Small wind power for rural locations - part 1

Wind energy harvesting basics,
resource assessment and
application for off grid systems.
Hanan Einav-Levy M.Sc.

Thursday, November 10, 2011

A bit about me
Hanan Einav-Levy M.Sc
• Aeronautical engineer
• Wind turbine technology advocate
• Experience in installing and building small
wind turbines in Israel and abroad for rural
electriﬁcation
• Consultant to several wind energy NGO’s
• Conducting PhD research in wind turbine
resource assessment


Aim of lecture


Aim of lecture
• Wind turbine systems are complicated systems


Aim of lecture
• We have 4 hours...


Aim of lecture
• You will gain a basic and comprehensive
understanding


Aim of lecture
understanding
• Many valuable references will be
mentioned for your future use


Aim of lecture
understanding
• Many valuable references will be
mentioned for your future use
• You will receive a starting point for
developing wind in rural communities in
your countries


Outline


Outline
• Part 1 (2 hours)


Outline

• Global wind resource (10)


Outline

• Modern wind turbine history (10)


Outline


• Wind energy theory (10)


Outline


• Technology -
HAWT,VAWT, Lift, Drag, BIG,
small (15)


Outline


• Technology -
small (15)

• Environmental considerations (5)


Outline


• Technology -
small (15)


• Wind speed variability (15)


Outline


• Technology -
small (15)


• Estimating the resource (15)


Outline


• Technology -
small (15)



• Off grid wind system components
(5)


Outline


• Technology -
small (15)



(5)
• Economic considerations(10)


Outline
• part II (2 hours)

• Technology -
small (15)



(5)


Outline
• Example project (50)

• Technology -
small (15)



(5)


Outline
• Small wind turbine product
• Wind energy theory (10) comparison (10)
• Technology -
small (15)



(5)


Outline
• Technology -
• Case studies
small (15)



(5)


Outline
• Technology -
• Case studies
small (15) • Practical action - Peru (10)


(5)


Outline
• Technology -
• Case studies
• AWP - Zimbabwe (10)

(5)


Outline
• Technology -
• Case studies
• WindAid - Peru (10)

(5)


Outline
• Technology -
• Case studies
• WindAid - Peru (10)
• CometME - Israel/PAU (10)
(5)


Before we start - a bit of extra motivation
American Economic Review 101 (August 2011): 1649–1675
http://www.aeaweb.org/articles.php?doi=10.1257/aer.101.5.1649

Environmental Accounting for Pollution
in the United States Economy †
By N Z. M ,R M , W N *

This study presents a framework to include environmental externali-
ties into a system of national accounts. The paper estimates the air
pollution damages for each industry in the United States. An inte-
grated-assessment model quanti es the marginal damages of air pol-
lution emissions for the US which are multiplied times the quantity of
emissions by industry to compute gross damages. Solid waste com-
bustion, sewage treatment, stone quarrying, marinas, and oil and
coal- red power plants have air pollution damages larger than their
value added. The largest industrial contributor to external costs is
coal- red electric generation, whose damages range from 0.8 to 5.6
times value added. (JEL E01, L94, Q53, Q56)

An important and enduring issue in environmental economics has been to develop
both appropriate accounting systems and reliable estimates of environmental dam-
ages (Wassily Leontief 1970; Yusuf J. Ahmad, Salah El Serafay, and Ernst Lutz
Thursday, November 10, 2011 1989; Nordhaus and Edward Charles Kokkelenberg 1999; Kimio Uno and Peter

Before we start - a bit of extra motivation
American Economic Review 101 (August 2011): 1649–1675
http://www.aeaweb.org/articles.php?doi=10.1257/aer.101.5.1649

Environmental Accounting for Pollution
in the United States Economy †
coal-ﬁred power plants have air pollution damages larger than their
By N Z. M ,R M , W N *
coal-ﬁred electric generation,awhose damages environmental externali- 5.6
This study presents framework to include range from 0.8 to
times value added into a system of national accounts. The paper estimates the air
ties
pollution damages for each industry in the United States. An inte-
grated-assessment model quanti es the marginal damages of air pol-
lution emissions for the US which are multiplied times the quantity of
emissions by industry to compute gross damages. Solid waste com-
bustion, sewage treatment, stone quarrying, marinas, and oil and
coal- red power plants have air pollution damages larger than their
coal- red electric generation, whose damages range from 0.8 to 5.6
times value added. (JEL E01, L94, Q53, Q56)

An important and enduring issue in environmental economics has been to develop
both appropriate accounting systems and reliable estimates of environmental dam-
ages (Wassily Leontief 1970; Yusuf J. Ahmad, Salah El Serafay, and Ernst Lutz
Thursday, November 10, 2011 1989; Nordhaus and Edward Charles Kokkelenberg 1999; Kimio Uno and Peter

Global wind resource

Wind Resource
Jacobson et al. 2009

Wind Resource
Wind energy potential at 100 m
Jacobson et al. 2010

Wind Resource

Modern wind turbine history


Modern wind harvesting history
1888, USA Cleveland Ohio, 17 m diameter,
12 Kw rated power, 20 year life time,
charged lead acid batteries (stand alone system)

Modern wind harvesting history
1980 - Bonus 30 Kw

Modern wind
2 Mw machines and more

Source: Garrad Hassan

Modern wind
2 Mw machines and more

Wind energy theory

How much can we get out of the wind?


