4.1. Economic Growth and Energy Security as Determinants of City Development
Optimizing the use of energy resources is needed for the development of the Metropolitan Mamminasata area, both for consumption and the production process for various economic sectors. Energy needs to be considered a determinant factor in regional development for divergence in energy planning [
83]. Modern cities must focus on achieving sustainable use of resources [
84]. Thus, management of energy resources in the Metropolitan Mamminasata area will require effectiveness and efficiency in meeting energy needs. The smart city concept requires investment in renewable energy sources (RES), which is currently a popular direction in urban transformation [
85].
The limited supply and the depletion of fossil energy reserves and the tendency of energy consumption to occasionally increase is a threat to the sustainability of the Metropolitan Mamminasata area. In other words, energy planning is important because of the high rate of economic growth and energy demand [
86]. Efforts to encourage efficient use of energy resources along with intensive searches for new, renewable energy sources are needed. Years of inadequate renewable energy policies and implementation have resulted in slow progress toward human development and economic sustainability [
87,
88]. Use of renewable energy is a necessity to support environmental sustainability toward the effectiveness and efficiency of the use of natural resources [
89,
90]. Thus, the stability of economic growth in urban areas will require sustainable energy security. The potential for the urban economic growth of Metropolitan Mamminasata is presented in
Table 6.
Table 6 shows the economic growth of the Mamminasata Metropolitan area. The urban economic growth of Makassar City is predominantly influenced by (i) the processing industry, (ii) the wholesale, retail, and repair of cars and motorcycles, (iii) construction, and (iv) education services. The urban economic growth of Gowa Regency is dominantly influenced by (i) agriculture, forestry, and fisheries, (ii) the wholesale, retail, and repair of cars and motorcycles, (iii) construction, (iv) information and communication, and (v) real estate. The urban economic growth of Maros Regency is dominantly influenced by (i) transportation and warehousing, (ii) the processing industry, and (iii) agriculture, forestry, and fisheries. The urban area of Takalar Regency is predominantly influenced by (i) agriculture, forestry, and fisheries and (ii) the wholesale, retail, and repair of cars and motorcycles. Thus, the growth of the Metropolitan Mamminasata economy is predominantly influenced by the strategic economic activity sector, i.e., industry, trade, agriculture, transportation, and educational services. To achieve sustainable development, effective tools are needed to facilitate the sustainability management process and enable the implementation of various strategies and programs that promote the development of strategic economic sectors [
91,
92].
In the Mamminasata Metropolitan Area, energy resources are very important to support the development of residential areas related to the supply of household energy, which tends to increase due to population growth over time. Energy needs and energy consumption are influenced by income and household size [
93]. Energy in households is currently predominantly used for lighting, cooking, heating, and air conditioning, as well as various other household activities. Thus, households consume fuel oil, gas, biomass, and electricity. To change household energy consumption patterns, it is necessary to formulate processed energy conservation and emission reduction policies [
94]. Household size, proximity to cities, climate, and topography can influence current and future energy demand growth [
95]. The Matrix of Metropolitan Mamminasata’s economic transactions in relation to energy demand distribution is presented in
Table 7.
The total expenditure of the agricultural sector is 150—3 is used as input for the agricultural sector, 8 for the industrial sector, 18 for the service sector, and the remaining 121 for the final demand as a consumer good. The total input from the agricultural sector is also 150—3 is the input from the agricultural sector, 33 from the industrial sector, and 15 from the service sector, and the remaining 99 are primary inputs as the gross added value, which reflects the GDP of Metropolitan Mamminasata, remuneration for the use of production factors (labor, land, and capital). The element that appears twice shows the interdependency between sectors in the economy. In recent years, sustainable economy policies and strategies have allowed for a reduction in pressure on the environment [
96,
97]. The implementation of economic circulation policies contributes to the competitiveness of the regional economy [
98].
The distribution of energy services in relation to the dynamics of urban development in the Metropolitan Mamminasata area shows three dominant sectors in energy use. First, the industrial sector is dominant in the Makassar industrial area (KIMA) in Makassar City, the largest industrial area in Eastern Indonesia, the KIMAMA industrial area in Maros Regency, the plantation industry (sugar factory) in Takalar Regency, and the paper industry in Regency Gowa. Second, the service sector is dominant in the urban centers of Makassar City, Gowa Regency, and Maros Regency. Third, the agricultural sector is dominant in the urban areas of Maros Regency, Gowa Regency, and Takalar Regency. The index of the linkage of the Metropolitan Mamminasata economic sector is presented in
Figure 5.
