WEM_02_2019

energy
magazine
#2
Volume 6
June
2019
Grid
Connection
When wind farms become power stations
Wieringermeer Wind Farm
Vattenfall is currently working on one
of the largest Dutch onshore wind
projects. What are the challenges
building in an area of around 300 km²?
u Page 06 - 09
Interview Prysmian Group
Future grid capacity is a hot topic in
the Netherlands at the moment.
What are the requirements in terms
of cable designs?
u Page 20 - 23
Solving the gridlock
The acceleration of the energy
transition requires extra grid
capacity. Is the grid ready for the
future influx of renewable energy?
u Page 30 - 33

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Editor’s note
In transition…
With the effects of climate change
being felt all over the world, the
pressure is high for all countries to
quickly reduce their CO2 emissions.
Moving away from fossil fuels, increasing the share
of renewable energy, electrification of the industry
and transport, these are just some examples of
solutions at hand. Found somewhere at the bottom of
the EU’s sustainable energy ranking list, the pressure
is even higher for the Netherlands.
We are facing an Energy Transition of such magnitude
that it will affect every aspect of our daily lives. It requires
changes and adaptions from all parties involved; energy
producers, electricity network operators, (national, regional
and local) governments, but also the energy consumers,
whether they are the industry or individual households.
But how can we reduce our CO2 emissions fast if there is lack of
agreement on the best practise? As the word transition already
suggests, everyone is still looking into best ways. Should we stop
immediately with gas and nuclear power or should these be phased-out
slowly while we are getting used to new ways? What alternative energies should
prevail? Lessons will have to be learned and innovations to be made.
30
Dutch
electricity
network
© TENNET
Whichever way we choose, it will affect the existing electricity network. Like the veins
and the heart keep the blood flowing, the electricity network ensures that all the energy
produced (supply) is delivered where it is needed (demand). With (large) renewable
energy projects being built in regions all over the country, including regions with low
energy demand, we are moving away from a centralised energy system. This will no
doubt require modifications to the existing electrical network system.
In this edition we explain the existing electricity network in the Netherlands and we
spoke to some of the players that are directly involved; like cable manufacturer
Prysmian Group and HSM Offshore who build the offshore substations for connecting
offshore wind farms with the national grid. We spoke also to Vattenfall who are working
on a large-scale onshore repowering project, Wieringermeer Wind Farm, where
formerly scattered wind turbines are replaced by more powerful wind turbines in
arranged line positions. Their experience provides an insight into the challenges that
are already being felt when it comes to grid connection.
Restyle
The Wind Energy titles are also going through a transition phase. We carried out a
restyle of the magazine as a first step. Our news sites Windenergie-nieuws.nl (NL) and
Windenergy-magazine.com (EN) will follow soon. Keep an eye on these websites as
they will offer you a useful starting point from which to explore the Dutch wind
industry and its players.
The Energy
Transition will
impact the
electricity network
Sabine Lankhorst
Editor in Chief
Wind Energy Magazine
presswem@vakbladen.com
02-2019 | 3

Contents
Wind farm in focus
Wind Energy Magazine Vol. 6 | 02-2019
energy
magazine
#2
Volume 6
June
2019
Wieringermeer Wind Farm 06
Theme: grid connection
Future offshore wind farms require bold solutions 14
Storms, sea mines and sand dunes 16
Stepping up to serve the future grid 20
The beating heart of a wind farm 24
Solving the gridlock 30
Grid
Connection
Innovation
Island at Sea 34
When wind farms become power stations
Ocean Grazer 38
Wieringermeer Wind Farm
Vattenfall is currently working on one
of the largest Dutch onshore wind
projects. What are the challenges
building in an area of around 300 km²?
Page 06 - 09
Cover
Interview Prysmian Group
Future grid capacity is a hot topic in
the Netherlands at the moment.
What are the requirements in terms
of cable designs?
Page 20 - 23
Solving the gridlock
The acceleration of the energy
transition requires extra grid
capacity. Is the grid ready for the
future influx of renewable energy?
Page 30 - 33
The Ocean Grazer Concept is a
hybrid modular offshore system that
combines wind, wave & storage and
potentially other sources of renewable
energy.
Regular features
Onshore Wind Farm News 10
Column ENVIR Advocaten 13
Offshore Wind Farm News 28
General news 40
Agenda & Publication dates 42
Page 38
GRID
Theme:
Grid Connection
Colofon
energy
magazine
VOLUME 6 | JUNE 2019 | ISSUE 02
Wind Energy Magazine, a quarterly trade
magazine for professionals who are involved or
interested in onshore and offshore wind energy
developments in the Netherlands.
Publication:
Wind Energy Magazine is a quarterly publication.
Publisher:
Roeland Dobbelaer
Publishing company:
Vakbladen.com
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PO box 19949, 2500 CX Den Haag,
The Netherlands
Website:
www.windenergy-magazine.com
www.windenergie-nieuws.nl
Editor in Chief:
Sabine Lankhorst
Contributors to this edition:
Erick Vermeulen, Martijn Bongaerts, Bart Stam,
Mirjam Tielen, Marieke Kaajan (ENVIR Advocaten)
Cover image:
Ocean Grazer BV
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Printed by: Veldhuis Media, Raalte
4 | 02-2019