Wind energy exploitation

• How much energy can we get out of
the wind?

• Wind turbine production proﬁle


Energy vs. wind speed

1 2 1 1
mv = ·ρ Avt·v = ρ Atv
2 3

2 2 2


1 2
1 2 1 1 mv
mv = ·ρ Avt·v = ρ Atv
2 3
2 1
2 2 2 = ρ Av 3

t 2


Swept area

S = Swept Area

1
P = ρSV Cp[Watt]
3

2
ρ = wind density [Kg / m ]
3

S = swept area [m ]
2

V = wind speed [m / s]
Cp = power coefficient < 0.593


1 3 ⎡ Watt ⎤
P = ρV ⎢ 2 ⎥
2 ⎣ m ⎦
1 ⎡ Watt ⎤
P = 1.225·6 = 132 ⎢ 2 ⎥
3

2 ⎣ m ⎦
Energy density

Power curve
1 2 3 4


1
P = ρSV Cp[Watt]
3

2
Power curve
1 2 3 4


Power vs. energy


Power vs. energy
• The power curve of the
turbine is measured in watts
vs. m/s


Power vs. energy
vs. m/s

• To calculate the energy the
turbine will produce in a given
time - say 1 hour, we need the
average wind speed during
this hour


Power vs. energy
vs. m/s

this hour

• The energy is measured in
kWh - kilo-Watt-hour


Power vs. energy
• The power curve of the • this is equal to
vs. m/s

this hour



Power vs. energy
vs. m/s • one thousand watt
operating for a hour
this hour



Power vs. energy
• a 100 watt operating for 10
hours
this hour



Power vs. energy
• a 100 watt operating for 10
hours
this hour • kWh = Watt X hour / 1000



Technology
VAWT - HAWT, Lift - Drag, Big - Small

What a good WT does
• Follows the wind
• Extracts wind energy with high efﬁciency
• Low cost of energy
• Low maintenance costs
• Long life


HAWT

7I7T 7hT

6-10. Horizontal-axis configurations. Upwind, downwind, one blade or two-it's all been tried at one time or another.
led from j. W. Twidell and A. D. Weir, Renewable Energy Resources.

HAWT

VAWT

~
////// ///}//

Figure 6-4. Darrieusconfigurations.
There are several other Darrieus configurations besidesthe common eggbeater
desil!n.

VAWT

BIG - small

Tilt up tower

Aerodynamic control in high winds


Systems -
furls "'vu~,
its
HR3
running position. This design includes a winch and cable for manually furling the turbine,

Aerodynamic control in high winds
rip I'ohlriin np Ins RecursosEnergeticosin Punta Arenas, Chile.


Technology summary

1
P = ρSV Cp[Watt]
3

2

-Marlec910F

_A;,.", - RWr.on

Technology summary

Figure Small wind turbine nomenclature. (1) Spinner or nose cone.
1-1.

(2) Rotor blades. (3) Direct-drive alternator. (4) Mainframe. (5) Yaw
assembly. (6) Slip rings and brushes. (7) Tail vane. (8) Nacelle cover. (9)
Winch for furling the rotor out of the wind. (Bergey Windpower)

Technology summary

Environmental considerations
• Rural areas - Small and medium wind turbines
• Main concern - noise
• Non issues -
• Birds
• EM radiation
• Shadow ﬂickr
• View obstruction

Fig
ure

Sound Power level dBA
120 19
-19805 -19905
110 L=22log D + 72
. 1999 . Small
. Micro tha
100 .. spe
po
90 dat
L=22 log 0 + 65 de
80 19
from
70 bin
Pu
60 bin
10 100 20
sio
Diameter (meters)
Te

Noise
inc

~


Noise

Wind speed Variability

Short term speed ﬂuctuations


Long term speed distribution


Yearly ﬂuctuations

Wind production vs. consumption in Denmark

Mw

hours
Source: www.energinet.dk

Dealing with variability in a grid connected system


Wind production vs. consumption in Denmark

Mw

hours
Storm front Source: www.energinet.dk



T+1 hour T+12 hour

Source: Garrad Hassan



Dealing with variability for off grid systems


Diverts the electricity according to battery status



Stores the excess energy (wind is blowing but
nobody is using the electricity)



when the battery is full (and the wind is blowing)



A word about loads
• The “Dump load” is a load used when the
battery is full

• A “load” is any electrical appliance
connected to the battery

• Such as

• light bulbs

• TV/radio

• computer

• cell phone charger

• Sewing machines ...


