Environmental Protection in the Planning of Large Solar Power Plants

Abstract

The global trend of reducing the “carbon footprint” has influenced the dynamic development of projects that use renewable energy sources, including the development of solar energy in large solar power plants. Consequently, there is an increasingly pronounced need in scientific circles to consider the impact these projects have on space and the environment. The fact that international financial institutions consider environmental effect to be a significant factor when funding solar energy projects is one of the main reasons this topic is so important in professional circles, particularly among solar energy investors. This paper highlights the fact that solar power plants can have both positive and negative impacts on space and the environment. Those impacts need to be defined in order to choose optimal spatial and territorial solutions that ensure preventive planning and active environmental protection. In the process, the application of strategic environmental assessment (SEA) in the planning and spatial organization of solar power plants becomes important. SEA is characterized by a holistic approach where complex interactions and correlations in the location of planned implementation of the solar power plant can be understood at the earliest stage of project development. By doing this, it is possible to prevent all potential risks that may emerge in the project’s later stages of implementation, which is favorable both from the aspect of effective environmental protection and from the point of view of investors investing in solar power plant projects. Optimal solutions that bring about the basic role of SEA are sought primarily in the analysis of the spatial relations of the solar power plant with regard to land, biodiversity, landscape, and basic environmental factors, which is particularly highlighted in the paper. Also, the basic methodological concept applied in SEA is demonstrated, combining different methodological approaches and methods for impact assessment, as part of a unique semi-quantitative method of multi-criteria evaluation of planning solutions.

1. Introduction

The ecological advantages of the production of electricity from renewable sources (RES), on the one hand, and the development of the population’s awareness of the need for environmental protection, on the other hand, represent a good basis for the dynamic development of projects in the field of application of “green” energy, which is based on the application of RES [1].

Therefore, in addition to economic benefits in the field of energy and energy transition, the ecological aspect is increasingly important, which becomes a dominant condition for the preservation of space and the environment, but also for the financing of projects by international financial institutions [2]. Today, the destruction of nature has become so intense that the use of RES is being imposed as part of the solution to the global problem. The emission of gases with the greenhouse effect is mostly a consequence of the burning of fossil fuels. The reason supporting the dynamic development of projects using RES on a global level by a large number of investors is twofold [3]:

• The construction of power plants using RES is aligned with the development of awareness of the importance of environmental protection and with international agreements concerning environmental protection and climate change. By analyzing data on the CO₂ emission during the production of electricity from different primary sources, it can be concluded that, compared to fossil fuel, renewable energy sources are incomparably more acceptable from an environmental point of view [4];
• The production of electricity in power plants using RES generates a significant profit [5].

Like many other development activities, solar power plants can have both a positive and negative impact on the environment. However, in order to talk about the possible environmental impact of solar power plants, it is necessary to understand the scale of large solar power projects (over 100 MW).

The solar power plant complex consists of infrastructure facilities for the production of electricity (solar panels), transmission of electricity (internal cable network and substation), and traffic facilities (internal access roads for construction and maintenance of the solar power plant).

Each of the functional parts of the solar power plant has a unique role and holds significant importance in the operation of the solar power plant system, solar panels being the most prominent in terms of space. Depending on the installed power in the solar power plant, the space occupied by solar panels can be large, which is why they are particularly significant from the aspect of possible environmental impact. Today, wind power plants from several hundred megawatts (MW) to even several gigawatts (GW) are being implemented worldwide, occupying hundreds and thousands of hectares of land. As an example, some of the biggest solar power plants in the world can be cited [6]:

• Bhadla—India (2.7 GW), covering an area of 14,000 hectares;
• Pavagada—India (2.05 GW), covering 13,000 hectares;
• Jichuan—China (1 GW), covering almost 9000 hectares.

The dimensions of the space occupied by large solar power plants can therefore be grand, so they must be viewed in the context of the use of land they are built on (e.g., degraded land, desert or high-quality arable land), which is especially significant considering the expansion of solar energy on a global level.

The size of the solar power plant, i.e., the installed power, is directly proportional to the land area required for its construction. It is precisely from this relationship that the assessment of the positive and negative impact of solar power plants on the environment starts.

The positive impacts of solar power plants have a wider context. This is achieved by reducing emissions of greenhouse gases in the energy sector, through reduced usage of fossil fuels, that is, by producing electricity without the emission of air pollutants and greenhouse effect gases. In the future, this should lead to reduced needs for thermal power plants generated energy. Given that the production of electricity in solar power plants does not create greenhouse gases, it represents an important step towards “stabilizing” the climate. To illustrate this scenario, one should refer to the results of a recent study by the US National Renewable Energy Laboratory [7], which concluded that a 25% increase in the use of RES will reduce greenhouse gas emissions by 30%. Therefore, the influence on slowing down climate change is another important positive impact of utilizing solar power and renewables in general, which further results in positive effect on the health of the population and planet’s biodiversity.

Energy efficiency is another advantage of using the energy of the sun in solar power plants compared to the use of fossil fuels. Namely, electricity produced in solar power plants is efficiently delivered by transmission lines to the place of usage, without additional processing, transport, etc., which is not the case when electricity is generated in power plants that use fossil fuels.

