Landscape and wind turbines

Landscape Dimensions - Reflections and proposals for the implementation of the European Landscape Convention

Emmanuel Contesse, avril 2017

INTRODUCTION

Wind turbines as a singular object are often perceived positively by both local and visiting observers. The assessment of wind farms is more nuanced. It is more difficult to assess whether the landscape in which wind farms are located is enhanced or diminished. Wind turbines do not hide themselves. The sheer size of wind turbines, combined with the very large areas required to build them, make them particularly visible in the landscape. As the principle of landscape integration is not, or only with difficulty, applicable to land-use planning for wind turbines, the basic premise of this report is to integrate wind turbines into the landscape, taking into account the specificities of the host landscape. Wind turbines can thus become a landscape planning tool that enhances or spares an area. The installation of wind turbines must therefore be the subject of a landscape project in the same way as any other type of infrastructure. It is also important to carry out landscape reflections for offshore wind turbines. Coastal marine areas should be considered as a landscape in the same way as the mainland. This project approach takes into account all elements, large or small, exceptional or ordinary, natural or man-made. It can ultimately determine the capacity or incapacity of absorption or transformation ensuring landscape coherence and thus a positive perception by the population and visitors. According to the European Landscape Convention, landscape is the result of the actions of man on his environment. The recommendations in this report are therefore not intended to protect ‘valuable’ landscapes from wind turbines, but rather to define a method of managing landscapes with wind turbines by transforming the landscape in a coherent way, while preserving its important elements. This report sets out the main general theoretical aspects which apply to all landscapes, with criteria and detailed analyses varying from area to area.

Context and issues

Renewable energy sources, of which wind power is one, are seen as essential for future energy autonomy. As a new component of the landscape, wind turbines and their « landscape integration » are the subject of much discussion. At the same time, the pressure on the landscape is also increasing and conflicts of interest are recurrent. The exponential development of wind energy creates an additional landscape challenge for the Member States. Given their large size and the problems associated with energy transport, noise and shadowing, among others, wind turbines are a particularly difficult issue to manage in spatial planning.

Approach

This report summarises the main issues related to the development of wind farms and the possible approaches to ensure a good landscape integration in the sense of the European Landscape Convention. It is not intended to be exhaustive and to provide a detailed approach to wind farm planning for each Member State. Indeed, the specific landscape, cultural and political characteristics of each territory and their apprehension are very different from one State to another. The first part defines the general approach to landscape planning for wind energy and the different important project phases. The second part deals with the landscape principles to be considered in any wind energy project. These are all the general aspects that are crucial for the successful insertion or exclusion of wind turbines in a landscape according to its specific characteristics. These two sections apply equally to a single wind farm project as to a region-wide master plan with several potential wind farms. The spatial planning approaches and landscape principles developed in this document are also valid for wind farms in coastal and offshore areas. These areas should be considered in the same way as the rest of the country and strategies should be developed to ensure that valuable views from and to the coast are not lost. The purpose of the report is to :

• to provide a general approach to landscape planning for wind turbines without fixing the methodology, so that it can be applied in all Member States;

• to propose tools and a general methodology for landscape-consistent planning of wind farms

• to define the landscape principles to be considered for the siting or exclusion of wind turbines.

1. LAND USE PLANNING

1.1 The need for spatial planning

Economic growth and the increasing needs it generates imply a continuous and rapid transformation of the territory, and consequently of the landscape. If this development is not planned and controlled, the legibility of the landscape can potentially become more complex. The identification with the landscape by the population can consequently disappear and imply a banalization of the landscape. Consequently, the public authorities have set up spatial planning instruments that enable them to influence territorial development. One of the challenges of spatial planning is to maintain or restore landscape coherence to territories, whether they are ‘beautiful’, specific and rare or, on the contrary, commonplace and everyday. Wind turbines, just like other infrastructures (roads, industry, housing, etc.), must be integrated into the spatial planning process. This does not only mean considering wind turbines per se, but also all necessary ancillary infrastructure (power lines, roads, etc.).

