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A multi-objective interactive approach to assess economic-energy- environment trade-offs in Brazil Ariovaldo Lopes de Carvalho b* [email protected] Carlos Henggeler Antunes a, c [email protected] Fausto Freire b [email protected] Carla Oliveira Henriques a, d [email protected] a INESC Coimbra, R. Antero Quental 199, 3000033 Coimbra, Portugal b ADAI-LAETA, Department of Mechanical Engineering, University of Coimbra, Pólo II Campus, Rua Luis Reis Santos, 3030-788 Coimbra, Portugal c Department of Electrical Engineering and Computers, Faculty of Sciences and Technology, Polo II, University of Coimbra, 3030290 Coimbra, Portugal d ISCAC, Polytechnic Institute of Coimbra, Quinta Agrícola, Bencanta, 3040316 Coimbra, Portugal *corresponding author and presenter: Tel.: +351 239 708580; Fax: +351 239 708589. ABSTRACT An interactive method devoted to multi-objective linear programming (MOLP) models is used to assess the trade-offs between economic, energy and environmental objectives in the Brazilian economic system. The MOLP model is based on a hybrid Input-Output (IO) framework, with monetary (R$) and physical (tons of oil equivalent) units, developed from the Brazilian IO table and the National Energy Balance. This framework is extended to assess different Greenhouse Gas (GHG) emissions, which are then aggregated into a single indicator (CO 2 eq). The model includes 435 variables, 582 constraints and 3 objective functions: maximization of Gross Domestic Product (GDP), minimization of energy consumption and minimization of GHG emissions. The interactive decision support tool enables a progressive and selective search of non- dominated solutions making the most of graphical displays, namely the parametric diagram associated with the objective function “weights”, to provide insightful information to the Decision Maker. A representative sample of non-dominated solutions has been computed in the interactive process, allowing to identify three main regions corresponding to solutions with different characteristics, i.e. different patterns of trade- offs between the conflicting objective functions. Illustrative results indicate that the maximization of GDP leads to an increase of both energy consumption and GHG emissions, while the minimization of either GHG emissions or energy consumption cause negative impacts on GDP. Keywords: Greenhouse Gas (GHG), Input-Output (IO) analysis, Multi-objective linear programming (MOLP), Multi-sectoral economy-energy-environment models, interactive methods. JEL: C61; C67; Q40. Conference topic: Energy Modelling; Environmental and Social Impact Assessment; Economic Growth and Sustainability.

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Page 1: 2013_ICEE_Carvalho_Antunes_Freire_Oliveira.pdf

A multi-objective interactive approach to assess economic-energy-

environment trade-offs in Brazil

Ariovaldo Lopes de Carvalho b*

[email protected]

Carlos Henggeler Antunes a, c

[email protected]

Fausto Freire b

[email protected]

Carla Oliveira Henriques a, d

[email protected]

a INESC Coimbra, R. Antero Quental 199, 3000–033 Coimbra, Portugal b ADAI-LAETA, Department of Mechanical Engineering, University of Coimbra, Pólo II Campus, Rua

Luis Reis Santos, 3030-788 Coimbra, Portugal c Department of Electrical Engineering and Computers, Faculty of Sciences and Technology, Polo II,

University of Coimbra, 3030–290 Coimbra, Portugal d ISCAC, Polytechnic Institute of Coimbra, Quinta Agrícola, Bencanta, 3040–316 Coimbra, Portugal

*corresponding author and presenter: Tel.: +351 239 708580; Fax: +351 239 708589.

ABSTRACT

An interactive method devoted to multi-objective linear programming (MOLP)

models is used to assess the trade-offs between economic, energy and environmental

objectives in the Brazilian economic system. The MOLP model is based on a hybrid

Input-Output (IO) framework, with monetary (R$) and physical (tons of oil equivalent)

units, developed from the Brazilian IO table and the National Energy Balance. This

framework is extended to assess different Greenhouse Gas (GHG) emissions, which are

then aggregated into a single indicator (CO2eq). The model includes 435 variables, 582

constraints and 3 objective functions: maximization of Gross Domestic Product (GDP),

minimization of energy consumption and minimization of GHG emissions. The

interactive decision support tool enables a progressive and selective search of non-

dominated solutions making the most of graphical displays, namely the parametric

diagram associated with the objective function “weights”, to provide insightful

information to the Decision Maker. A representative sample of non-dominated solutions

has been computed in the interactive process, allowing to identify three main regions

corresponding to solutions with different characteristics, i.e. different patterns of trade-

offs between the conflicting objective functions. Illustrative results indicate that the

maximization of GDP leads to an increase of both energy consumption and GHG

emissions, while the minimization of either GHG emissions or energy consumption

cause negative impacts on GDP.