Vattenfall: Jorrit Lousberg
20
Interview: Prysmian Group
Future grid capacity is currently a hot topic in
the Netherlands. With the wind projects
becoming larger, especially at sea, what are
the requirements in terms of cable designs?
06
24
The beating heart of a wind farm
In 2002, HSM Offshore built the offshore substation
for the first offshore wind farm, Danish
Horns Rev A. 17 years later, the manufacturing
company is still building offshore platforms.
Realising the largest Dutch
repowering project
Wieringermeer Wind Farm
Vattenfall is currently building one of the largest Dutch wind farms in the
Wieringermeer. In this enormous stretched area, covering around 300 square
kilometres, the wind has free play at all times. With 82 wind turbines, this is also
the company’s largest Dutch onshore wind project developed by themselves.
30 38
Solving the gridlock
There is an acceleration of the energy transition: in more and
more places, renewable energy is being produced. This supply
of renewable energy requires extra capacity of the grid.
Ocean Grazer - When supply and demand meet
The University of Groningen developed the Ocean Grazer
Concept, a hybrid modular offshore system that combines
wind, wave & storage.
02-2019 | 5

Wind Farm in Focus
Sabine Lankhorst
Vattenfall: Jorrit Lousberg
6 | 02-2019

Wieringermeer Wind Farm
Realising the
largest Dutch
repowering project
Vattenfall is currently building one of the largest Dutch wind farms in the
Wieringermeer. In this enormous stretched area, covering around 300 square
kilometres, the wind has free play at all times. With 82 wind turbines, this is also
the company’s largest Dutch onshore wind project developed by themselves.
We talked to Ruben Lindenburg, Project Director
Construction for the wind farm to hear the experience
so far.
Vattenfall will build 82 of a total of 100 wind turbines that
shape Wieringermeer wind farm. Are you still working with
the developers of the remaining 17 wind turbines?
Wieringermeer wind farm is a repowering project. The Dutch
Government provided a permit for 100 wind turbines. The permit
would be granted to one party only. Vattenfall already had some
small wind farms in this area. Together with research centre ECN
and Windcollectief Wieringermeer, we joined forces to apply for
the permit. In September 2017, we acquired the 32 turbines from
Windcollectief Wieringermeer. Up to the decision of the Council
of State (Raad van State) we worked together with ECN but once
the permits were in place, we each followed our own path.
Of the 82 wind turbines, 78 are located on agricultural land
and 4 in the Robbenoordbos forest. Was it really necessary
to build in the forest?
We often get this question. And if you look at the surroundings as
an outsider, I can understand the question. The layout of the wind
farm was determined by the Government’s so-called
‘Structuurvisie’ (structural concept), around 12 years ago. For one,
the turbines had to be installed in single line position. That already
rules out parts of the area. Also, back then, the Government invited
all the stakeholders from the region. During the stakeholder
process, all stakeholders, varying from farmers, communities, defence,
airport, energy companies, nature conservation organisations,
etcetera, could provide their input or restrictions. In the initial
plan, 6 wind turbines were located in the forest but after research
and consultation with our ecological experts, two wind turbines
were scrapped. To construct the four wind turbines in the forest,
around 3.5 has of space had to be cleared. But we are planting new
trees in an adjacent area of 4 has, so we are returning more than
we removed. All was done in good cooperation and in consent with
nature conservation organisation Staatsbosbeheer who wish to
combine forests with renewable energy production. In the design,
we made sure the wind turbines would be optimally integrated in
the landscape. We also provided special facilities for bats as this
area is a popular place for bats.
What is the current status of the construction activities?
At the moment, 42 foundations and around 70% of the road and
internal cable construction have been completed. Hearing me say
this actually makes me realise how happy I am to see that we are
half way and have made this progress. We have faced quite some
challenges along the way and this has affected the original planning.
Next week, the components of the first Nordex wind turbines
should be arriving. I sincerely hope that the turbine installation will
be a smooth process. Fingers crossed!
You mention there were some challenges. Can you mention
a few?
Keep in mind that the Wieringermeer wind farm is a rather unique
case for Vattenfall in the Netherlands. This is the largest onshore
wind project that we are developing on our own here and I don’t
think we will see many more of this size in this highly populated
country. The total site covers an area of 300 square kilometres.
02-2019 | 7

