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A MULTICRITERIA METHOD FOR ESTIMATING THE DESIGN FLOW OF RUN-OF-RIVER HYDROPOWER PLANTS Massimo Alberti Christian Severino Studio Seta s.r.l. Via Risorgimento, 2 48018 Faenza (RA) Italy +39-546-623640

Prof. Montanari A., Prof. Bragadin G. - University of Bologna - DISTART Alberti M., Severino C., Zanotti P. - Studio Seta s.r.l. Mussoni L. - degree thesis Spada G. - degree thesis Montesi M. - degree thesis


WORK PURPOSE The design flow of a run-of-river hydropower plant is one of the most vexed question and one of the question with more impact

The WORK PURPOSE is setting up a methodology, that can be used even in the preliminary planning phase, to determine the design flow evaluating both • technical and economic aspects • environmental impacts Studio Seta s.r.l. Massimo Alberti Christian Severino


A MULTICRITERIA METHOD 1.

Defining indicators  objective, complex, noticeable; we obtain a NUMERICAL VALUE for each indicator

2.

Defining usefulness functions  to pass from a numerical value to an objective JUDGEMENT

3.

In order to elect a solution, a COMPARISON between judgements is carried out by means of WEIGHTS

Studio Seta s.r.l. Massimo Alberti Christian Severino


Phases • Choice of the evaluation criteria • Definition of the indicators • Definition of usefulness functions • Definition of weights

• How to choose the optimal solution • Experimentation of the method on 15 plants Studio Seta s.r.l. Massimo Alberti Christian Severino


Definition of the indicators Environmental indicators Disturbance of the local community

Dlc Dlc

Disturbance of the local fauna

Df Df

Temporary visual impact of the construction site

Ivc Ivc

Permanent visual impact of the new works

Ivnw Ivnw

Reduction in the fluvial habitat volume

IHa IHa

Renewable energy produced

E

Reduced carbon dioxide emissions

CO2A

Changes in the hydrological regime – big variation in the natural flow of the river (functioning period with residual flow)

T(RF) Studio Seta s.r.l. Massimo Alberti Christian Severino


Technical-economic indicators

Economic benefits for the community – Total Amount of costs

TAc TAc

Net Present Value of the investment

NPV NPV

Internal Rate of Return

IRR IRR

Functioning period at full power

T(Qmax)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Disturbance of the local community [m2路 month]

u [adim] coeff. concerning the number of the people who bear the consequences of the building site;

Ac [m2] area of the building site

value from 1 to 10 (10 for inconvenience to more than 1000 people)

Du

Ac u su T 4 10

su [adim] coeff. of sensivity of the area

T [month] duration of the building site

value from 1 to 10 (10 when hospitals or schools are within 200 m from the site)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Temporary visual impact of the construction site [m2路 km 路 month]

Ac [m2] area of the building site

Ivc

Ac 103

[adim] coefficient of aesthetic armony between the site and the surrounding area

FV [km] visibility factor

FV T

T [month] duration of the building site

value from 1 (site not in armony with the environment) to 3 (site in armony with the environment and less recognizable) Studio Seta s.r.l. Massimo Alberti Christian Severino


Net Present Value of the investment [â‚Ź]

r internal rate of return n number of years in the evaluation period

NPV

(1 r)n 1 (R G M T ) I0 n r (1 r)

annual gross profit

initial investment cost concession operation

manteinance

Studio Seta s.r.l. Massimo Alberti Christian Severino


Indicators matrix A matrix is associated to any plant project. The 12 indicators (rows) are calculated for 10 different project alternatives (columns) which differ from one another only for the maximum diverted flow Qmax Alternative

Q(m3/s)

1

2

3

4

5

6

7

8

9

10

0,187

0,210

0,233

0,257

0,280

0,303

0,327

0,350

0,373

0,397

Indicators

Dlc

84,19

84,89

85,55

86,17

86,75

87,31

87,84

88,35

88,84

89,31

Df

67,35

67,91

68,44

68,93

69,40

69,85

70,27

70,68

71,07

71,45

Ivc

28.625

28.863

29.086

29.296

29.495

29.684

29.865

30.038

30.204

30.365

Ivnw

16,35

16,87

17,37

17,86

18,33

18,79

19,25

19,69

20,13

20,55

IHa

0,832

0,821

0,811

0,801

0,793

0,785

0,779

0,772

0,767

0,762

T(RF)