Keywords: Greenhouse Gas (GHG), Input-Output (IO) analysis, Multi-objective linear

programming (MOLP), Multi-sectoral economy-energy-environment models,

interactive methods.

JEL: C61; C67; Q40.

Conference topic: Energy Modelling; Environmental and Social Impact Assessment;

Economic Growth and Sustainability.

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1. INTRODUCTION

Energy and environmental concerns have gained a significant role in public

policy agenda. Economic growth usually leads to an increase of energy consumption,

which in turn has adverse effects on the environment since current energy supply is

heavily reliant on fossil fuels, which are an important source of Greenhouse Gas (GHG)

emissions. On the other hand, restrictive energy and environmental policies may lead to

negative impacts on economic growth and social welfare. Hence, it is relevant to assess

the interactions and trade-offs between economic, energy and environmental indicators

in order to provide consistent tools for planners and decision makers (DM) (Oliveira

and Antunes, 2004).

The current economic growth in Brazil has influenced positively the welfare and

energy consumption. Although renewable energy supply has been increasing, fossil fuel

production has also been raising namely due to the exploitation of new oil extraction

areas. As a result, more fossil fuel consumption has led to higher impacts in terms of

GHG emissions, which is a drawback for current and prospective economic growth.

Input-Output Analysis (IOA) has been traditionally used to study the inter/intra-

relationships among different sectors in the economic system, describing the

relationship between the inputs used and the outputs produced (Leontief, 1985; Miller

and Blair, 1985). The IO models have been modified to account for environmental

impacts: generalized IO models including additional rows and columns within the IO

system to incorporate the environmental impacts (Leontief, 1970), economic ecological-

models utilizing intra/inter-sector sub-matrices linking the economic and environmental

sectors (Daly, 1968), and commodity by industry models considering the ecological

commodities as products (Victor, 1972). An external expansion of the IO framework

can also be made to incorporate the environmental impacts, assuming a proportional

relation between the output of the sectors and the corresponding impact levels (Suh and

Huppes, 2005).

IO hybrid models have been developed to assess the Brazilian economic system,

investigating the interactions between employment and sector’s output levels and

carbon and energy intensity (Hilgemberg and Guilhoto, 2006), as well as the energy

intensity and CO2 emissions related to a specific region (Figueiredo et al., 2009).

Some studies have developed linear programming (LP) models coupled with the

IO framework for different purposes (Moulik et al., 1992; Hristu-Varsakelis et al.,

2010). However, MOLP models coupled with IO framework can provide a more

complete assessment of different axes of evaluation of potential policies, enabling to

exploit the trade-offs between competing objectives. IO MOLP models have been

applied to study the impacts of regional policies on the employment, water pollution

and energy consumption (Cho, 1999), evaluate the impact of energy conservation

policies on the cost of reducing CO2 emissions (Hsu and Chou, 2000), investigate the

impact of mitigating CO2 emissions considering the maximization of the GDP and the

minimization of CO2 emissions (Chen, 2001), analyze alternative development options

for a national economy considering the maximization of GDP and foreign trade balance

and the minimization of the energy requirements (Kravtsov and Pashkevich, 2004).

Zhou et al. (2006) proposed a modified multiple objective dynamic IO optimization

(MODIO) model considering a set of objective functions and a set of dynamic IO

constraints. Borges and Antunes (2003) implemented an interactive approach to deal

with fuzzy MOLP problems applied to an IO energy-economy planning model. San

Cristobal (2012) applied an Environmental IO MOLP model combined with goal

programming to assess economic, energy, social and environmental goals. Oliveira and

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Antunes (2004, 2011, 2012) constructed IO MOLP models to assess the trade-offs

between the maximization of GDP and employment level, and the minimization of

energy imports and environmental impacts. Antunes et al. (2002) developed an IO

MOLP model using the TRIMAP interactive environment to analyze the interactions of

the energy system with the economy for Portugal. TRIMAP is an interactive method

devoted to three-objective linear programming models that enables a progressive and

selective search for non-dominated solutions to grasp the trade-offs between the

conflicting objective functions.

