Sector-Specific Pathways to Sustainability: Unravelling the Most Promising Renewable Energy Options

Abstract

Energy consumption across industries accounts for more than seventy-five per cent of total greenhouse gas emissions in the European Union. Energy is a top priority for achieving climate goals and low greenhouse gas emission levels. The comparison of sustainable development patterns in renewable energy sources is carried out for all the different sectors analysed for the study, such as industry, services, agriculture, transport, and households. Specifically, researchers examined trends in each of these sectors. This study aims to create a model that combines qualitative and quantitative research approaches to obtain the most objective and descriptive data on RES technologies used in different sectors of the economy. According to the results, both solar energy and biomass have strong development potential overall, which is reflected in the higher average values of the overall results. This is also the case when looking at the impacts individually.

1. Introduction

The European Green Deal adopts essential measures to support progress towards the 2030 climate targets set and to achieve climate neutrality in European Union member states as early as 2050 [1]. The European Green Deal states that increased use of renewable energy sources (RESs) to replace fossil fuels should be a priority [2,3]. Fossil fuel use is one of the significant contributors to greenhouse gas emissions from residential heating and cooling systems, commercial and institutional buildings, transportation systems, agricultural machinery, and industrial activities [4]. The residential sector of the energy industry accounts for more than 39% of total energy consumption in Sweden, which is more than fifty per cent of the whole consumption in Saudi Arabia, more than 26% of the energy sector in Japan, and more than 25% of total consumption in the United States [1]. As the wealth of part of the population and the population as a whole increases, the service sector has also experienced rapid development and, at the same time, an increase in energy consumption among the population [2].

The service sector can be understood as a set of different services that need to be provided on a daily basis, such as various hospitality services, tourism services, hotels and guesthouses, retail and wholesale trade, various technology and research services, sports and cultural services, and educational services [3]. In terms of employment, the service sector has experienced one of the largest increases among the sectors [4,5].

It is estimated that, on average, the service sector [6] accounts for a quarter or a third of total energy demand. It is projected that energy demand in residential and service sectors could average about 40% of total energy demand by 2050 [7,8,9]. According to current research findings, the usage rate of RESs in the commercial sector has increased in recent years [9]. However, the possible potential of renewable energy resources is not utilised; for example, the potential energy source from heat residues is not fully used [10,11,12]. Looking at specific countries and their progress in the use of RESs as a substitute for fossil energy resources, we can mention China, which, in recent years, has made progress in the development of solar and wind energy technologies and an increase in the share of production, and these technologies are used worldwide, as well as renewable technologies, whose production has reduced the cost and investment required to install the equipment. In recent years, large-scale production companies such as British Petroleum and Shell have invested in electric cars, charging them with RESs. Countries such as Pakistan, Srilanka, Nepal, and India are also investing more and more in expanding the use of solar, biomass, wind, and hydropower instead of fossil fuels [12]. In the industrial sector, various processes need to be supplied with thermal energy [13,14]. Based on the indicators of the member states of the European Union, it is calculated that, on average, more than 28% of the required thermal energy is generated in industrial sectors such as pulp and paper, tobacco, food and beverage, steel and iron production, and oil and chemical industries [14]. Another sector that produces a significant amount of greenhouse gas emissions is agriculture, which is responsible for more than 21% of total greenhouse gas emissions due to processes such as mechanical intensive tillage and intensive fertilisation [15,16]. In agricultural production plants, one of the most energy-intensive processes is drying. Here, new solutions are being sought to ensure the necessary energy, for example, through the use of solar panels to ensure the temperatures required for drying [17]. In the transport sector, there are several ways to reduce emissions to zero by 2050. One of the solutions to reduce emissions is electric cars, the use of which is increasing but depends on the existence of a suitable infrastructure [18]. The use of electric cars, which is increasing, is one of the possible answers to the problem of replacing fossil fuels and reducing emissions to reach zero emissions by 2050. However, the use of electric cars is limited by several issues, including the need to develop appropriate infrastructure and the accessibility of charging stations [18]. It is predicted that electrification of the transport sector can achieve a CO₂ reduction of 25–30%. For a more sustainable energy system development, electrification and increasing the share of renewable energies in combination with smart technologies and combined systems are important elements [19].

Therefore, a more in-depth study on the renewable energy potential in each sector of the leading sectors of the economy (industry, agriculture, household, services, and transport) is needed to assess which RES technologies are more appropriate for each sector. It is crucial to understand in which sectors a high potential of using RES technologies is possible but in which technologies there are significant obstacles in their implementation. Using this method, it is possible to assess which policies would be useful to implement now and which RES solutions should be given a lower priority.

The study compares the sustainable development of RESs between the sectors examined in the study—industry, services, agriculture, households, and transport. The analysis carried out aims to find out which of the RESs is the most promising and sustainable in each sector and what conditions determine this. In addition, in order to evaluate the potential of renewable energies, a mutual evaluation of the advantages, limitations, and development speed of renewable energies for the above-mentioned sectors has been carried out. This study does not refer to the economy of any particular country. The objective of this study was to gain a comprehensive understanding of the key benefits and limitations associated with the development and implementation of RESs in various industries using a novel approach. The analysis includes an extensive literature review in various countries around the world, including China, India, the United States, Bolivia, and European countries such as Spain, Iceland, Finland, Norway, Denmark, Sweden, Lithuania, Latvia, Greece, France, Germany, etc. It is essential to realise that the applications of RESs in different industries depend on various factors that may vary from country to country. Several critical considerations need to be taken into account, including resource availability (such as wind or sunlight availability and proximity to water sources), spatial and geographical constraints, cost considerations, specific energy demand profiles, and other relevant factors. These factors collectively contribute to determining the feasibility and suitability of RES deployment in specific industries and countries.

The initial framework applied to the research is found in section one, section three highlights the primary insights gained through the composite sustainability index, and the final section provides a comprehensive overview.