177

181

185

188

191

194

196

198

199

201

CO2A

1.665

1.783

1.890

1.987

2.073

2.153

2.224

2.288

2.342

2.394

E

2.081

2.228

2.362

2.484

2.592

2.692

2.779

2.859

2.928

2.992

TAc

809

843

876

907

938

967

995

1.031

1.067

1.102

NPV

224

261

291

316

336

352

363

363

358

350

IRR

0,125

0,132

0,137

0,141

0,143

0,144

0,145

0,142

0,138

0,134

137

125

114

105

95

87

79

72

65

59

T(Qmax)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Definition of usefulness functions (in general non-linear) These functions transform the indicators values in merit judgements (between 0 and 1) in order to define them

detailed information concerning technical aspects and environmental impacts of 15 hydropower plants has been collected Studio Seta s.r.l. Massimo Alberti Christian Severino


Location of the 15 hydropower plants

Studio Seta s.r.l. Massimo Alberti Christian Severino


Definition of the Fu of landscape type Six stakeholders who play various roles in the environmental impact evaluation of a hydroelectric plant have been interviewed. Each of them has been asked to associate a judgement connected with the impact entity that the plant produces on the different environmental components considered

The judgement has been expressed trough votes (from 0 to 1) where 1 = negligible impact 0 = very considerable impact Studio Seta s.r.l. Massimo Alberti Christian Severino


Fu of landscape type are:

- non-linear - tared on absolute impact - not derived from a classification of the considered solutions In Environmental Impact Assessment procedures linear and relative usefulness functions are often used. These ones assign value 0 to the worst project alternative and value 1 to the best. This kind of approach, even if is simple, has considerable approximations which can bring to significantly different classifications for project alternative that have indeed the same impact

Non-linear and absolute functions allow more objective judgements on the impacts, because they actually give similar judgements to similar alternatives and permit to differentiate only solutions which are objectively different from one another Studio Seta s.r.l. Massimo Alberti Christian Severino


Disturbance of the local fauna 1.0 0.9 0.8 0.7

Fu(Df)

0.6 0.5 0.4 0.3 0.2 0.1 0.0 0

1

Fu(Df )

10 Df

e

100

1.000

0.45510 2 Df

Studio Seta s.r.l. Massimo Alberti Christian Severino


Fu(Ivnw)

Permanent visual impact of new works 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 1

10

100

1.000

Iv nw

Fu Ivnw

0.925 e

0.2 10 2 Ivnw

0.21 10 1 log10(Ivnw) 0.75 10 1 Studio Seta s.r.l. Massimo Alberti Christian Severino


Definition of the Fu of non-landscape type They have been defined: - on the basis of literature indications

- by interviewing experts

T(Qmax) T(Qmax)

IRR IRR NPV NPV T(RF) T(RF)

- on the basis of indications of the Region of Lombardia (northern Italy) E E - in a relative way with reference to the maximum value of the indicator IHa IHa CO2A CO2A Studio Seta s.r.l. Massimo Alberti Christian Severino


Changes in the hydrological regime (Big variation in the natural flow of the river)

Fu(T(FR))

Function period with Residual Flow

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

60

120

180

240

300

360

T(RF)

Fu(T(RF)) = 1

for T(RF)<60 days

Fu(T(RF)) = 0

for T(RF)>300 days

Fu T RF

5 1 T (RF) 4 240

for intermediate values Studio Seta s.r.l. Massimo Alberti Christian Severino


Net Present Value of the investment 1.0 0.9 0.8

Fu(NPV)

0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0

1.0 NPV/max(NPV)

Fu NPV

NPV max(NPV)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Fu(IRR)