Negative impacts of solar power plants can occur during the construction of the solar power plant at a specific location, during its operation, and after its closure. There are several key environmental impacts of solar power plants:

• Land occupation: The land that is occupied is in direct correlation with the size (installed power) of solar power plants. Land occupation refers to the space under the solar panels, so large solar power plants can occupy large areas.
• Impact on biodiversity: This primarily refers to the potential endangerment of habitats, that is, the potential change in habitats and their existing conditions, as well as to changes in the characteristics of hunting territories for wild species occupying those territories. Namely, the change in one element affects the change in another. In this case, purposeful modification or removal of certain, e.g., floristic, stands in the location where the realization of the solar power plant is planned directly influences the change in the habits and behavior of certain individuals of the fauna in that location.
• Impact on the landscape: According to the European Landscape Convention [8], a landscape is an area whose character is the result of the action and interaction of natural and/or anthropogenic factors. Therefore, it encompasses both the natural and cultural values of a certain area [9,10,11]. Large solar power plants can take up large areas and completely alter the landscape characteristics of the location. However, the impact of the visibility of solar power plants on the landscape is based on subjective preferences.

In addition to the abovementioned main impacts, it is important to address other minor effects that occur during the construction phase of a solar power plant, such as noise generation and potential pollution of the basic environmental factors, impacts on archaeological remains, but also impacts arising from solar panels that are damaged or whose useful life has ended.

The assessment of the negative impacts of solar power plants on the environment is determined during its planning, design, construction, and operation. This paper presents the use of strategic environmental impact assessment (SEA) as an instrument for identifying and assessing the impact of (spatial/territorial) solar power plants on the environment, and showing how these negative impacts can be minimized or completely eliminated by applying the principle of preventive protection at the earliest project development phase [12,13,14].

To achieve a higher level of applicability of the research carried out for the purposes of this work, this paper used the results of the SEA study conducted for the needs of the agrisolar power plant “Agrosolar Kula” (800 MW) in Serbia—a case study.

2. Initial Position

In this paper, the results of the SEA study of the agrisolar power plant “Agrosolar Kula” (2024) were used as an illustration. The main reasons to take the agrisolar power plant “Agrosolar Kula” as a case study are as follows:

• The specificity of the combination of agricultural and energy activities in the agrisolar power plant; the specificity of the biological and landscape features, which made the project particularly challenging from the aspect of SEA application and the application of the principles of preventive protection;
• The project’s spatial coverage and substantial installed power of approximately 800 MW made it one of the largest solar power plants;
• The improvement in standards in the application of SEA was made feasible by the readiness of the project investor to apply the principles of preventive environmental protection and all the related procedures.

The area of the planned agrisolar power plant ‘Agrosolar Kula’ is located in the northwestern part of Serbia, on the territory of the municipality of Kula (Figure 1).

The area is a flat region of the Pannonian plain. The location of the planned “Agrosolar Kula” agrisolar power plant is located in an area that has been mostly anthropogenically altered by agricultural activities, so there are sporadic fragments of preserved natural micro-locations. The location of the designed power plant is neither within the protected areas with initiated or implemented protection procedures, nor within the spatial coverage of ecological corridors of international, regional, or local importance of the Ecological Network of the Republic of Serbia. In the wider surroundings of the location, there are several ecologically significant areas of the Ecological Network of Serbia, elements of other ecological networks, as well as a few protected areas. Less than 1% of the total area of the site is under forests, which are characterized by a certain ecological and conservation value. There are (semi-) natural habitat types on the site. These are mainly fragments of forest and shrub vegetation and agricultural land in different stages of succession, forming a mosaic typical for the location. In such a specific and ecologically demanding area, it was a challenge to apply the principles of preventive protection in the SEA process and determine the possibility of effective environmental protection during the realization of an agrisolar power plant. The presentation of the SEA process focuses on the methodological approach and some important findings that are sufficient to provide an overview of the application of SEA in the sustainable planning of solar power plants.

3. SEA as Environmental Protection Instruments in the Planning of Solar Power Plants

Today, various environmental impact assessment instruments are utilized globally. Certain instruments, such as the traditional life cycle assessment (LCA), provide a comprehensive overview of the development of the project. The idea is to look at the consumption of energy used in the creation of a product in relation to the time it takes to “return” that energy in the process of work, that is, exploitation. In the case of solar power plants, this would mean quantifying all impacts in the range of energy usage for the construction of a solar power plant (cumulative effect) and the possibility to produce that energy again in the shortest possible time [15]. In addition, it is extremely important to consider the impact on the environment in the process of obtaining the product in correlation with the benefits of the product on the environment.

There are diametrically opposed approaches based on the so-called partial assessment [2,14,16,17,18]. In the context of the assessment of the impact of solar power plants on the environment, one could speak of a partial assessment of the impact of solar power plants on, for example, biodiversity or landscape. Yet, a single impact assessment that applies a holistic approach to the evaluation of the environmental impact of solar power plants is the only one that justifies a partial assessment for individual environmental elements.

Finally, we come to the instruments for environmental protection, which at the global level have the most widespread application in environmental impact assessment, not only for solar power plants, but also for all other development plans, strategies, programs, policies, and projects. Those are the SEA, EIA (environmental impact assessment), and supplemented ESIA (environmental and social impact assessment).

Given that the focus of this work is on environmental impact assessment in the earliest phase of project development, i.e., during planning when SEA is used, there will be no further elaboration on the application of EIA/ESIA. These instruments are applied as a logical continuation of the SEA process into the windfarm design phase that follows the planning process. The application of EIA/ESIA can be read in the works of many authors [19,20,21,22,23], so here, we move directly to the application SEA.