Each unit produced by the agricultural sector requires an input of 2% of the sector’s input itself, 22% of the industrial sector, and 66% of primary input. The Mamminasata Metropolitan GDP of these three sectors will increase by 225 units after final demand. Employment opportunities will increase per person by 42,933 in the agricultural sector, by 13,475 in the industrial sector, and by 8500 in the service sector. The job opportunity of each sector for the job opportunity multiplier shows: First, the type I income multiplier, among others: (i) the agricultural sector income multiplier is 0.50, (ii) the industrial sector income multiplier is 0.38, and (iii) service sector revenue multiplier by 0.20. The highest coefficient of income is in the industrial sector, with a value of 1.74%, meaning that each increase of one unit of final demand for sector output in the Metropolitan Mamminasata city will increase the industry sector’s income by 1.74, so it is a priority to increase job opportunities. Second, the type II income multiplier, obtained results, namely (i) the agricultural sector income multiplier of 3.72, (ii) the industrial sector income multiplier of 3.87, and (iii) the service sector income multiplier of 6.95. The dispersion power describes the effect that a unit increase in final demand has on the output of all sectors in the Metropolitan Mamminasata economy. The service certificate has the highest type II revenue multiplier coefficient of 6.95, so the development of the service sector will benefit Metropolitan Mamminasata.
Third, the work opportunity multiplier (output multiplier) obtained results, namely (i) agricultural employment opportunity multiplier of 1.12, (ii) industrial employment multiplier of 1.96, and (iii) service employment multiplier of 1.45. These results indicate that the industrial sector has the highest income multiplier of 1.97. Furthermore, direct forward linkages were obtained, namely (i) direct future linkages to agriculture of 0.42, (ii) direct forward linkages to the industrial sector of 0.50, and (iii) direct linkages to the future services sector of 0.21. A direct backward linkage is obtained, namely (i) a direct backward linkage of the agricultural sector of 0.32, (ii) a direct backward linkage of the industrial sector of 0.29, and (iii) a direct backward linkage of the service sector of 0.50. The dispersion power describes the effect that arises on an increase in one unit of the final demand output of a sector on the increase in the output of all sectors in the economy of the Mamminasata Metropolitan urban area.
The spreading power of the economic activity sectors can be described as follows: (i) the spreading power of the agricultural sector is 0.97, (ii) the spreading power of the industrial sector is 0.92 and the spreading power of the service sector is 1.12. Furthermore, the sensitivity of the results obtained, namely (i) the agricultural sector by 1.03, (ii) the industrial sector by 1.13, and (iii) the service sector by 0.84. The development trend between sectors varies greatly in the economic structure of Metropolitan Mamminasata. Therefore, the service sector and industry need priority to increase income, employment opportunities, and economic growth in the long term. Thus, the industrial and service sectors play a strategic role and are predicted to require high amounts of energy; these two sectors will dominate the future use of Metropolitan Mamminasata’s urban space and are closely related to the scarcity of the fossil energy currently used. The mitigation of climate change and the substitution of fossil energy sources present many technical, economic, and social challenges [
99].
Urban transportation services in the Mamminasata Metropolitan Area that tend to increase will require support in the distribution of energy services. Development of a sustainable urban transportation system according to city size means that expansion flexibility, the adoption of travel modes, and environmental protection have an impact on the application of electromobility and on, air pollution [
100,
101]. Thus, energy for transportation facilities is needed to support the mobility of goods and people and to integrate urban systems. Sustainable mobility is one of the objectives of transportation policy focused on energy use, and sustainable development requires that urban development strategies be achieved through the cooperation of all stakeholders [
102,
103].
Field observations show that energy consumption in the transportation sector in the Metropolitan Mamminasata areas increases 12.6% per year in total energy demand. This confirms that the growth of transportation means has increased by an average of 5.6% per year. The increase in the flow of transportation movements is closely related to the increase in the per capita income in the community. The urban climate is closely related to urban development, human activities, and an increase in per capita income [
104,
105]. In the Metropolitan Mamminasata area, an increase in community income is closely related to the productivity of a growing business and relates to an increase in energy consumption. The per capita income of the Metropolitan Mamminasata community is presented in
Figure 6.