2. Methodology

This study examines sustainable development trends of renewable energy resources (RESs) across different sectors such as industry, services, agriculture, transport, and households. The analysis of RESs includes solar, wind, hydro, biomass, and geothermal energy resources, which are analysed separately for each sector. The study’s main objective is to determine which RESs are the most competitive and sustainable across all sectors and which factors contribute to these results. First, the methodological approach is presented to conduct the analysis and obtain research results. Then, the obtained results are demonstrated in each sector, describing the most important factors influencing the results.

The scientific novelty of the research is the development of a method that allowed quantifying the qualitative assessment of the research. A large number of scientific papers were reviewed to develop the assessment.

The results generate a view on a comprehensive assessment of differences between the sectors and how identifying these differences can help to develop more tailored and sector-specific policies. The results allow us to spot and highlight the untapped potential of specific renewable energy resources in each sector. Therefore, policymakers could focus on tackling the identified barriers and using the full potential of identified opportunities.

The conceptual and methodological basis of this research is shown in Figure 1. The model combines both qualitative and quantitative research methods to provide an in-depth assessment of the key factors affecting the competitiveness and sustainable development of each RES technology in each sector.

2.1. Description of the Methodology for Qualitative Assessment

In the beginning, a comprehensive qualitative analysis was conducted. This analysis is based on the literature, in-depth studies, reports, and other accessible sources of information on the use of RESs, development trends, and characteristics in each of the sectors studied. Three essential criteria and aspects were put forward to perform the full value analysis, which was examined separately for each resource compared to the examined sectors.

First, a qualitative assessment based on a comprehensive literature review of the use of RESs in each sector was conducted. The literature review includes a review of recently published scientific publications, research papers, and assessment reports. A total of 100 sources of information were used for the qualitative assessment.

Table 1. Sources of literature for qualitative assessment.

Sector	Topic	Source of Literature
Industry	The experience of renewable energy use in the transport sector, limiting factors, and future forecasts. Characteristics of the development of RES extraction and production technologies. Development potential assessment for RESs, RES technology innovation opportunities, and technology combinations. Experience of industrial companies using PV panels and collectors. Assessment of opportunities and challenges in the industrial sector.	[11,14,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55]
Services	The increase in the use of technology in the future; technological development and increase in utilisation rate; and RES technology innovation opportunities and technology combinations. Assessment of opportunities and challenges in the service sector.	[38,51,56,57,58,59,60,61,62,63,64,65,66,67,68,69]
Agriculture	Experience and possibilities of using biomass technologists in agriculture. Assessment of opportunities and challenges in the agriculture sector	[17,20,55,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95]
Households	The increase in the use of technology in the future. Cost savings (EUR, %). Using solar energy technology combined with smart technology. Energy savings (kWh, MWh, %). Assessment of opportunities and challenges in the household sector.	[17,20,24,55,70,71,72,74,75,76,77,78,79,80,81,84,86,87,88,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117]
Transport	The presence of any restrictions on the use of the resource and RES technology innovation opportunities and technology combinations. Assessment of opportunities and challenges in the transport sector.	[38,51,56,118,119,120,121,122,123,124,125,126,127]

provides an overview of the main literature used for the RES assessment of each sector.

In order to create a collection of the scientific literature on RESs (biomass, solar energy, water, wind energy, and geothermal energy), we used possibilities and answers to questions such as

• The increase in the use of technology in the future;
• Technological development and increase in utilisation rate;
• RES technology innovation opportunities and technology combinations;
• Using solar energy (for heat and electricity) technology combined with smart technology;
• The presence of any restrictions on the use of the resource;
• The availability of RESs as a limiting factor for resource use. Payback period of investments (years);
• Cost savings (EUR, %);
• Energy savings (kWh, MWh, %);
• CO₂ reduction.

System boundaries of this research:

The research evaluated the development potential of RESs across various sectors, considering on-site renewable energy generation and the potential for self-consumption within each sector.

CO₂ emissions are not directly included in the assessment but are based on scientific publications—reviews and articles describing case studies where the use of RES technologies reduced CO₂ emissions compared to the situation before the equipment was installed. In cases where the scientific literature does not indicate specific numbers that confirm the reduction in emissions using specific RESs, when analysing the AER potential for each source, it is taken into account that the studies show a reduction in emissions. A more qualitative assessment can be prepared for those sectors and RES sources where case studies confirm specific emission reductions. It is taken into account that one of the factors that affected the reliability of the results obtained in the study is the limited numerical information in the scientific literature about specific industries.

Figure 1 illustrates the main steps of the methodological framework in a simple way.

2.2. Description of the Methodological for Quantitative Assessment

The methodology includes (1) conducting in-depth qualitative research; (2) setting the criteria and determining the point scale (1–5); (3) the allocation of points to each AER in each of the sectors; (4) score normalisation; (5) score weighting; (6) score aggregation; (7) a final index score; and (8) ranking technologies (Figure 2).

2.2.1. Determination of Evaluation Point Scale and Allocation of Points

The three most important criteria and aspects were put forward, which were discussed in more detail separately for each of the resources compared to the examined sectors.

The cross-sectoral comparison from the literature review is based on evaluating three main criteria—RES development tendencies, the main advantages of RESs, and the limitations of RES implementation. A five-point rating scale was developed for each criterion, with one representing the lowest score and five representing the highest score. Points are awarded for each type of RES and sector based on the conclusions of the qualitative analysis.

Table 2. Criteria for the assessment and description of the evaluation scale.