Estimating the resource

Looking at the long term distribution again


Wind atlas

• Several resources:

• SWERA

• NREL

• RISOE

• Include average yearly wind
speed at several heights, and
energy density


How to Estimate average yearly/monthly/daily production



Using the wind
speed distribution



Using the wind
speed distribution

multiplying by
the power curve



Using the wind
speed distribution

summing up to
receive the AEP

ng by
er curve


A more simplistic way to estimate the AEP
• Starting from the Weibull distribution.
• For k = 2, we get the Rayleigh distribution:
2
1⎛ u ⎞
u − ⎜ ⎟
2⎝ V ⎠
f (u) = 2 e
V
• For the Rayleigh distribution the energy density can
be calculated in a simpler way:
1
E = ρV ·1.91[W / m ]
3 2

2
• where 1.91 comes from the form of the Rayleigh
distribution.


Simple AEP estimates
8760 π D 2
AEP = E· Cp[Kwh / year]
1000 4
E: power density
from wind atlas, or measurement
Cp: power coefﬁcient
0.2-0.25 for small wind
D: diameter


Simple AEP estimates


Capacity Factor (CF)
• Alternative way to describe the wind resource
at a site
• Used wildly in the energy sector - not just in
wind energy
• AEP = 8760 × P × CF[kwh / year]
• The capacity factor is a function of the wind
distribution and the power curve
• But can be estimated for a generic power curve


On land wind capacity factor


Measurement
campaign
• Minimal equipment

• 10 meter tilt up tower

• Single Anemometer

• Best practice

• 15 meter tilt up tower

• 2 Anemometers

• 1 wind vane

• 1 temperature probe

• Alternatives

• Install small wind turbine
immediately


Wind shear
• Wind speed increases with
height

• Putting a small turbine on a
tall tower is aways a good
economic move

• Insures steady winds - longer
life for the blades


Economic considerations

Wind development
costs
• Pre-feasibility study

• Big wind - major effort, 200,000$ /
Mw

• Off grid small wind - basic
measurement campaign, trial and
error. 200-1000$ for
measurement system.

• Wind turbine system

• Battery bank, Inverter

• BOS (cables, breakers ...)


Example costs - Battery-less wind
turbine system (Installed cost)


Example costs - Battery-less wind
turbine system (Installed cost)
Avg. Simplistic cost
Diameter Swept area Energy
cost [$] wind of energy (15
[m] [m^2] production
speed year life time)
120 kwh/m^2/
2000 $/m^2 X
year X 3.14
2 3.14 3.14 m^2 = 4 m/s 1.1 $/kwh
m^2 = 376.8
6280$
kwh/year
260 kwh/m^2/
year X 3.14
2 3.14 $6280 5 m/s 0.51 $/kwh
m^2 = 816.4
kwh/year


Balance of system

• Charge
controller

• Dump load

• Battery

• System meter

• Inverter


Balance of system
Included in previous assessment

• Charge
controller

• Dump load

• Battery

• System meter

• Inverter


Crash course on
Batteries


Crash course on
Batteries
• The heart of an off-grid electric system


Crash course on
Batteries

• Typically Lead-acid


Crash course on
Batteries


• 150 year old technology


Crash course on
Batteries



• Many different models


Crash course on
Batteries




• A car battery is cheap - and lasts 1-3 years


Crash course on
Batteries





• A deep-discharge battery is more expansive,
but lasts longer


Crash course on
Batteries





but lasts longer

• Typical voltage is 12 volts


Crash course on
Batteries





but lasts longer


• Capacity measured in Ah


Crash course on
Batteries





but lasts longer


• Capacity measured in Ah

• Energy is AhXVolt/1000 in kWh


Example battery costs


Example battery costs

• Israel battery costs (Lead Acid): (source: Comet-ME)
• Gel type - 1000 shekel/90Ah 12V (Israel manufacturer) ~ 250$/kWh, ~50$/kWh/year
• 3000Ah 48V OPZF (2V units)
OPK (15 year life) 85,000 euro (German manufacturer) ~820$/kWh, ~55$/kwH/year


Example inverter costs


Dealing with battery costs
• Batteries are used frequently in rural areas
• Charged occasionally by transporting to the
closest grid connected town for a considerable
cost
• If batteries are bought speciﬁcally for the wind
project they can become a major cost of the
system
• If the batteries exist already, they can be charged
more cheaply by the wind turbine


Example meter costs
• Using a meter to measure the electricity
used is crucial to success of wind-project
• simple meter 100$-150$
• Pay by use meter - costs are the same, but
software is expensive - one time licensing fee
10,000Euro
• There is a standard in the world for these
type of systems (the encoding method)


Next up -
Examples and case studies
part 2


Small wind power for rural locations - part 1

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Small wind power for rural locations - part 1