Strategic Environmental Impact Assessment for Onshore Windfarm Siting in Greece

The distance between theory and practice in the strategic environmental assessment (SEA) process is particularly noticeable. The development of an integrated, comprehensive and systematic approach guided by the related literature is considered to be an ideal condition for enhancing the value of SEA and increasing its effectiveness. The aim of the present paper was to develop a methodological approach of the most technical and critical stages of SEA for onshore wind farm (OWF) siting. The methodological framework included the proposal of the SEA objectives along with the indicators’ development, the identification of alternatives, the selection of a ‘most viable or sustainable’ alternative, the identification of potential impacts, their assessment, and finally, the proposal of a SEA monitoring system using both qualitative and quantitative methods, tools, and techniques. OWF siting within low and/or moderate sensitivity areas was considered as the most viable/sustainable alternative. SEA highlighted that OWF siting caused moderately to highly significant negative impacts on the thematic section of biodiversity and extremely significant positive impacts on the thematic sections of renewable energy sources, economy, and society. Although the proposed methodology was applied on SEA of OWF siting in Greece, it can be used universally to identify the impacts of OWF siting planning.


Introduction
The conceptualization of SEA started much earlier, almost in parallel with environmental impact assessment (EIA) at a project level. The main purpose of strategic environmental assessment (SEA) is to facilitate an early and systematic consideration of potential environmental impacts in strategic decision-making [1,2]. In recent years, SEA has evolved and been applied worldwide in a variety of sectors and in various ways to identify and assess the potential environmental impacts of policies, plans, and programs (PPPs), as well as to identify and evaluate alternatives to avoid, mitigate, or compensate for these impacts [3][4][5][6][7].
During this time, several critical issues relating not only to its theoretical framework, but also to its methodological approach, have appeared. Regarding the implementation level, these issues can be categorized into two basic groups. The first concern the lack of a SEA guideline and the second, the lack of training by experts [8]. In the first case, the lack of a comprehensive, systematic, and formal guideline on SEA techniques and methodology [8,9] strengthens its methodological uncertainty and key questions that remain unanswered, such as how SEA should be conducted according to the implementation level PPPs; the sector, and their impact on the environment, economy, and society [10]; which analytical and participatory methods and tools should be used and in which stages of SEA process, etc. Noble et al. [9] highlighted that present discussions and surveys on a SEA methodology renewable energy development has been limited to a few studies (e.g., [27]). This paper is the first international English-speaking publication on SEA in Greece.