This is the largest onshore wind
project that we are developing on
our own here and I don’t think
we will see many more of this size
in this highly populated country
In this enormous area we are installing 82 turbines. Imagine, it takes
a 175 kilometre long round to drive from turbine to turbine.
This requires quite some organisation.
We already knew we had to relocate a glider airport and so we did.
The new glider facility is taken over since October last year and is
fully operational. Next, the soil conditions in the Wieringermeer
are varying and hence challenging. We need to examine those before
we create a technical design. At the start of the process, soil
samples are taken at different spots across the area to determine
the site specifics. Based on this, the technical design is created.
For Wieringermeer, it took 5 months to create this design.
Wieringermeer is built on a combination of clay and sand
grounds. These require different construction approaches for the
roads, crane hardstands and to a lesser extent, the foundations.
People tend to think that the transportation and installation of
the wind turbine components (tower, hub and blades) are the
most challenging aspects of building a wind farm. However, the
construction of the roads, the crane hardstands, and the foundations
are the most critical part. You have to imagine that ten
thousands loads of sand, concrete, asphalt and steel are required
during the road, cable and foundation construction work. The
municipality did reinforce some existing bridges in the area to ensure
that the heavy weight transport could pass. The crane hardstands
have to be able to support the heavy installation cranes
and their loads, and the foundations need to be able to support
the turbines and towers.
As an example of the variety of soil condition, in the north-western
section there is an underground current running which was formed
back in the ice age. Using vibro piles would be impossible as the
concrete would flow away. Here we had to use pre-fab piles. The
crane hardstands had to be piled in this area. Also, the ground water
in the Wieringermeer is relatively salty when you go a little bit
deeper than usual. As a result, excess water that is pumped up during
the cable burial work cannot be released in the surrounding
ditches. We had to use pipes, of sometimes 7 kilometres in length
and with a diameter of 60 centimetres, to transport the excess water
all the way from the western part of the site to the IJsselmeer lake.
All this has to be taken into consideration when creating the technical
design. However carefully you design every aspect, you might
learn that for some practical reasons, some of the elements are not
viable in reality. This could be a road being allocated where there is
a crossing or an underground cable running. You will have to modify
the route. However, this means that you first have to take new
Vattenfall: Aerophoto Schiphol
soil samples again. If the soil is for example softer, then you will
have to use concrete instead of asphalt.
It is not only the contractors that request for a change in the design.
The farmers on which lands we are building the turbines have
their expectations as well. It has happened more than once that
when we were about to start construction activities, we were pointed
at a possible problem. For example, where a road would cross a
drainage system. Then the question rises where to lay the cable,
above or below the drainage system? There is no standard burial
depth for drainage systems and we hit drainage canals quite some
times. In addition, there are several flower farmers that will raise
their ground water levels in July, August. It would be impossible to
install a crane then. These are all examples that kept on occurring,
leading to additional expenses and delay. That’s why we have
two-weekly meetings with the farmers involved, to take them
through our plans and to provide them with the opportunity to express
possible concerns or share ideas.
Another change in the plan concerned the activities of our contractors.
In the initial plan, Van Gelder would be responsible for the
construction of the roads, the staging areas and the cable installation.
BAM would follow to build the foundations and then Nordex
would install the turbines. Seven months down the road, we had to
change this. In some parts of the area, BAM did start before Van
Gelder, building temporary roads to start the construction of the
foundations, followed by Van Gelder, Nordex and in the end Van
Gelder again to finish up.
The project was delayed for nine months due to problems
with the substation. What is the current status?
In the wind farm, all our turbines are connected in groups to 15
small client stations. An electrical engineer would say we have 15
small wind farms. These client stations are connected by Liander
to the substation at the Agriport A7 business park in Middenmeer.
8 | 02-2019

