An inventory of locations suitable for wind energy in Flanders region.

The purpose of the work is to draw up an inventory of suitable locations for wind turbines in Flanders region. The study will focus on technical aspects like wind speed, grid capacity and environmental considerations, noise & visual intrusion etc. The work will accelerate the implementation of wind-energy in Flanders and is funded by the Flemish Research for Energy Technology (VLIET/970322/VUB-TW-STRO).

Text: Y. Cabooter (V.U.B.), L. Dewilde (V.U.B.), M. Langie (ODE-Vlaanderen).


  2. The Department of Fluid Mechanics belongs to the Faculty of Applied Sciences of the V.U.B. (Free University of Brussels). The Department is active in different domains: calculations on fluid dynamics, experimental analysis of fluids, wind engineering, wind energy.

    ODE-Vlaanderen (Organization for Renewable Energy in Flanders) is an organization that aims to promote the use of sustainable energy systems and to stimulate energy saving. Through thematic conferences, brochures and newsletters this organization wants to inform and educate the public.


    1. Synopsis
    2. The application of wind-energy is in a situation of rapid development in both technical and economical aspect. The new generation of wind turbines is very reliable, has a high profit and is cost-effective with good fringe benefits. This evolution will continue during the next years. The scaling up of the industry and the technological developments will lead to a continuing decreasing cost price.

      In some countries, a vast experience has been realized with wind energy. The result is that in these countries, a flourishing industry has been developed with enormous export possibilities. In spite of wind energy being a clean form of electricity production, this energy technology didn't break through in Flanders in comparison with the neighboring countries. Since the realization of the windpark at Zeebrugge, no further projects where erected. Nevertheless, there are recent developments and several project-developers and utilities are in search for new and good locations. Wind energy is especially a new topic for policy people and many directors have numerous questions to technical, planological and environmental aspects.

      Different researchers have estimated the realizable potential of Flanders concerning wind energy. The figures vary between 200 MW [1] and 600 MW [2] on land. Both studies point out the necessity for a pragmatic exploration towards suitable locations and a supporting policy. The most important impediments for the implementation of wind energy in Flanders aren't economical, but are planological, governmental and environmental. It's difficult to find locations that are remunerative for the investors and that are acceptable for the municipality and other relevant actors.

      This project wants to realize a practical working instrument to come to a justified introduction of wind energy in Flanders and to support all actors in wind energy projects.

    3. Flemish goal and situation
    4. In the policy note 1996-1999 of the Flemish Ministry of Energy and Economy, it is clearly formulated that it should be possible to enlarge the contribution of renewable energy sources in Flanders. Following targets have been formulated:

      • Compared to 1995: doubling the contribution of renewable energy in the total energy production by the year 2000 ;
      • A 5 % contribution of renewable energy in the total energy production by the year 2020.

      Previous studies revealed that the technical realizable share of renewable energy in Flanders is much larger then what has been assumed. Moreover, there is a strong decreasing cost price for most of these renewable energy techniques.

      Moreover, in Flanders, there exists a deep gap between technological know-how and its application. The development of a home market for wind turbines can support the industry to pick up a grain from the international market.

      The most important limit for the implementation of wind energy in Flanders is the search for good windy locations for which a legal license can be obtained, i.e. locations which are economical attractive for investors, acceptable for municipals, and tolerable for relevant pressing groups.

      The realization of a good windplan is seen as an important support measure. This windplan has to offer economical guarantees and has to bring solutions for some relevant planological, environmental and social factors. The project faces the development of a policy instrument for directors, policy officials and municipals at the domain of the implementation of wind energy in Flanders. The global target is a plan for the implementation of wind turbines in Flanders which is technical and economical realizable and which forms guide-lines for the local authorities concerning environmental and social problems related to the erection of wind turbines.


      1. Flow Chart
      2. Figure 1 Flow chart of the project

      3. Analysis of the territory
      4. Previous studies from the V.U.B. in charge of the European Community reveal that the wind-rich zone in Flanders is situated at the West side of the geographical axis Courtray-Ghent-Antwerp.

        Figure 2 Map of Flanders with the wind-swept area at the West side of the geographical axis Courtray-Ghent-Antwerp.

        Also the European Wind Atlas [3] mentions that an important share of Flanders is located in the most interesting but one wind zone of Europe.

        When investigating the surface of Flanders for wind energy applications, there will have to be drawn up some criteria in collaboration with the responsible authorities for the following areas: habitats, isolated dwellings, military areas, natural sceneries, forests, highways, waterways and high tension grids. For each of this type of area, minimum distances will have to be respected wherein wind turbines are forbidden. The responsible authorities will be: provincial and municipal directions, ministry of physical planning and military authorities.

