small wind power for rural locations - part 2

Wind energy harvesting basics, resource assessment and

application for off grid systems.part 2

Hanan Einav-Levy M.Sc.

Thursday, November 10, 2011

Outline


Outline• part II (2 hours)



• Example project



• Example project

• Estimating the wind resource (5)



• Example project


• Estimating the needs (10)



• Example project



• Sizing the turbine (5)



• Example project




• AC or DC (5)



• Example project




• AC or DC (5)

• Sizing the battery bank (10)



• Example project




• AC or DC (5)


• Sizing the inverter (5)



• Example project




• AC or DC (5)



• Economics (10)



• Example project




• AC or DC (5)



• Economics (10)

• Small wind turbine product comparison (10)



• Example project




• AC or DC (5)



• Economics (10)


• Case studies



• Example project




• AC or DC (5)



• Economics (10)


• Case studies

• Practical action - Peru (10)



• Example project




• AC or DC (5)



• Economics (10)


• Case studies


• AWP - Zimbabwe (10)



• Example project




• AC or DC (5)



• Economics (10)


• Case studies



• WindAid - Peru (10)



• Example project




• AC or DC (5)



• Economics (10)


• Case studies



• WindAid - Peru (10)

• CometME - Israel / Palestinian authority (10)


Example project

Resource: ITDG_2001_bookletwind.pdf


Small wind development by technology transfer



• ITDG (now called Practical Action)




• One method to develop wind turbines for rural communities - there are others.





• We will use this to study the design of the system






• Estimating the wind resource







• Estimating the needs








• Sizing the turbine









• AC or DC









• AC or DC

• Sizing the battery bank









• AC or DC

• Sizing the battery bank

• Sizing the inverter


Current situation

• 12V Car batteries are used for radios and TVs

• 60Ah or 90Ah battery typically used

• A large market for existing battery users (300,000 households)

• Monthly battery cost 6.5$ (5$ battery replacement, 1$ travel, 0.5$ charging)


Estimating the wind

• Anecdotal evidence

• The local vegetation

• The Beaufort scale

• Wind map

• Installing an anemometer+data logging equipment - 200-1000$

• Installing a wind turbine with data logging equipment with the same funds


Beaufort scale


Siting the wind turbine• The highest

point

• Open to prevailing winds

• Not too far from load

• On a tall tower!



point




Highest point



point




Highest pointToo far from loads


Choosing AC vs. DC

• For a wind turbine installed far from the load normally the battery voltage will be as high as possible (48V)

• If not enough - using an DC-AC inverter at the tower makes sense

• Allows to work at 230 volts, and therefor less current

• Losses are proportional to the current squared

• Benefit: Allows to work with regular 230V AC loads


Choosing AC vs. DC

• But cost of DC-AC inverter can be substantial

• Alternative - site wind turbine close to load

• Shorter cables - less loss

• Downside: only DC loads


Conservative estimate of monthly electricity production

• Assuming efficiency is 15% (see previous lecture for more refined estimate by Paul Gipe)

• E = D2 ×V 3

10kWhmonth

⎡⎣⎢

⎤⎦⎥

V = average wind speed [m/s]D = diameter [m]


Estimating the loads

• What the wind shouldn’t power:

• Electric heaters

• Electric cookers

• For whom will the system be designed?

• Single household

• Several households


Single household


Single household

Rule of thumb - battery charging losses


Breaking down the load for a typical day


3 households sharing a turbine


Sizing the turbine

1. Identify wind resource

2. Identify electricity needs

3. Size turbine accordingly

4. Size battery bank according to measured wind pattern

In an ideal world -


Sizing the turbine for our two examples



Enough spare energy



Not enough energy


Sizing the battery

• The battery is charged and discharged over a period of hours or days.

• This is a cycle

• Two parameters important in a battery life:

• Number of cycles

• The depth of discharge


Sizing the battery


Sizing the Battery

• Calculate Ep, the daily consumption in Wh(for example Ep = 400 Wh/day)

• Choose N, number of days of autonomy, typically 3-5 days(for example N = 3 days)

• Choose maximum allowable depth of discharge, D (for example D = 0.5, which means 50%)

• Choose U, battery voltage (typically 12,24 or 48 volts)(for example U = 12V)


Sizing the Battery

• Calculate Ep, the daily consumption in Wh(for example Ep = 400 Wh/day)

• Choose N, number of days of autonomy, typically 3-5 days(for example N = 3 days)

• Choose maximum allowable depth of discharge, D (for example D = 0.5, which means 50%)

• Choose U, battery voltage (typically 12,24 or 48 volts)(for example U = 12V)

C = Ep × ND ×U

[Ah]

= 400 × 30.5 ×12

= 200[Ah]

Calculate C, battery capacity:


Cost of wind turbine - 2 meter diameter, 100 watt rated


Economics• Financing ownership by battery charging services

• Current batteries are 60 Ah car batteries (DOD 50%)

• To charge battery (with efficiency of charging loss of 25%) 0.5X60X12X1.25 = 450 Wh

• 2 meter diameter at 3.5 m/s site produces 17 kWh/month or 600 Wh/day on average