Criteria	Research Question	Evaluation Scale
Development	How fast is the technological development of a specific type of RES?	5—the most rapid development 4—fast development, there are limiting factors 3—limited development 2—very slow development 1—no development observed
Advantages	Which of the RES has the greatest advantages in use?	5—greatest advantages 4—second-greatest advantages 3—fewer advantages, there are significant constraints 2—there are many constraints 1—no significant advantages observed
Limitations	How significant are the constraints and limitations of a specific type of RES in the sector?	5—almost no limiting factors or severe limitations are observed 4—minor limitations are observed that affect the use of the specific RES 3—there are few disadvantages that limit the use of the specific RES 2—numerous disadvantages limit the use of the source 1—Many limitations hinder the utilisation of RESs

provides an overview of the evaluation criteria and a description of the valuation scale. For each type of RES (solar, wind, hydro, biomass, and geothermal) in each sector (industry, services, agriculture, households, and transport), corresponding points are assigned according to Table 2. The points are summarised in tables, using MS Excel software.

Table 3. Collected scores based on literature assessment based on defined criteria.

Sector
Industry Sector	Solar Energy	Wind Energy	Hydropower	Biomass	Geothermal Energy
Development	5.0	3.5	3.5	4.0	3.5
Advantages	4.5	3.5	3.0	4.0	3.5
Limitations	3.0	3.0	3.5	3.5	4.0
Total	12.5	10.0	10.0	11.5	11.0
Service sector
Development	5.0	3.0	3.0	3.5	4.0
Advantages	4.5	3.0	3.0	3.5	4.0
Limitations	4.0	3.0	3.0	3.5	4.0
Total	13.5	9.0	9.0	10.5	12.0
Agriculture sector
Development	4.0	3.0	3.0	5.0	3.0
Advantages	5.0	3.5	3.0	5.0	3.0
Limitations	5.0	3.0	3.0	5.0	4.0
Total	14.0	9.5	9.0	15.0	10.0
Household sector
Development	4.0	3.5	4.0	4.5	4.0
Advantages	4.5	4.0	3.5	3.5	4.0
Limitations	4.0	3.5	3.5	3.5	3.0
Total	12.5	11.0	11.0	11.5	11.0
Transport sector
Development	4.5	4.5	3.5	5.0	3.0
Advantages	4.0	4.5	3.5	5.0	3.0
Limitations	5.0	3.5	3.0	5.0	3.0
Total	13.5	12.5	10.0	15.0	9.0

shows the evaluation performed; each resource in each of the sectors is evaluated on a scale from 1 to 5. The evaluation was based on the scoring system developed in Table 2. These ratings are further used to perform quantitative analysis and create an index for each of the RES.

2.2.2. Data Normalisation, Score Weighting, and Final Index Score

After data collection, the data were processed and normalised using the min–max normalisation technique, as shown in Equation (1). Normalisation scales the assigned points in a range from 0 to 1, where 0 is the lowest value and 1 is the highest value.

$$S_{Ni}=\frac{S_i-S_{min}}{S_{max}-S_{min}}$$

(1)

where $S_{Ni}$ is the normalised score, $S_i$ is the score obtained from qualitative assessment, $S_{min}$ is the minimum score of the evaluation scale, which is equal to 1, and $S_{max}$ is the maximum score of the evaluation scale, which is equal to 5.

Furthermore, weights are assigned to each normalised value. In this study, all three criteria are weighted equally because the pace of development, advantages, and limitations of specific RES technologies have an equal impact on the further progress of RESs in each sector. The normalised and weighted values are aggregated into an index according to Equation (2).

$$SI=\sum w_i\times S_{Ni},w_i=\frac{1}{n_i}$$

(2)

where SI is the final index value for the deployment potential of the evaluation categories i (development, i = 1; advantages, i = 2; and limitations, i = 3), $w_i$ is the determined weight of the indicator, and $n_i$ is the number of indicators in the evaluation, which is equal to 2 [100,128,129,130].

The aggregated results of each RES show the trend and potential of long-term sustainable development and competitiveness. The closer the result is to 1, the higher the long-term development and potential in a particular sector [131,132].

Based on the literature assessment, the criteria selected (development, advantages, and limitations) were evaluated on a scale of 1–5 (see Table 2).

Table 4. Evaluation score from qualitative assessment in the industry sector.

	Solar Energy	Wind Energy	Hydropower	Biomass	Geothermal Energy
Criteria
Development	5	3.5	3.5	4	3.5
Advantages	4.5	3.5	3	4	3.5
Limitations	3	3	3.5	3.5	4
Total	12.5	10	10	11.5	11

shows the evaluation score in the industry sector based on the criteria presented in Table 2.

All further calculations are made using the formulas given in Equations (1) and (2), using the industry sector as an example (

Table 5. The score for each criterion and total index for the industry sector.

	RES Technologies
	Solar energy	Wind Energy	Hydropower	Biomass	Geothermal Energy
Criteria
Development	1	0.7	0.7	0.8	0.7
Advantages	0.9	0.7	0.6	0.8	0.7
Limitations	0.6	0.6	0.7	0.7	0.8
Development	0.33	0.23	0.23	0.27	0.23
Advantages	0.30	0.23	0.20	0.27	0.23
Limitations	0.20	0.20	0.23	0.23	0.27
Total	0.83	0.67	0.67	0.77	0.73

).

3. Results and Discussion

The following is a comparison of the sustainable development of RESs in the most important sectors of the economy.

3.1. Industrial Sector

The results show that solar energy and biomass are the key dominators for the industry compared with other types of RESs, as shown in Figure 3. Solar energy has the highest value compared to other resources, with a value of 0.83 on the value index. This is mainly because the resources have developed the fastest and have greater technological advantages. Solar energy drives many company processes. Industrial companies install solar energy systems to save 50–70% of energy consumption. The technological development of solar energy systems has significantly maximised the solar energy utilisation potential in the industry over the past decade. The use of solar energy has become more attractive thanks to a number of technological advances in solar energy systems. These include integrated systems that make it possible to control the temperature required for industrial production processes and ensure that solar energy is used for crucial production processes such as water heating, steam generation, drying, and other processes. However, the amount of solar energy generated depends highly on the weather, so significant energy supply shortages might appear in seasons with low solar radiation. For industrial companies, uninterrupted energy suppliers are critical to ensure a flawless production process. Therefore, the possibility of energy supply shortages is considered the most important obstacle limiting production plants in the implementation of solar energy systems. This explains why the overall index score for solar energy was below the maximum score of 1, which is the highest possible score. However, due to the rapid technological development of solar energy and the advantages of its use, as well as the shorter payback period of the investment, these limitations are not a major obstacle to the potential use of this energy source. Moreover, solutions already exist to compensate for the limiting factors of solar energy and to achieve greater use of solar energy in industrial enterprises.