In Makassar City, 67.8% of per capita income is held by wholesalers, 33.5% by medium traders, 10.4% by small traders, 2.6% by farmers, 2.3% by private employees, 2.5% by daily workers, 1.7% by fishermen and civil servants each, and 0.5% by daily workers and the informal economy each. These results confirm that the Metropolitan Mamminasata area shows a differentiation in terms of community income in relation to energy consumption. Thus, differences in income levels are positively associated with differences in energy needs and consumption. Renewable energy resources are becoming increasingly important due to the depletion of energy resources and the damage these resources cause to the environment [
106].
The increase in the population and urban activities of Metropolitan Mamminasata has increased the distribution of energy services, i.e., fuel oil (BBM), gas, and electrical energy. High reliance on fossil energy is positively associated with a decrease in the quality of the urban environment. This condition is characterized by an increase in the pollution load on soil, water, and air. Increased productivity is also accompanied by strategic space functions, i.e., industry, commercial activities, services, education, and health services, which meet the needs of housing and settlement facilities that tend to occasionally increase. These socio-economic activities directly affect the hierarchical formation of energy service centers. Digitalization will encourage an increase in energy consumption, since an increase in various activities means an increase in service centers, which will encourage excessive energy consumption [
107,
108]. The hierarchy of urban energy service centers for Metropolitan Mamminasata is presented in
Table 8.
The service area of Makassar City has a complete service structure in relation to energy services. One location, functions as a primary service center, one functions as a secondary service, one functions as a tertiary service, (iv) two function as regional service centers, and six function as environmental unit services. In the service structure of Gowa Regency, three locations function as secondary services, two function as tertiary services, and six function as regional services. In the service structure of Maros Regency, three locations function as secondary services, one functions as a tertiary service, and eight function as regional services. In the service structure of Takalar Regency, one location functions as a primary service, two function as secondary services, five function as regional services, and one functions as an environmental unit service. This illustrates that the distribution of energy services is directly related to the hierarchy of urban service centers in the Mamminasata Metropolitan and is influenced by factors of accumulated activity, the transportation network system, and the presence of housing and settlements. Thus, a hierarchy of urban service centers accumulated in certain locations and easy accessibility are positively associated with the distribution of energy services. Harmony between regulations and the functional aspects of the city requires a spatial information system for monitoring planning as well as governance in spatial information management, including the distribution of energy services in a sustainable manner [
109].
The development index of the Metropolitan Mamminasata area is not only influenced by population growth but also related to the availability of facilities and infrastructure, the functions of socio-economic activities, and the distribution of services for energy needs. These three categories are the basis for assessing the level of development of the Metropolitan Mamminasata area. The development index for the Metropolitan Mamminasata area is presented in
Table 9.
In terms of the urban development index of Makassar City, two sub-districts are categorized as very fast, two as fast, four as moderate, two as slow, and five as very slow. Of Gowa Regency, one sub-district is categorized as fast, one as moderate, two as slow, and seven as very slow. Of Maros Regency, one area is categorized as fast, three as moderate, one as slow, and seven as very slow. Of Takalar Regency, three areas are categorized as moderate, three as slow, and two as very slow. Thus, the development of the Mamminasata Metropolitan area is characterized by an accumulation of socio-economic activities in line with population growth, and the developed areas are positively associated with service levels and energy distribution. City growth is accompanied by the development of infrastructure, and the power network is highly related to economic development [
110].
Fulfilling the energy needs of the Metropolitan Mamminasata area is related to the area’s ability to provide service functions that are accessible to residents. Service coverage is measured based on distance, travel time, and costs. These service areas will provide information related to the effectiveness and efficiency of meeting energy service needs. The service area index in relation to meeting energy needs in the Metropolitan Mamminasata area is presented in
Figure 7.
The index of services to meet the needs of household services for electric energy is categorized as very good and effective. The index of energy fulfillment services for households related to the availability of oil refueling stations is good. The LPG gas service index to meet household service needs is sufficient. The retail fuel service index for household services is poor. Thus, the energy service index in the Metropolitan Mamminasata area is influenced by distance, land use, and the level of accessibility, since the smaller the settlement distance is to energy services, the more effective and efficient they will be, and the economic costs incurred by the community will be lower.
4.2. Energy Security and Use of Renewable Energy
The previous section explains the dependence of the Metropolitan Mamminasata area on fossil energy sources in relation to the development of the Metropolitan Mamminasata area. The use of fuel oil is categorized as very high. The sustainability of petroleum-based fuel has gained broad attention from the global community due to the increase of its usage in various sectors, the depletion of petroleum resources, and the uncertainty around crude oil market prices [
111]. The need for oil tends to increase occasionally, in line with economic growth and increasing urban activity and population. In macro terms, a decreasing oil production capacity has an impact on the adequacy of energy services when needed in the Metropolitan Mamminasata area. The crude oil price chain is affected by different types of interconnections in different time windows [
112].