Environmental, Economic, and Social Baseline of the Study Area
Greece covers 131,957 km and its total population was estimated at 10.7 million people in 2018 [28], showing a steadily downward trend. It displays a variety of environmental elements of particular interest. According to land cover data, the largest area of the country is covered by agricultural land, forests, and developed land, with the former two showing a shrinking of 0.04% (total area 51,269 km 2 ) and 0.17% (total area 24,872 km 2 ) respectively, while the latter, an increase of 0.69% (total area 3741 km 2 ) for the period 2000-2012 [29]. Moreover, there is a remarkable and complicated biodiversity, ranking it among the richest countries in Europe for biodiversity [30]. In order to protect and preserve this diversity, many areas are subject to more than one national (National and Regional Parks, Preserved Monuments of Nature, Wildlife Refuges, etc.) or international (Natura 2000 Network, Wetlands of International Importance-Ramsar, etc.) protection regime. A remarkable number of protection regimes concerning cultural heritage protection and reservation-e.g., UNESCO World Heritage Sites and Monuments, archaeological sites, traditional settlements, etc.-exist in the country. Figure 1a,b illustrate the environmentally protected areas defined by these conventions and the country's cultural heritage accordingly. According to the national program, "monitoring of the water quality of river, lake, coastal and transitional waters of Greece for the implementation of Article 8 of the Water Framework Directive 2000/60/EC" (i) with respect to the quantitative status, 81-83% of the monitoring points are classified as good status, 15-17% as bad status and roughly 2-3% remain in an unknown condition due to the lack of measurements and insufficient data; and (ii) with respect to the qualitative (chemical) status, 58-60% is in good status, 30% is in bad status [30].
A declination tendency for the main pollutant gases emission levels (NOx, SOx, CO, PM2.5, PM10, NH3, NMVOC) exists and reductions in the range of 20-80% were observed for all pollutants in 2015 (base year 1990) [30]. More specifically, 2015 emissions of sulfur oxides (SOx as SO2) were reduced by 80% in comparison to 1990. Emissions of nitrogen oxides (NOx as NO2) also diminished by 31% since 1990, and similar reductions (37% and 34% for 2015 since 1990) have been also recorded for emissions of NMVOCs and PM2.5, respectively. The decline of emissions of NH3 and PM10 has been of a lesser magnitude: (22%) and (20%), respectively [30]. Regarding climate change, Greece is in full compliance with the goals of the Paris Agreement 2015 under the United Nations Framework Convention on Climate Change [31]. Particularly, there is a gradual reduction of greenhouse gas (GHG) emissions level for the period 2007-2015, with emissions from energy production diminishing by 31.3% and from transport by 26.3% [30].
Regarding economic situations and trends, the number of employed persons in Greece was estimated at 3830.99 thousand people in 2018 and the seasonally adjusted unemployment rate edged up to 18.4% in December 2018 [28]. The gross value added generated by mines and quarries, energy processing, water supply, water treatment, and waste management, shows a significant variance for the period 1995-2017, where in 2017, it increased and reached almost 25,000 million euros [32]. The main energy indicators that outline Greece's energy profile are as follows [33]: (i) RES production was 1.  According to the national program, "monitoring of the water quality of river, lake, coastal and transitional waters of Greece for the implementation of Article 8 of the Water Framework Directive 2000/60/EC" (i) with respect to the quantitative status, 81-83% of the monitoring points are classified as good status, 15-17% as bad status and roughly 2-3% remain in an unknown condition due to the lack of measurements and insufficient data; and (ii) with respect to the qualitative (chemical) status, 58-60% is in good status, 30% is in bad status [30].
A declination tendency for the main pollutant gases emission levels (NO x , SO x , CO, PM 2.5 , PM 10 , NH 3 , NMVOC) exists and reductions in the range of 20-80% were observed for all pollutants in 2015 (base year 1990) [30]. More specifically, 2015 emissions of sulfur oxides (SO x as SO 2 ) were reduced by 80% in comparison to 1990. Emissions of nitrogen oxides (NO x as NO 2 ) also diminished by 31% since 1990, and similar reductions (37% and 34% for 2015 since 1990) have been also recorded for emissions of NMVOCs and PM 2.5 , respectively. The decline of emissions of NH 3 and PM 10 has been of a lesser magnitude: (22%) and (20%), respectively [30]. Regarding climate change, Greece is in full compliance with the goals of the Paris Agreement 2015 under the United Nations Framework Convention on Climate Change [31]. Particularly, there is a gradual reduction of greenhouse gas (GHG) emissions level for the period 2007-2015, with emissions from energy production diminishing by 31.3% and from transport by 26.3% [30].
Regarding economic situations and trends, the number of employed persons in Greece was estimated at 3830.99 thousand people in 2018 and the seasonally adjusted unemployment rate edged up to 18.4% in December 2018 [28]. The gross value added generated by mines and quarries, energy processing, water supply, water treatment, and waste management, shows a significant variance for the period 1995-2017, where in 2017, it increased and reached almost 25,000 million euros [32]. The main energy indicators that outline Greece's energy profile are as follows [33]: (i) RES production was 1. Finally, the results of the Report on Health Profile of Greece on health situations and trends show that it is constantly improving, as 74% of the population declare themselves as healthy, exceeding the European average [34]. The life expectancy is 81.5 years, the healthy years are up to 65 and most deaths are due to heart diseases and cancer, and an important factor causing health problems is the exposure to certain atmospheric pollutants such as NO 2 and O 3 [34].

Methodological Framework
The SEA process encompasses the following stages: identifying PPP objectives (screening), setting goals (scoping), selecting indicators (baseline), predicting impacts (scenarios), and public consultation and monitoring [2,35]. The methodological approach deployed in this paper includes the following six stages: (i) the development of SEA objectives and indicators, (ii) the identification of alternatives, (iii) the selection of the 'most viable or sustainable' alternative, (iv) the identification of potential impacts, (v) impact assessment, and (vii) the proposed monitoring process. Figure 2 presents the methods, tools, and techniques used as well as the main outputs of each stage.

