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, â&#x20AC;Ś)
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&#x201A;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