1.2 Integration of Wind Turbines into Land Use Planning

This section gives general principles to be considered when integrating wind turbines into land use planning. Specific landscape-related elements (landscape analysis, criteria, selection, exclusion, etc.) are defined in the next section. Wind power planning is usually done in a sectoral plan, which will be integrated into an overall scheme. The wind power plan should be coordinated with the administrative bodies of neighbouring areas. In any case, the planning of wind power installations should be done at the highest administrative level of the state concerned. Furthermore, coordination with other sectoral plans (tourism, housing, industry, etc.) is important in order to avoid conflicts in planning and to concentrate the different infrastructures in the territory in the best way. In short, it is necessary to :

• to allocate the planning of wind power plants to the most supra-regional state bodies possible

• to coordinate planning principles with neighbouring states or administrative regions

• to coordinate wind energy planning with other sectoral planning

• to apply the principle of concentration at regional level by defining planning zones and exclusion zones

• to encourage clustering with other infrastructures and thus create clusters for renewable energy and other compatible industrial uses.

2. PROJECT APPROACH FOR LANDSCAPE INTEGRATION

The landscape project for the insertion of wind turbines should not be carried out independently. It is part of a package of parallel or preliminary studies which must be carried out in order to achieve coherent spatial planning. In summary, good planning consists of :

• negative: exclusion of areas for technical (grid connection, wind potential, noise, etc.), biological (protection of chiropterans and birdlife) and landscape (protected or emblematic areas) reasons

• positive: selection of favourable areas for wind and infrastructure.

All these sectoral studies must be part of an iterative process with continuous coordination. The landscape project comes into play especially after the negative planning phase. In this way, the project will be as consistent as possible, avoiding frequent adjustments to the project and consequently a continuous rethinking of its concept.

2.1. Definition of the perimeter

Wind turbines can easily reach a total height of 140 m or more (180 m for the latest models), and are visible for more than 10 km on cloudy days, and at much greater distances on clear days. With their size, they form remarkable and imposing elements that stand out from the classical landscape proportions. By way of comparison, Strasbourg Cathedral is 142 m high. In the case of a wind farm or master plan, the area of analysis should therefore extend far beyond the planned siting area. Ideally, the whole area of visibility of the wind turbines should be considered. In the extended study area, issues of co-visibility with other wind farms should be considered. In the 5-10 km close study areas, depending on the size and number of machines planned, issues of scale and proportion will play an important role. Within the close study areas, all landscape principles must be considered. Collaboration with the neighbouring regions of the planning area should be foreseen in order to improve the coherence of the landscape project and its acceptance by the local population.

2.2. Assessment of non-landscape aspects

In the case of landscape planning, other aspects (wind potential, access, energy transport, species protection) should be dealt with as best as possible in order to anticipate problems and, if necessary, to abandon or adapt the site or the strategic planning areas. In the case of community-led master planning, such pre-analyses are more difficult to carry out because of the costs involved. By developing cooperation with the different actors involved in wind energy, financing mechanisms can be found.

2.3. Technical aspects

In addition to wind potentials, the possibilities of energy transport and access must be known. On this basis a sector classification can be made. It determines which areas are to be retained, excluded, or for which additional coordination is required. For noise and shadow protection, the scientific knowledge is not yet solid enough. Cases of noise problems after the construction of wind turbines have already been identified. Sufficiently large buffer zones should therefore be provided around residential areas. In this way, problems with operating restrictions resulting in financial losses can be avoided later on.