SEA is applied at the strategic level of planning, i.e., at the earliest stage of project development. It serves for both the assessment of spatial/territorial impacts on the environment and the optimal site selection. It helps to solve environmental, social, and economic problems that may arise from the implementation of public and private investment projects in a certain area. It comprises a systematic, documented, periodic, and objective assessment of how well pollution control and environmental management systems can be achieved in the operation of a particular system [24].

The primary role of SEA is to facilitate timely and systematic assessment of potential impacts on the environment, which serves as a basis for decision-making regarding development policies at the strategic level and their acceptability from the sustainability standpoint [5,25,26].

From the mid-1990s until today, many authors have written about the role and importance of SEA in the creation of spatial development [13,17,27,28,29,30,31,32,33,34,35,36]. The authors largely agree on the importance of applying SEA in policy-making and optimal decision-making about spatial development. This statement is confirmed by the fact that an increasing number of international institutions introduce requirements for the application of SEA in order to increase the number of development initiatives that are in accordance with the environment [37].

The essence of the application of SEA is to steer the planning process in the direction of the defined objectives of sustainable development, on the one hand, and to assess and identify strategically significant territorial impacts of a certain policy that serve to make a decision on spatial development, on the other hand. Based on the information and results of the SEA process, a significant contribution is made to the decision-making process on the future development of an area [38].

3.1. The Possibility of Applying SEA in the Planning of Solar Power Plants

Although there is little in the scientific literature dealing with the application of SEA in the planning of solar power plants, the application of SEA in this case must also be based on the application of the principle of preventive protection and guidelines for the selection of optimal options to minimize or completely prevent potential conflicts in space that may arise in the correlation of solar power plants with elements of the environment. Optimal options are sought in the analysis of spatial relationships of solar power plants with respect to land occupation, biodiversity, landscape, and socioeconomic aspects of development.

The specifics of SEA in the planning of solar power plants are that there are often certain technical characteristics in the initial phase of project development (usually only one project is covered, many technical details are known, e.g., the type of equipment and solar panels that will be installed, etc.). The mentioned circumstances may point to the direct application of EIA/ESIA, without carrying out the SEA process, because there are elements for such a thing (one project–one location–known technical details of the project). It can be an attractive option for investors because it acts as an opportunity to save time (“time is money”), especially in cases where investors are not aware of the importance of documents in the field of environmental protection when approving loans for project implementation by international financial institutions. Namely, international financial institutions prefer the principle of preventive protection as the most effective approach in effective environmental protection, and such an approach can only be achieved through the SEA process. This is supported by the application of the concept of preventive protection, whereby the spatial micro-location determination of solar panels within the solar power plant is affected at the planning level and by the application of SEA, thereby preventing the impact on the landscape, biodiversity, and occupation of quality land. In addition, international financial institutions and creditors pay special attention to the aspect of the project’s impact on the environment within the so-called assessment of financial risk; therefore, applying the principle of preventive protection within the SEA procedure is the only correct approach [5].

3.2. Methodology of Strategic Environmental Impact Assessment

Unlike the sophisticated software packages used in engineering, the methodological approach in SEA is rather unclear [39]. Some authors [40,41] claim that there is no generalized SEA methodology that applies to all plans and development policies and that the SEA methodology should be treated as a set of tools in one “toolkit”, each user of which can choose their tools depending on their specific needs. Marsden [42] points out that SEA mainly relies on qualitative review, which is why expert judgment plays a key role. The issue of choosing the appropriate evaluation methodology used in a specific case should be correlated with the appropriate implementation experiences accumulated through comparative studies of previously applied methodologies that have shown good results in the implementation of SEA [39].

The application of expert qualitative methods provides great opportunities for adapting and combining the methodological approach in SEA, in order to obtain the best results in the specific case. Given that qualitative expert methods are characterized by subjectivity, it is necessary to apply techniques and tools that will achieve the greatest possible objectivity in impact assessment. The role and importance of the application of GIS technology and other software models for partial assessment in this procedure are highlighted in this context [43,44,45,46]. In doing so, one should always consider the possibility of combining several methodological approaches in order to obtain the best results in EA based on the specific case [47].

One of the most frequently used methods for impact assessment within SEA is the multi-criteria evaluation (MCE) method of planning concepts. The MCE method is considered a well-developed scientific field supported by a large number of scientific references [48,49,50]. The main role was to obtain relevant information so that the optimal decisions could be made. The development of MCE methods has reached the point where the entire concept of application is focused on the process of making optimal decisions, implying the inevitable involvement of the public in the MCE process [51]. In this context, participance is one of the important characteristics of the SEA process.

The methodological approach in the preparation of SEA for solar power plants does not differ from the usual approach, so it is also possible to apply different qualitative expert methods [52,53] in combination with quantitative methods applied for partial impact assessments. In other words, the specifics of solar power plant project planning are conditioned by the selection of a combination of methodological approaches, that is, a combination of methods and techniques that are often formulated in the form of a semi-quantitative method of multi-criteria evaluation.