A hybrid IO MOLP model is herein presented and applied to the Brazilian

economic system aimed at assessing the trade-offs associated with the maximization of

GDP and the minimization of the total energy consumption and GHG emissions,

considering the timeframe of 2017. The TRIMAP interactive method, which is

described in section 2, has been used to make a progressive and selective search for

non-dominated solutions. The extended hybrid IO model formulated in this study is

analyzed in section 3. Some illustrative results are presented in section 4. Some

conclusions and future developments are drawn in section 5.

2. AN INTERACTIVE DECISION SUPPORT TOOL FOR MOLP

The TRIMAP method plays a key role in an interactive decision support tool

enabling a progressive and selective search for non-dominated solutions, thus

facilitating to focus the computational effort on the non-dominated regions where

solutions more interesting for the Decision Maker (DM) are located. TRIMAP is

designed for problems with three objective functions in which graphical tools, in

particular the parametric diagram, provide the DM insightful information about the

trade-offs at stake in those regions. TRIMAP combines three main procedures:

parametric diagram (objective function “weight space”), introduction of constraints

directly in the weights, and introduction of constraints in the objective function space

that are then translated into the parametric diagram (Clímaco and Antunes, 1987; 1989).

The parametric diagram display is used for collecting and presenting to the DM the

information obtained during the search process. The parametric diagram is filled with

the indifference regions corresponding to the (basic) non-dominated solutions already

computed, i.e. the regions defined by the objective function weights for which the

optimization of a (scalar) weighted-sum function aggregating the multiple objective

functions leads to the same (non-dominated) solution. Another graph shows the non-

dominated solutions already computed, also enabling to identify non-dominated edges

and faces of the feasible polyhedron in the objective function space.

This interactive system offers the DM the possibility of progressively exploiting

and learning the characteristics of the non-dominated region, and then narrowing down

the search toward a solution (or set of solutions) according to his/her preferences. The

TRIMAP search process generally starts with a broad strategic search to gather

information about distinct solutions, in particular those that individually optimize each

of the conflicting functions, and then gradually focus onto regions in which more

interesting solutions are found taken into account the trade-offs unveiled throughout the

interactive procedure. In this way irrelevant solutions, from the DM’s point of view, are

avoided and a learning process of the characteristics of solutions and the trade-offs at

stake between the competing objectives is privileged. Also a clarification of the own

DM’s preferences and judgments is facilitated. The interactive process continues until

the DM has gathered "sufficient knowledge" about the set of non-dominated solutions

rather than pre-specifying a given number of iterations or any other stopping condition.

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3. EXTENDED HYBRID INPUT-OUTPUT MODEL

The first step to build this Extended Hybrid IO model is rearranging the IO table

to make the energy use coefficients directly available in hybrid units (physical units per

monetary units). In this step, the energy flows in the Brazilian National Energy Balance

(MME, 2009) are incorporated into the 2009 Brazilian IO table (Guilhoto and Sesso

Filho, 2010) by considering artificial sectors (see also Oliveira and Antunes, 2004,

2011, 2012). For this purpose some adjustments and inclusion of new rows and columns

in the IO table are necessary in order to incorporate the different energy sectors (or

commodities). This procedure generates a new transaction matrix, thus leading to a new

technical coefficient matrix and new vectors for final demand and the total output with

hybrid units, in which energy flows are considered in physical quantities of energy (tons

of oil equivalent, toe) and all non-energy sector flows are measured in monetary units.

The adjustments performed in the IO framework provide: a square matrix with 109

activity sectors split into 51 economic sectors, 6 energy producing sectors, 5 artificial

sectors used for distributing the energy consumed by each means of transportation and

47 artificial energy product sectors; 6 column vectors with the components of final

demand (exports, public consumption, resident consumption, gross fixed capital

formation - GFCF - and stock changes); 1 column vector for competitive imports

(considered for energy products only); and 6 row vectors for the primary inputs (wages,

gross mixed income, gross operating surplus, other production taxes and other

production subsides).