        Figure 3 Wind resources at 50 m above ground level. At the coastline of Belgium, the average wind speed varies between 7.0 and 8.5 m/s, the potential energy density varies between 400 and 700 W/m≤. For the more inland part of Flanders varies the average wind speed between 5.5 and 6.5 m/s for open plain with an potential energy density between 200 and 300 W/m≤ (source [3]).

        In a second phase, regional zoning maps are used for the definition of the territory, how it's organized and what are the different areas and parties involved. A large contribution of the different municipalities and provinces is involved regarding to physical planning and building regulations. There are areas where little problems are to be expected, e.g. at the border of industrial area, ports etc. At the other hand, there will be zones, like agricultural zones, where clear structural rules will have to be formulated for the implementation of wind turbines.

        With these criteria, a number of interesting locations in Flanders will remain. These will have to be investigated on topography, roughness, obstacles in the vicinity and scenery value. The work will use to a large extend existing geographical data sets for topography, land-use, orthophoto maps and digital terrain models in a suitable GIS software pack, which will allow to produce the necessary roughness and orography charts. The geographical data sets are available from GIS-Vlaanderen, a Flemish government agency who collects all geographical data and make them available for decision and policy makers.




        Figure 4 Regional zoning map of Flanders with autoroutes, waterways, agricultural areas, living areas, green areas, industrial areas and others

        Figure 5 Detail of the regional zoning map for the coastline of Belgium

      5. Wind potential, refinement of existing studies for wind-swept areas
      6. Reliable wind data is the basis for an economical success of wind energy projects. The European Wind Atlas [3] is available since 1989 by the European Community. Coupled at the statistical data of the European Wind Atlas is a software pack, WAsP, for the analysis and applications of the data and to produce regional wind charts. WAsP will be used for the statistical process of the available wind data in Flanders and surroundings. The input of WAsP exists of wind data (wind speed and wind directions) at the one hand and topographical information, roughness and obstacle descriptions at the other hand.

        The reference meteorological stations will be those mentioned in the European Wind Atlas for Flanders, extended with stations in Wallony-region, the Netherlands, Germany and France which are close to the Flanders borders. This data will be extended and compared with data gathered from regional measurements over a shorter period of time. The latter data will be measured at higher level. Since the data from the European Wind Atlas is coming from measurements typically on 10 m height, reference measurements are required on higher level in order to support the interpolation techniques of the statistical data from the European Wind Atlas to higher level. The new measurements take place at typically 30, 50 or 60 m. Also the interpolation between a gauging station at the coast to a site more inland will be refined with these additional measurements.

        The result of the analysis of the territory together with the WAsP analysis will be a map of Flanders with numbered zones. For each zone, the potential energy densities on different heights will be determined. Other derived quantities will be the average wind speed, the Weibull scale and shape factor, turbulence and the wind rose for different heights.

      7. Overview of the grid-connection
      8. In a third phase the capacity of the grid and cost of grid connection will be studied. This will be done in co-operation with the utilities. Grid connection is an important and most often unknown factor to determine the cost price of electricity from wind turbines. The study will give a map of the existing situation of the high, medium and low tension grid. Moreover, the capacity of the supply transformers has to be examined and the eventual consequence on cost to enforce this capacity. In the end, itís necessary to clarify the rules concerning grid connection. A comparison will be made with the surrounding countries.

      9. Alternative designs
      10. Besides the distance between wind turbines in a windpark which has to be respected for technical reasons (e.g. 6 x rotor diameter), it is also well known that the implantation of wind turbines in the landscape has to be done with care. Therefore, several rules have to be respected. An in-line design can stress on some landscape effects. Wind turbines with different hub heights, different rotor diameter and different speed give a chaotic impress. Alternative designs of windparks and its visualization can be made with specialized computer simulation programs. This software is also used to determine the noise contours around a windpark or wind turbine. These noise contours will also be evaluated and can influence the design of the windpark. Noise production has to be limited and be conform to the Vlarem-standard.


        Day-time db(A)

        Evening-time db(A)

        Night-time db(A)













        Table 1 Vlarem-standard for noise in open air: (1) Rural and recreation area, (2) Habitats and rural area on distance less than 500 m from industrial area, (3) Industrial area


    6. RESULTS
    7. The final result of the work is an inventory of possible locations suitable for the implementation of wind turbines. Every location will be accompanied with a data set describing the appropriate building regulations, grid situation and environmental aspects to be met. Further the cost of the generated electricity will be estimated for the different locations. Finally the study will give a more accurate idea of the potential of wind energy in Flanders with respect to the government policy.



      [1] Prof. J. De Ruyck, Potential of durable energy sources for electricity production in Belgium, V.U.B., Brussel

      [2] W. De Groote, Possibilities and limits of renewable energy in Flanders, ODE-Vlaanderen, Leuven, 1997

      [3] I. Troen, E.L. Petersen, European Wind Atlas, Risø National Laboratory, Roskilde, 1989