4. Application of the Semi-Quantitative Method of Multi-Criteria Evaluation in SEA When Planning the Agrisolar Power Plant “Agrosolar Kula”—A Case Study

In the parts of the work that preceded this chapter, the predominant application of expert qualitative methods for the evaluation of planning solutions for spatial development applied in SEA, as well as the importance and possibility of applying the semi-quantitative method of multi-criteria evaluation, were pointed out. In this context, the semi-quantitative method of multi-criteria evaluation of planning solutions of spatial development, which was applied in the preparation of the SEA for the complex of agrisolar power plant “Agrosolar Kula”, is presented below.

The backbone of applying the concept of semi-quantitative multi-criteria evaluation consists of several key methodological steps: defining SEA goals and indicators and evaluating the variant and planning solutions. The following methodological steps are elaborated.

4.1. Definition of SEA Objectives and Selection of Indicators

General and special SEA objectives are defined based on the following: requirements and objectives regarding environmental protection in other plans and programs; environmental protection goals established at the international, national, regional, and local levels; collected data on the state of the environment; and significant issues, problems, and proposals regarding environmental protection in a specific plan.

Special SEA objectives are defined based on the general goals and spatial coverage of the plan, planned contents in the area of the plan, and environmental conditions at the location in question and its wider environment. This represents the basis for evaluating the strategic impact of the plan on the environment. Specific SEA objectives are a concrete, partially quantified statement of general objectives given in the form of change and action-related guidelines by which those changes will be implemented. Specific SEA objectives form the methodological benchmark used to assess the effects of the solar power plant plan on the environment. They should provide decision-makers with a clear picture of the essential environmental impacts of the solar power plant plan. Specific SEA objectives are the basis for evaluating the territorial environmental impacts of the solar power plant plan (Table 1).

In addition to the SEA goals, defining the indicators in relation to which the trends of changes in the location and the environment are evaluated and monitored is of particular importance for impact assessment. For each specific SEA objective, one or more related indicators are determined. In the case of the SEA for the agrisolar power plant complex “Agrosolar Kula”, the selection of indicators was made from the basic set of UN indicators of sustainable development, which was legally established in the Rulebook on the National List of Environmental Protection Indicators [54]. The selected set of indicators (Table 1) fully reflects the principles and goals of sustainable development and is in line with the planned activities in the area of the agrisolar power plant complex “Agrosolar Kula” and their possible impacts on the quality of the environment.

Table 1. SEA objectives and related environmental receptors [55].

Environmental Receptors	Special Goal of the SEA	Indicators
Protection of biodiversity	Reduce harmful impact on fauna	- Number and status of potentially endangered species
	2. Reduce harmful impact on flora	- Number and status of potentially endangered species
	3. Preserve biodiversity and habitats	- Species diversity
Protection of basic elements of the environment	4. Preserve air quality	- Number of days when the emission limit value for PM particles, CO, SO2, and NO2 was exceeded as a result of the construction of the solar power plant
	5. Reduce impact on climate change	- Contribution to the change in GHG emissions (CO2, N2O, CH4, SF6, HFC, PFC (%)), as a result of the construction of the solar power plant
	6. Preserve water quality	- Serbian water quality index (SWQI) - Emissions of pollutants into water bodies - Drinking water quality
	7. Preserve soil quality	- Percentage of contaminated surfaces - Change in land use
Protection of the landscape	8. Protect landscapes	- Number and spatial arrangement of planned solar panels - Exposure/visibility of the location
Protection of cultural heritage	9. Preserve cultural heritage	- Number of potentially endangered sites with cultural heritage
Protection from non-ionizing radiation	10. Reduce non-ionizing radiation	- Sources of non-ionizing radiation of special interest - Number of buildings that may be affected by non-ionizing radiation as a result of the solar power plant project
Population and socioeconomic development	11. Reduce population exposure to project impacts	- Number of buildings in a zone with increased noise levels and accident risk - Total noise indicator
	12. Promote economic growth and the use of renewable energy sources	- Number of employees involved in the construction and operation of the solar power plant - Revenue of the local community, companies, and individuals from the project implementation - Consumption of primary energy from renewable sources

Table 1. SEA objectives and related environmental receptors [55].

Environmental Receptors	Special Goal of the SEA	Indicators
Protection of biodiversity	Reduce harmful impact on fauna	- Number and status of potentially endangered species
	2. Reduce harmful impact on flora	- Number and status of potentially endangered species
	3. Preserve biodiversity and habitats	- Species diversity
Protection of basic elements of the environment	4. Preserve air quality	- Number of days when the emission limit value for PM particles, CO, SO2, and NO2 was exceeded as a result of the construction of the solar power plant
	5. Reduce impact on climate change	- Contribution to the change in GHG emissions (CO2, N2O, CH4, SF6, HFC, PFC (%)), as a result of the construction of the solar power plant
	6. Preserve water quality	- Serbian water quality index (SWQI) - Emissions of pollutants into water bodies - Drinking water quality
	7. Preserve soil quality	- Percentage of contaminated surfaces - Change in land use
Protection of the landscape	8. Protect landscapes	- Number and spatial arrangement of planned solar panels - Exposure/visibility of the location
Protection of cultural heritage	9. Preserve cultural heritage	- Number of potentially endangered sites with cultural heritage
Protection from non-ionizing radiation	10. Reduce non-ionizing radiation	- Sources of non-ionizing radiation of special interest - Number of buildings that may be affected by non-ionizing radiation as a result of the solar power plant project
Population and socioeconomic development	11. Reduce population exposure to project impacts	- Number of buildings in a zone with increased noise levels and accident risk - Total noise indicator
	12. Promote economic growth and the use of renewable energy sources	- Number of employees involved in the construction and operation of the solar power plant - Revenue of the local community, companies, and individuals from the project implementation - Consumption of primary energy from renewable sources

The importance of SEA goals and indicators (Table 1) in the semi-quantitative method of multi-criteria evaluation is exceptionally high. Namely, the evaluation procedure of planning solutions is carried out with respect to them. This is achieved by forming matrices in which planning solutions are intersected with SEA goals and indicators, and then evaluated in relation to the defined criteria.

