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Techno economic evaluation of windmill forwater pumping in coastal areas for aquaculture

M.J AYANTH I AND T. RAVIS H ANK ARCentr al I nstitu te of Br acki shw ater Aquacultu re, 75, Santh ome hi gh road, Chennai

ABSTRACTWind energy industry is relatively new, rapidly expanding and offers the po-

tential to substan tiat e suff icient a mount of power w ithout causing pollution t o

the environment. With the Kyoto protocol aimed at reducing the greenhouse

gas emissions across the globe, wind energy sector assumes greater impor-

ta nce as a n a l ternat ive source of energy. An a ttempt h as been ma de to develop

a framework for techno-economic evaluation of windmills for water pumping.

The discharge rate of windmill and its performance at 3m, 4m and 5 m heads

were evaluated. The highest discharge was 175.68m 3/da y a t 23 Km/hr a t 3m

head and the lowest discharge rate was 51.49m 3/da y a t 6km/hr a t 5m h ea d.

The unit cost of water and energy delivered by the windmill were estimated.

The monetary benefits that accrued to the end-user have been quantified in

terms of the a mount of diesel and electricity sa ved. The Net P resent Value a nd

Internal rate of returns for wter pumping using windmill , diesel pump and

electric motor ha ve been w orked out t o understa nd t he efficiency of each syt em.

The investment opportu nities a nd support mechanism s were a lso highlight ed.

Introduction

En ergy consumption is an economic

i n d i c a t o r t h a t s h o w s t h e l e v e l o f

development of the country. Supply of

energy should be reliable, sufficient and

timely to support a nd orient t he ta rgeted

fisca l growt h a nd societal developments.

Adoption of unsusta inable st ra tegies of

development coupled with the use of

capita l-intens ive high energy consum ing

t e c h n o l o g i e s h a s o f t e n c r e a t e d

formidable environmental problems by

making development unsustainable in

the long run. In developing countries,

energy consumption goes up rapidly in

accordance with increase in economical

g r o w t h . T h e w o r l d t o d a y c o n s u m e s

a pproximat ely t en times as m uch energy

per person a s it did hundered year s a go

a nd most of th is energy is of commercia l

one, which merely accelerates global

warming . This t rend i s expected to

count inue in th e futur e. The only known

and viable solution to meet the energy

deman d w ithout a ffecting the ecological

b a l a n c e i s t o u s e r e n e w a b l e e n e r g y

sources which have added advantages

s u c h a s b e i n g c l e a n , e n v i r o n m e n t

friendly and inexhaustible.

In recent years, the possibi l i ty of

u t i l i z a t i o n o f t h e w i n d p o w e r f o r

pumping water is drawing considerable

a tt ention a mong all user groups. St udies

on wind data analysis have shown that

insta lla tion of wind mills in va rious part s

o f t h e c o u n t r y m a y b e f a v o u r a b l e

particularly in coastal areas where long

spells of high w ind speed a re a va ilable.

In di an J. Fish., 52(4) : 413-419, Oct.-Dec., 2005

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The aspects o f energy on which ourf u tu re de ve l o p m e n t w i l l de p e n d a re

ma king more energy a va ilable for useful

work and making most efficient use of

the available energy (Patel et al .,1999).

C oa s t a l a q u a cu lt u r e f a r m s a r e

mostly located in remote areas and the

freshwater demand of these farms can

be largely met by pumping water using

wind pumps. Keeping this in view, a

s t u d y w a s c a r r i e d o u t t o a s s e s s t h e

t e c h n o - e c o n o m i c f e a s i b i l i t y o f t h e

w i n d m i l l f o r w a t e r p u m p i n g i naquaculture farms.

T h e p o w e r i n t h e w i n d i s

p ro p o r t i o n a l t o th e a re a o f w i n dm i l l

being sw ept by the w ind, the cube of the

w ind speed. Wind turbines tr a nsform the

e n e r g y i n t h e w i n d i n t o m e c h a n i c a l

power, which can then be used directly

for many purposes. The wind power is

calculated using the power in the wind

a s

w

= 0.014AV3

Where, w

= Power in wa t ts a vai lab le

from the windmill

A-Sw ept r otor a rea in squa re metres

V - Wind speed in K ilo metr es per hour

The estima ted potent ial w ind pow er

in India indicat ed that the a vailable power

ra ng ed f rom 200-400 W/m 2scat ered over

the country. Tamil Nadu, Gujarat and

Andhra Pradesh had highest potential

compared to Rajasthan, Karnataka and

Madhya P radesh .

