Framework for Assessing Urban Energy Sustainability

Abstract

The social, economic, and environmental impacts associated with fuels used to power cities cause the sustainability of energy produced and consumed in our urban environment to be constantly challenged. In order to address the issue of urban energy sustainability, we propose a Framework for Assessing Urban Energy Sustainability (FAUES), whose main approach relies on defining a method for determining critical indices associated with the major criteria of sustainable energy generation and consumption. The framework is based on developing a three-step process that integrates historical data regarding energy consumption and production and forecasted parameters on energy sustainability and can be used both in urban energy operations and in planning new urban settlements. The framework was implemented in Brazil as a representative case study, given that its cities lack social inclusion, economic stability, and environmental protection when it comes to energy. The framework functions so that policy makers and managers can assess the sustainability of energy produced and consumed in urban environments on the basis of relevant criteria for the city in which the energy is being evaluated.

1. Introduction

Energy use in urban regions contributes to drastic environmental impacts worldwide [1]. More than 60% of the energy generated in large cities negatively affects social and environmental aspects [2], being the main factor responsible for the emissions of greenhouse gases and for the reduction of water quality [3]. Approximately 75% of natural resources are consumed to operate buildings in urban regions, in terms of energy usage. The problem is further exacerbated by the population increase expected to occur; in 1950, only 30% of the population resided in urban areas. In 2014, this percentage had grown to 54%, and the perspective is that by 2050, 66% of the world’s population will be living in urban areas [4,5], which will increase consumption, which today corresponds to 70% of global energy [6,7]. In a significant portion of countries, especially underdeveloped and developing ones, energy demands are challenging to be met in a sustainable way, which demands intelligent management that considers the relationship between availability and demand [8]. In large cities such as the Brazilian cities Rio de Janeiro, São Paulo, and Brasília, the rapid growth in energy demand has been witnessed over the last two decades, mainly due to the increased demand for fossil fuels [9].

As part of the findings of a report published by the United Nations (UN) on its development program, cities of the developing world are not well equipped to face a massive urban population growth, with over 1.6 billion people worldwide without access to adequate energy [10]. The projection is that around 75–80% of greenhouse gas emissions will be produced in urban areas due to energy consumption by 2050 [11,12], thus indicating a severe environmental challenge that will face cities in the near future.

Current challenges reported in the literature for cities include: (i) ensuring the environmental, economic, and social sustainability of cities to meet the needs of consumers; (ii) the need for environmental protection in the wake of developments taking place [3]; (iii) ensuring the reliability and sufficiency of energy resources; and (iv) assessing budgetary constraints and economic efficiency of existing cities [13].

Energy consumption due to social parameters is mostly related to growth in the number of households. Such social developments occur, for example, due to the emergence of new industries and the growth of certain sectors [2]. As the number of people living in urban regions grows, urban networks and infrastructure to meet their needs also tend to grow. These needs and challenges have to address the improvements in the increased living standards and meet sustainable energy and resource consumption [14]. The relationship between urban energy growth and economic scope is linked to economic development in cities, where the economic growth results in an increase in consumption and an increase in demand for services and housing [15]. Economic growth also results in demand for more complex networks [16]. In terms of environmental parameters, the works associated with increased construction works and transportation networks that are built consume more natural resources as more energy is needed to power such developments.