4.2. Environmental Impact Assessment

The main goal of implementing the SEA procedure is to look at all aspects of possible impacts that may arise in the environment as a result or consequence of the implementation of a specific spatial development policy. This is achieved by predicting future trends in the environment, after which guidelines are determined for the implementation of the planned concept of spatial development, which prevent conflicts in space and present conclusions based on which decisions are made about future spatial development in a certain area.

According to the size and characteristics of the location where it is planned, the agrisolar power plant “Agrosolar Kula” can have certain positive and negative effects on space and the environment. That is why it was necessary in the SEA to look at all possible changes in the environment related to the spatial (not technical) aspects of the construction and operation of the solar power plant. This is initially carried out by comparing variant solutions of spatial development, and then the impact of the selected variant is evaluated in relation to individual planning solutions.

4.2.1. Assessment of the Impact of Variant Solutions

Variant solutions represent different options for the spatial organization of the solar power plant, primarily of the solar panels within the solar power plant and their compliance with the results of spatial analyses and observations of biodiversity at the location. To evaluate the impact of variant solutions, matrices were created in which SEA areas were used for the evaluation. Illustrative presentation of the matrices for the evaluation of variant solutions for the agrisolar power plant complex “Agrosolar Kula” is given in

Table 2. Illustrative presentation of the evaluation of variant solutions in the form of matrices [55].

SEA Area	Alternative Solutions	SEA Goals
		1	2	3	4	5	6	7	8	9	10	11	12
Spatial unit 1 for electricity production in APP	A	−	−	+	0	−	0	−	0	+	0	0	+
	B	0	0	0	0	0	0	−	0	−	0	0	−
Spatial unit 2 for electricity production in APP	A	−	−	+	0	−	0	−	0	+	0	0	+
	B	0	0	0	0	0	0	−	0	−	0	0	−
Areas for agricultural activity in zone APP	A	−	−	+	0	−	0	−	0	+	0	0	+
Area for construction of high-voltage SS	B	0	0	0	0	0	0	−	0	−	0	0	−
…	A	…	…	…	…	…	…	…	…	…	…	…	…
	B	…	…	…	…	…	…	…	…	…	…	…	…
n	A	…	…	…	…	…	…	…	…	…	…	…	…
	B	…	…	…	…	…	…	…	…	…	…	…	…

Meaning of symbols: APP: agrisolar power plant; SS: substation; +: overall positive impact; −: overall negative impact; 0: no direct impact or unclear impact; A: plan implementation option; B: no implementation option.

.

Although Spatial unit 1 (354 ha) and Spatial unit 2 (360 ha) form one functional unit planned for the installation of solar panels, they are separated into two spatial units because they are physically separated by existing spatial restrictions, protective infrastructural corridors, and other modes of space use. Due to the fact that the micro-locations where the two spatial units are located here have spatial peculiarities, they are also treated as separate units in the SEA.

The assessment of the impact of variant solutions took place in SEA through several stages:

• Phase I—Initial positioning of solar panels and functional zones based on the initial desire of the investor, without spatial analysis and consideration of possible environmental impacts. It served as a basis for creating spatial analyses and obtaining the conditions of relevant institutions;
• Phase II—Positioning of solar panels and functional zones based on conditions and guidelines of relevant institutions;
• Phase III—Positioning of solar panels and functional zones based on detailed spatial analyses and observations of biodiversity;
• Phase IV—The final version of the positioning of solar panels and functional zones in relation to the results of the previous phases and with the consent of the relevant institutions.

After the selection of the most favorable variant solution, the evaluation of planning solutions was conducted employing the semi-quantitative method.

4.2.2. Evaluation of the Impact of Planning Solutions with the Definition of Evaluation Criteria

The evaluation of the characteristics and importance of the impact of planning solutions in SEA was carried out using a semi-quantitative method in relation to groups of criteria that determine importance, spatial scale, probability, and the duration of the impact of planning solutions, as well as in relation to SEA objectives and indicators. The evaluation criteria are presented in the

Table 3. Criteria for impact assessment [55].

Magnitude of Impact	Lebel	Description
Critical	−3	Overloads the capacity of the space
Higher	−2	Significantly damages the environment
Smaller	−1	Minimally damages the environment
Neutral	0	No impact
Positive	+1	Minor positive changes in the environment
Favorable	+2	Favorable changes to environmental quality
Very favorable	+3	Changes considerably improve the quality of life
Impact significance	Lebel	Description
National	N	Possible national impact
Municipal	M	Possible municipal impact
Local	L	Possible local impact
Probability of impact	Lebel	Description
100%	C	Impact certain
Over 50%	Pr	Impact probable
Less than 50%	Po	Impact possible

.

Additionally, further criteria can be derived based on the duration of the impact or its consequences. In this sense, temporary intermittent (T) and long-lasting (Ll) effects can be defined.