This substation is a project by regional operator Liander and national
grid operator TenneT. Initially the completion of the substation
was planned for July 2018 but this was delayed. It’s the chicken-and-egg
story really, both TenneT and Liander wouldn’t start
with the construction until we confirmed that we were going to
build the wind farm and we couldn’t build the wind farm if there
was no guaranteed grid connection. When we finally managed to
find a short-cut, they didn’t have a contractor available. The result
was a delay of 9 months. This meant we had to postpone our tender
for contractors also. The substation was ready and switched on
in December last year but was shut down again soon after to already
extend the substation for new customers.
Do you know when you can expect to get the wind farm
connected to the substation?
We had hoped to make the next available connection slot, in
March, but unfortunately this didn’t happen either. Currently,
u Wind farm facts
Owner: Vattenfall
Total power: 295.2 MW
Wind turbines: 3.6 MW (Nordex N117/3600)
Number of turbines: 82
Site preparations: Van Gelder
Construction foundations: BAM
Client stations: 15
Substation: TenneT & Liander. 150/20 kV at Agriport A7
business park in the municipality of Hollandse Kroon
Cables: 20 Kv
Cable installation: Combinatie HPV (Heijmans,
Gebroeders Pol, Van Voskuilen) by order of Liander
Operational: expected in 2019
we’re about to energize the first client station and we’re thrilled we
came to this stage. Again, it’s a complex situation where the substation
will not solely connect our wind farm. At the moment there
are many developments taking place in this region. Google is going
to build their facility, Microsoft is expanding and the Ministry of
Waterways and Public Works is doing work at the Afsluitdijk. In the
meantime we need electricity, for all the drainage systems and the
work on the client stations. Last month, for example, we installed
the first client station. In order to continue with our work we rented
a mobile green battery to ensure electricity is available.
Sustainability is high on the agenda for Vattenfall. You already
mentioned the green battery, are there more examples
of sustainable initiatives?
Vattenfall aims to become fossil free within one generation. With
everything we do, we try to do it in a most sustainable way. For
example, the information centre/office that we have set up on site is
almost energy neutral. We use wind energy, heat pumps, led lightning
and re-use rain water. This building will be removed when the
wind farm is operational but the new service station, the clubhouse
of the former glider airfield, will be fully energy neutral. We recently
finished this service centre. At the wind farm, our employees drive
electric cars or cars driven by blue diesel (Hydrotreated Vegetable
Oil). In March, we won our company’s ‘Environmental Award’
award and we’re really proud we’re taking a step extra to build this
wind farm as environmentally friendly as possible.
Talking about sustainability, have you considered installing
solar fields near the wind turbines?
We did look at it but we decided first to concentrate on this wind
farm and later in the project look at the possibilities to install solar
panels. We know it is possible because we are realizing this also in
other places. And if we do, they can easily be connected to the
available grid system.
02-2019 | 9