Development of SEA Objectives and Indicators
In order to integrate sustainable development principles into OWF siting planning, the objectives and indicators (OI) effectiveness criteria by [5,36], as well as the OI development guide proposed by [36] were adopted.
The development of an OI system is a rather difficult and complicated process in most cases. Therivel [5] and Donnelly et al. [36] argued that objectives and indicators should have the following characteristics: being understandable, referring to the corresponding scale of PPPs, requiring available data, avoiding overlapping, showing compatibility, focusing on results, being defined in technical terms, providing a quick update, and referring to corresponding conditions. Donnelly et al. [36] proposed a systematic guide for developing objectives and indicators which is considered as a highly significant methodological step and as one of the rare handful attempts for SEA methodology formulation. The main objective of the guide is to develop a diagrammatic process based on a sequence of questions that finally recommends an effective and integrated system of objectives and indicators.

Development of SEA Objectives and Indicators
In order to integrate sustainable development principles into OWF siting planning, the objectives and indicators (OI) effectiveness criteria by [5] and [36], as well as the OI development guide proposed by [36] were adopted.

Identification of Alternatives
The existing legal framework for OWF siting in Greece (SFSPSD-RES) [25] suggests a siting approach using several national-level siting criteria that are adapted to the characteristics of the host regions. The present paper proposes the following alternatives considering both the SFSPSD-RES and the contemporary literature on OWF siting: Although numerous studies in the literature suggest criteria and their minimum allowed limits for OWF development at global level (e.g., [37][38][39][40][41][42][43][44][45][46]), in this paper, the literature review is restricted to Greek case studies found in the literature (e.g., [47][48][49][50]). Finally, a few criteria were suggested by the authors and not found either in the SFSPSD-RES or in the literature review (e.g., continuous and discontinuous urban web). The criteria, as well as their minimum limits applied for alternative 2, are presented in Table 1. The same criteria were also applied for alternative 3, apart from the criterion of 'protected areas', whose minimum allowed distance was set equal to 0 m.

Selection of the 'Most Viable or Sustainable' Alternative
One of the most common methods of the decision-making process is the use of criteria. Criteria provide the opportunity for comparability and assessment of different development scenarios in order to identify the one that best meets planning needs [5,[55][56][57][58]. In addition, SEA is considered to be a strategic decision-making tool as its stages are developed in a similar way to those of strategic decision-making [5]. In this paper, various decision-making criteria ( Table 2) were suggested to compare and assess the three proposed alternatives for OWF siting in Greece.

Identification of Potential Impacts
Extensive literature investigating the environmental, economic, and social impacts of OWF energy is available. The land use conflict, the shrinkage of areas with remarkable environmental elements, the loss of biodiversity, the aesthetics of OWF, and public opposition towards OWF projects (not in my back yard (NIMBY) Syndrome), the impacts on human health, and economic profit are only a few of the issues that incite intense controversy and discussions in the international community (e.g., [59][60][61][62][63]). It should be noted that although NIMBY syndrome as a social phenomenon appears mainly in cases of projects and activities such as landfilling, mining, etc., renewable energy sources with strong general support are also subject to local opposition (e.g., Town of the Blue Mountains, Ontario [64]). At this stage, an effort was made to identify impacts on TS1 and TS2, considering not only the impacts that come directly from wind turbines themselves, but also the impacts attributed to their associated facilities/projects such as roads, support structures, networks, stations, etc.

Impact Assessment
Impact assessment is one of the most crucial stages of SEA. In order to respond satisfactorily to the requirements of this stage, the present paper adopted both qualitative and quantitative assessment to evaluate any potential impact that might be caused by the planning of OWF siting.

Qualitative Impact Assessment
The qualitative impact assessment process was performed in two steps. More specifically, a set of criteria (direct/indirect, short/long-term, construction phase (CP)-operation and maintenance (O/MP)-withdrawal (WP) phase of appearance, cumulative or not) was developed to identify the key characteristics of the impacts at each TS. In the second step, several criteria, including type (positive/negative), extend (low/moderate/high), duration (CP-O/MP-WP), intensity (low/moderate/high), time of appearance (primary/secondary), and probability of appearance (low/moderate/high) were used to further qualitatively assess the individual impacts of the OWF siting.