It was decided that the impacts of strategic importance for the agrisolar power plant complex “Agrosolar Kula” are those that have a strong or greater (positive or negative) effect on the entire location or on an area that is larger than the space within the boundaries of the planned solar power plant, according to the criteria in

Table 4. Criteria for evaluating the importance of impact [55].

Scale	Magnitude		Significant Impact Label
National Level: N	Strong positive impact	+3	N +3
	Stronger positive impact	+2	N +2
	Strong negative impact	−3	N −3
	More severe negative impact	−2	N −2
Municipal level: G	Strong positive impact	+3	M +3
	Stronger positive impact	+2	M +2
	Strong negative impact	−3	M −3
	More severe negative impact	−2	M −2
Local level: L	Strong positive impact	+3	L +3
	Stronger positive impact	+2	L +2
	Strong negative impact	−3	L −3
	More severe negative impact	−2	L −2

.

Based on the criteria for assessing the size, spatial scales, estimation of the probability, and duration of the impact of specific planning solutions (

Table 5. Presentation of part of the planning solutions included in the impact assessment [55].

No.	Planning Solution
1	Unit 1 for the production of electricity in an agrisolar power plant (AE)
2	Unit 2 for the production of electricity in an agrisolar power plant (AE)
3	Areas for agricultural activity in the zone of the agrisolar power plant (AE)
4	Area for the construction of a high-voltage substation (SS)
…	…
n	…

) on SEA goals and indicators, a multi-criteria evaluation procedure and the determination of the significance of the identified impacts were performed.

The assessment of the impact on the environment and elements of sustainable development was carried out in matrices, i.e., in

Table 6. Illustrative presentation of the assessment of the size of the impact of planning solutions [55].

Planning Solutions	SEA Objectives
	Reduce Harmful Impact on Fauna	Reduce Harmful Impact on Flora	Preserve Biodiversity and Habitats	Preserve Air Quality	Reduce Impact on Climate Change	Preserve Water Quality	Preserve Soil Quality	Protect Landscapes	Preserve Cultural Heritage	Reduce Non-Ionizing Radiation	Reduce Population Exposure to Project Impacts	Encourage Economic Growth and Use of RES
Unit 1 for electricity production in APP	−1	−1	−1	+1	+2	−1	−1	−1	−2	0	0	+3
Unit 2 for electricity production in APP	−1	0	−1	+1	+2	−1	−1	−1	−1	0	0	+3
Areas for agricultural activity in zone APP							−1
Area for construction of high-voltage TS	0	0	0	0	0	−1	−1	−1	−1	−1	0	+3
…	…	…	…	…	…	…	…	…	…	…	…	…
n	…	…	…	…	…	…	…	…	…	…	…	…

criteria according to Table 3.

,

Table 7. Illustrative presentation of assessments of the spatial scales of the planning solution’s impact [55].

Planning Solutions	Objectives of SPU
	Reduce Harmful Impact on Fauna	Reduce Harmful Impact on Flora	Preserve Biodiversity and Habitats	Preserve Air Quality	Reduce Impact on Climate Change	Preserve Water Quality	Preserve soil Quality	Protect Landscapes	Preserve Cultural Heritage	Reduce Non-Ionizing Radiation	Reduce Population Exposure to Project Impacts	Encourage Economic Growth and Use of RES
Unit 1 for electricity production in APP	L	L	L	L	L	L	L	L	N			N
Unit 2 for electricity production APP							L
Areas for agricultural activity in zone APP	L	L	L				L	L
Area for construction of high-voltage TS						L	L	L	N	L		N
…	…	…	…	…	…	…	…	…	…	…	…	…
n	…	…	…	…	…	…	…	…	…	…	…	…

criteria according to Table 3.

and

Table 8. Illustrative display of the identification of impacts of planning solutions [55].

Planning Solutions	Identifying Strategic Impacts		Explanation	Smaller Impacts on SEA Objectives	Explanation
	SEA Objec.	Rank
Spatial units for electricity production in APP	5	N + 2 /Po /Ll	The construction of the solar power plant will have a strong positive impact on increasing the usage of RES and improving the RS portfolio in this area. This strategically important influence goes beyond local frameworks and has national significance. Given the unexplored nature of the planning area in the context of immovable cultural assets, it is theoretically possible that during the works such findings are encountered and damaged. This influence, however, is conditional because preventive archaeological supervision is foreseen in the SEA.	1, 2, 3, 6, 4, 5	Bearing in mind the results of biodiversity observations and the application of the principle of preventive protection in planning, minor negative impacts on biodiversity and environmental factors are only theoretically possible and can mostly occur during construction, so their character is temporary, while positive impacts relate to climate change and air quality.
	12	N + 3 /C /Ll
Areas for agricultural activity in zone APP	/	/	/	7	The possibility of using of chemicalization in agriculture can have a negative impact on the quality of the soil in the location.
Area for construction of high-voltage TS	12	N + 3 /C /Ll	A strategically significant positive impact relates to enabling the use of RES in the solar power plant, i.e., creating preconditions for its connection to the electrical grid.	6, 7, 8, 9, 10	Smaller negative impacts refer to the construction period in which there may be a temporary impairment of the quality of the environment. In addition, non-ionizing radiation is expected at the source, but there is no exposure of people and objects to these influences.
…	…	…	…	…	…
n	…	…	…	…	…

.