Biomass was determined to have a potential use of 0.77, placing it second among all sectors in terms of potential use. The rapid development of the potential of biomass utilisation can already be observed and predicted for the future. Higher biomass consumption is observed in pulp, paper, and wood production industries, all of which generate waste in the form of biomass as a byproduct of their production processes. Technological solutions are mentioned as the main advantages of biomass, such as reaching the temperature range required for efficient industrial processes. Constant energy supply throughout the year without energy shortages is highlighted as the main advantage of biomass use in industry, which has been identified as the main limitation of solar energy use. Most biomass comes from the many types of organic waste produced in forests, on uncultivated land, and by agricultural and forestry operations. However, the main disadvantage of using biomass in industry is that there is not enough biomass available to meet the energy needs of the sector, unless agricultural residues are used for energy production.

Geothermal has not yet achieved an assessment score (0.73) for deployment potential in an industry that could compete with solar (0.83) or biomass (0.77). On the other hand, geothermal energy has many advantages that could help it become more essential and accelerate its widespread use in the commercial sector. Geothermal energy allows the storage and reuse of heat, which greatly improves the efficiency of production processes, even at high loads. In addition, geothermal energy can be combined with other technologies to provide uninterrupted power to facilities when solar energy is limited. The technological advantages of geothermal energy can significantly reduce production costs, especially for high-capacity manufacturing plants. The main limitation associated with using geothermal energy in industry is the availability of the resource.

Deployment potential index scores in the industry for wind energy and hydropower each reached a value of 0.67, which is the lowest value compared to other RES energy resources. Both resources are developing at a limited pace compared to other RESs. The deployment potential of hydropower depends on the availability of hydropower resources in the region where the manufacturing company operates. Wind energy, like solar energy, is limited due to energy generation dependency on seasons. However, wind energy can be used in combined systems where another RES can make up for a shortage of wind energy. One significant advantage of wind energy application in the industrial sector is that wind turbines possess the capability to generate a greater amount of energy per unit area and time compared to solar photovoltaic systems, assuming equal potentials for both in the given region. However, solar energy offers several key advantages over wind energy in the industrial sector, primarily resulting from its lower capital expenditure, reduced maintenance requirements, and simplified integration into the grid and existing energy supply model. In terms of limitations, both technologies are constrained by their intermittent production nature and geographical needs, requiring substantial spatial demands. Hydropower also has limited advantages because it requires a high capital and technical capacity to produce energy. However, hydropower is able to adapt and compensate for bottlenecks and interruptions in wind energy. Despite the industry’s slower development pace of wind and hydropower technologies, both RESs are expected to develop more rapidly.

3.2. Service Sector

Figure 4 shows the potential of RESs in the service sector—according to the results, the use of solar energy has the highest value of 0.90. The pace of development of technological solutions for solar energy has accelerated in recent years, so the demand for solar technologies in the service sector continues to grow. The growth rate in the development of solar technology solutions is favoured by combining these technologies with smart solutions or integrating smart technological solutions with solar technologies. In recent years, more solar technologies are used together with integrated smart meters. Such technological solutions are also used in educational institutions and other public buildings to better control the energy consumed and the load. One of the subsectors of the service sector, tourism, is increasingly using solar solutions that can cover a large part of the required energy.

Solar solutions have a growing trend, such as heat recovery from wastewater, using heat pumps in addition to PV solar solutions. Solar solutions are suitable because they are suitable for both low and medium temperatures required for operation in the service sector.

It has been studied that integrating solar solutions with smart technologies can directly reduce the consumption of thermal energy, electricity, and hot water in the service sector. In recent years, there is a trend that solar solutions have a shorter and shorter payback period, so these technologies are becoming more and more financially favourable, and the payback period of these technologies is less than 10 years. Therefore, solar solutions have become more accessible and interesting for the service sector. A disadvantage of using solar technology in the service sector is the insufficient amount produced during the relevant months of the year. This disadvantage could be eliminated by using an additional source that provides the necessary energy throughout the year. The solution lies in the use of combined systems. For example, heat pumps, which are also increasingly common in the household and service sectors, can compensate for energy shortages at a lower cost compared to the industrial sector.

According to the results, the use of geothermal energy in the service sector achieves a high score of 0.80. Geothermal energy as an energy resource is mainly used in the tourism sector, especially in the recreation sector. Geothermal energy is relatively underutilised in other service subsectors. However, it is expected that the use of geothermal energy in other service sector subsectors will also increase.

In the qualitative analysis, the second-greatest advantage is attributed to geothermal energy, since using this energy source does not require large investments. Regarding the use of geothermal energy, the absence of such use is the least valued. Geographical and regional differences affecting the availability of resources can be mentioned among the disadvantages of exploitation. On the other hand, the third place (0.70) in evaluating sustainable development is occupied by the possibility of using biomass. Compared to the other RES sources discussed above, the use of biomass in the service sector is considered slower in terms of development speed. On the other hand, especially in the hospitality sector, the development speed of biomass utilisation has been increasing, and it is expected that the development speed of utilisation will continue to increase in the future. The hospitality industry collects biological waste and non-recyclable residues from various hospitality facilities. It then transports them to the appropriate biogas plants, which are processed into biogas.