Internal Rate of Return 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

30% 20%

6% 0%

10%

20%

30%

40%

IRR

Fu(IRR) = 0 Fu(IRR) = 1 Fu IRR

for IRR<0.06 for IRR>0.3

15.476 IRR2 9.7381 IRR 0.5286 for intermediate values Studio Seta s.r.l. Massimo Alberti Christian Severino


Usefulness matrix Alternative 1

2

3

4

5

6

7

8

9

10

0,187

0,210

0,233

0,257

0,280

0,303

0,327

0,350

0,373

0,397

Dlc

0,77

0,77

0,77

0,77

0,76

0,76

0,76

0,76

0,76

0,75

Df

0,17

0,16

0,15

0,15

0,14

0,14

0,13

0,13

0,13

0,12

Ivc

0,16

0,16

0,15

0,15

0,15

0,14

0,14

0,14

0,14

0,14

Ivnw

0,44

0,43

0,42

0,41

0,40

0,39

0,38

0,38

0,37

0,36

IHa

0,77

0,73

0,70

0,67

0,65

0,62

0,60

0,59

0,57

0,56

T(RF)

0,75

0,70

0,66

0,63

0,60

0,58

0,55

0,54

0,52

0,51

CO2A

0,52

0,60

0,68

0,74

0,80

0,85

0,90

0,94

0,97

1,00

E

0,51

0,54

0,57

0,59

0,61

0,63

0,65

0,66

0,67

0,68

TAc

0,54

0,60

0,65

0,71

0,76

0,81

0,86

0,91

0,95

1,00

NPV

0,47

0,61

0,73

0,82

0,89

0,94

0,98

1,00

1,00

0,99

IRR

0,62

0,70

0,74

0,76

0,76

0,76

0,75

0,74

0,71

0,68

T(Qmax)

1,00

1,00

1,00

0,87

0,82

0,73

0,58

0,43

0,25

0,06

Q(m3/s)

Indicators

Studio Seta s.r.l. Massimo Alberti Christian Severino


Definition of weights The hierarchical analysis method proposed by Saaty (1980) has been used

This procedure consists of asking to the person interested in the environmental impact evaluation to establish the importance of any indicators in comparison with the others, doing a series of pair comparisons between each couple of indicators that is possible to do Studio Seta s.r.l. Massimo Alberti Christian Severino


Importance The person is asked to quantify the importance of the i indicator in comparison with the j one, with i and j variable from 1 to n

SAATY RELATIVE IMPORTANCE SCALE Preference intensity of i to j Numerical translation Same importance 1 Weak importance 3 Significant importance 5 Strong importance 7 Absolute importance 9 Intermediate values 2,4,6,8

Studio Seta s.r.l. Massimo Alberti Christian Severino


Interviewed stakeholders Six stakeholders who play various roles in the environmental impact evaluation of a hydroelectric plant have been interviewed

1. 2. 3. 4. 5. 6.

a client (entrepreneur who builds the plant) an ecologist a planner a consultant a representative from an environmental protection agency a technician of the regional environmental protection agency REPA

Studio Seta s.r.l. Massimo Alberti Christian Severino


Two methods to define weights 1. Doing pair comparisons between all the indicators (General) (it can be diffucult to compare difficult kind of indicators) 2. Dividing the indicators into three kindred groups Subdivision TEMP-PERM-ECO: Temporary environmental impact indicators (Dlc, Df, Ivc, TAc); Permanent environmental impact indicators (Ivnw, IHa, E, CO2A, T(RF)); Economic indicators (NPV, IRR, T(Qmax)). Subdivision LOC-GLOB-ECO: Local environmental impact indicators (Dlc, Df, Ivc, Ivnw, IHa, T(RF)); Global environmental impact indicators (E, CO2A, TAc); Economic indicators (NPV, IRR, T(Qmax)). Pair comparison was at first carried out within each group; then the method has been applied again between the groups, expressing the importance of any group to the others. Studio Seta s.r.l. Massimo Alberti Christian Severino


Method 1 (Ecologist) Pair comparisons matrix [si,j] obtained by doing pair comparisons between all the indicators