In the matrices (Table 6 and Table 7), planning solutions are crossed with SEA objectives and evaluated according to the basic groups of criteria (Table 3) for the assessment of the size and the spatial scale of the impact. Strategically significant impacts are identified in relation to these two basic groups of criteria (Table 4). They additionally determine values according to the remaining two basic groups of criteria: probability of impact and its duration/frequency. An illustrative presentation of the multi-criteria evaluation is given in Table 6 and Table 7.

Given that the elaboration of the results of the applied method is essential for making optimal decisions by decision-makers who often do not have the necessary level of knowledge in the field of environmental protection, it is extremely important that the presentation of the obtained SEA results is clear and simple. In this context, graphs (Figure 2) were used to display the total results, which fully represent the results obtained in the matrices with a simple display of the negative (to the left of the y axis) and positive (to the right of the y axis) impacts of each individual planning solutions in relation to SEA objectives.

The identification of strategically significant impacts and other (minor) possible impacts of individual planning solutions on the environment (Table 8) was approached after the multi-criteria evaluation of planning solutions had been carried out. Identified strategically significant impacts were then ranked by their influence. The rank of influence was determined for each individual planning solution according to which a strategically significant impact (positive and negative) was achieved. The identification of minor possible impacts, which do not have a strategic character, is also presented in this table. Smaller impacts are also important for seeing the whole picture of all the implications that may arise in the area as a consequence of the implementation of the planning propositions.

The multi-criteria evaluation process ends with the identification of potential impacts and their corresponding importance; however, the SEA process remains open. The environmental protection measures that must be put in place during project implementation, the guidelines for the EIA/ESIA procedure, and the monitoring of the environmental condition during the installation and operation of the solar power plant are all defined in the SEA, based on the findings of the environmental impact assessment. This usually includes continuous monitoring of habitats, flora, and fauna (both structural and operational) in order to take appropriate action in the event that new facts regarding the potential impact of the construction of the solar power plant on natural values is discovered.

5. Discussion and Conclusions

There are positive and negative impacts of solar power plants on the environment. As a rule, the positive impacts of large solar power plants have wider social and ecological significance, that is, they must be seen in a wider spatial, ecological, social, and energy context. This mainly refers to two dominant positive influences:

• Reducing the emission of polluting substances into the air: The production of electricity in solar power plants, unlike the production of electricity using fossil fuels, excludes emissions into the air, which indirectly has a favorable effect on the health of the population, biodiversity, and other elements of the environment. An additional contribution is that the development of solar energy in the future leads to a reduction in the use of fossil fuel power plants whose negative impact on the quality of the environment is multiple;
• Climate changes: Obtaining electricity in solar power plants does not produce gases with the greenhouse effect, so their contribution to the “stabilization” of the climate is significant. Thus, the positive impact on slowing climate change is another important and positive aspect of solar power plants, especially when coupled with the proportionate closure of fossil fuel-based power plants.

As for the possible negative impacts of solar power plants on space and the environment, they depend on the size and concept of the project and the specificity of the location where their realization is planned, and are mostly localized to a specific location and its immediate surroundings. The dominant negative impacts of solar power plants are related to the occupation of large areas of land, biodiversity, and the landscape.

All the negative impacts of solar power plants come from the occupation of large areas of land. However, it should be kept in mind that the importance varies depending on whether the areas that are devastated (quarries or areas where mining activities took place in the past) or are unusable for any other human activity (desert areas or barren lands) are occupied, or whether they are high-quality agricultural land, meadows, pastures, or other areas rich in biodiversity and specific landscape features. In the context of the impact on the land, sustainable solutions are needed, which can be achieved by optimally choosing the location of the wind farm at the earliest stage of project development, that is, by adequate solutions in the planning process and SEA. In addition, certain conceptual solutions are possible that can affect the relativization of the problem of occupying better quality land for the realization of solar power plants. Examples are the so-called agrisolar power plants like agrisolar power plant “Agrosolar Kula”, which is taken as a case study in this paper. Agrisolar power plants, in addition to using solar energy, ensure the continual usage of land for agricultural purposes, which is a well-known practice in developed and ecologically oriented countries. As part of the agrisolar power plant, solar panels are placed on a structure raised to a height sufficient to cultivate and maintain the plants below them, while achieving the optimal angle for receiving solar energy and transforming it into electricity. In addition to avoiding a change in the use of agricultural land, agrisolar power plants have the following benefits for cultivated agricultural crops: there is no direct light, there is a specific microclimatic effect, protection from hail, reduced evapotranspiration, and higher water efficiency. In this way, yields are increased, while at the same time the carbon footprint of agriculture is decreased. In addition to the above, the use of pesticides, herbicides, fertilizers and other toxic substances that pollute soil and water is usually not foreseen in agrisolar power plants. This helps the land to regain its microbiologically repaired, and sometimes even organic state, which raises the value of the land.