2.4. Species and biotopes

The protection of species and biotopes should be dealt with at an early stage of landscape planning. During the preliminary studies, a comprehensive analysis of the existing basic data should be carried out and a strategy for the preservation of natural areas, protected areas and species should be determined. This includes areas protected by decrees or laws (e.g. Natura 2000 areas). For all these different areas, it is important to define a general strategy at regional or national level and to stick to it. It is important to determine whether the protection goals of these areas are compatible with the siting of wind turbines, or how the landscapes are to be developed in the future. However, it is preferable to exclude classified and/or protected areas in order to limit conflicts and planning difficulties (specific studies, etc.). Chiropterans and birdlife are two groups of species particularly affected by wind turbines. A poorly placed wind turbine site (migratory corridors, hunting areas or swarming sites for bats) can have a significant impact on the populations of these species. Experts of these fauna groups are able to make pre-analyses of an area and give an assessment of the risks. They do not generate high costs compared to the costs that may arise from a lack of knowledge of the issues. The Swiss Coordination Centre for the Study and Protection of Bats (CCS) has developed a method for assessing wind farm sites with a five-level risk classification. Similar studies are also proposed for avifauna.

2.5. Reading the landscape: initial state

A study for the insertion of wind turbines in the landscape should be seen as a landscape project for the future. The preliminary analysis and understanding of the area is an integral part of the project. This phase should not be minimised. It allows the planner to develop his objectivity on the landscape diagnosis. The work of analysing the landscape must be carried out in an iterative way with the projection phase. In this way, the project ideas can be confronted with the reality on the ground, and then adapted according to the deepening of the knowledge on the ground. The understanding of the existing landscape, its history, its social characteristics and its evolution are fundamental elements thanks to which the project will take shape in a coherent way and will be able to be inscribed in the continuity. It is not only a question of conservation at all costs, but also of controlled development in the appropriate areas based on the key characteristics of the landscape. These can be identified through the analysis of the site.

2.6. Morphology

For a wind energy project, particular attention should be paid to the morphology of the landscape. This involves noting and understanding the sequence of topographic movements, their regularity or irregularity, the distance of horizons, the relationships of proportions between landscape components (e.g. height of a hill in relation to other landscape structures). Landscape units and their relationships to each other (transition and break zones) should be delineated. The understanding of the morphology is the basis of a landscape project and will influence the subjective aspects of the cultural aspects of the landscape and its perception.

2.7. Landscape heritage

Landscape heritage does not only consist of exceptional spaces. As a result of human actions, all landscapes have a specific witness value. This value can be more or less difficult to identify depending on whether it is exceptional or ordinary. All elements forming the identity of a landscape should be identified by researching historical documents and the knowledge of the local population. The structure of the land, the forms of farming, the structure of the buildings are some of the elements to be taken into account. Particular attention should be paid to recognised emblematic spaces and places. These should not lose their importance through the installation of wind turbines. Exclusion of iconic areas or sites is therefore desirable.

2.8. Socio-cultural aspects

The landscape in the sense of a « postcard » is linked to the experience and social context of the observer. In general, the perception of the « beautiful » and the « banal » is similar for most inhabitants of a region. These constants of landscape perception have to be identified and understood, in order to orientate the landscape project so that it can be understood and assimilated by a large proportion of the local population. The aim is not to ask the population whether wind turbines can be integrated or not. The key factors or components which form their perception of ‘beautiful’ or ‘commonplace’ elements should be identified and an integration plan developed accordingly.

2.9 Identification of issues and objectives

On the basis of the different data from the analysis phase, the issues related to the landscape and other planning elements can be identified. It is also during this phase, which should be continuous from the beginning of the project, that the interrelationships between the landscape and the other planning aspects are identified and coordinated. All elements, however insignificant, must be identified. Only in a further phase of cross-sectional analysis of factors and weighing up of interests will the issues to be addressed be selected. During this assessment phase, clear objectives will have to be determined and validated by a maximum of partners. The objectives set the landscape strategy and prioritise the issues identified. The desire for conservation (exclusion zones), transformation or addition will be defined and justified for each sector or landscape factor.

