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Chapter 2. Offshore wind energy development in the Belgian
part of the North Sea & anticipated impacts: an
update
R. Brabant*, S. Degraer & B. Rumes
Royal Belgian Institute of Natural Sciences, Management Unit of the North Sea Mathematical Models
(MUMM), Marine Ecosystem Management Section, Gulledelle 100, 1200 Brussels
*Corresponding author: R.Brabant@mumm.ac.be
Photo MUMM / RBINS Turbine transport and installation on the Thorntonbank
R. Brabant, S. Degraer & B. Rumes 10
2.1. Context
The European Directive 2001/77/EC on the promotion of electricity produced from renewable
energy sources in the internal electricity market, imposes upon each Member State a target figure of
the contribution of the production of electricity from renewable energy sources that should have been
achieved in 2010. For Belgium, this target figure was 6 % of the total energy consumption. In January
2008, the European Commission launched its new Climate Plan, and a new target for Belgium was set
at 13 % to achieve by 2020. Offshore wind farms in the Belgian part of the North Sea (BPNS) are
expected to make an important contribution to achieve that goal.
With the Royal Decree of 17 May 2004 a zone in the Belgian part of the North Sea (BPNS) was
reserved for the production of electricity. It is located between two major shipping routes: the north
and south traffic separation schemes (TSS). In 2011, the zone was adjusted on its Northern and
Southern side because of the need for a safer shipping traffic in the vicinity of the wind farms. After
this adjustment the total surface of the area is 238 km² (Figure 1). The initial surface was 264 km².
Prior to installing a wind farm, a developer must obtain (1) a domain concession in the zone
reserved for wind energy development and (2) an environmental permit. Without an environmental
permit, a project developer is not allowed to build and exploit a wind farm, even if a domain
concession was granted.
When a project developer applies for an environmental permit an administrative procedure,
mandatory by law, starts. That procedure has several steps, including a public hearing during which
the public can express any objections. Later on during the permit procedure, the Management Unit of
the North Sea Mathematical Models (MUMM) of the Royal Belgian Institute of Natural Sciences
renders advice on the possible environmental impact of the future project to the Minister responsible
for the marine environment. MUMM’s advice includes an environmental impact assessment, based on
an environmental impact study that is set up by the project developer. The Minister then grants or
denies the environmental permit in a duly motivated decree.
The environmental permit includes a number of terms and conditions intended to minimize or
mitigate the impact of the project on the marine ecosystem. Furthermore, as required by law, the
permit imposes a monitoring programme to assess the effects of the project on the marine
environment. The environmental monitoring is a legal obligation and is a competency of the federal
government. The monitoring has two goals:
• to enable the authorities to mitigate or even halt the activities in case of extreme damage to
the marine ecosystem;
• to understand and evaluate the impact of offshore wind farms on the different aspects of
the marine environment and consequently support the future policy regarding offshore
wind farms.
The monitoring is lead by MUMM, but MUMM collaborates with several other institutes that
each have a specific expertise of the marine environment. The costs of the monitoring program are
paid by the permit holders.
At present, four companies were granted a domain concession and an environmental permit to
build and exploit an offshore wind farm: C-Power in 2004, Belwind in 2008, Northwind (formerly
Eldepasco) in 2009 and Norther in early 2012. C-Power had its permit revised in 2006 and 2008, and
the monitoring programme was adapted accordingly (Table 1).
C-Power and Belwind have already started their construction activities at the Thorntonbank and
Bligh Bank, respectively, while Northwind’s construction activities (72 turbines of 3MW) on the
Lodewijkbank (formerly Bank zonder Naam) are expected to start in April 2013. The Norther project
is located in the southernmost part of the wind energy zone and will presumably start its construction
in 2014. More detailed information on projects can be found via www.c-power.be, www.belwind.be
& www.northwindenergy.eu. Information on the Norther project can be found on the websites of
www.airenergy.be and www.electrawinds.be.
Three other projects, Rentel, Seastar and Mermaid, were granted only a domain concession so far
(Figure 1). Rentel, obtained a concession in between C-Power and Northwind (Figure 1). On July 2nd
Chapter 2. Offshore wind farms and anticipated impacts 11
2012, they have submitted their application to obtain an environmental permit. The concession of
Seastar, in between Belwind and Northwind, was withdrawn in 2011, but, on June 1st 2012 the project
obtained a new concession. Finally, on June 25th 2012, the project Mermaid was granted a domain
concession in the northernmost part of the zone reserved for energy production. This is the seventh
and, for now, last concession foreseen for the construction of wind farms in the Belgian part of the
North Sea.
Figure 1. Zone reserved for the production of renewable energy by the Royal Decree of 17 May 2004
(http://www.mumm.ac.be/EN/Management/Atlas)
R. Brabant, S. Degraer & B. Rumes 12
Table 1.
Overview of the dates when the projects were granted a domain concession and an environmental permit.
