users perform most

repairs, network of service

centres for serious

problems





• How successful have each of these case studies been?

How can we make sure this is a sustainable solution?




The real picture.

CRASH!!! Wow! Aren’t

wind turbines so great?!




Critical success factors

• Create a resilient energy system – Involve the community as much as possible – Set up a service network – Establish/strengthen supply chains

• Target windy areas with favourable environmental conditions

• Empower the end-users

How does a wind turbine work?




Wind turbine design

• Main components – Blades – Generator – Tail – Tower – Electrical system

• Batteries, controller, etc.




Blade design

• Horizontal Axis (HAWT) • Vertical Axis (VAWT)




Blade design

• DISCUSSION: What factors influence the design of a set of wind turbine blades? – Cost – Ease of installation – Ease of maintenance – Weight – Ease of transportation – Safety – Wind resource (low and steady vs. high but

variable)




Lift and Drag

• Lift = perpendicular to flow • Drag = parallel to flow




Lift and Drag

LIFT

DRAG




Aerofoil Section

• Device that provides reactive force when in motion relative to the surrounding air

• Blade aerofoil design is critical and minor changes can significantly alter the power curve

• Some HAWTs used NACA 44 and NACA 63 series – 44 series: more resistant to surface

dirt – 63 series: better power curves for

low/medium wind but more sensitive to surface dirt




Aerofoil terminology.

AIR

FLO

W

LEADING EDGE AVERAGE CAMBER

LINE

CHORD

TRAILING EDGE

THICKNESS

ANGLE OF ATTACK (AoA)




Lift & drag on an aerofoil.

LIFT

DRAG

RESULTANT FORCE

AIR

FLO

W




Aerofoil terminology

LIFT

DRAG

RESULTANT FORCE

REL

ATIV

E AI

RFL

OW

THRUST

TORQUE

THRUST

TORQUE

THRUST

TORQUE

TORQUE THRUST




Stall.

ANGLE OF ATTACK, α X

X

X

X

LIFT




Stall.

• String flow visualisation – http://youtu.be/WFcW5-1NP60?t=50s

• Why are wind turbine blades twisted?

http://youtu.be/WFcW5-1NP60?t=50s




Lift & drag on an aerofoil.

LIFT

DRAG

RESULTANT FORCE

AIR

FLO

W




CHORD

α (LIFT/DRAG MAX ≈ 12-16º)

Airflow at tip (normal operation).

WIN

D




Airflow at root (normal operation).

WIN

D

AIRFLOW FROM BLADE

MOTION

RELATIVE AIRFLOW

α (LIFT/DRAG MAX ≈ 12-16º)

β




Twist

• Match operating conditions along blade span β small

β large




Airflow at tip (starting).

WIN

D

α = 90°

β ≈ 0°

RELATIVE AIRFLOW




WIN

D

RELATIVE AIRFLOW

β ≠ 0

Airflow at root (starting).

α = large TORQUE




Taper

• Structural requirement

• Starting performance – Lift

proportional to chord length

Small chord

Large chord




Blade number




Blade number

• Cost • Balance • Power = torque x rpm

– High rpm better for electricity generation – High torque better for mechanical applications




Tower design

• DISCUSSION: What factors influence the design of a wind turbine tower? – Cost – Ease of installation – Ease of maintenance – Footprint – Ease of transportation – Safety – Wind resource (height) – Weight




Guyed tower




Lattice tower




Monopole tower




Questions?

• 10 min break, start back at 11am

Model Wind Turbine Workshop




The Challenge

• To generate electricity from the wind using only newspaper, kitchen roll tubes, a motor, a cork, some drawing pins and some sellotape.




Rules of the game

• The “wind” will be provided by a desktop fan from table height, whilst the wind turbine’s supporting structure may only rest on the ground (sellotaping to the ground is allowed).

• The wind turbines will be judged by the voltage they produce.




Time limit

• 30 minutes building time • 20 minutes testing time

Slide Number 1Jon LearyWind power for sustainable rural electrification.Key questions.IntroductionWhy electrify rural areas?Renewable power generationRenewable power generationHow can a wind turbine provide electricity access to a remote community?Typical off-grid wind power systemImport or manufacture locally?Import or manufacture locally?Case studies of local manufactureCase studies of local manufactureCase studies of local manufactureCase studies of local manufactureCase studies of local manufactureCase studies of local manufactureCase studies of local manufactureHow can we make sure this is a sustainable solution?The real picture.Critical success factorsHow does a wind turbine work?Wind turbine designBlade designBlade designLift and DragLift and DragAerofoil SectionAerofoil terminology.Lift & drag on an aerofoil.Aerofoil terminologyStall.Stall.Lift & drag on an aerofoil.Airflow at tip (normal operation).Airflow at root (normal operation).TwistAirflow at tip (starting).Airflow at root (starting).TaperBlade numberBlade numberBlade numberTower designGuyed towerLattice towerMonopole towerQuestions?Model Wind Turbine WorkshopThe ChallengeRules of the gameTime limit

Documents

Wind Power – A Sustainable Solution for Rural Electrification? · CEDECAP for demonstration & training . Multiple centres for demonstration & training . Innovative Learning Week