The Indonesian government has issued Presidential Decree No. 5/2006 on the National Energy Policy and Presidential Decree No. 1/2006 on Biofuels (BBN). This energy policy is the basis for local governments, businesses, and communities to develop potential new energy sources as an alternative to fuel oil, such as biomass. Biomass energy can be used for raw material, is easy to obtain, has abundant potential, and is more environmentally friendly. In order, to support sustainable development and economic growth, it will require support for the use of technology for the use of renewable energy in relation to the distribution of energy supplies [
113]. Thus, biomass can be used as a substitute for oil in the Metropolitan Mamminasata area. The potential depletion of fossil fuel and climate change have globally accelerated the demand for renewable and alternative energy [
114].
Biomass is organic material produced through photosynthetic processes, in the form of either products or waste. Thus, the potential for biomass from plants, agricultural waste, forest waste, feces, and livestock manure can easily be obtained from community activities. Biomass that can be used as an energy source is found in wood, sawdust, straw, seed waste, animal manure, paper waste, household waste, and wastewater [
115]. In support of the urban development of Metropolitan Mamminasata, biomass potential can be obtained in the form of bioethanol as a substitute for gasoline to produce biodiesel. Sugarcane and maize production is quite abundant in the urban areas of Takalar Regency. Forest waste is plentiful in the urban areas of Gowa Regency and Maros District. Fecal waste is also dominant in the urban areas of Makassar City, and livestock manure is produced in urban areas of Gowa Regency and Maros Regency. These four energy sources are environmentally friendly and easy to obtain. The modern renewable energy share includes energy generated from biomass fuels, such as solid biomass and biogas for electricity and heat generation, using modern technologies [
116]. Biogas is produced through anaerobic digestion using feedstock sources such as livestock manure, agro-industrial residues, and landfills [
117].
Energy sources are related to potential natural resources that can be used to support the development of the Metropolitan Mamminasata area. Geographically, the location of the Jenneberang watershed encircles two urban areas, namely Gowa Regency and Makassar City which have the potential to be used as a hydroelectric power plant. The Jeneberang River is able to provide raw water of 3300 L/s, which is currently being used to irrigate agricultural areas with an area of 24,585 ha. In addition, it is also used for hydroelectric power plants (PLTA), with an installed capacity of 20.1 MW, The potential of the Maros watershed also has the potential for hydroelectric power generation, which is currently only used to irrigate an agricultural area of 50,000 ha and for drinking water for Maros Regency and Makassar City, with a total use of 4530 L/s The potential of wind resources in Takalar Regency with a speed of 5–8 knots can be used as much as 100 MW for wind power generation. These three energy sources have the potential to meet the needs of electrical energy and support energy security in Metropolitan Mamminasata.
The potential for renewable energy resources in Metropolitan Mamminasata has not been fully optimized to support the energy needs of various socio-economic activities and households in a sustainable manner. Field observations provide an overview of (1) the energy consumption of the community, (2) the support for the availability of infrastructure, and (3) the use of renewable energy. Data are presented in
Figure 8.
Figure 8A,B shows the use of renewable energy and people’s understanding of renewable energy. 43.3% of energy is used for transportation, 21.1% for community economic business activities, 13.3% each for social activity services and for household needs. 72.1% of the community does not understand the use of renewable energy, and 27.9% does. These results illustrate that the implementation of policies on the use of renewable energy has not been used optimally due to the implementation of government policies that have not been optimal in involving the role of the private sector and public participation. The use of renewable energy sources can provide a path toward sustainable development and regional energy independence [
118]. Urban infrastructure and residents meeting the energy needs of the community are presented in
Figure 9.
Of respondents, 44.5% stated that it is easy to obtain services for energy needs, 55.5% stated that it is difficult to obtain services for energy needs, 36.7% stated that the availability of energy infrastructure is supportive of energy services, and 63.3% stated that the availability of energy infrastructure was limited. This confirms that the distribution of energy services in the Metropolitan Mamminasata area has not been supported by adequate infrastructure. Thus, the limited energy infrastructure causes a less-than-optimal distribution of energy services in the Mamminasata Metropolitan area. Thus, a strategy is required to guarantee affordable, reliable, and sustainable energy access to all people through the use, of modern energy systems [
119]. The effect of economic growth, energy consumption savings, infrastructure availability, and renewable energy on the environmental quality of the Metropolitan Mamminasata city is presented in
Table 10.