Windmil l pumping equipment is

a v a i l a b l e w i t h d i s c h a r g e c a p a c i t i e s

ranging from 1000 to 500 000 litres per

day. I t can lif t water up to 90 meters

vertically. The choice of pumping is

usua lly decided by the source of th e wa ter

supply. For pumping from bore wells,

cylindrical pumps a re used (Mike Ha rries,

2002).

Materials and methods

The windmill Type WF 305G was

ins ta l led a t Mut tukadu exper imenta l

s t a t i o n a t C e n t r a l I n s t i t u t e o f

B r a c k i s h w a t e r A q u a c u l t u r e a n d

evaluat ed for its performa nce at different

heads. The windmill rotor diam eter wa s

3m and tower hight w a s 10m. The gear

ratio was 3.29:1. The stroke length was

7.5. The pump suction diameter was

ma de to 4 inches t o get more output . The

water source was a dug wel l wi th a

dia meter of 1m an d depth of 3 to 6m. Theminimum wind speed to operate the

w indmill wa s 6Km/hr. The dischar ge ra te

was measured to f ind out the delivery

capacity of the windmill. The discharge

obta inable from a windmill was calculated

a s

Q= 0.09936 V3n/H

Q= Windm ill discha rge/sec

V- Wind s peed in K ilo metr es per h our

H - Tota l head metren-Overall efficiency of windmill

The diesel engine a nd electr ic motor

of one H.P wa s compared w ith w indmill

to assess the discharge rate and cost

energy. The Net Present Value, internal

ra te of returns for t here wa ter pumping

syst ems such as wind mill, electr ic pump

and diesel pump were worked out.

Results and discussion

The energy requirements of the

c o u n t r y i n c r e a s e s d a y b y d a y t o

c o m m e n s u r a t e w i t h t h e r a t e o f

d e v e l o p m e n t . L o o k i n g a t t h e

requirements of energy for di f ferent

a ctivities, an earlier survey indicat ed tha t

the major energy demand in India was

for residential activities followed by the

tr a nsporta tion industr y. We need 56%of

energy for residentia l a ctivities follow ed

by 27%for industrial activities and 12%

M .Jayanthi and T. Ravishankar

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TABLE 1: Estimated wi nd power potenti al i n I ndi a

S ta t e G ross D emonst ra t ion P riva te Tota l

P ot ent ia l P roject s S ector Ca pa cit y

(MW) (MW) P roject s (MW)

(MW)

Andhra P ra desh 8275 5.4 93.4 98.8

G uja ra t 9675 17.3 184.7 202.0

Ka rna t a ka 6620 4.6 204.6 209.2

Kera la 875 2.0 0.0 2.0

Ma dhya P ra desh 5500 0.6 22.0 22.6

Ma ha ra sht ra 3650 8.4 399.0 407.4

Orissa 1700 - - -

Ra ja stha n 5400 6.4 172.1 178.5

Ta mil Na du 3050 19.4 1342.2 1361.6

West B enga l 450 1.1 0.0 1.1

45295 65.2 2418 2483.2

MW-Mega Watts

Source : MNES, Annual report, 2004

Fig.1. Discharge rate of wind mill at different head

M3/day

for transportat ion. But the worldwide

consumpt ion was more in industr i a l

sector (37%) th a n resident ia l act ivities

(27.4%).

The sta te-w ise wind energy potent ial

a nd t he projects t ha t ar e under opera tion

are given in Table 1. Among the states,

Tamil Nadu and Maharashtra lead in

production of wind energy. India had

2483.2MW wind energy projects in the

year 2004, out of which 65 MW was

demonstration projects and 2418 was

i n s t a l l e d p r o j e c t s . T a m i l N a d u

cont ribut ed 1361.6MW capa city followed

by 407.4 MW from Maharashtra, 209.2

MW from Karnataka and202 MW from

Gujarat. There are wind

pumps of various designs

p r o v i d i n g w a t e r f o r

agriculture, afforestation

a n d d o m e s t i c p u r p o s ewhich are a l l sca t tered

over the country. Wind

energy accounts for 3%of

t h e o v e r a l l g e n e r a t i o n

c a p a c i t y i n t h e p o w e r

sector.

Th e d i sch arg e r a te

measured at different w ind

speed and at different head

Techno economi c evalu ati on of win dm il l for wat er pumpi ng

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TABLE2:

Econom

icana

lys

isfort

hree

typeso

fwa

terp

umpingsys

tems

Year

Windmill

Electricmotor*

Dieselpump**

Cost

Ben

efit

Net

Cost

Benefit

Net

Cost

Benefit

Net

Rs

Rs

cashflow

Rs

Rs.