Weights wi

Pair comparisons matrix elements si,j

Studio Seta s.r.l. Massimo Alberti Christian Severino


Method 2 (Ecologist) Subdivision TEMP-PERM-ECO

Subdivision LOC-GLOB-ECO

Studio Seta s.r.l. Massimo Alberti Christian Severino


Weights - Ecologist Weights ECOLOGIST 0.700

0.600

Weights

0.500

0.400 General TEMP - PERM LOC _ GLO

0.300

0.200

0.100

Dlc

Df

Ivc

Ivnw

Har/Han

T(RF)

CO2a

E

TAc

NPV

IRR

T(Qmax)

Indicators

Studio Seta s.r.l. Massimo Alberti Christian Severino


Weight vector In order to determine the weight vector wi the method proposed by Laniado (1988) has been used; this method consists of minimizing the quantity n

n

Eq

si, j i 1 j 1

wi wj

2

Weights wi

imposing that n

wk 1 k 1

e wk 0

Pair comparisons matrix elements si,j

To solve the calculation, VISPA (Integrated Evaluation for the Choice between Alternative Projects) software (Laniado, 1988), developed by Milan Polytechnic has been used Studio Seta s.r.l. Massimo Alberti Christian Severino


Differentiation of the vectors with reference to the interviewed

Weight vector for each stakeholder (average of the 3 group hypothesis of the indicators, i.e. General, Temp-Perm-Eco, Loc-Glob-Eco) and Mean values of the answers obtained by the six interviews. Studio Seta s.r.l. Massimo Alberti Christian Severino


Two methods for choosing the optimal alternative Method of the order vector The optimal project alternative is identified multiplying the mean weight vector wi (just calculated) and the usefulness matrix Ui,j, obtaining a vector which puts the alternatives in order; the solution characterized by the highest evaluation will be the optimal one

Method of the unanimous acceptability Hypothesizing that a deviation of x% from the solution each stakeholder deems to be ideal would be admissible, an optimal solution that is acceptable to all with a minimal deviation (x%) is elected

Studio Seta s.r.l. Massimo Alberti Christian Severino


EXAMPLES: Valle Ianca power plant Evaluation matrix: each row is the order vector for each stakeholder

Best solution for each stakeholder

Solution unanimously acceptable TOLERANCE 1% Studio Seta s.r.l. Massimo Alberti Christian Severino


EXAMPLES: Valle Ianca power plant NPV reduction 5%

economic criteria tolerance 1%

using the mean weight vector

Studio Seta s.r.l. Massimo Alberti Christian Severino


EXAMPLES: ScifĂ II power plant Evaluation matrix: each row is the order vector for each stakeholder

Best solution for each stakeholder

Solution unanimously acceptable TOLERANCE 3,5% Studio Seta s.r.l. Massimo Alberti Christian Severino


EXAMPLES: ScifĂ II power plant

tolerance 3,5%

NPV reduction 22% economic criteria

using the mean weight vector Studio Seta s.r.l. Massimo Alberti Christian Severino


Conclusions The proposed method introduces the evironmental components (on the basis of a classical EIA methodology) in the initial choices of the planning process of small run-of river hydropower plants Application examples show how a unanimously acceptable solution (miminum tolerance) is always present. For that reason the problem of the different perception of the stakeholders does not significantly affect the solution choice

Application examples show how the identified solution is anyway economically acceptable Studio Seta s.r.l. Massimo Alberti Christian Severino


Future developments Since usefulness functions are absolute, the proposed method could be used not only for the determination of the maximum diverted flow, but also for other choices concerning the buildign of the plant (channel and penstock lay-out, position of the intake, shape and position of the powerhouse, type of RF modulation, ‌)

Therefore, other indicators and relating usefulness functions must be defined

Studio Seta s.r.l. Massimo Alberti Christian Severino


THANK YOU FOR YOUR KIND ATTENTION ! massimo.alberti@studioseta.it christian.severino@studioseta.it Studio Seta s.r.l. Via Risorgimento, 2 48018 Faenza (RA) Italy +39-546-623640