A large number of studies on urban characteristics and energy consumption have been published since 1980. However, relatively few researchers have investigated the link between urban forms and energy use in developing countries [2]. For example, Dhakal [17] examined the urban energy use and CO₂ emissions in China, presenting the energy-economy pathways in the last two decades in 35 large Chinese cities. The author highlighted that the largest cities in China account for 40% of urban energy use and CO₂ emissions in the country. Mi et al. [18] analyzed the urban carbon emissions due to energy consumption in 11 Chinese cities using input–output theory. The authors presented the important role of interregional cooperation in tackling climate change at the city level. Huang et al. [19] conducted a comparative analysis to examine the unfolding of the urban energy transition in two Chinese cities concerning the deployment of solar water heating systems; the authors found that the urban energy transition in China depends basically on the fit between the urban development contexts and applied technologies in the country. Sun et al. [20] examined the energy associated with Urban Traffic Infrastructure Investment (UTII) and air pollution in 85 Chinese cities. Sustainability impacts of changes in fuel consumption in Finland were examined in [21], where national databases were utilized along with expert opinion. The results indicated that shifting from fossil fuel to woody biomass has a number of sustainable advantages, though the cost associated with production was predicted to increase. In Reference [22], energy production via grassland was examined in Germany, with several sustainability advantages resulting in terms of environmental and social perspectives. A study in Spain determined that urban energy sustainability is rendered as a very important issue, and a clear way of measuring its improvement is lacking [23]. The authors developed a method based on international indices focusing on the analysis of sustainability, energy, and cities to assess air quality, fossil fuel usage, energy affordability, and energy supply quality. Gaps in the current indices were identified, and an Urban Energy Sustainability Index (UESI) was determined. In a study focusing on the challenges of the energy transition and energy needs in the future with an energy nexus, Dasaraden Mauree et al. [24] reviewed the literature of assessment methods for the urban environment, and its energy sustainability guaranteed climate adaptation of future cities. The review observed a gap in the literature dealing with these topics and pointed out that more studies are needed to bring knowledge and tools for this area. One of the findings concluded that energy systems need to integrate more renewable energies and decrease urban areas’ carbon footprints. The development of a methodology for the construction of an urban-energy diagnosis approach to foster cities’ sustainability with an application to La Plata in Argentina was presented in [25]. The study establishes urban-energy diagnoses of different city areas and identifies critical urban-energy aspects in different city areas. In [26], Fish and Calvert discussed the functionality of online solar energy maps and their value in accomplishing urban energy sustainability via cartographic representation in geographic information systems of urban-scale solar energy maps in the United States.

Although several tools exist to analyze energy in the literature, most of them rely on the concept of Life Cycle Assessment (LCA). In particular, Life Cycle Energy Analysis (LCEA) is used to compute energy use in buildings, accounting for the environmental impacts associated with energy production [27]. The idea, however, is that sustainability encompasses economic and social aspects that need to be accounted for. It is also more difficult to extend LCEA to cover all aspects of energy production and use in the urban environment.

Cities need to be designed to reduce their carbon emissions with enhanced resilient levels [28]. Sustainability challenges facing cities worldwide all point to the need for an approach to urban energy efficiency that can be critically examined under a defined set of relevant criteria. As stated in Reference [1], strategic frameworks for ensuring the sustainability of cities require a methodological approach for monitoring and evaluating systems currently embedded in cities, which requires the use of multicriteria decision analysis (MCDA).

The present study contributes to filling this gap by proposing a Framework for Assessing Urban Energy Sustainability (FAUES), which describes how to obtain a set of indicators related to energy efficiency in the urban environment, generated to account for the interactions between economic, social, and environmental impacts. The framework is based on developing a three-step process that integrates historical data regarding energy consumption and production and forecasted parameters on energy sustainability, which are submitted to multicriteria decision analysis (MCDA). The framework is validated by experts working in the field of energy sustainability.

FAUES collaborates with policymakers and managers by guiding the process of seeking indicators related to energy efficiency in the urban environment, generated to account for the interactions between economic, social, and environmental impacts. By using a multicriteria analysis process, FAUES is well suited for performing sustainability evaluations due to its capacity in the dialogue between stakeholders, analysts, and scientists.

When discussing the future energy matrix and renewable energies, the United Nations Conference on Trade and Development argued that the global energy demand has continued to increase and that the driving forces come from developed countries, where fossil fuels still play an important role in the world energy balance [29]. It also noted the urgent need for the energy matrix to move towards more sustainable and renewable energy sources to solve long-term energy sustainability issues. For this, decision makers must use sustainability assessment frameworks suited to the characteristics and specificities of urban energy sustainability, such as the one proposed in this work. In this sense, the framework can be used both in urban energy operations and in planning new urban settlements.

The Brazilian case study was adopted whose characteristics are challenging. The Brazilian reality is similar to that of many countries, especially developing ones, in which sustainable energy is significantly harmed. These regions face problems of poverty and equity at different levels compared to developed countries [30]. Thus, the aspects of the Brazilian reality presented in this work are experienced by most cities in developing countries to a greater or lesser extent, making the proposed framework generalizable.

This paper is structured as follows: Section 2 presents the structure of the proposed framework and details its components. Section 3 uses the city of Rio de Janeiro as a case study for applying the framework. Section 4 discusses the research results. The conclusions are provided in Section 5.