This considerably lowers the amount of discarded and unprocessed waste. Utilising surplus from the hospitality industry can reduce the total amount of waste that is not properly used because the hospitality industry generates a large amount of organic waste that is not recycled. Unlike solar or wind energy, biogas can be used year-round regardless of weather conditions, and it is also possible to use a range of organic wastes as feedstocks for biogas. The application of biogas in the service sector is limited by the fact that while the hospitality industry generates a sufficient amount of organic residues and waste, other areas of the service sector must generate a sufficient amount of organic waste for further use in biogas. This prevents the service sector as a whole from fully realizing the potential benefits of biogas.

Similar to the industrial sector already reviewed, hydropower and wind energy use in the service sector was rated as having the lowest development potential, with each resource RES receiving a rating of 0.60. The use of both resources and the rate of development in the service sector are influenced by social factors such as the public’s opinion of using these resources, the impact on the landscape, and the quality of the environment. The prevailing opinion in society is that the construction of hydroelectric power plants will negatively impact fauna and will change water quality and the landscape. Wind energy parks, in turn, are associated with a negative impact on tourism development. At the same time, the number of hotels in the tourism industry thinking about sustainable tourism and energy use is increasing, and so is the tendency to use small wind turbines in this type of hotel or guesthouse to generate the electricity they need. Despite the above-mentioned trends in recent years regarding the use of wind energy in socially responsible hotels and guesthouses, the rate of use of both wind and hydroelectric power is significantly influenced by social factors, so the use of these resources is characterised by slower rates of development compared to other RES resources.

3.3. Agricultural Sector

Figure 5 shows the assessment of RES potential for the agricultural sector. The use of biomass for energy production was rated with the highest development potential among the analysed RES. In evaluating biomass development potential, it received the highest possible rating. Biomass in the agricultural sector is evaluated as the most competitive among RESs. The high rating is justified because agricultural processes generate a significant amount of agricultural leftovers and biological waste that can be converted into energy. Biomass use in agriculture is rapidly increasing, and fossil fuels are expected to be replaced in the near future by RESs. One of the most demanded biomass feedstocks in biogas plants is manure enriched with agricultural residues and residues from cereals and sugarcane. The demand for biomass fuels for biogas production is expected to continue to increase. Biomass can be used year-round, unlike other RESs. Its advantages have been evaluated for use in combined systems, for example, to meet necessary energy needs during solar power outages.

In the agricultural sector, the second-greatest development potential for using solar energy was identified after using biomass. The use of solar energy technologies in agriculture is characterised by a rapid rate of development in recent years and is expected to continue growing. Smart technologies combined with solar panels and collectors ensure agricultural processes. Such integrated, combined technologies are used, for example, to monitor various parameters such as soil moisture. The increase in solar energy use in agriculture is also favoured by economic sustainability, the payback period of investments is less than ten years, and there are more and more RES support programs that can reduce the necessary investment in installing solar technologies. It is estimated that solar energy in combination with the Internet of Things has the potential for use on farms. This combination of technologies can be used, for example, to more accurately determine the amount of nutrients needed for crops. Using solar energy makes it possible to ensure a number of agricultural processes, for example, by operating equipment necessary for production, such as for the operation of grain threshing machines or ensuring a certain temperature in greenhouses. The least constraints were identified for using solar energy in the agricultural sector, since agricultural processes are usually carried out in the season when it is possible to generate solar energy in sufficient quantities, possibly in combination with an additional source. To avoid solar energy interruptions, you can choose smart systems that control the energy needed.

Geothermal energy (0.67) received the third highest score in the sustainability development potential assessment. The potential for geothermal energy development is limited by resource availability, influenced by geographic conditions. Examples show that geothermal energy has been used as a resource in aquaculture farms to provide the specific temperature required for trout farming.

Similar to the service and industrial sectors discussed above, wind energy use and hydropower use in agriculture have a lower sustainability potential score compared to other RESs—wind energy with 0.63 and hydropower use with 0.63. Similar to the sectors mentioned above, social factors affect the development potential of hydropower and wind energy in agriculture. Local cooperatives and energy communities can promote the use of wind energy. The use of wind energy is also affected by geographic conditions—places with insufficient wind speed to meet necessary demand and windless conditions that cause wind energy interruptions.

The limitations of wind energy use can be eliminated by combining wind energy with cogeneration. Wind energy can be used for numerous agricultural processes where it is necessary to meet the required electricity demand. Wind energy can be used to power a variety of agricultural activities, including water pumping and electrochemical soil cultivation.

Similar to using wind energy, opportunities to use hydropower are limited by geographic conditions and resource availability. Thus, similar to the use of wind energy, the use of hydropower is influenced by social factors such as the population’s attitude and environmental factors including the impact on fauna and landscape. The evaluation of the potential of hydropower utilisation is based on scientific research, case studies, and review articles on the possibilities and advantages of hydropower utilisation in agriculture. The correctness of the obtained results is influenced by the number of literature sources and case studies studied, which was lower compared to other technologies. The more scientific literature there is that evaluated the possibilities of using hydropower in agriculture, the higher the assessment of sustainability potential is likely to be.

3.4. Household Sector

Figure 6 shows the sustainability potential rating of the previously discussed RES types. When comparing the sustainability potential of the RES types, solar energy received the highest score of 0.83 among the RES types. This is explained by the fact that in recent years, there has been an increase in the use of microenergy production and the installation of solar panels on the roofs of houses. The use of solar solutions at the household level is promoted by subsidy programs that cover part of the necessary investments for the installation of technologies, and the payback period of the invested funds becomes shorter, which is favoured by the annual decrease in the cost of solar energy technologies. It is possible to produce solar energy electricity with solar cells installed on building roofs or facades, as well as to produce the necessary thermal energy with the help of solar collectors, which promotes energy independence. The use of solar energy makes it possible to reduce the cost of energy consumed and improve the energy efficiency of buildings.