Disturbance of the local fauna [m2路 month]

Ac [m2] area of the building site

Df

sf

Ac T 4 10

sf [adim] coeff. of sensivity of the area

T [month] duration of the building site

value from 1 to 10 (1 for areas of poor faunistic regard, 10 for national parks)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Permanent visual impact of new works [m2路 km]

Ai [m2] area of the single work

Ivnw

FVi [km] visibility factor

Ivi i

i

Ai hi 103 Ki

i

FVi

[adim] coefficient of aesthetic armony between the site and the surrounding area

Studio Seta s.r.l. Massimo Alberti Christian Severino


Changes in the habitat volume in the river reach subtended by the diversion [adim]

redisual habitat volume (when the diversion is operating)

I Ha

Ha'R Ha'N natural habitat volume ' N

Ha

1 365

365

Ha QN ( t ) t 0

Studio Seta s.r.l. Massimo Alberti Christian Severino


Economic benefits for the community Total Amount of costs [â‚Ź]

r internal rate of return

TAc I0

(1 r)n 1 (G M T ) r (1 r)n

n number of years in the evaluation period

initial investment cost concession operation

manteinance

Studio Seta s.r.l. Massimo Alberti Christian Severino


Internal Rate of Return [-] IRR internal rate of return that makes NPV equal to 0

n number of years in the evaluation period

(1 IRR)n 1 (R G M T ) IRR (1 IRR)n concession

annual gross profit operation

I0

0

initial investment cost

manteinance

Studio Seta s.r.l. Massimo Alberti Christian Severino


Disturbance of the local community 1.0 0.9 0.8 0.7 Fu(Dlc)

0.6 0.5 0.4 0.3 0.2 0.1 0.0 0

1

10

100

1.000

D lc

Fu(Dlc ) 0.8 e

0.2510 2 Dlc

0.5 10 1 log10 Dlc

0.15 Studio Seta s.r.l. Massimo Alberti Christian Severino


Fu(Ivc)

Temporary visual impact of the construction site 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 100

1.000

10.000

100.000

1.000.000 10.000.000

Iv c

Fu(Ivc) = 1 Fu(Ivc) = 0 Fu(Ivc )

0.1467 ln Ivc

for Ivc<3350 for Ivc>3000000

2.1906

for intermediate values Studio Seta s.r.l. Massimo Alberti Christian Severino


Reduction in the fluvial habitat volume

Fu(Ha r/Han)

1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

Ha r /Ha n

Fu( I Ha ) I Ha

1

HaR' HaN' Studio Seta s.r.l. Massimo Alberti Christian Severino


Reduced carbon dioxide emissions 1.0 0.9 0.8

Fu(CO2a)

0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0

1.0 CO 2a /CO 2a max

Fu CO2 A

CO2 A max(CO2 A )

Studio Seta s.r.l. Massimo Alberti Christian Severino


Renewable energy produced 1 0.9 0.8 0.7

Fu(E)

0.6 0.5 0.4 0.3 0.2 0.1 0 0

5000

10000

15000

20000

25000

E

Fu(E) = E/10000 Fu(E) = 1

Fu E

for E<5000 MWh for E>20000 MWh

E 1 30000 3

for intermediate values Studio Seta s.r.l. Massimo Alberti Christian Severino


Economic benefits for the community Total Amount of costs

1 0.9

Fu(TAc)

0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0

1

TAc

Fu TAc

TAc max(TAc)

Studio Seta s.r.l. Massimo Alberti Christian Severino


Functioning period at full power 1

120

0.9 0.8

90

Fu(T(Q max)

0.7 0.6 0.5 0.4 0.3 0.2 0.1 50 0 0

20

40

60

80

100

120

140

T(Q max )

Fu T Qmax

Fu(T(Qmax)) = 0

for T(Qmax)<50

Fu(T(Qmax)) = 1

for T(Qmax)>120

0.191 10 3 T 2 Qmax 0.467 10 1 T Qmax 1.857 for intermediate values Studio Seta s.r.l. Massimo Alberti Christian Severino


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