2. Framework for Assessing Urban Energy Sustainability (FAUES)

The Framework for Assessing Urban Energy Sustainability (FAUES) is composed of two steps: defining the scope and energy analysis.

2.1. Defining the Scope

Defining the scope of the energy analysis requires understanding the management of energy supply and demand within a city. For energy production, this involves determining the methods used to generate energy for the demand needed in the country. Most countries rely on fossil fuels for their energy production, rendering the process nonsustainable [31]. Each city has its energy matrix from which several types of energy are generated to meet demands [32].

In FAUES, the energy life cycle (Figure 1) is closely examined to determine the main aspects of energy consumed and produced in various sectors within a city, including buildings, transportation, construction, operation and maintenance, material processing, and waste processing. In terms of energy consumption, the highest energy levels are consumed by buildings and transportation networks of cities [33,34].

2.2. Energy Analysis

The second step, “Energy Analysis”, was structured in four phases (Figure 2). This step involves an energy analysis where data are collected on what constitutes important parameters for assessing the sustainability of cities. In this sense, it is essential that research papers and energy reports are consulted across the first three phases.

2.2.1. Phase 1

In the first phase, it is necessary to define the set of sustainability criteria that reflect the impacts of energy production and consumption related to social, environmental, and economic aspects (Figure 3). It is important to emphasize that, over time, new technologies and uses may require new indicators. Thus, besides being adherent to the local reality, the indicators must also reflect state of the art. Concerning environmental impacts, the focus is on three main areas; atmosphere, water, and soil. For the atmosphere, indices that can be incorporated include measures such as climate change and air quality [35]. Concerning water, they can be considered mediated related to extraction, processing, and sewage [36]. Concerning land, some important measures include deforestation and solid waste produced [35]. About social impacts, we have adopted three measures in line with the United Nations Environment Program [37]: working conditions, local community, and society in general. With regard to economic impacts, the EPA guidelines emphasize the importance of energy use, efficiency of supply, and production as key elements that support energy savings [38]. The per capita price for people who use energy can be adopted as one of the main indexes of energy use. In terms of supply efficiency, the energy conversion that assesses transformation losses due to energy transmission to users can be used as a representative index [39]. The UNCSD recommends using the production reserves ratio for energy production measures, calculated by accounting for the recoverable reserve and the total energy produced, together with the production resources ratio, which uses estimated total resources and total energy production [40].

The strategy used was to, after having retrieved some basic criteria from the literature, ask professionals in the field to indicate the final set of criteria. The criteria used to select experts were based on the detected expertise required to address specific questions and problems related to the expected outcomes of the urban energy sustainability study. This was also the case of disregarding some possible choice of experts considered in a first look that did not meet these criteria to be selected despite being available. The profiles of the specialists must be focused on the fields of energy and sustainability, with decision-making capacity and experience in the public and private areas. In this study, the strategy used was to ask professionals in the field to indicate the set of criteria. The professionals who participated in the study were selected considering the following inclusion criteria: have expertise or work in areas related to the researched theme and have qualifications related to energy in conjunction with sustainability. More specifically, we took the opportunity to interview four members of the IEA (International Energy Agency) that were in Brazil to deliver courses held by the agency. We have also interviewed three scholars from different Brazilian universities, one professor of a Spanish university, and another from an Australian university. Another group of interviewees comprised four professionals (mostly engineers) working in the energy field in Brazil in different positions (consultants, energy operator, and project engineer). Lastly, we interviewed three professionals in the Rio de Janeiro Center of Operations, directly involved in gathering and analyzing information from several sources in real-time analysis and generation of data. We used the authors’ relationships and the opportunities that were created to come up with these interviews, and all interviewees had proven expertise in the researched subject.

The respondents answered the following question: what are the most important criteria for assessing urban sustainability energy? All criteria mentioned by at least two respondents were considered relevant. They were free to point out several remarks and determine what they believe was important to be included in the set of criteria to achieve the decision-making objective.

2.2.2. Phase 2

Once the sustainability criteria have been outlined and the associated indices for each criterion are highlighted, Phase 2 requires understanding how such measures evolved with time. This requires looking at historical data and determining how much each of the impacts had fluctuated with the change in energy production and consumption. A literature review needed to be conducted based on local and global reports in order to understand the nature of energy consumption and production in a particular country. Some examples of reports and guidelines to review include International Energy Agency reports [41,42,43,44]; the UN Energy for Sustainable Development [45,46]; the Institute for European Environmental Policy [47]; the Directorate-General for Energy of the European Commission [48,49]; the European Environmental Agency [50]; the US Environmental Protection Agency [51] and its associated NREL National Renewable Energy Laboratory publications [52]; the Council of Australian Governments (COAG) Energy Council [53]; Australian Department of Industry, Science, Energy, and Resources [54]; the International Gas Union [55]; the Brazilian Ministry of Mines and Energy [56]; documents from the Overseas Development Institute [57]; and book chapters on climate change [58].