Applying solar energy in a household is associated with the fewest potential disadvantages. A limitation is related to insufficient solar intensity, but in case of interruptions in solar radiation, the needed energy can be obtained with the help of hybrid systems, which provide additional sources to cover the shortage and storage systems.

Biomass use had the second-greatest sustainable development potential (0.77). Biomass fuel is used both in centralised heat supply and for heating and hot water in individual households. One of the benefits of using biomass is the possibility of generating heat and electricity from biomass residues before they undergo thermal treatment. This is made possible by the fact that biomass residues can be used. It is estimated that the development rate of biomass residue utilisation may also increase in the future and that biomass residues are increasingly used for energy production.

For wind, geothermal, and hydro energy, the development potential in the household is estimated to be the same (0.73). Regarding wind energy, it is anticipated that the installation of small wind turbines on residential rooftops will increase in the future, and it is expected that the installation of these turbines will become less expensive. The energy generated in the household can be used to cover the household’s own consumption or to form energy communities. The advantages of wind energy utilisation are related to the fact that it is possible to integrate wind energy into hybrid systems. For example, it is expected that wind energy will be increasingly used in combination with solar panels at the household level, thus avoiding energy interruptions and increasing efficiency. In places where resource availability is assured, the development potential of using hydropower to meet electricity demand will increase. As for hydroelectric power, the use of hydraulic systems (PHP systems) that do not first require the construction of a dam system is increasing. Such systems can meet the necessary electricity needs for villages and communities of up to 30 households. Even though hydropower has several advantages, the use of this resource is at the same time affected by the accessibility of the resource and the impact of hydropower plants on the surrounding environment and landscape. The aforementioned PHP systems are better suited for use in mountainous regions. In countries with colder climates, it is expected that the installation of heat pumps powered by geothermal energy will continue to increase. Although installing heat pumps requires a particular investment and is more complicated than other RES technologies, it has been shown that heat pumps have the second-highest savings potential for households.

Wind, hydro, and geothermal energy technologies demonstrate moderate progress in the residential sector, with notable advancements seen in small-scale solutions. However, at the individual household level, their sustainability and viability are limited. Therefore, the formation of energy communities, which unite multiple households, presents a more sustainable option for the future. This approach enables the integration of larger-scale wind, hydro, and geothermal technologies that are further developed and offer enhanced efficiency compared to small-scale solutions.

3.5. Transport Sector

Figure 7 compares the RES potential of various resources for use in the transport sector. From the results, it can be concluded that the highest potential score was for using biomass, which received the highest possible score in the transport sector (1). This is because improving biomass quality and obtaining biomethane that can be used as fuel for vehicles should have a high potential for current and future use in the transport sector. It has been determined that biomass-derived biofuel is one of the most effective ways to replace fossil fuels in transportation and meet climate goals. Compared to other RES types, biomass use in transportation was rated with the lowest use constraints. However, one drawback that significantly determines whether biomass can be used to power vehicles is the quality of the biomass and which biomass feedstocks are used and in what proportions. A high methane concentration is required to produce biomethane that can be used in vehicles, and not all biomass raw materials can achieve the concentration required to produce biomethane.

The use of solar energy received the second-highest potential score for use in transportation (0.90) among RESs. Based on the analysis, the use of solar technology in vehicle charging will also likely increase in the future. The proportion of electric car use has increased in recent years, and it is expected that to achieve the set climate targets for transport, the use of electric cars will also increase. With the growth of electric cars, the demand for environmentally friendly car charging will also increase. One such solution is offered by solar energy technologies, which make it possible to charge cars in a decentralised manner, for example, by using energy generated in households with solar panels to charge electric cars. The advantages of using solar panels include the fact that solar panels can be adapted for use in different infrastructures and that with solar panels, it is possible to generate the necessary amount of electricity to ensure the charging of cars. Solar modules can be used in homes and businesses as well as in public charging stations that are in public charging stations integrated into road infrastructure. Similar to other sectors, solar energy constraints are associated with intermittency. When it is necessary to use an additional source to meet demand, one of the solutions is to use solar energy accumulation.

The potential of using wind energy in the transportation sector was given the third-highest score (0.83). As the number of hydrogen-powered cars increases, the share of wind energy in transportation will also increase. It is predicted that with the increase in hydrogen-powered cars, the number of cars powered by wind energy will also increase. To achieve the climate targets set, it is expected that compressed hydrogen will be used as an energy source to power cars, using wind energy rather than fossil energy to produce it. Similar to the sectors described above, there are constraints on the use of wind energy in the transportation sector, such as geographic limitations. A certain speed of wind energy is mandated when it is not possible to meet the necessary demand.

Among the types of RESs studied, hydropower in the transport sector was given the lowest rating. The study concludes that, similar to wind energy, hydropower can be used as an energy source for the production of hydrogen, which is used to power cars. Although the use of hydropower for hydrogen production is recognised as an environmentally friendly and feasible alternative, the potential for using hydropower is geographically limited. To avoid a false comparison with other RESs, the potential of using geothermal energy in transportation was not analysed because there were not enough studies to compare it with other types of RESs.

Table 6. The final index score for RES.

Sector	Solar Energy	Wind Energy	Hydropower	Biomass	Geothermal Energy
Industry Sector
Development	0.33	0.23	0.23	0.27	0.23
Advantages	0.30	0.23	0.20	0.27	0.23
Limitations	0.20	0.20	0.23	0.23	0.27
Total	0.83	0.67	0.67	0.77	0.73
Service sector
Development	0.33	0.20	0.20	0.23	0.27
Advantages	0.30	0.20	0.20	0.23	0.27
Limitations	0.27	0.20	0.20	0.23	0.27
Total	0.90	0.60	0.60	0.70	0.80
Agriculture sector
Development	0.27	0.20	0.20	0.33	0.20
Advantages	0.33	0.23	0.20	0.33	0.20
Limitations	0.33	0.20	0.20	0.33	0.27
Total	0.93	0.63	0.60	1.00	0.67
Household sector
Development	0.27	0.23	0.27	0.30	0.27
Advantages	0.30	0.27	0.23	0.23	0.27
Limitations	0.27	0.23	0.23	0.23	0.20
Total	0.83	0.73	0.73	0.77	0.73
Transport sector
Development	0.30	0.30	0.23	0.33	0.00
Advantages	0.27	0.30	0.23	0.33	0.00
Limitations	0.33	0.23	0.20	0.33	0.00
Total	0.90	0.83	0.67	1.00	0.00

shows the final index scores for each RES in each sector (Table 6).