2.10. Drawing up the landscape insertion scheme

The landscape project can be based on two types of approach: the definition of landscape criteria for the selection or exclusion of sites; or the elaboration of a drawing of the new landscape with wind turbines justified by explanatory texts. The first approach is to define landscape criteria based on the landscape analysis and the objectives set after the identification of the issues. The application of these criteria then allows sites to be excluded or retained from a landscape point of view. The criteria should be as pragmatic and understandable as possible. Before applying these criteria, it is advisable to have them validated by as many stakeholders as possible. Consultation reduces the subjective part of the landscape approach because the criteria are validated and understood. The drawing approach is more conceptual. The success of such an approach depends on good justification and quality graphic illustrations. Despite this, the subjective part is more difficult to limit. The ideal solution is to use both methods simultaneously. The conceptual approach defines the general scheme of the wind farm or sites in a region, and the landscape criteria regulate the details of the concrete factors. Two examples of typical criteria are the definition of buffer zones around areas to be preserved or the establishment of proportional rules to be respected from viewpoints.

2.11. Communication of the project

Project communication should ideally take place during all phases of the planning process. Consultation during the landscape analysis and issue definition phase is as important as the final project. As already mentioned, the landscape analysis is an integral part of the landscape project and gives it clear direction. The inclusion of representatives of the region or of various interest groups during the analysis phase and during all subsequent phases of the project will give the final document greater credibility. Other aspects of spatial planning (species protection, noise, etc.) should also be integrated into the communication strategy. The communication strategy should not focus on the landscape, but present the overall concept. All other aspects are equally important and will have a considerable effect on the perception of the environment by the population affected by wind turbines. Today’s technologies offer various possibilities for visual communication (3D modelling, photomontages, films, etc.). These tools should be used, but should not be the only means of communicating a project or planning. The choice of a point of view for a photomontage, for example, has a subjective element. When using visual tools, it is therefore important to select many viewpoints, including from ordinary areas, in order to achieve a certain completeness with regard to the future visibility zones of wind turbines. The elaboration of visibility rasters based on a digital terrain model (DTM) - a three-dimensional digital grid of an area - is essential. These rasters are used to identify all areas from which wind turbines will be visible.

3. LANDSCAPE PRINCIPLES

This chapter identifies the main effects of wind farms on the landscape in the sense of the European Landscape Convention, i.e. the natural, visual and lived landscape. The categories of effects are described in the sections below.

3.1 Scale, rhythm and coherence of units

The landscape can be divided into landscape units. These are clearly delineated landscape units which are homogeneous in terms of topography, land use and landscape structure. A unit may be very large, especially in lowland areas, or very small (in mountainous and hilly areas). In the case of small units, the views are varied and the skylines are close. An area with small units imposes continuous changes in morphology and views. The geomorphology of the territory is one of the key factors of the landscape. It defines the sequence of structures and determines the homogeneity or lack of homogeneity of the landscape. A very hilly landscape will offer a great diversity of views at 365°, all different from each other. A very homogeneous landscape, on the other hand, is less varied and will be shaped mainly by plant and building structures. The structuring elements of the landscape (bocage, villages, roads, land registry, etc.) constitute, together with the geomorphology, the basis of the landscape identity. These are therefore naturally the most important aspects to be dealt with when siting wind turbines.

In the analysis, the topographical and structural lines of the landscape should be identified and described. This will determine which strong elements should be preserved or supported by the siting of wind turbines in order to maintain the landscape value or to develop it in a consistent way. Wind turbines have a significant effect on the landscape because of their size. They are often much larger than existing landscape components or are visible beyond a single landscape unit. Landscape planning must take into account the geomorphology and its proportions, and the arrangement of structures, to avoid wind turbines obliterating, overpowering or disturbing landscape features. Wind turbines should therefore fit into homogeneous spaces and avoid hilly areas with many changes in morphology, as well as areas densely structured by various components. Furthermore, geomorphological or structural features should be emphasised or preserved according to their size and identity value. It is also important that wind turbines are placed in the rhythm of the geomorphology and landscape structures. All of these principles apply on both a small and large scale depending on the situation. For example, a road can be considered an important linear structuring element, just as a river in a valley. In general, a large, flat landscape with distant horizons is more favourable for the insertion of wind turbines than a hilly or mountainous landscape. Below are some schematic examples related to geomorphology and landscape structures.