Economic growth has a positive effect on environmental quality, with a coefficient value of 0.591, Saving energy has a positive effect, with a value of 0.905, The availability of infrastructure has a positive effect, with a value of 0.963, Renewable energy has a positive effect, with a value of 0.654. Thus, economic growth, energy consumption savings, infrastructure availability, and renewable energy all have a positive effect on the environmental quality of the Metropolitan Mamminasata area, with a coefficient of determination of 82.3%. The importance of renewable energy is increasing because certain energy sources and excessive use will damage the environment [
120]. Thus, renewable energy is important for contemporary energy consumption and for future energy development [
121].
The effects of economic growth, energy consumption savings, infrastructure availability, and renewable energy on the sustainability of the Metropolitan Mamminasata system are presented in
Table 11.
Economic growth has a positive effect on the sustainability of urban systems, with a coefficient value of 0.340; saving energy has a positive effect, with a value of 0.476; the availability of infrastructure has a positive effect, with a value of 0.873. Renewable energy has a positive effect, with a value of 0.677. Thus, economic growth, saving energy consumption, availability of infrastructure, and renewable energy positively affect the sustainability of the Metropolitan Mamminasata system, with a determination coefficient of 75.7%. Thus, it is important for the government to formulate policies that synergize urban land use and the availability of natural resources [
122].
4.3. Renewable Energy Management Strategy and Urban System Sustainability
Economic growth that is oriented toward the excessive use of fossil energy in support of the development of the Metropolitan Mamminasata area will cause environmental degradation. The link between economic growth and environmental protection remains important for sustainable development, in the sense that environmental problems caused by economic activity are an integral part that needs to be addressed as a regional development system [
123]. The use of fossil fuels as the main energy source has a negative impact on the environment, causing global warming and air pollution [
124]. This condition is marked by an increase in urban productivity, i.e., industry, transportation systems, offices, education, health, trade, and services, as well as housing and settlement developments. These urban activities contribute to environmental degradation due to excessive energy use.
An increase in urban activity that runs parallel to an increase in population has an impact on changes in urban spatial use toward the exploitation of natural resources. Urban economies are responsible for more than half of global greenhouse gas emissions and substantially affect biodiversity and natural resource degradation [
125]. Thus, it is necessary to make an optimal and wise use of natural resources toward the use of renewable energy. This means that the wise use of energy resources will not only encourage an increase in socio-economic productivity but will also help in restoring the quality of the urban environment in a sustainable manner. This means that strategic steps are needed in the management of renewable energy resources to support the sustainable development of the Metropolitan Mamminasata system. Thus, cooperation is needed in order, to accelerate access to clean energy by promoting renewable energy sources, energy efficiency, investment for energy infrastructure development, and sustainable energy technology [
126]. The renewable energy management strategy in supporting urban development for Metropolitan Mamminasata is presented in
Table 12.
This strategy will require government policy support to maximize energy use for a sustainable urban system. Implementing this policy will require adequate regional regulations and the involvement of actors in the management of renewable energy resources, i.e., the private sector and the community. The use of renewable energy sources will provide complementary opportunities between energy security, energy access, and climate change mitigation [
127]. Sustainable ecosystems, as a community goal, will be related to local wisdom, autonomous, (independent), and according to community needs [
128,
129].
The use of renewable energy for urban development will require instruments for controlling space use: (1) zoning arrangements for space use, supported by the availability of adequate energy infrastructure, (2) the optimal use of land, in terms of providing energy facilities and infrastructure in a sustainable manner, (3) effective and efficient energy resource use based on changes in community behavior, and (4) use of energy resources effectively and efficiently, followed by government policies toward increasing the productivity of community businesses in a sustainable manner. The required government policy interventions are presented in
Figure 10.
Use of renewable energy must be oriented toward the optimal use of new energy sources, namely air, wind, geothermal, gas and solar energy. The five energy resources have the potential to meet the use of electrical energy in the Mamminasata Metropolitan urban area in a sustainable manner. Energy security that supports development in Metropolitan Mamminasata must adapt to climate change and use environmentally friendly technology. Optimal renewable energy use needs to be supported by government policies through public and private participation (investors). Government policies on the use of renewable energy can translate into strategic programs according to targets set and mutually agreed upon by all stakeholders [
130]. Bioenergy is a key strategy for climate change mitigation, and government plays an important role in developing renewable energy policies [
131,
132].