Cashflow

Rs

Rs

Cashflow

1

65,7

50

17,500

-48250

32,7

00

21,8

74

-10826

32,00

0

21874

-10126

2

1,0

00

17,312

16312

14,5

00

21,5

79

7079

10,70

0

21579

10879

3

2,5

00

17,182

14682

14,7

50

21,2

96

6546

12,47

0

21296

8826

4

2,7

50

16,970

14220

18,9

00

22,6

24

3724

21,31

7

22624

1307

5

3,0

25

16,813

13788

15,7

50

22,3

29

6579

14,24

9

22329

8080

6

3,3

00

16,666

13366

16,7

50

22,0

46

5296

16,27

4

22046

5772

7

3,6

00

16.533

12933

22,2

50

23,3

71

1121

27,38

6

23371

-4015

8

4,0

00

16,408

12408

17,0

00

23,0

79

6079

16,50

0

23079

6579

9

4,4

00

16,292

11892

18,7

50

22,7

96

4046

17,62

5

22796

5171

10

4,8

50

16,183

11333

25,7

50

24,1

24

-1626

32,73

1

24124

-8607

NPV

18038.8

7

11788.1

7

116150.0

5

IRR

25.7

748

52.7

883

79.2

994

*-EngineandDieselcost

**-Motorandelectricitycost


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( F i g . 1 ) i n d i c a t e d t h a t t h e h i g h e s tdischarge rate was 175.68m 3/da y a t 23

km/hr w ind speed a t 3m h ea d. The lowest

discha rge ra te w a s 51.49m 3/da y a t 6 km/

hr w ind speed at 5m hea d. I t can be seen

tha t for all wind speed the delivery ra te

decreased as the head increased. The

total functional days for the windmill

wa s calculat ed as 250 days ba sed on the

wind speed dat a of previous yea rs.

Norma lly, the requirement of wa ter

at the start of aquaculture is very high.

The tota l wa ter requirement t o ma inta in70cm water depth in 0.5 ha pond is

3500m 3. Consider ing the f reshwater

requirement t o bring down 1m 3of the 30

ppt w a ter t o 15 ppt is 0.5m3, the quanti ty

of fresh water needed will be 1750 m 3.

Each windmill is capable of feeding at

least two 0.5 ha ponds and it can be

effectvely used in high saline remote

a rea s. The expected energy from t he wind

lies in th e medium ra nge wh ich could be

used as a n a lternat ive source of energy,

specially in the summer months whenthe energy is most needed (Som and

Ragab, 1993).

R e ce n t l y m o s t o f th e f a rm s a re

shifting towards zero water exchange.

Eve n i f su ch a sys te m n e e ds w a te r

exchange, i t wi l l be an easy task to

maintain water level. As the windmill

delivery totally depends on wind speed,

the avera ge delivery ra te wa s uncerta in.

It is better to construct t he stora ge tan k

to store the wa ter pumped by t he windmill

a nd a lso to facilitat e unat tended pumpingduring night hours. The storage tank

should have sufficient capacity to meet

the freshwa ter requirement a nd, if needed

filtra tion and prior t reat ment can be done

before lett ing the wa ter into the far m.

For a ssessing t he economic feas ibility

of w indmill , compa rison w as ma de with

other wa ter pumping syst ems like diesel

engine with pump and electric motor

wi th pump. I t was assumed that thereduction in discharge rate was 2.5%

every yea r a nd the w at er cost is sa me for

a ll systems a s Rs. 500 for 12 T capa city.

The cost of windmill, electric motor

and diesel pump were Rs. 65,750,3500

and 8500 respectively. Life time and

delivery rate for windmill was 10 years

a nd 18.2T/da y. The delivery r a te w a s t he

sa me a s 2500l/h for both diesel pump a nd

electric motor. To calculat e retur ns, t he

price range was fixed for each unit of

wa ter lif ted. For ten trips, by 12t t a nks,the rent wil l be Rs.500. Every year,

additon of Rs. 250 will compensate the

other maintenance cost . The cost of

pum ping w a s Rs.41.66/m 3. From the

a na lysis output, (Ta ble 2) the Net P resent

Va lue w a s 18038.87, 11788.17, 116150.05

and Internal Rate of Returns (IRR) was

25.77%, 52.78%, 79.29% for w ind mil l,

e l e c t r i c m o t o r a n d d i e s e l p u m p ,

respectively.

As th e initia l cost of insta llation wa s

high in ca se of windmill, the diesel enginewith pump is economically suitable. But

for t he places where th e resources ar e not

a vailable and a n unat tended pumping is

required, windmill ca n be the best remedy.

Since , the demand for convent ional

resources is increasing a nd a vailability is

becoming a problem, non-conventional

r e s o u r c e s l i k e w i n d m i l l s h o u l d b e

encouraged. At macro level, burden on

exchequer on account o f subsid ized

electricity genera tion will be lessend wit h

windmil l . In due course of t ime, byinsta llat ions of more and more windmills,

th e production cost per unit of w indmill is

likely to come down.