Project Concession obtained Permit application Permit obtained
C-Power
27/06/03 17/6/2003
22/9/2005
-
14/04/2004
10/05/2006
25/04/2008
Belwind 5/6/2007 19/6/2007 20/2/2008
Northwind 15/5/2006 12/12/2008 19/11/2009
Norther 5/10/2009 10/5/2011 18/1/2012
Rentel 4/6/2009 2/7/2012 procedure ongoing
Seastar 1/6/2012 No application yet
Mermaid 25/6/2012 No application yet
2.2. Ongoing wind farm projects
2.2.1. C-Power
The C-Power project is located on the Thorntonbank (Figure 1). This is a sandbank located 27
km of the Belgian coast. Water depth in the concession area varies between 18 and 24 m.
The C-Power concession is divided in two sub-areas (A and B). Across the two sub-areas 54
turbines will be installed. Phase I (30,5 MW), a pilot phase, consists of six turbines that were installed
on row D of sub-area A and the first 150 kV offshore cable (Figure 2). The six 5MW Repower
turbines are operating since the 10th of May 2009. Phase II and phase III will each consist of 24
turbines of 6.15 MW. The installed capacity of the entire wind farm will be 325 MW.
Figure 2. Layout of the C-Power project.
C-Power used gravity based foundations (GBF) for its phase I. These GBFs are hollow, concrete
structures that are filled with sand, upon installation on the seabed. More detailed information can be
obtained from Peire et al. (2009) and Brabant & Jacques (2010).
The foundation type for the phase II and III turbines is different from the pilot phase since jacket
foundations, instead of the GBFs, were installed. These foundations consist of a steel jacket with four
Chapter 2. Offshore wind farms and anticipated impacts 13
legs. The foundations were installed using the pre-piling concept: four pin-piles were driven into the
seabed and the legs of the foundation were grouted on the pre-piles. The piles vary in length
depending on the water depth at their location and are in the range of 21.0 to 49.5 m.
C-Power started on April 7th 2011 with the piling works. On August 21st 2011, all pin-piles for
the phase II and phase III turbines were in place. Before the pre-piling of the pin-piles started, bottom
surveys were conducted in 2010 and the seabed needed to be prepared. Details on this can be found in
Brabant et al. (2011). All jacket foundations were installed in 2011 and the first half of 2012 (Figure
3). The installation of the 6 MW Repower turbines is now ongoing, 24 of the turbines were already
installed by the end of June 2012. The offshore transformer station (OTS, figure 4) and the second
export cable are already installed. Both sub sea power cables come ashore near Ostend.
Figure 3. Phase III jacket installation (Photo C-Power).
Figure 4. The OTS was installed on March 17th 2012. On the background the six phase I turbines (photo C-
Power).
R. Brabant, S. Degraer & B. Rumes 14
2.2.2. Belwind
The Belwind project is situated on the Bligh Bank at about 40 km off the Belgian coast (Figure 1
& 5). The water depth in the concession area varies between 15 and 40 m. Once finalized, the park
will consist of 110 Vestas V90 turbines and an offshore high voltage station (OHVS), with a total
installed capacity of 330 MW. The construction of the park is divided in two phases.
Figure 5. Lay out of the Belwind project.
In 2010, Belwind completed the first phase of their wind farm: 55 Vestas V90-3MW turbines, an
OHVS, infield cables and an export cable. The 55 wind turbines are operational since January 13th,
2011 (Figure 6). Details on the construction of this first phase can be found in Brabant et al. (2011).
No construction works were done in 2011. The start of the construction of phase II is foreseen in
2014.
Figure 6. Phase I wind turbines on the Bligh Bank (Photo MUMM / RBINS).
Chapter 2. Offshore wind farms and anticipated impacts 15
2.3. Anticipated environmental impacts
With the construction and exploitation of the above described projects a new offshore activity
started in the BPNS. While offshore wind farms help achieving the goals set by 2001/77/EC on the
promotion of electricity produced from renewable energy and help in the struggle against climate
change, the construction and exploitation of offshore wind farms will also have certain impacts on the
marine environment. These can be neutral, positive and/or negative for the marine ecosystem.
The environmental impact assessments (MUMM, 2004, 2007, 2009 & 2011) anticipated a variety
of possible impacts. Some of those impacts are already being revealed during the first years of
environmental monitoring (Degraer et al., 2010 & 2011), e.g.:
- Increased erosion of the natural sandy sediments around wind turbine foundations because of
accelerating currents next to the foundations;
- Increased turbidity during the construction of the wind farms;
- Increased underwater noise pressure, generated during the construction and exploitation
phases and the associated impact on marine mammals and fish;
- Colonisation of the introduced hard substrata (i.e. foundations) by epifouling organisms and
its consequent stepping-stone effect on invasive species;
- Attraction of fish by the introduced hard substrata;
- Changes within the soft-substratum macro- and epibenthos and fish as a result of e.g. fisheries
displacement, altered sediment characteristics and organic enrichment of the sandy sediments
by (local) deposition of organic matter produces by the hard substrate epifauna;
- Altered spatio-temporal distribution, densities and migration routes of seabirds and marine
mammals;
- Altered public perception of offshore wind farms.