Quantitative Impact Assessment
Once the impacts were identified, analyzed, and prioritized through the qualitative impact assessment process, a quantitative impact assessment followed in order to further identify the major-positive and negative-impacts under three possible OWF siting scenarios of different total output capacity scales. These scenarios were developed to incorporate different OWF siting characteristics. Thus, the first scenario (Scenario 1) concerned the case that OWF development is characterized by (i) small land occupation, (ii) small wind turbine size, and (iii) small distance between wind turbines. The second scenario (Scenario 2) is characterized by (i) medium land occupation, (ii) medium wind turbine, and (iii) medium distance between wind turbines. The third scenario (Scenario 3) is characterized by (i) extended land occupation, (ii) large wind turbine, and (iii) large distance between wind turbines. In this context, the rapid impact assessment matrix (RIAM) initiated by Pastakia and Jensen in 1998 [65] was applied as an assessment tool which allows subjective judgments to be quantitatively recorded.
The RIAM method is based on adaptive and categorized assessment criteria which are given an indicative value system to provide an accurate and independent score. The assessment criteria are categorized into two pre-defined groups. The first group (Group A) includes criteria that are of high importance and can individually affect the score obtained, and the second group (Group B) includes criteria that are of high importance but individually do not have a significant effect. In this paper, the criteria of the qualitative assessment that preceded were used, and the defined groups were formed as follows: Group A included type (A1), area (A2), duration (A3), and intensity (A4); while Group B included the time of appearance (B1), the probability of appearance (B2), and cumulative impacts generation (B3). These criteria were further attributed to a scoring system based on their escalating intensity and significance displayed in the three OWF development scenarios (Table A1). Then the method determined the application of the following formulae (1,2,3) to allow weighted scores to be defined on the same basis.
where, ES is the final assessment score that is the result of the multiplication of the scores of the Group A criteria with the sum of the scores of the Group B criteria.
Once formulas (Equations (1)-(3)) were applied, ES was recorded, and the impacts were demonstrated using scales. The proposed ES range and range bands are presented in Table A2, where positive and negative impacts range from 6 (extremely significant positive impact) highly significant to -6 (extremely significant negative impact).

Proposed Monitoring Process
Article 10 of the SEA Directive (ED 2001/42/EC) underlines that "the development and the implementation of a monitoring system is very crucial for identifying the likely adverse impacts and mitigate or even eliminate them". The present paper aimed to develop an appropriate monitoring system including not only environmental components but also economic and social parameters. In addition, this system complies with the SEA objectives and indicators system proposed in the first stage in order to achieve compatibility in the exported results and raise its effectiveness.

SEA Objectives and Indicators
Analyzing and evaluating the current situation of the environment, as well as measuring the performance baseline of OWF deployment, can be a tedious and complex process which requires an integrated, systematic, and consistent approach. The Development Guide by Donnelly et al. [36] was initially applied and the indicators were further elaborated to adapt and conform to available and accessible data. The final system of the SEA objectives and indicators for OWF siting in Greece is summarized in Table 3. It should be noted that the proposed OI System integrates and highlights the major environmnental, economic, and social factors related to OWF siting issues.

Identification of OWF Siting Areas in Greece (Based on Alternatives)
Taking into account the criteria presented in Table 1, as well as their constraints, and processing their data with the use of multiple tools in a geographic information system (GIS) environment, the maps in Figure 3a,b were created. These maps are the main output of the above process proposing the appropriate areas for OWF siting in Greece based on alternatives 2 and 3 (Section 3.2). It should be noted that the basic differentation of alternatives 2 and 3 relates to protected areas criterion management, where in alternative 2, OWF siting within them was avoided, as opposed to alternative 3 (however with an additional environmental study submitted).
The appropriate areas for OWF siting in Figure 3a are quite limited compared to the areas presented in Figure 3b, due to more severe environmental restrictions. The largest part considered as appropriate for OWF siting is located mainly in Western Macedonia, in a part of Central Greece and Peloponnese. Several individual areas also appear in Eastern Macedonia and Thrace and Crete and less in Central Macedonia, Epirus, and Western Greece. The appropriate areas for OWF siting in Greece are numerous both in the mainland and islands, especially in cases where OWF sitting is suggested within or close to environmental protected areas (Figure 3b).  The appropriate areas for OWF siting in Figure 3a are quite limited compared to the areas presented in Figure 3b, due to more severe environmental restrictions. The largest part considered as appropriate for OWF siting is located mainly in Western Macedonia, in a part of Central Greece and Peloponnese. Several individual areas also appear in Eastern Macedonia and Thrace and Crete and less in Central Macedonia, Epirus, and Western Greece. The appropriate areas for OWF siting in Greece are numerous both in the mainland and islands, especially in cases where OWF sitting is suggested within or close to environmental protected areas (Figure 3b).