An external expansion of the IO model is made to estimate GHG emissions from

energy combustion, industrial processes, agriculture activities, waste management,

wastewater treatment and discharge, and fugitive emissions. In this step, based on the

IPCC (2006) methodology, emission factors for GHG emissions from carbon dioxide

(CO2), methane (CH4) and nitrous oxide (N2O) are used in combination with the level of

activity of specific sectors and final demand components. These estimates give a vector

with the environmental impacts per unit of output of the sectors and the final demand,

considering the corresponding Global Warming Potential (100-year horizon: 25 for

CH4, 298 for NO2) relative to CO2 (IPCC, 2007).

Finally, the MOLP model based on IO analysis proposed by Oliveira and

Antunes (2004, 2011, 2012) for Portugal is adapted to the Brazilian economic system,

which has a very different structure leading to important changes in the mathematical

model. The model includes (internal) coherence constraints derived from the IO

analysis and other sets of constraints associated with the structure of the economic

system, employment and energy consumption, which are briefly described below.

Further details about the multi-objective model can be found in Carvalho et al. (2013).

3.1 Model constraints

Coherence constraints are used to determine that the intermediate consumption

and final demand of each activity sector shall not exceed the corresponding total amount

available from national production and competitive imports.

The GDP (expense approach) is computed considering the final demand minus

imports at FOB (free on board) prices (including tourism). The GDP (production

approach) is computed by the sum of gross value added and the total of taxes less

subsides on products that are not included in the production.

The gross value added is given by the sum of wages, gross mixed income, gross

operating surplus, other production taxes minus other production subsides.

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Taxes less subsidies on goods or services are calculated for the intermediate

consumption and final demand items.

The model also establishes some assumptions for several consumption relations:

the households’ consumption on the territory includes the consumption on the territory

by resident and non-resident households; the residents’ consumption includes the

consumption of households and Non-profit Institutions Serving Households (NPISH);

the resident households’ consumption on the territory is linearly dependent on the

available income; and the tourism imports is given as a proportion of the residents’

household consumption.

The GDP at current prices is estimated considering the components of GDP

(expense approach) at constant prices and the corresponding deflators. Additionally, the

consumption of goods and services by the public administration at current prices and the

GFCF at current prices are exogenously defined.

The residents’ disposable income at current prices is computed by subtracting

the public administration and (non-financial and financial) corporations’ disposable

incomes from the National Disposable Income.

Public debt is given by the summation of the previous period debt with the

symmetrical value of the public administration global balance, plus an adjustment

variable.

Public administration’s global balance is computed by subtracting the public

administration’s expenditures from the public administration’s revenues.

The employment level is obtained by using labor gross productivity coefficients

for each sector.

The total energy consumption is obtained from the sum of national and imported

energy excluding the energy consumed for non-energy purpose. Specific technical

coefficients are applied to the intermediary consumption and final demand.

3.2 Objective Functions

The model considers three competing objective functions:

- F1: Maximization of GDP as an indicator of global economic performance

(thousand R$).

- F2: Minimization of total energy consumption to assess the impacts associated

with economic growth and GHG emissions, taking into account that energy supply in

Brazil is mostly domestic (thousand toes).

- F3: Minimization of GHG emissions considering the links with economic

activity (and energy use) as well as the international agreements on the reduction of

GHG emissions (Gg of CO2 equivalent).

The detailed presentation of the multi-objective mathematical model can be

found in Carvalho et al. (2013).

4. RESULTS AND DISCUSSION

The MOLP model has been supplied with realistic data gathered from several

Brazilian sources (MME, 2009; Guilhoto and Sesso Filho, 2010; MCT, 2010) and

estimates for the year 2017 (Carvalho et al., 2013). The MOLP model has 435 decision

variables, 582 constraints and 3 objective functions. Some illustrative results obtained

with the interactive decision support tool briefly described in section 2 are herein

described.