2.2.3. Phase 3

In Phase 3, future predictions on the sustainability criteria and indicators need to be performed. Phase 3 involves setting up a road map that delineates the progress of a particular nation in terms of energy production and consumption. National documents need to be reviewed to determine the internal forecasting nature of energy development in a particular region. For the case study presented in Section 4 of this paper, the Brazilian National Energy Agency—ANEEL—publications, as well as the Brazilian Energy Research Office (EPE) documents [59,60], UN reports including the environmental program and International Energy Agency [61], and the IEA “World Energy Outlook” [62,63] are utilized.

2.2.4. Phase 4

Phase 4 conducts a multicriteria analysis to prioritize the set of urban energy sustainability criteria, with alternatives using the weight proposition for the criteria [6,7]. A hierarchy of the criteria is established, and weights associated with each criteria based on expert evaluation to determine the importance of key sustainability indicators. It is important to ensure that the experts’ profiles are focused on the energy and sustainability domains, with decision capacity and experience in the public and private areas. The consistency of the hierarchy priorities of the criteria is then analyzed to ensure consistent application for energy sustainability in cities. AHP was chosen as the multi-criteria decision analysis method due to its ease of use and for having one of the most familiar approaches for academics and industry personnel [64]. According to [65], AHP is used by 65.1% of the authors who use the multicriteria decision-making process.

It is important to stress that an energy analysis conducted jointly with a multicriteria decision analysis allows a structured set of relevant criteria and associated indices to be assessed for their relative importance given the energy climate of the urban region being examined.

3. Case Study

A case study is adopted to highlight how multicriteria FAUES works. The city analyzed was Rio de Janeiro in Brazil, given the social, environmental, and economic challenges that the city faces when it comes to energy. The framework is suitable for energy generation projects and new settlement developments. Here, the example is only related to energy generation projects, but based on similarities, they also can be applied in the case of new settlements.

3.1. Brazil Energy Consumption

A typical feature of developing countries is population growth. Brazil, the fifth largest country in size and the sixth in population, is the seventh-ranked country in energy consumption and the thirteenth-largest emitter of CO₂. Thus, Brazil plays an important role in the global energy market and in impeding climate change [66].

When examining Brazil’s energy consumption over the past four decades, a constant increase can be noticed. In the period from 1980 to 2001, consumption exceeded production capacity. From 2002 onwards, the scenario was reversed, with energy production higher than consumption. The International Energy Agency (IEA) report considers that between 2010 and 2020, Brazil’s total energy demand will grow by more than 60%, with two-thirds of total consumption in the industrial and transport sectors. Regarding generation, the plan estimates that the participation of hydroelectric plants will fall from 76% to 67%. Nevertheless, this decrease will be offset by the increase in generation from renewable sources, such as wind and thermal plants, to biomass, which should double from 8% to 16% in ten years [67].

The IEA reports indicate that the share of renewable energy in total energy production is decreasing. The possibility of matching energy consumption with the production of renewable energy is far from achievable in Brazil. Nevertheless, Brazil performs better than many countries, with 42% of all energy production being derived from renewable energy. Hydropower represents almost a fifth of the overall electricity generation capacity, and likewise, ethanol accounts for almost a fifth of the energy demand for transportation [68]. The expansion of renewable energies is foreseen in the 2020 Brazilian Energy Plan, which expects renewable energies to reach 46.3% of the total primary energy supply by the end of 2020. However, according to the International Energy Agency, this percentage in 2015 is equal to 43%.