3.2. Respect for lines of force

The landscape has lines of force (rivers, roads, valley axes, ridges) which play an important role in the coherence of a landscape. These are often elements which have influenced the whole landscape over the centuries or, in the case of infrastructure, which have adapted to natural and morphological constraints. The siting of wind turbines should emphasise rather than erase these features.

Figure 1: Examples of wind turbine siting along a line of force or a structuring element. Here a road

3.3. Proportion and Rhythm

If wind turbines are placed on either side of a high point, one should also be placed at the top of the high point to avoid being overshadowed by the other two turbines (Figures 2 and 3).

Figure 2: Schematic diagram for siting wind turbines near and on a high point. Avoidance of visual blurring of landscape scales

Figure 3: Siting situation to be avoided. The proportions of the natural morphology are erased

On hilly terrain, the same turbine sizes should be used throughout the site and the machines should fit into the terrain (Figures 4 and 5). It should also be avoided that the wind turbines do not respect the morphological forms from a viewpoint due to the perspective effect.

Figure 4: Schematic diagram of wind turbine siting in areas with uneven morphology. It is important to try to follow the ground movements with the wind turbines and to reproduce the existing movements

Figure 5: Landscape rhythm imposed by the topography: The yellow dashed line symbolises the horizon line that the turbines should follow from a viewpoint determined in the landscape study. This is to respect the rhythm imposed by the topography. Source: Natura biologie appliquée Sàrl.

Wind turbines should not be as high as the ridge on which they are located, so as not to disturb the landscape scales imposed by its morphology. Ideally, the ridge should be twice the height of the planned turbine (Figures 6, 7 and 8).

Figure 6: Diagram showing the height proportions between a wind turbine and the height of a ridge

Figure 7: Wind turbines on a low ridge (Source: Natura biologie appliquée Sàrl.)

Figure 8: Wind turbines on a ridge with a height much greater than the height of the wind turbines (Source: Natura biologie appliquée Sàrl.)

Optical effects, such as low-angle views, increase the size of the wind turbines. Wind turbines should be placed within the limits of the existing slope lines in order to avoid low-angle effects (Figure 9).

Figure 9: Wind turbines at the top of a ridge. Diagram of wind turbine siting on a ridge. Avoid siting on the edge of the plateau to reduce the impression of crushing the viewer from the plain.

3.4. Covisibility and saturation

The attractiveness of wind turbines to the public is often mentioned, as they are new and symbolic of sustainable energy production. However, a level of saturation can be reached where wind turbines are no longer an attraction, but a disturbance to the public, if too many wind farms are located in a region and are visible from one location. In a given view axis, the wind turbines are dominant and take up a lot of space. If there are wind turbines in every frame or view axis, this can lead to a feeling of saturation or weariness in the viewer. The planning of a new wind farm in a region must therefore take into account the problems of covisibility. The aim is to identify areas from which several wind farms will be visible. Areas with a high concentration of settlements, tourist areas with a high landscape quality, or special viewpoints should not be in a situation of covisibility of several sites. The covisibility analysis should not only be carried out for sites at the same distance from a viewpoint, but should take into account all parks within the study area defined at the beginning of the study. Visibility rasters of wind turbines are very useful for this analysis. The term covisibility is also sometimes used to describe the simultaneous visibility of a wind turbine and another landscape element, for example a church tower.