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Firstly, each objective function was optimized individually, resulting in 3

distinct non-dominated solutions. These solutions provide a first overview of the range

of variation of the objective values within the non-dominated region. The

characterization of these solutions (objective function values, decision variable values,

indifference region in the parametric diagram) is presented to the DM. Therefore the

DM should indicate a set of weights not yet belonging to an indifference region in the

parametric diagram to compute a new non-dominated solution. The weight specification

should be understood not as a precise “importance coefficient” but rather as an

indication of the objective functions to be (temporarily) privileged in the subsequent

search. Note that the area of the indifference region in the parametric space also gives

an indication of the solution “robustness” regarding weight changes. Information about

some solutions may lead the DM to conclude that it is not worthwhile to proceed with

the search using weights in-between the corresponding indifference regions because the

solutions then obtained would not be so different and therefore would not be relevant

for decision support purposes. This enables a progressive and selective search of the

non-dominated solution set using the parametric diagram as a valuable visual feedback

enabling to identify sub-sets of solutions sharing similar characteristics, namely trade-

offs between the competing objectives, until a satisfactory compromise solution is

identified. In this example, the parametric diagram has been filled with indifference

regions corresponding to 20 non-dominated (basic) solutions that have been considered

providing sufficient information about different policies - see figure 1, in which

( denote the weights assigned to each objective function (F1, F2, F3) to build

a scalar weighted-sum function to be optimized leading to the identification of the

corresponding indifference region using the multi-objective simplex tableau.

Analyzing the objective function values, for example, of solutions 11 and 12 it is

possible to conclude that the DM has information to conclude that it is not worthwhile

searching for new solutions in the parametric diagram region located between the

indifference regions corresponding to those solutions. The visual information displayed

in the parametric diagram thus contributes to minimize the computational effort and the

number of irrelevant solutions generated during the exploitation of the problem (and

thus the information processing effort required from the DM).

A useful tool offered by the TRIMAP interactive method is the possibility to

impose additional bounds on the objective function values in order to narrow the scope

of the search to regions of interest of the non-dominated solution set. This information

stated in the objective function space (which is the most familiar space for the DM) is

translated via an auxiliary problem into the parametric space, in which the regions of

weights leading to solutions satisfying those bounds can be computed. In this example,

the DM established two bounds in the values of F1 ≥ R$ 3,903,355 x 103 and F2 ≤

237,249.5 toe x 103 (see figure 2). These bounds represent the expression of reservation

levels, i.e. the DM stating that he/she is not interested in solutions providing inferior

values than those stated for those functions. This restricts the search process to regions

that include the solution 12 and a still not yet searched region nearby this solution (in

which new non-dominated solutions can be found if the DM wants to). This feature of

TRIMAP is particularly valuable to reduce the scope of the search aligned to the DM’s

preferences (see Clímaco and Antunes, 1987 and 1989, for technical details).

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Figure 1 - Decomposition of the parametric diagram into indifference regions (corresponding to

basic non-dominated solution).

Figure 2 - Additional bounds on the objective functions and regions in the parametric diagram

satisfying them.

The objective function values of the 20 non-dominated solutions computed using

the TRIMAP interactive method are presented in table 1. The values in bold are the

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components of the ideal solution with the optimal values for F1, F2 and F3 (GDP,

energy consumption and GHG emissions, respectively).

Table 1 – Objective function values for some non-dominated solutions Solution F1 (10

3 R$) F2 (10

3 toes) F3 (Gg CO2 equiv)

1 4,465,863 271,392 2,708,369

2 3,902,394 237,248 2,537,554

3 3,900,231 237,267 2,537,377

4 4,465,863 271,449 2,708,333

5 4,465,863 271,544 2,708,327

6 4,465,863 271,244 2,708,918

7 4,465,863 271,392 2,708,369

8 4,465,863 271,392 2,708,369

9 3,924,972 237,499 2,542,324

10 4,022,372 240,443 2,565,221

11 3,901,036 237,249 2,537,409

12 3,903,358 237,248 2,537,659

13 3,938,117 238,387 2,543,422

14 3,962,958 238,748 2,548,863

15 4,002,566 240,061 2,558,992

16 4,044,838 241,818 2,570,861

17 4,037,694 241,175 2,569,085

18 3,955,369 238,299 2,547,625

19 3,932,868 238,036 2,542,672

20 4,015,388 240,242 2,562,830

A more detailed analysis of the characteristics of the solutions can be made

using the results of the model decision variables besides the objective function values.

However, the illustrative results herein described will be focused on their most relevant

aspects and characteristics of the main variables.