3.6. A Cross-Sector Comparison to Assess the Sustainability Potential of the Use of RES

The second part of the study produced a score reflecting an assessment of the sustainable development potential of each resource and a comparison of sectors by RES type (Figure 8).

Table 7. Summary of RES normalised points by sector.

	Solar Energy	Wind Energy	Hydropower	Biomass	Geothermal Energy
Industrial sector	0.83	0.67	0.67	0.77	0.73
Service sector	0.90	0.60	0.60	0.70	0.80
Agricultural sector	0.93	0.63	0.60	1.00	0.67
Household sector	0.83	0.73	0.73	0.77	0.73
Transport sector	0.90	0.83	0.67	1.00	0.00
Average values	0.88	0.69	0.65	0.85	0.59 (0.73 *)

* The average value of four sectors, excluding the transport sector.

summarises the points obtained, clearly showing the normalised result for each RES type, with which it is possible to characterise the RES utilisation potential.

The potential of biomass use in the agriculture and transport sectors achieved the highest assessment level for sustainable development. In these two sectors, biomass received the highest possible score, 1. Thus, in both the agriculture and transport sectors, the rapid development of biomass energy production has already been observed and predicted for the future. The second-highest potential rating was given to the potential of biomass use in industry and households.

The potential of solar energy use is currently and in the future estimated to be highest in sectors such as services, households, and industry. Solar energy received the second-highest potential rating in agriculture and transport, right after biomass use after biomass use. According to the average score, the use of solar energy ranks first with a score of 0.88, while in second place according to the score is biomass (0.85), which has the fewest constraints for use in transport and agriculture among RESs. Compared to the potential use of solar energy and biomass, the other three RES types, whose development can be described as slower, scored lower in the evaluation. Wind energy is still in the development phase of its potential, which is limited by geographical conditions as well as by social factors and the population’s aversion to wind turbines near their homes. Despite the limitations mentioned above, the potential for using wind energy in the transport sector and residential sector received the third-highest rating in these sectors.

The potential of wind energy is to replace fossil energy resources for hydrogen production and to meet the electricity demand required for installing micro power plants in households. The combined results of the study reveal that equal values were obtained for wind energy and hydropower in the industrial and service sectors and for wind energy, hydropower, and geothermal energy in the household sector. This can be explained by the fact that there are similar constraints for these technologies that limit their use and affect the overall results of the index for the technologies. Based on the utilisation of a five-point scale, as indicated in Table 2, it can be inferred that there were no significant variations in the outcomes across different sectors of technology. This can be attributed to the implementation of a limited range of evaluation scale dispersion.

3.6.1. Solutions for the Development of Solar Energy and Biomass Use

Solar Energy

Industry. Combined systems that compensate for solar deficits or accumulation are used to improve market competitiveness, reduce energy consumption, and lower the price of the required energy. Solar energy technologies have increasingly lower prices and shorter payback periods, which increase their acceptance.

Services. There are numerous applications in the public sector, including the tourism industry, office buildings, and data on solar energy systems in public facilities, including providing thermal energy and electricity for schools. It is evaluated as an effective solution when combined systems are used to cover peak loads during the cold season. This already provides the actual and potential ways of using this energy.

Agriculture. Solar and wind energy shortages can be offset with biomass, including agricultural residues, smart technologies that compensate for solar energy shortages by using energy exactly when it is generated, and smart agricultural monitoring. Solar panels collect and store the energy needed to power an Internet of Things sensor node, which is then used to charge the sensor node. The Internet of Things (IoT) is becoming increasingly prevalent in the agricultural sector. The solar energy obtained has a wide range of applications—it can be used, for example, in irrigation systems, in drying processes, for higher efficiency through hybrid drying systems combining several RESs, for wastewater treatment, and for cleaning the soil from heavy metals and herbicides. As technology advances, it is expected that a greater portion of energy needs will be met by solar sources. Hybrid drying systems can compensate for solar energy deficits and improve drying efficiency and product quality. Similarly, the use of thermal energy storage systems can compensate for the lack of solar energy during bad weather.

In households, there is the possibility of using smart grids, smart meters, and other smart technologies that can use solar energy more efficiently as a source of energy. The use of solar energy contributes to regional and national energy independence. Solar panels and collectors can be incorporated into a wide range of building components. Since collectors and PV panels are often used in passive houses, it is expected that these technologies will increase in the future.

Solar street technologies are becoming more common and are also essential for increasing the share of electric cars, as they provide a solution to the problem of charging station availability. Solar road technologies can be an indispensable component of a decentralised energy supply. Wind-generated compressed and stored hydrogen can be used as a fuel in the transportation sector, reducing imports of fossil fuels and greenhouse gas emissions.

Biomass

In the industrial sector of biomass use, there is considerable potential for use in the food and beverage industry, where residues and wastes from the same processes can be used to generate energy for other operations. In different subsectors of the industry, actual and potential uses are estimated to be lower.

In the catering industry, processing biodegradable waste from kitchens in biogas plants offers further potential applications. Biogas is enriched with organic kitchen waste to produce biomethane that can be used in vehicles. The processing of waste generated in the catering industry has a high potential for energy production. However, there is not enough information on the other service sectors to make an assessment.