3.5. Special landscapes

The term « special landscape » refers to all areas with a special legal status, where landscape aspects are of primary importance. They may also be areas which do not have a specific legal status, but which are recognised for their landscape qualities, e.g. a regional landmark or a tourist area with special landscapes. When planning a wind farm, the question of special landscapes should no longer arise. The exclusion of landscape areas should take place in the spatial planning phase. In spatial planning, it is necessary to define which landscapes should be excluded or enhanced by wind turbines. This choice should be based on the criteria defined in the landscape analysis. In general, and in order to avoid conflicts of interest later on, landscapes which are legally protected should be excluded. Natura 2000 areas are an example of areas to be avoided. This also applies to areas without special protection status. If, however, the insertion of wind turbines seems compatible with the area, a great deal of justification and communication work must be done. It is the landscape project that should justify the siting of wind turbines or not. Communication is done by describing the whole project process, from the analysis phase to the proposed final result. The heritage and historical aspect of the landscape, its rarity and its frequentation by the population are factors to be taken into account when developing selection or exclusion criteria. In addition, research should be carried out into the socio-cultural and political events that have taken place in relation to the area concerned. Such an analysis can reveal aspects that are not visible, but which may be an important factor in the value attributed to the landscape by the population.

Finally, when analysing a particular or protected landscape, it is necessary to consider the whole landscape unit or area of visibility in which the protected site is included. The quality or distinctiveness of a landscape area recognised by policy may extend beyond the map and form a coherent whole with its surroundings. The siting of a wind turbine in the vicinity of the protected area can therefore have as much impact as if it were sited within the perimeter. For this reason, it is recommended that buffer zones be established around particular or protected landscapes. In general, it is important to consider the landscape as a whole and not simply exclude or select areas defined by a policy boundary.

3.6. Relationship to built-up areas

This section focuses only on landscape aspects related to built-up areas. It does not deal with aspects such as noise or shadowing. However, it is important that these two elements are treated with great care and caution. Indeed, a study that does not sufficiently address these aspects risks generating numerous social problems during the operational phase. The issues of scale also apply to built-up areas. These are important landscape elements that attract the viewer’s eye and are often linked to the surrounding landscape structures, thus forming a coherent whole. In homogeneous landscapes with distant horizons, buildings and villages have an even greater structural importance than in hilly areas. Compared to a wind turbine, a building, even a large one, becomes insignificant and loses its striking character in the landscape. From an analysed point of view, a wind turbine in the axis of a village or building should not be more than one height of the building in question (figures 10 and 11). Ideally, the wind turbine should not be located in the line of sight of important viewpoints defined in the landscape analysis.

Figure 10: Wind turbine siting: situation to be avoided. Avoid siting wind turbines in the axis of a village or isolated monument.

Figure 11: Buildings dominated by wind turbines: situation to be avoided. Example of the blurring of building proportions by wind turbines. Situation to be avoided. (Source: Natura biologie appliquée Sàrl.)

Views from a locality into the open space should also be considered. Views from streets or squares towards the outside of the locality should be avoided in order not to disturb the perspectives and proportions defined by the buildings in place.

CONCLUSION

Like other major infrastructure, wind turbines should be planned at the scale of the area, applying the principles of spatial planning. This is the key to a good integration in the landscape and, consequently, to an overall coherence that is understandable and accepted by a large part of the population. This report only gives the general basis for a good landscape projection with wind turbines. All the aspects dealt with must be more or less elaborated according to the specificities of the state or region concerned. To this end, it is recommended that the authorities develop their own landscape criteria in line with the European Landscape Convention, and that they draw up comprehensive territorial plans for wind energy. In areas where wind energy is not yet present, the development of comprehensive plans will help to anticipate many of the conflicts that are more difficult to resolve when concrete projects are submitted to the permitting authorities. The exchange of information and experience between the Member States and the request for support from the Council of Europe are also very important. In this way, the specific knowledge of the many areas affected by wind turbines, which is sometimes still lacking, can be strengthened as soon as possible.

Références