When it comes to the impact on biodiversity, it refers to the change in conditions at the location of the solar power plant, and therefore to the habitats and species that directly or indirectly depend on these habitats. In order to insure the preventive protection of biodiversity (habitats, flora, and fauna) in the area of the future solar power plant, it is necessary to optimally micro-locate solar panels based on detailed continuous observations of biodiversity that are part of the planning and SEA process. Interesting research by a group of scientists was published in the study “Solar parks can improve bird diversity in an agricultural landscape” [56]. Research has shown that solar power plants can play a positive role in promoting biodiversity, especially in birds, in the agricultural landscapes of central Europe, as they offer food availability and nesting sites. Thirty-two solar farm plots and thirty-two adjacent control plots were analyzed in Slovakia during one breeding season. During the research, 353 individuals from 41 species were observed in the solar power plants and 271 individuals from 40 species in the control plots. According to the researchers, the species richness, diversity, and number of invertebrate-eating species were higher in the solar power plants than in the control plots. Among the reasons cited by the research team is the availability of food for insectivorous birds, as solar panels attract different types of water-seeking aquatic insects. Given the low food availability in winter, it can be assumed that solar power plants may have a positive impact on birds in agricultural land outside the nesting season, as they can serve as stopover, feeding, and roosting sites during migration and wintering, because the ground under solar panels is often snow-free in winter. It was also observed that certain species of birds nested in the support structures of solar panels made of pipes, or in uncultivated or extensive vegetation under the solar panels or next to the fence. The study emphasized that the solar power plants used in the research were designed solely for electricity production, and that the benefits for biodiversity would be even greater if they were managed synergistically with a stronger focus on biodiversity.

When it comes to the impact of solar power plants on the landscape, their influence exists, but is smaller compared to energy facilities based on the use of fossil fuels (such as thermal power plants, surface mines, tailings, etc.). However, even in the case of an impact on the landscape, we come to the importance of the appropriate site selection through the process of planning and preparing the SEA. Today, the literature [57] points to the transformation of the landscape during the implementation of solar power plants and suggests addressing the issue through a combined spatial layout of the solar power plant and the landscape in the so-called solar landscape. Solar landscapes aim to achieve additional benefits (e.g., visibility reduction, habitat creation) alongside electricity production. There is an emphasis on the need to find new compromises between landscape characteristics and different types of solar landscapes. Some studies [58] highlight the importance of the social aspect in assessing the impact of the solar power plant on the landscape. Specifically, with the increase in the number of solar power plants in South Korea over the past decade, more than half of the country’s district governments have adopted restrictions for solar power plants. These restrictions are quite restrictive, as they reduce the available land for the solar power plant placement, reducing the contribution to decarbonization. The research implies that the development of solar power plants at the national level may face obstacles from local communities if there is no rational and even spatial distribution of development projects in the field of solar energy. Otherwise, there may be radical impacts on the landscape, and a radical approach towards the development of solar power plants in a particular area. This should definitely be taken into account when planning the space.

There are different approaches in assessment of the impact of solar power plants on the landscape. Most authors agree that the assessment must be carried out with the help of different instruments, models, and methods for simulating and visualizing possible impacts, whether it is wind [59,60,61], solar, or other power plants. In this context, different software models, GIS technologies, photomontage, and other methods can be used to make predictions about the impacts of the planned solar power plant on the landscape, i.e., to visualize and simulate the visibility of the solar power plant before it is realized in a specific area.

The scale of possible negative impacts of solar power plants on the environment depends on specific conditions at the micro-locational level. However, when determining the scale of possible negative impacts of solar power plants on the environment, one should always keep in mind the benefits of implementing such projects compared to the impacts of some other power plants (especially those that operate on the principle of using fossil fuels). The comparative analysis carried out in this way leads to the conclusion that even certain negative impacts of solar power plants on the environment are relative, because, in a broader context, they lead to certain positive trends in the environment and energy.

In any case, whether it is about predicting the positive or negative impacts of solar power plants on the landscape and the environment, the planning process plays a crucial role, applying SEA as a key instrument in implementing the principle of preventive environmental protection when selecting the location and initiating the development of the solar power plant project. In addition to the possibility of applying the concept of preventive protection in SEA, it is characterized by a holistic approach in understanding the interactions in a specific area. This makes it possible to prevent all potential risks that may arise in the later stages of project implementation, which is particularly important from the perspective of investors investing in solar power plant projects.

The application of SEA in the planning of solar power plants is based on the selection of optimal solutions that prevent conflicts in space. As demonstrated in this paper, this process, in a methodological sense, is achieved by a combination of different methodological approaches and impact assessment methods.

The basic methodological principles of the application of the semi-quantitative method of multi-criteria expert evaluation in the planning of solar power plants are illustrated in this paper using the concrete example of the application of SEA for the agrisolar power plant complex “Agrosolar Kula”. The results of the application of this impact assessment method served as a support in making decisions about the spatial development of the wind farm in the specific area.

In summary, the semi-quantitative method of multi-criteria expert evaluation is a useful support in evaluating the impact of a solar power plant in SEA, preventive environmental protection in the area where the construction of the solar power plant is planned, and in the process of making optimal decisions about spatial development.

After the implementation of the SEA procedure, the logical continuation is the implementation of the EIA/ESIA procedure in the phase of technical documentation drafting, which can be relaxed once potential conflicts in the area are avoided through the application of the concept of preventive protection in SEA.

The negative context of the SPU application in relation to the stated views can be twofold:

• In the assessment of the impact of those elements in SEA that are based on the subjectivity of expert opinions;
• In the decision-making based on the results of SEA, because it does not always depend solely on the quality of processing the results, but on the attitudes and knowledge of decision-makers.

Therefore, in both cases, the term “subjectivity” appears, so, at least in the SEA process, it is necessary to achieve the maximum possible objectivity by applying available techniques (e.g., software and mathematical models, observations based on quantitative statements of results), along with the continuous education of decision-makers.