In terms of energy demand, the sectors that stand out the most in a city are buildings and transport networks. In analyzing the evolution of the percentage of the total consumption of energy of each of these sectors in the years between 1980 and 2015, three points stand: (i) there is a significant reduction of energy use in the residential building sector; (ii) an increase in the energy demand of the transport sector equals that of the industrial building sector, and (iii) a slight reduction in consumption in the industrial building sector. The significant reduction of energy use in the residential sector is in response to the efforts that have been made to make residential dwellings more energy effective; this is also supported by some studies in the literature [66,67,68]. The growth of consumption in the transport sector is a reflection of the growing development of cities. As the number of city inhabitants grows, so does the demand for many kinds of services, primarily transportation. Companies are being pressured to invest in more sustainable marketing and production in the industrial sphere, thus reflecting the good practices in relation to energy consumption. Such results indicate a permanent challenge in providing means for supporting growing needs and higher standards of consumption parallel to maintaining the sources of these services and assets available and reliable. In these terms, sustainable growth is envisioned and perceived as the only form that allows this cycle of prosperity to become effective. It explains why it is essential to propose a method that examines essential criteria related to assessing the impacts of urban energy production and consumption in an urban environment.

3.2. Framework Application

The criteria related to the triple-bottom line of sustainability relevant to the city of Rio de Janeiro were compiled. To conduct the energy analysis, interviews with experts working in energy analysis and at the COR—Rio Centre of Operations—were conducted to further narrow down the list of indicators to those that were most relevant.

Reports and data on historical and projected energy use such as ones published by IEA [69], the National System Operator (Operador Nacional do Sistema ONS) [70], ANEEL, the Brazilian Electricity Regulatory Agency [71], and EPE / Empresa de Pesquisa Energética [72] were utilized to identify indicators related to energy consumption and production in the city of Rio de Janeiro.

An analysis of urban plans and technical visits carried out in operational centers in Rio de Janeiro was used to generate outlooks on energy generation and consumption in the future. Energy sources were derived from retrieved information on their sites, from talks to technical personnel, and some of their available online tools. One of these centers is the Rio Centre of Operations. Built in December 2010 and modernized in 2015, it functions as an integration headquarters for urban operations in Rio de Janeiro. With high technology for managing the information on energy use and supply, the center can record and retrieve information on sustainability parameters that are relevant to the adopted framework. The operations of the center highlight the process involved in gathering information on energy use and supply. From the center, some experts were engaged.

A list of compiled indicators for assessing economic, environmental, and social impacts of energy in Rio de Janeiro is illustrated in

Table 1. Urban energy sustainability dimensions and criteria.

Social Aspects	Economic Aspects	Environmental Aspects
Poverty alleviation	Energy prices	Energy savings
Health and well-being	Macroeconomic impacts	GHG emissions
Employment	Industrial production	Local air pollution
	Public budgets	Resource management
	Disposable income

.

For each criterion and subcriterion, from the bibliographic review and expert opinions, the list of indicators was narrowed down to the ones displayed in the first column of

Table 2. Metrics of criteria, subcriteria, and indicators.

Criteria	Subcriteria	Families of Indicators
Social	Poverty alleviation	Households with access to electricity and other fuels [73,74]
		Satisfaction of inhabitants with the power plant [73]
	Health and well-being	Accident fatalities per energy produced by fuel chain [75,76]
	Employment	Investment in clean energy, as a proxy for job creation [77]
Economic	Energy prices	End-use energy prices by fuel and by sector [75]
	Macroeconomic impacts	Per capita GDP (Gross domestic product) [76,78]
	Industrial production	Resources-to-production ratio [75]
		Reserves-to-production ratio [75]
	Public budgets	Burden of energy investments on the public sector [77]
	Disposable income	Share of household income spent on fuel and electricity [75]
Environmental	Energy savings	Energy self-sufficiency [79]
	GHG emissions	Sum of released CO2 equivalents due to energy use [75]
		Greenhouse gasses from transport [80,81]
		GHG emissions from energy production [75,82]
	Local air pollution	Ambient concentrations of air pollutants in urban areas [75]
		Air-pollutant emissions from energy systems [75]
	Resource management	Contaminant discharges in liquid effluents from energy systems [75,82]
		Ratio of solid-waste generation to units of energy produced [75,82]
		Share of renewable in total energy production [74,79]

, which were then utilized for conducting the energy analysis.

