Wind Power:
Using a Renewable Resource in Developing Countries
created by Marjorie D. Ely
April 22, 2002
About Wind Power Why Wind Power? Countries Planning and Design
Commponents of a Pumping System Pre-desing Planning Water Storage Windmill Components
Links:General Info, Projects, Wind Energy Policy/ Wind for Electricity, In the Future, Problems of Implementation of Renewable Resources Articles and Other Resources:
Policy,Water Pumping Wind Power Systems,Electrical Windmills,General Case Studies of Wind Energy,
Glossary

About Wind Power
Wind is air in motion caused by the rotation of the earth and the uneven heating of the atmosphere by the sun.  Air rises as its particles spread out from being heated (making the air less dense and thus lighter.)  Unheated or cool air comes in to take the place of the rising heated air.  This process is calledconvection.   Wind patterns vary according to seasonal, diurnal,and landscape variability and due to changing wind patterns, physical obstacles, in the area, slope, etc.  Wind power machines are classified as mechanical (without electric generators) and electrical.  Mechanical are the ones focused on here, as they are mostly used in rural and remote areas for water pumping.  Electrical windmills connect to a power grid and produce energy converted to electricity for heating, transportation, and other mechanized power.

Photo from "Wind pumping, A Handbook"
by Joop van Meel and Paul Smulders
World Bank Technical Paper #101 ©1989

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Why Wind Power?

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Countries Using Wind Power or Researching in the Wind Power Use:
 *This list is not all inclusive.  These are the findings of my research.
 
Argentina Canada Germany Japan Netherlands Sri Lanka Tobago
Belgium Cape Verde Greece Jordan Oman Spain Trinidad
Botswans China India Kenya Pakistan Sudan Tunisia
Brazil Denmark Ireland Mexico Portugal Sweden UK
Cameroon France Italy Mozambique Scotland Tanzania USA

                                                                 Rural windmills still in use in the Netherlands.                                              Back to top
 
 

Planning and Design of a WATER PUMP SYSTEM
using Wind Power in Remote Areas

**The following text and illustrations are adapted from "Wind Pumping : A handbook" by Joop Van Meel and Paul Smulders, World Bank Technical Paper Number 101, Industry and Energy Series. 1989

Components of a Pumping System

                                                    1. Wind Pump
                                                    2. Well or Water Source
                                                    3. Suction  and Delivery Lines
                                                    4. Storage Tank
                                                    5. Distribution System
                                                    6. Field Application System (for irrigation)

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Pre-design Planning:

                      Ask the questions:

1.How much water is needed?

           This includes daily use plus irrigation for a year round water supply.
           You need to calculate water need accurately as the amount of water necessary for
           the system to pump is directly proportional to the size of the rotor, which in turn is
           directly proportional to the cost.  The rotor and the water storage set up are the major
           components of the cost of the system.
 
 
 

Amount of water 
needed to pump==========>>

Size of rotor 
necessary================>>
Cost of wind pumping system
         ;
         ;
Water storage 

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2.What size system will pump the water necessary?
           To answer this question, we need to calculate the amount of energy needed to pump
           the determined volume of water.  These calculations must allow for loss of energy due
           to converting from one form of energy to another and head loss.  Diameter size of the
           piping in the system can be increased to account for the head loss. Power is the rate the
           energy is used in a given period of time.  You must determine the power needed and
           use this to decide the size of the water pumping device needed to fulfill the demands
           in that period.  NOTE: Calculating the power of your wind supply is complex due to
           the variations in wind and landscape described above.  Attaining an expert in this area
           is more apt to save costs in the long run as precise numbers are important to keep
           system costs down.
 

One important aspect of these calculations is to determine your Critical Month.  This is where your demand of water most exceeds your wind potential.  This the month you should design your pumping system around.  REMEMBER: Rain water may be available to supply some of the water needs during the determined Critical Month and thus your demand of pumped water may not be as high.  Another month may actually have more demand on the wind pump and therefore is your real Critical Month.
 
 

When the Critical Month has an average wind speed of 5 meters/ second (m/s) or higher, then using a windmill is the best option for an energy system.  If the Critical Month has winds of less than 5 m/s, then a hand pumpt might be installed for use during that time or other low wind times.  Wind Power for water pumping is most economical for year round water supplies.

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Photo from "Wind pumping, A Handbook"
by Joop van Meel and Paul Smulders
World Bank Technical Paper #101 ©1989

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Water Storage
Water storage should be utilized for two main purposes:

1. To effeicently use times of higher wind speeds by storing the extra water pumped for later days of less wind.
2. Because wind pumps bring in a irregular modest flow rate all day long while normal use is at high rates for short periods of the day.

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Windmill Components:
From Chapter 2 - Wind Pump Technology, in "Wind Pumping : A handbook" by Joop Van Meel and Paul Smulders.
This chapter goes through the details on how water pumping windmills work.  The basics are explained here.

The Rotor captures the wind's energy and converts it into useful mechanical shaft power.  Recent designs have 4, 6, 8, or 12 blades and operate at higher tip speeds than classical models.  The rotor is fixed to a steel shaft.  Rotors of water pumping windmills range from 1.5 to 8 m in diameter.  In a 4 m/s wind, a rotor of 1.5 diameter may produce up to 24 Watts of mechanical power, and an 8 m diameter windmill up to 680Watts.  In a 5 m/s wind, these values nearly double (46 and 1320 Watts respectively)

A Transmission conveys the energy from the rotor to the pump (rod), sometimes involving intermediate energy conversions.  The pump rod transmits power to the pump.  The efficency of the transmission is somewhere between 70% and 90%. Windmills driving piston pumps (see Handbook for details on other types of windmills) have the most widespread use and therefore are the ones people have the most experience with.  There are two types:

1. Classical windmills typically have a heavy multi-bladed rotor and low speed of operation.  The smaller sizes incorporate a gear box.

2. Modern wind pumps are more varied, including one or more of the following innovations: lighter construction, higher speed of operation, starting helps such as a starting nozzle, balanced pumprod, no gearing, etc.  Therefore modern models have become much more efficient and less costly than older ones.

The Safety System protects the windmill during gusts and storms.  Usually this system is combined with an orientation system.  At low wind speeds the rotor is oriented into the wind; with increasing wind speeds the rotor is gradually turned out of the wind so as to limit the speed of the pump and the forces acting on the structure.  Normally it can be operated manually to stop the windmill.

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Links: Each link has the web address listed next to it as well in case the link fails.

General Info:

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Projects:

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Wind Energy Policy / Wind for Electricity:

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The Future of Wind Power and Other Renewables:


Problems of Implementation of Renewable Resources and how NGO’s can overcome these barriers:
Experiences of NGO’s with Renewable Energies in Developing Countries: Some Selected Cases and Lessons Learnt”  http://www.eadi.org/news/RenewableEnergies.pdf

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Articles and Other Resources:

Policy:

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Water Pumping Wind Power Systems

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Electrical Windmills

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General Case Studies of Wind Energy:

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Glossary

Critical Month: where the ratio of demand of hydraulic energy to the available wind potential  of that month is largest
diurnal: varying within the course of a single day
head loss: energy loss per unit of weight of the fluid in a tube (or pipe) due to frictional forces within the fluid
Wind Power Potential: simply the amount of wind power available at a site.  Calculations can be found in  Section 1.3 in Wind pumping, A Handbook  by Joop van Meel and Paul Smulders World Bank Technical Paper #101 ©1989. (Potential Wind Speed: wind speed which would be observed in completely flat and open terrain)
Wind Power Machine: prime mover driven by wind power.  It may be used to drive any kind of load: pump, electric generator, etc.

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