'Most Viable or Sustainable' Alternative Selection
Based on the criteria (C1-C10) presented in Table 2, the three proposed alternatives were qualitatively assessed. Table A3 presents the interactions of alternatives with each criterion individually and estimates the effects using key symbols as follows: (++) in case the alternative covers satisfactorily the criterion; (+) in case the alternative covers the criterion; (−) in case the alternative does not cover the criterion; (?) in case there are doubts as to whether the alternative covers the criterion or not.
The qualitative assessment indicates that alternative 2 satisfies the criteria in most cases and more effectively (+++++++++++?+−+). More specifically, alternative 2 fully meets criteria C1, C2, C3, C5, and C6. It also adequately covers criteria C4, C8, and C10. However, there are doubts concerning the extent to which the second alternative is accepted by the local population without generating any conflict (C7) as the degree of acceptance depends on several factors such as the technology used, environmental education, etc. Finally, the selected alternative follows the directions of previous and existing policies and thus its innovation (C9) is considered low.

Identification of Impacts
The main impacts of OWF siting in the examined TS of natural and anthropogenic environment are briefly introduced in Figure 4.

Identification of Impacts
The main impacts of OWF siting in the examined TS of natural and anthropogenic environment are briefly introduced in Figure 4.

Qualitative Impact Assessment
Tables 4 and 5 are indicative illustrations of the qualitative impact assessment. More specifically, Table 4 presents the general structure of the first step of qualitative impact assessment (step 1), applied in one of the TS (biodiversity), while Table 5 presents the corresponding structure of the second step of qualitative impact assessment, applied in one of the impacts of biodiversity (loss,

Qualitative Impact Assessment
Tables 4 and 5 are indicative illustrations of the qualitative impact assessment. More specifically, Table 4 presents the general structure of the first step of qualitative impact assessment (step 1), applied in one of the TS (biodiversity), while Table 5 presents the corresponding structure of the second step of qualitative impact assessment, applied in one of the impacts of biodiversity (loss, fragmentation, and/or degradation of habitants).  Table 5. Second step of the qualitative impact assessment. Following the technical process steps of RIAM method by categorizing the proposed assessment criteria in the defined categories, attributing a scoring system based on the intensity and significance of criteria for each OWF development siting scenario and applying the formula system as previously described in Section 3.5.2, Table A4 in the Appendix A was developed, displaying the results of ES as well as their matching with the appropriate Range Band (RB).

TS/Impact Biodiversity/Loss, Fragmentation and/or Degradation of Habitants
More specifically, an expert panel (the authors of the paper) evaluated the impacts of each of the three defined scenarios against the main impacts of OWF siting in the examined TS and determined a score for each impact, based on the assessment criteria, providing a measure of expected impact. The panel members were exposed and well informed about the current situation of the region (Greece), background information about aspects of SEA planning work, as well as theoretical framework and technical aspects of the RIAM process. It should be mentioned that their expertise covered a variety of fields such as environmental planning, land-use planning, water resources, renewable energy sources, impact assessment.
A score for each main impact of OWF siting in the examined TS for the three scenarios was determined by expert judgment. In performing this task, the experts relied on the criteria described in Section 3.5.2 (Group A: type (A1), area (A2), duration (A3), and intensity (A4); Group B: time of appearance (B1), probability of appearance (B2), and cumulative impacts generation (B3)). In this way, each impact received a score based on the A and B criteria. If the scores for the A1, A2, A3, A4, B1, B2, and B3 criteria differed, depending on the expertise of the panel, the mean of the scores was selected to represent the A and B criteria for a given impact.
According to the results obtained in Table A4, the most critical impacts that may be caused under the first OWF siting scenario are changes in physical phenomena and RES promotion with very significant negative and positive impacts, respectively. Considering scenario 2, extremely significant negative impacts were caused due to loss, fragmentation and/or degradation of habitats, collision risk, and cultural heritage quantity and quality degradation, whereas RES promotion, job growth, and market diversification caused extremely significant positive impacts. Finally, scenario 3 presents almost the same impacts are scenario 2, although it caused extremely significant negative impacts because of habitat disorder and displacement.