3.3. Multicriteria Decision Analysis

To determine the importance of the indicators refined by the experts in Phase 4, it is necessary to establish the relative importance of each one. The AHP method is adopted for this purpose. In summary, the steps involved are as follows: First, a hierarchy of criteria is established where each criterion corresponds to either the social, environmental, or economic aspect of urban energy sustainability. Under each criterion in the hierarchy, the relevant indicators are established. The indicators serve to rank energy generation projects according to their impacts on sustainability. The fact that reducing the impacts of energy production and consumption is one of the sector’s main challenges means that a significant portion of the indicators reflects these impacts. The indicators are used to rank the alternatives proposed in terms of energy generation projects in the country. Second, a pairwise comparison matrix across all indicators is established based on input from the energy experts. We used Saaty’s fundamental scale (

Table 3. The fundamental scale of judgment.

Verbal Scale	Numerical Scale
Same	1
Moderate	3
Strong	5
Very strong	7
Absolute	9
2-, 4-, 6-, and 8-intermediate levels

) to express one criterion’s dominance over the other. For elaborating the pairwise comparison matrices, we used a form that followed the format generally used in surveys using the AHP method: in the rows and columns, the criteria, and in the cells, the value of the judgment. The comparison matrix is established in accordance with the scale of relative importance. Third, the pairwise comparison matrix is normalized. Fourth, the weights of each indicator are calculated. The families of criteria and subcriteria are shown in Figure 4, and the proposed weights suggested during the study distributed in the hierarchical structure are shown in Figure 5. The sum of each subcriterion column totals 100%, as well as the sum of all criteria.

Two alternatives in terms of energy generation projects were analyzed via assessment of the criteria in the AHP evaluation. The alternatives were: (1) clean technology investment and (2) social inclusive energy investment. These alternatives were adopted in view of the Brazilian reality of growing scarcity of energy, of increase in operating costs caused by the activation of generation plants with high production costs, and the process of exclusion in access to electricity, which still occurs in several regions the country, both in terms of the unavailability of the service and the inability of the citizens to bear the costs. These alternatives embed concepts and possible developments on renewable energy sources, new job prospects in the energy markets, and expansion of service for households through differentiated tariffs for socially disadvantaged groups.

Based on the elaborated hierarchical structure, the software IPE 1.0, a system developed with the support of the National Council of Technological and Scientific Development in Brazil (CNPq), was used to run the AHP analysis. After inserting all the criteria, subcriteria, and indicators, having the support of specialists (expert opinion), each indicator’s importance was generated. All possible combinations of these indicators were compared, and their preference was judged. The fundamental scale of judgment proposed by Costa [83], creator of the software, is shown in Table 3. Nine levels of importance were employed, which correspond with the numbers 1–9 intensity rate.

4. Results and Discussion

The descriptions of the subcriteria in this study were needed to convey the items with accuracy. The descriptions adopted were closely related to well-known items found in the literature and immediately recognized by stakeholders (Table 2 and Figure 4). In particular, descriptions such as contaminant discharges in liquid effluents from energy systems are self-explanatory and allow nonspecialized stakeholders to grasp the concept behind the indicator.

The AHP decision process using the IPE version 1.0 was implemented to generate weights for each indicator. After including the project alternatives, pairs of indicators were contrasted (given two alternatives). Each combination is analyzed according to its performance in light of the criterion for each subsequent subcriterion. The scale is as shown in Table 2. After entering the degree of importance of the alternatives, the program calculates the results. It also presents, after the combinations are ranked, pairwise comparisons to verify the level of consistency of the analysis that serves as a beacon to measure the result (value must be within the standards ≤1). Each pair of alternatives is compared in this sequence, and their position in the ranking is confirmed, or the whole process is not validated due to inconsistency. With the final ranking achieved, one can provide the decision maker with a list of alternatives that are assessed having other constraints and inputs outside the technical/scientific approach (political, organizational, etc.), to make a final decision for actions.

Figure 5 reveals that the social criterion stands out (53.9%), followed by the environment and the economic criterion. The social criterion is linked to the quality of life, which is low in developing countries such as Brazil [84], thus explaining why it is of relatively higher importance compared to other sustainability parameters for the case analyzed. To obtain the absolute relative importance of each indicator, the weights for each indicator displayed in Figure 5 are multiplied by the weights of the parent criteria. Under the social criterion, Households with access to electricity (Social) (53.9% × 42.3% = 22.8%) is the index that ranks the highest. It aligns with the Sustainable Development Goals of the UN/CDP Policy Review No. 7, SDG 7, Affordable and Clean Energy Target 7.1, ensuring universal access to affordable energy services [85]. These figures can be understood when the context of the Brazilian city in the case study is examined. In Reference [86], it was highlighted that the slums (favelas) in Rio de Janeiro are one of the most neglected regions, with over 25% of the population residing there not have regular access to electricity.