With the monitoring programme, MUMM and its partners (1) assess the extent of the anticipated
impacts on the different aspects of the marine ecosystem and (2) aim at revealing the processes behind
the impacts. The first objective is basically tackled through the baseline monitoring, focusing on the a
posteriori, resultant impact quantification, while the second monitoring objective is covered by the
targeted or process monitoring, focusing on the cause-effect relationships of a priori selected impacts.
As such, the baseline monitoring deals with observing rather than understanding impacts and hence
leads to area-specific results, which might form a basis for halting activities. Targeted monitoring on
the other hand deals with the understanding of the processes behind the impacts of a selected set of
hypothesized cause-effect relationships highly relevant to the wind energy sector. This step is not only
a pre-requisite for effective regulatory application, but also permits (1) current and future impact
mitigation, (2) better prediction of future impacts, as well as (3) moving away from site-specific
observations to more generic knowledge. More details on this topic can be found in Degraer &
Brabant (2009) and Degraer et al. (2010).
In 2009, we reported on the lessons learnt and recommendations from the first two years of
environmental monitoring (Degraer & Brabant, 2009). The integrated Degraer et al. (2010) report
focused on the natural spatio-temporal variability and the evaluation of the early and localized
environmental impacts at the C-Power and Belwind sites. This report presents a selection of major
findings from the baseline and targeted monitoring activities from 2011, and aims at a continued
heading towards an understanding of environmental impacts of offshore wind farms.
2.4. References
Brabant, R., Degraer, S. & Rumes, B., (2011). Offshore wind energy development in the Belgian part
of the North Sea & anticipated impacts: an update. In: Degraer, S., Brabant, R. & Rumes, B.,
(Eds.) (2011). Offshore wind farms in the Belgian part of the North Sea: Selected findings from
the baseline and targeted monitoring. Royal Belgian Institute of Natural Sciences, Management
Unit of the North Sea Mathematical Models. Marine ecosystem management unit. pp. 9-16.
R. Brabant, S. Degraer & B. Rumes 16
Brabant, R. & Jacques, T.G., (2010). Offshore wind energy development in the Belgian part of the
North Sea and anticipated impacts. pp. 9-18. In: Degraer, S., Brabant, R. & Rumes, B., (Eds.)
(2010). Offshore wind farms in the Belgian part of the North Sea: Spatio-temporal variability and
early impact assessment. Royal Belgian Institute of Natural Sciences, Management Unit of the
North Sea Mathematical Models, Marine ecosystem management unit. 184 pp. + annexes.
Degraer, S. & Brabant, R., (Eds.) (2009). Offshore wind farms in the Belgian part of the North Sea:
State of the art after two years of environmental monitoring. Royal Belgian Institute of Natural
Sciences, Management Unit of the North Sea Mathematical Models, Marine ecosystem
management unit. 287 pp. + annexes.
Degraer, S., Brabant, R. & Rumes, B., (Eds.) (2010). Offshore wind farms in the Belgian part of the
North Sea: Spatio-temporal variability and early impact assessment. Royal Belgian Institute of
Natural Sciences, Management Unit of the North Sea Mathematical Models, Marine ecosystem
management unit. 184 pp. + annexes.
Degraer, S., Brabant, R. & Rumes, B., (Eds.) (2011). Offshore wind farms in the Belgian part of the
North Sea: Selected findings from the baseline and targeted monitoring. Royal Belgian Institute
of Natural Sciences, Management Unit of the North Sea Mathematical Models. Marine
ecosystem management unit. 157 pp. + annex.
MUMM, (2004). Milieueffectenbeoordeling van het project ingediend door de n.v. C-Power. Rapport
van het Koninklijk Belgisch Instituut voor Natuurwetenschappen, departement Beheerseenheid
van het Mathematisch Model van de Noordzee (BMM). 155 pp.
MUMM, (2007). Milieueffectenbeoordeling van het BELWIND offshore windmolenpark op de Bligh
Bank. Rapport van het Koninklijk Belgisch Instituut voor Natuurwetenschappen, departement
Beheerseenheid van het Mathematisch Model van de Noordzee (BMM). 183 pp.
MUMM, (2009). Milieueffectenbeoordeling van het ELDEPASCO offshore windmolenpark op de
Bank zonder Naam. Rapport van het Koninklijk Belgisch Instituut voor Natuurwetenschappen,
departement Beheerseenheid van het Mathematisch Model van de Noordzee (BMM). 168 pp.
MUMM, (2011). Milieueffectenbeoordeling van het NORTHER offshore windmolenpark ten
zuidoosten van de Thorntonbank. Rapport van het Koninklijk Belgisch Instituut voor
Natuurwetenschappen, departement Beheerseenheid van het Mathematisch Model van de
Noordzee (BMM). 189 pp.
Peire, K., Nonneman, H. & Bosschem, E., (2009). Gravity Based Foundations for the Thornton Bank
Offshore Wind farm. Terra et Aqua, 115, 19 – 29.