It is possible to verify a conflicting relation between GDP and energy

consumption (or GHG emissions). In solution 1, which maximizes GDP (R$ 4,465,863

x 103), both energy consumption and GHG emissions values are very close to their

worst value known in the non-dominated region (271,392 toe x 103 and 2,708,369 Gg

of CO2 equivalent, respectively). On the other hand, for solution 2, which minimizes

energy consumption, GDP achieves a value (R$ 3,902,394 x 103) not far from its worst

one (see table 1) and GHG emissions are very close to the optimum (2,537,554 Gg of

CO2 equivalent). In addition, for solution 3, which minimizes GHG emissions

(2,537,377 Gg of CO2 equivalent), GDP achieves the worst level (R$ 3,900,231 x 103)

while energy consumption is only 0.01 % higher than the optimal level.

Three main regions can be distinguished in the parametric diagram

corresponding to solutions with different characteristics. It is possible to note that

solutions 4, 5, 6, 7 and 8 are alternative optima of solution 1 with respect to F1. It is also

possible to recognize through the visual inspection of the parametric diagram that a well

defined “cut” exist marked by the “western” boundaries of the indifference regions

associated with those solutions (1, 4, 5, 6, 7 and 8). Until that boundary the values for

GDP is the same (the optimal one) with small variations in F2 and F3 values. The GDP

value decreases smoothly for solutions beyond that boundary as the weight assigned to

F1 approaches zero (that is, 1=0 and 2+3=1). Different combinations of 2 and 3

with 1=0 enable to obtain solutions 2, 11 and 3. An important characteristic of those

regions is the high values obtained for the Gross Fixed Capital Formation (GFCF) and

employment, which achieves its highest value in solution 5 (56,818,158 employees).

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The sectors that have the highest output improvement are linked to the energy,

construction and manufacturing industries.

A second region involves solutions 2, 3, 11 and 12, where the values for all

objectives are very similar varying less than 0.1% for GDP and 0.01% for energy

consumption and GHG emissions. This region is characterized by lower values for GDP

and values close to the optimum for energy consumption and GHG emissions. An

important drawback of these solutions is the negative impact on the employment level,

which achieves its lowest values, especially in solution 3 (50,749,014 employees). The

industrial sectors with negative impacts on their outputs in solutions 2 and 3 are the

energy intensive sectors, such as the extractive industry, petroleum refining and coke,

chemicals and cement.

Finally, the region containing solutions 10, 15, 16, 17 and 20 is characterized by

intermediary values for all objective functions, with a variation of 1.0% for GDP, 0.7%

for energy consumption and 0.5% for GHG emissions. Solution 20 is representative of

the main characteristics of the solutions within this region, with well-balanced values

also for employment (52,146,818 employees).

5. CONCLUSION

Since, in general, energy, economic and environmental aspects of distinct

policies have conflicting interactions, a broad scrutiny of these evaluation axes and a

thorough appraisal of the trade-offs at stake are important for the policy making

process. In this context MOLP models enable to exploit the trade-offs between those

competing objectives and provide an important tool in the assessment of distinct

policies associated with different non-dominated solutions.

In this paper a hybrid IO framework is used to develop an MOLP model applied

to the Brazilian economic system, which is investigated by using the TRIMAP

interactive method. The aim is to assess the trade-offs between economic, energy and

environmental objectives through a progressive and selective search of non-dominated

solutions in order to provide decision support to DMs. The TRIMAP interactive

environment has been used to perform a progressive and selective search based on the

parametric diagram. The non-dominated solutions computed allowed to unveil some

patterns and the main characteristics of three main regions in the parametric diagram

corresponding to sub-sets of solutions sharing the same features. The illustrative results

obtained with this model provide valuable insights about the trade-offs involved and

allow identifying the performance and trends of the main variables. The IO framework

coupled with the MOLP model provided an important tool to assess the interactions and

trade-offs between the objective functions. The TRIMAP interactive method has

provided great flexibility to the analysis, allowing a progressive and selective

exploration of the compromise solutions in a user-friendly graphical environment.

Future developments of this work will involve the use of other multi-objective

interactive methods within an integrated framework to facilitate the DM’s tasks and

provide a user-friendly interactive environment to assess the merits of distinct policies.

Acknowledgements

This work has been framed under the Initiative Energy for Sustainability of the

University of Coimbra and supported by the Energy and Mobility for Sustainable

Regions Project CENTRO-07-0224-FEDER-002004, and the Portuguese Foundation

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9

for Science and Technology (FCT) under grant SFRH/BD/42960/2008 and projects

MIT/SET/0014/2009, PEst-C/EEI/UI0308/2011 and PTDC/SEN-TRA/117251/2010.

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