The results highlight the need to focus on the social aspect of urban sustainability in a city that is highly impacted by the social aspects affecting residents’ quality of living. Due to the highlighted importance of both the social and environmental sustainability aspects, the weight composition also shows that macroeconomic gains and environmental quality improvements can change the weighting attributed to each criterion.

Due to its influence on energy consumption and production, the environmental criterion has the greatest number of indicators compared to other sustainability parameters. In terms of relative importance attributed to the environmental criterion, the AHP results generated a value of 29.7%, indicating a substantial impact on the overall alternative assessment. It is attributed to the importance of environmental considerations when assessing the viability of energy generation project alternatives and their associated negative impacts on the local, regional, and global scale of a region [80]. The least-valued environmental indicator is the ratio of solid-waste generation, with 1.51% relative importance, which is very closely followed by the share of renewable in total energy production with a little more than 1.51%. Brazil’s energy matrix is mainly based on renewable energy and is thus not impacted heavily by solid-waste generation [87]. Emphasis was placed on indicators related to air quality; the highest environmental indicator was Ambient concentrations of air pollution (16/3%). It seems to agree with the literature that emphasizes that air pollution is a major concern that impedes the public’s quality of life and well-being [88].

The economic indicator, though weighted relatively low in comparison to other criteria, should not be ignored. It is because energy consumption is closely linked to the city’s urbanization process that occurs in parallel with its economic growth and is hence integral to the decision-making process involved in energy production in urban environments [89]. The highest relative weight was attributed to Per capita GDP (gross domestic product) (30.5%) and Share of household income spent on fuel and electricity (26.8%). Such indicators are in line with the social and economic construction of Rio de Janeiro, where income is limited, and GDP per capita is the lowest [90]. Brazil needs effective measures to ensure increased wages for an enhanced share in prosperity [91].The economic aspect had the lowest weighted subcriteria Burden of energy investments on the public sector, with 1.53% relative importance, reflecting doubts cast on public investments, their importance, and on how their benefits are transferred to individuals; the IEA in its Flagship report—May 2020/World Energy Investment 2020 emphasizes this, and highlights that many of these investments do not achieve what was expected from them [92].

Brazil’s strategic plans confirm that most of the country’s expected investments should be directed to the energy sector [59,60]. The performed analysis aims at the importance of having enough installed capacity to supply present and future needs of energy. Generation and consumption in a national and international context, contrasted with an installed and expansion plan evaluation, are discussed using actual data and prospective analysis to give direction to investments and support policymaking.

After the AHP final ranking of the two alternatives proposed, the final ranking of alternatives was as follows: alternative (1) received 38% weighting, while alternative (2) obtained 62% weight. These results reflect the situation of Brazilian cities regarding energy production and use. One can perceive that the Clean technology investment alternative was less important than the Socially inclusive energy investment. Although the Environmental aspect seems highly influential in sustainability decisions, the Social aspect has received a much higher weight in this study and has thus strongly influenced the results.

Other studies highlight the importance of renewable energy sources as the primary focus of electricity production [93] and examined and assessed the optimal cost system of electricity generation for socioeconomic sustainability. This study also demonstrated how important the need is for sophisticated analysis to measure the role of renewables, and its result shows an optimal cost solution and flexibility in how increased electricity demand would be achieved and sustained via shifting to renewable sources such as solar, wind, and hydro. We need to address the problem of how the COVID-19 pandemic has affected the life of people and the economic impact on cities [94]. This is a new and unresolved problem that will gain huge importance in the next years and has the potential to change the whole decision-making process.

The social component was ranked as the most important and influential aspect. Although only having four subcriteria listed, they were comprehensive and allow future split in more detailed subcriteria as one can develop this study further. There is a growing need and interest in studies that comprise the Social Life Cycle Assessment [95] and in the perception of the society on aspects related to green energy, its adoption, and implications [96]. Studies like these deal with a growing awareness that the societal aspects are not just closely related to the environmental and economic ones but a driving force that cannot be forgotten or underestimated. The effects on the social component of the society and the perception of this driving force require more sophisticated studies and the development of specific tools to better understand its outcomes.