I n d i a R e n e w a b l e E n e r g y

D e ve l o p m e n t A g e n cy ( I R ED A ) w as

formed in 1987 to provide assistance in

obta ining loa ns from World Ba nk, Asia n

D e v e l o p m e n t B a n k , a n d D a n i s h

I n t e r n a t i o n a l D e v e l o p m e n t A g e n c y


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(DANID A) for renew a ble energy projects .IRE DA acted as a conduit for World B a nk

loan s tot a ling $78 million, specifically for

wind energy projects. India has a large

wind a ssessment progra m w ith over 600

s t a t i o n s i n 2 5 s t a t e s t o p r o v i d e

in format ion about the bes t s i tes for

d e v e l o p m e n t . T h i s c a p a c i t y i s

concentra ted in the sta tes of Ta mil Nadu

and Gujarat . Tamil Nadu and several

other sta te electricity boards ha ve agreed

to purchase w ind pow er wit h th e following

discounts. Five-year tax hol idays onincome from sa les from renew a ble energy;

accelerated depreciation on investment

in capital equipment in the first year;

excise duty and sale tax exemptions for

wind t urbines; import duties on a var iety

of component s w a ived; moving towa rds a

production tax incentive to encourage

performance.

Wind energy enjoys an acce lera ted

deprecia tion benefit of 80per cent a nd it

ha s brought a large a mount of investment

in recent yea rs. All the insta llations havebeen ba sed on ba lan ce sheet finan cing by

t h e c o m p a n i e s w h o s e w i n d e n e r g y

investments ha ve been a pa rt of their tax

planning stra tegy.

W i n d e n e r g y i s n o t y e t g e n e r a l l y

competitive with alternate sources such

as fossil fuels. Thus, it is dependent on

non-market support for development to

ta ke place. With the K yoto protocol a imed

a t reducing the greenhouse ga s emissions

a c r o s s t h e g l o b e w i t h e f f e c t f r o m

16.02.2005, th e need of win d energ y s ectora ssumes grea ter importa nce. Renewa ble

energy technologies are capita l intensive

a nd require high initial investment, which

invest ors could not mobilize in t he a bsence

of f inancial support including capital

subsidy from the government. Research

a nd development t o improve efficiency of

th e devices for genera tion of wind energy

and to bring down the cost should be

encouraged. Due to the high initial cost,it is not possible to generate sufficient

demand for these items, though people

are aware o f the advantages . Pr iva te

investment should be encouraged and

promoted in renewable energy through

suita ble policy initia tives a t sta te level.

Field units should be esta blished at loca l

level.

En e rg y e f f i c i e n t bu i l d i n g s th a t w i l l

c o n s e r v e e n e r g y t o m e e t e n e r g y

requirements from naturally available

resources should be encoura ged (Na gwa ,1994). Since the discharge of windmill is

low, attention is paid to increase the

efficiency and longer life. Appropriate

and sui table extension strategies and

met hods should be employed for effective

disseminat ion / tra nsfer of renewa ble

energy technologies like Participatory

Rura l Appraisa l (P RA); Self Help Group

approach (SHG); Cyber Extension to

create awareness among rural people.

The windmill can be recommended, if

wind conditions a re relia ble, una tt endedpumping is required for long periods,

w hen th ere is no other power s ource an d

a lso user requires environment a lly clean

power.

References

Louise Guey Lee 2005. Wind Energy

Developments: Incent ives in Selected

C o u n t r i e s www.e ia .doe .gov /

fuelrenewable.html

Mike Harries 2002. Disseminating wind

pumps in rura l Kenya - meeting rura l

w a t e r n e e d s u s i n g l o c a l l y

manufactured wind pumps. Energy

Policy, 30, (11&12): 1087-1094.

Nagwa A. , Gada h EI Da m 1994. Financial

- economic an a lysis of wind a nd d iesel

driven water pumping systems in

Su dan . Renewable energy, 5(1-4):

653-657.


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P a t e l , B . R . , M . M . P a r i k h a n d P . K .Shr ivas tava 1999. Feas ib i l i ty o f

wind mill irriga tion in coa sta l region.

J .In di an Soc. Coastal A gri . Res.,

17(1&2): 105-108.

Som A.K. and F .M. Ragab 1993. A

prel iminary study of wind power

p o te n t i a l i n Bah ra i n . Renewable

energy, 3 (1) 67-74.


D a te of Receipt : 04-05-2005

Dat e of Acceptance : 18-05-2005

7106-15453-1-sm

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