Agricultural residues in combination with manure offer broad opportunities for biomethane production. The agricultural sector assesses biomass and its residues as one of the most important sources of renewable energy with even greater prospects for the future. By using biomass residues or wastes, it is possible to compensate for the lack of other energy sources such as solar or wind.

Agricultural residues, which can be used in various ways in all five resource categories, are increasingly being used as feedstock for biomethane with high methane content. Biomethane can also be used in commercial vehicles, buses, and certain heavy-duty trucks.

3.6.2. Previous Research

Previous studies regarding the determination of RES potential show that there are several studies to assess the potential of renewable energy. However, the studies provide conflicting results and depend on the technologies used. The potential of the RESs and their combinations is evaluated based on payback durations, energy generation, and reduction in CO₂ emissions [27,133,134,135].

According to previous research, for 100% self-sufficiency in energy production, the Latvian energy system can rely not only on renewable energy systems that are economically viable in the short term (such as biomass) but also on systems that are less economically attractive in the short term (such as wind power and solar PV) [136,137].

Previous studies have shown that solar panels have payback times of less than 7 years, and solar hybrid systems have an average payback period of 5.5 to 6.5 years.

Previous studies have also assessed that geothermal energy has the potential to replace traditional fossil resources. However, one of the main factors limiting the use of the resource is the geographical location and, therefore, the availability of the resource [138].

3.6.3. Limitations of the Study

When collating the data, it was found that in places, the points awarded in the qualitative analysis ranged, for example, between 4 and 5, based on 4 reflecting the current situation and 5 being expected in the near future. As mentioned in this example, the average value was taken, i.e., 4.5 (in this example).

In addition, it was observed that three objects were not given a specific mark in the qualitative analysis because there was insufficient information about any of the RESs in the particular sector. The result was a data gap. For example, in the agricultural sector analysis, very limited information was available on hydropower development trends and limitations in using the specific sector. In that case, the model assigned a score of 3, the most neutral value on the scale. In addition, the lack of information on any use of RESs in the industry suggests that the lack of information to provide a degree of development or other considerations in the qualitative analysis means that the development of a particular RES is limited. This explains the rating—a score of 3 reflects certain limitations in developing a particular AER.

Data processing and normalisation were performed after data collection and replacement of missing values. The obtained points for each criterion and each AER in the corresponding sectors were normalised so that the obtained values range from 0 to 1, where 0 is the lowest value and 1 is the highest value. Assuming that each criterion has the same impact on sustainable RES development, they were assigned the same impact weight categories on the overall RES sustainable development result. Such a data normalisation technique is often used in sustainable development analysis and research to produce transparent and verifiable results. The range of scores from 0 to 1 makes it possible to interpret the results and draw valuable conclusions about the current performance of each RES and the sector’s sustainable development level.

The overall score obtained for each RES reflects its sustainable development performance and overall long-term potential. The closer the score is to 1, the higher the long-term development and assessed potential of the respective industry. Literature-related specific criteria and sectors are a limiting factor impacting the index results.

4. Conclusions

This study examines the potential of RESs in various sectors, focusing on agriculture, transportation, industry, and households. By assessing the sustainable development of biomass, solar, wind, hydro, and geothermal energy, we aim to identify untapped opportunities and remove barriers to their full integration. The results will enable policymakers to prioritise strategies to overcome barriers and harness the enormous potential of RESs to promote a sustainable and green future.

The potential for biomass use in agriculture and transport received the highest rating for sustainable development. In these two sectors, biomass received the highest possible score, 1. Rapid growth in biomass energy production has been observed in both agriculture and transportation and is expected in the future. The second-highest score for heat potential was given to the potential for biomass use in industry and households. Solar energy and biomass derived from agricultural residues are subject to the fewest restrictions on their use. It is predicted that the potential for solar energy use will increase and that solar cells will be increasingly used to charge electric cars. In the overall assessment across all sectors, solar energy is rated the highest regarding the potential use of RESs at 0.88, and biomass use potential is rated second at 0.85.

For solar energy, the investment required to install solar technology has decreased in recent years. The payback period for the investment is less than ten years and continues to decrease as solar technology becomes cheaper and cheaper. The periodicity of solar energy is considered one of the limiting factors for the use of the resource. It can be solved by using energy storage systems, and it is also possible to use an additional source for heating, such as a heat pump or biomass. Technologies powered by solar energy are increasingly being combined with smart technologies that allow energy to be used wisely and processes to be controlled remotely, reducing overall energy consumption.

To deal with the periodicity of wind energy, it is necessary to provide an additional source through combined systems. With the help of smart technological solutions, it is also possible to determine when wind strength is sufficient and when it is necessary to compensate for the lack of wind energy. Geothermal energy can be combined with heat pumps to generate the necessary thermal energy in the environment. The potential of using geothermal energy depends mainly on the availability of resources, which is determined by the geographical location. The use of geothermal energy is limited to the service sector, industry, and agriculture. However, there is a small number of studies on the potential of using geothermal energy in the transport sector.

The results allow us to spot and highlight the untapped potential of specific renewable energy resources in each sector; therefore, policymakers could focus on tackling the identified barriers and using the full potential of identified opportunities. This study assessed the overall potential and limitations of renewable energy deployment across various sectors without conducting a detailed analysis of technoeconomic parameters and indicators. Additional investigations should prioritise the careful analysis of the economic viability of renewable energy across diverse industries, in order to acquire a comprehensive comparison of the economic viability considering sector-specific variables.

The method can serve as an initial risk analysis to evaluate the effectiveness of measures and the risks, drawbacks, and benefits of their implementation using indicators, first descriptively and then numerically. To obtain accurate results, it is crucial to define relevant indicators and select enough relevant information. The developed method is a practical solution necessary to evaluate the implementation of planning documents and specific actions, performing an analysis based on indicators and assigning them a score.