Several important issues have arisen from the development of the framework. For example, there is a growing difference between countries toward the adoption of renewables. Countries that already have incentives towards renewables have to approach this issue in other ways as countries (mostly underdeveloped or developing) which there have not yet adopted this avenue for the increase in renewable energy in their share. Buildings, agriculture, and general industry can play a major role in the transition to a greener energy model. Achieving urban sustainability in energy would need to address major issues as social awareness toward energy generation and consumption; access to energy and energy self-sufficiency; effects of energy generation in the health and safety of the society, including workers protection; and the close relation on the social aspects and the other two, economic and environmental, are normally overestimated.

As a final remark on the discussion, a summary of the benefits of the proposed approach is highlighted: an informed decision via the inclusion of several relevant criteria and indicators enabled an in-depth examination of urban energy sustainability. Firstly, the proposed approach built structured decision support with key information and organized data collection. Secondly, the hierarchy, presented in a visual form, determined an enhanced and easier understanding of the perception of the criteria that impact the sustainability of energy consumption and production in urban regions. Thirdly, the ranking of alternatives produced and/or developed during the multicriteria study allowed informed choices of energy investment alternatives to ensure sustainable energy use and production. Weights that were generated in the AHP analysis determined the ranking position for each alternative proposed, allowing them to be chosen or not. Other possible alternatives were envisaged such as: Solar factories, Direct investment in energy for households, and the like. These other possible alternatives were very specific and may be too narrow for the analysis herein, but if they are part of the AHP problem, the decision maker would have to estimate to form an extended list of alternatives to be ranked. In our case, generating a list, in order of importance, of possibilities to be taken into consideration and putting them into practice also means that both alternatives (1) and (2) could have been implemented, either in a chronological order or in a weighted share of investments order. This means that one can choose only one alternative from the ranking or more than one respecting the analysis made and wisely using the knowledge provided by the method.

5. Conclusions

This paper examined urban sustainability from an energy aspect. A Framework for Assessing Urban Energy Sustainability (FAUES) was proposed to investigate how social, economic, and environmental parameters are impacted by the energy production and consumption of urban regions. Some of the key social indicators examined include work conditions related to energy generation projects, the influence of energy generation projects on the local community, particularly regarding social development, and impact on general society as assessed via access to energy and job opportunities created by energy generation projects. For environmental indicators, the impacts of energy consumption and production in cities on the atmosphere, water quality, and land were examined. Finally, to examine economic indicators, measures such as energy-use prices, energy conversion, and energy production efficiency were analyzed. A multicriteria decision approach based on Analytic Hierarchy Process (AHP) was deployed to weigh the indicators associated with each of the sustainability criteria and guide decision makers on the most appropriate energy generation project in terms of energy sustainability. FAUES was validated via self-evaluation of experts working in organizations such as the International Energy Agency (IEA). To showcase the application and robustness of the developed framework, it was adopted on a Brazilian city that is currently experiencing a serious economic, political and social crisis, namely Rio de Janeiro.

There are many low-carbon energy generation projects in the Brazilian energy sector. The main examples of investments that can generate gains, especially in energy efficiency, are concentrated in the transport sector, as new renewable energy sources and renewable biofuels are developed. Using FAUES to assess energy generation projects in urban regions enables decision makers to build effective strategies for the sustainable development of cities. AHP was utilized in FAUES to understand the emphasis and importance placed on various indicators regarding energy sustainability. It is important to note that the general indicators are applicable to any worldwide city. However, the weightings that resulted from the AHP analysis are very specific to the case study examined. As such, for other scenarios, the weights could show a different composition across the indicators due to the local needs and conditions of the city analyzed.

We did not find works in the researched literature that addressed urban energy sustainability from the perspective of this work, especially concerning the sustainability of energy production and consumption in cities that have the characteristics and specificities of developing countries. We found studies that use multicriteria decision analysis that focus on specific aspects, such as energy production efficiency, energy systems’ resilience, the sustainability of energy generation technologies, and the selection of alternatives for energy production and renewable energy dissemination. Some limitations exist in the study. Firstly, the subcriteria relationship is not exhaustive, and further analysis can be carried out by considering more indicators. Secondly, the calculations for the weights in the AHP method reveal that some of the social subcriteria could have been further split into more detailed items, as they may have been too few, given that their relative importance was much higher compared with other indicators. Third, for ranking energy generation projects, approaches other than AHP can be explored, including Fuzzy-AHP, TOPSIS, or multiattribute methods.