SEA Monitoring System
Monitoring could be facilitated and performed in a systematic and simple manner through the use of indicators. According to [5], the system of objectives and indicators developed at an initial stage (development of SEA objectives and indicators), should also be maintained at the monitoring stage.

Conclusions
Strategic environmental assessment has been widely recognized as an assessment tool, especially in recent years. This recognition stems from its own value and ability to support a strategic decision-making process towards sustainable development. More particularly, the ability to develop a sustainability strategy through objectives and indicators, identifying and selecting the most suitable alternative based on this strategy, as well as identifying and addressing the cumulative impacts of policies, plans and programs (PPPs) at early stages in planning, are key advantages over other assessment tools (e.g., health impact assessment (HIA), environmental impact assessment (EIA), risk assessment (RA)).
Although SEA has many advantages, there is an appreciable and crucial distance between its theoretical and methodological approaches. This distance is mainly caused by the lack of a formal, systematic, and comprehensive guideline, with methodological proposals and clarifications on several aspects and critical questions related to SEA implementation.
The present paper attempted to develop a methodological approach for the most technical stages of SEA, combining both qualitative and quantitative methods. More specifically, this paper developed a framework that included the following stages: (i) the development of SEA objectives and indicators, (ii) the identification of alternatives, (iii) the selection of the 'most viable or sustainable' alternative, (iv) the identification of potential impacts, (v) impact assessment, and (vii) a proposed monitoring process.
The system of objectives and indicators includes 19 objectives and 30 indicators considering literature review related to SEA effectiveness, national and European legislative frameworks, energy studies requirements, and personal judgment. The system of objectives and indicators addresses not only the thematic sections proposed by the SEA directive, but also other thematic sections, covering economic as well as social aspects of sustainable development, providing an integrated system of objectives and indicators. At the second stage, three alternatives were developed: (i) OWF siting considering the existing siting criteria, (ii) OWF siting within low and/or moderate sensitivity areas considering several exclusion criteria, and (iii) OWF siting within or close to high sensitivity areas considering several exclusion criteria. This stage presents, implements, and visualizes through thematic maps, realistic alternatives that fulfil certain environmental, economic, and social criteria and restrictions, minimizing potentially incompatible land-uses and consequently unsustainable development. At the third stage, the alternative that satisfies more efficiently the proposed assessment criteria (C1-C10) was selected through qualitative assessment (second alternative). The proposed set of assessment criteria can provide an integrated assessment of alternatives based on monitoring the extent of the achievement of national and SEA objectives, as well as their effectiveness. In the fourth stage, the identification of potential impacts concerns both natural and anthropogenic environment. The involvement of an anthropogenic environment in the SEA process distinguishes this work from similar efforts. In the next stage, the main potential impacts caused by the second OWF siting alternative were identified and then qualitatively and quantitively assessed. In terms of qualitative impact assessment, several criteria were used to evaluate the impacts at TS level as well as each individual impact separately, while in terms of quantitative impact assessment, a modified RIAM method was applied in order to further identify the most crucial impacts for three OWF sitting scenarios. The modified version of the RIAM method includes different assessment criteria and scaling. Finally, a system of objectives and indicators were developed to support the monitoring process, following the SEA objectives and indicators' direction suggested at the first stage of the methodology.
The key findings of this study were (a) OWF siting within low and/or moderate sensitivity areas considering several technical, environmental, and economic restrictions, as well as various social aspects were considered as the most viable/sustainable alternative of OWF siting; (b) OWF siting caused moderate to extremely significant negative impacts on the thematic section of biodiversity and extremely significant positive impacts on the thematic sections of renewable energy sources, economy, and society; and (c) SEA monitoring should be achieved by the constant monitoring of a proposed system of indicators (impact monitoring indicators-IMI).
The attempt to develop a methodological approach for the technical stages of the SEA is a laborious, time-consuming process that might conclude to an undoubtedly effective proposal. A single and systematic SEA guideline that will include holistic methodological proposals is necessary, not only to facilitate but also to coordinate the whole process. The proposed methodology for SEA of OWF siting planning in Greece adapts and combines several remarkable tools and techniques. The distinct stages that the relevant methodology includes can be applied in relation to various study areas and diverse planning scales, contributing effectively to sustainable development.