• Therefor one battery charged per day

• charging 1 day a week for the owner, and the rest for customers


Economics


Final system components



Sizing according to local need and wind resource


Final system componentsSizing according to wind variability and “spares”

requirement


Final system componentsFor an AC system - according to maximum

load


Small wind turbine market


z : \ a l l \wi nd tu rb \ sa l es l i t \m an ua l \wt60 00 \s s spec sh ee t s \60 00 s s 00 1 rev2 .d oc

Proven WT6000 6kW Wind Turbine Proven TM900 9m (or TM1500 15m) Self-Supporting Mast Performance Cut-In Wind Speed 2.5 metres/second (5.6 mph) Cut-Out Wind Speed none Rated Wind Speed 12 metres/second (25 mph) Rotor Type Down-wind, Self-Regulating Number of Blades 3, Flexible Rotor Diameter 5.6 metres Blade Material Wood/Epoxy/PU Generator Type Brushless, Direct Drive,

Permanent Magnet (No Gear-Box, Zero Maintenance)

Output 48V/120V/240V/300V 3-phase AC (25Hz nom)

Rated RPM 200 nominal Rated Power 6000 Watts Annual Output 7000-18 000 kWh depending on site TM900 Mast Type Self supporting/Tilt Down. Hub Height 9m Foundations 35 Newton Concrete Pad 2.5 x 2.5 x 1 m Tube ! 175 mm top A/F 350 mm bottom A/F 530 mm square mast base TM1500 Mast Type Self supporting/Tilt Down. Hub Height 15m Foundations 35 Newton Concrete Pad 3 x 3 x 1.2 m Tube ! 200 mm top A/F 440 mm bottom A/F 750 mm x 739mm mast base Noise (approximate) <45dB At 5m/s <60dB At 20m/s 70-80dB Car 15m away at approx 40 mph. Weight WT6000 500 kg TM900/6000 360 kg (+ 70kg gin pole) TM1500/6000 656 kg (+ 240kg gin pole)

0

1000

2000

3000

4000

5000

6000

7000

0 5 10 15 20Wind speed in metres/second

(multiply by 2.2 for m.p.h.)

Pow

er O

utpu

t (W

atts

)

Rotor Speed Control Above 12m/s (25mph) the blade pitch is automatically adjusted to maintain 200 rpm and full output

High Build Quality

All components are hot-dipped galvanised steel, stainless steel or plastic.

Low Speed Equals Durability Low rotor speed (half the speed of comparable machines) ensures extended durability of blades and bearings. It also means that Proven WTs are the quietest in the world!

WT brochure

• Includes many details

• Most important parameter - diameter, or swept area

• Make sure is intended for battery charging

• Must have aerodynamic control option



Source - American magazine.

2 mph = 1 m/s



Most important parameter


Case studies


small wind: 0.2$-1.15$ / kWh

solar PV:1.21$ / kWh


African Wind PowerThursday, November 10, 2011

African Wind Power

• Example of technology transfer


African Wind Power

• Example of technology transfer

• Turbines now installed from Africa to Antarctica!


AWP - Zimbabwe - Masampa Village Lake Kariba

• AWP3.6 - 48V 13.5M tilt up tower, 275Ahr 48V Battery bank, 3KW sine wave inverter, 12V battery charging station.


AWP - Zimbabwe - Masampa Village Lake Kariba

• AWP3.6 - 48V 13.5M tilt up tower, 275Ahr 48V Battery bank, 3KW sine wave inverter, 12V battery charging station.

• This fishing co-operative village is on the shores of Lake Kariba, 45Km by boat from the nearest town. Crocodiles inhabit the shore line and Hippos amble through the village at night while foraging ( startling a hippo is not good for your health). With funds provided by the Dutch government via the NGO ZERO, AWP implemented the entire project in all its stages:

• (1) Initial location of the people in need

• (2) discussions with the village committee

• (3) resulting in motivation of the villagers to contribute labour to the installation, transportation of all materials to site, construction and commissioning

• (4) and finally training of operators.

• The system provides lighting for the main thoroughfares and also a popular 12v car battery charging center which draws customers from a 20 Km radius. Income from this activity is used for village development.


WindAid - Peru


Comet-ME


Comet-ME• The systems are designed for producing 2-3 kWh/

day for a large beduin family.

• Systems are DIY wind turbines and solar PV panels

• Systems used for powering:

• Lights

• Refrigirator

• Butter churn

• TV

• Cellphone charging

• Costs are between 5000$-8000$


Resources


http://www.scoraigwind.com/



http://practicalaction.org/

http://practicalaction.org/

http://www.africanwindpower.com/

http://www.africanwindpower.com/

http://wind-works.org/books/WindEnergyBasicsRevised.html



http://www.windpower.org/en/

http://www.windpower.org/en/

http://swera.unep.net/index.php?id=wind

http://swera.unep.net/index.php?id=wind

http://www.retscreen.net/


https://homerenergy.com/

https://homerenergy.com/

Resources





small wind power for rural locations - part 2

Business

wind resource

wind energy

hours example projectthursday

battery bank

resource assessment

case studiesthursday

windaid peru

awp zimbabwe