Onshore
Wind Farm News
8
5
© WINDPARK KRAMMER
1
Wieringermeer Wind
Farm
See page 6 - 9.
2
De Drentse Monden en
Oostermoer Wind Farm
At the start of May, the
foundation for the first wind
turbine was built. The turbine,
type N131 from Nordex, is
expected to be installed
during June. It is the first of 7
wind turbines in a line. Also
completed were the cables
(and a pipe for the optical
fibre cable) that connect the 7
wind turbines to the client
station from where the
generated electricity is
supplied to the electricity
network. The wind farm will
comprise 45 wind turbines in
total, to be installed in 6 single
line positions in an area in the
municipalities of Borger-
Odoorn and Aa en Hunze.
3
De Veenwieken Wind
Farm
In April, a ground-breaking
ceremony took place to mark
the start of the construction.
By mid-May, the piling
activities for the foundations
were completed. Throughout
the summer, contractor Meyer
Sonderbau will build the
concrete foundations. The
wind farm is located between
Dedemsvaart, Ommen and
Hardenberg, in the eastern
part of the Netherlands. 10
Enercon, type E-103, wind
turbines will rise here. Six are
owned by De Wieken
(Windunie, Greenchoice and
ABN Amro Energy Transition
Fund) and 4 by Raedthuys
Pure Energie.
4
Samen Voor de Wind
Wind Farm
All 7 wind turbines alongside
the Overijsselse tocht, nearby
Swifterbant in the municipality
of Dronten, have been
dismantled. A start is made on
the construction of the
foundations, starting with
piling activities. The old
Enercon, type E66, turbines
are replaced by 7 Enercon,
type E82, turbines. These
generate approximately
35,000,000 KWh annually, the
equivalent of the total energy
consumption of around 9,000
households, against 1,500
households previously. Samen
Voor de Wind is an initiative of
7 farmers. It will supply
electricity to Greenchoice.
4
5
Zeewolde Wind Farm
All the contracts are in place
for the 320 MW wind farm.
The 83 wind turbines that will
replace the old 220 wind
turbines will be supplied by
German wind turbine
manufacturer Enercon and will
consist of 74 EP3 and 9 EP2
wind turbines. Dura Vermeer
and GMB will be responsible
for the installation of roads,
cables and foundations.
Vattenfall will purchase the
electricity under a 15-years
agreement. The operationaltechnical
management
contract has been concluded
with specialist company
OutSmart. ABB Power Grids
will supply the substation and
the 6.5-kilometre long cable
connection between the
substation and the TenneT
high-voltage grid. It will also
supply two 240 MVA
transformers. Construction
activities are planned to start
at the end of 2019. Zeewolde
wind farm is owned by a
partnership of 220 farmers,
wind turbine owners and
residents.
6
Energy Park Rijnenburg
en Reijerscop
The municipality of Utrecht
has plans to facilitate the
development of up to 11 wind
turbines and 227 hectares of
solar parks in the Rijnenburg
and Reijerscop polders near
Utrecht. In April, the Municipal
Executive of Utrecht
presented a draft proposal for
this energy park which could
potentially provide 96,000
local households with green
energy in the future. The
initiators Rijne Energie, Eneco
and BHM Solar will explore the
possibilities, together with the
communities.
7
Energie A16
In April, representatives of
governments, initiators and
neighbourhood and
community councils signed a
new covenant for the
development of wind energy
along the highway A16. In
2020, 28 wind turbines with a
combined power of 100 MW
will be installed in an area of 1
km on both sides of the
highway. The project is an
initiative of the province,
together with the
municipalities of Breda,
Drimmelen, Moerdijk and
Zundert.
8
© WINDPARK ZEEWOLDE
Krammer Wind Farm
On May 15, the wind farm was
officially openend. In
December 2018, the last of 34
Enercon E 115 wind turbines
was installed. At the end of
March the 102 MW wind farm
was fully operational.
Krammer is a project by the
cooperatives Zeeuwind and
Deltawind. With around 5,000
members, it is the largest
citizens’ initiative in the
Netherlands.
10 | 02-2019

1
2
4
3
5
6
8
7
Read the full news
on www.windenergymagazine.com
(EN) or
www.windenergienieuws.nl
(NL)
02-2019 | 11

SMART
MARITIME
TECHNOLOGY
Disruptieve technologie in de maritieme sector
13 JUNI 2019
Welke technologie brengt de komende jaren revoluties teweeg in de maritieme
sector? Vakblad Maritiem Nederland organiseert in juni 2019 voor de tweede maal
het congres Smart Maritime Technology (SMT).
Dit congres laat managers en technici uit de maritieme sector zien wat de
technologie is waar we op moeten inzetten, om de boot straks niet te missen.
Tijdens SMT krijgen de deelnemers, naast een inspirerende netwerkdag,
een overzicht van baanbrekende technologieën, waar ieder maritiem bedrijf
zich in zou moeten verdiepen en in mee zou moeten gaan om ook op lange
termijn succesvol te zijn.
Locatie VNAB
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Rotterdam
Datum: 13 juni 2019
Tijd: 11.00 - 17.30 uur
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Column
Marieke Kaajan
Lawyer ENVIR Advocaten
Grid connections
The energy transition presents us all with a major challenge. Electricity companies
are forced to think about other, more sustainable forms of energy production.
Onshore and offshore wind energy are the best known of these. However, it is
generally accepted that wind farms are not sufficient to achieve the objectives of
the energy transition. Other known forms are solar energy and the electrification of transport.
Consideration is also being given to the possibilities of storing sustainably produced electricity.
Consider, for example, the plans for an energy island in the North Sea. Saving energy is also
a permanent part of the energy transition. Other solutions are still needed, solutions that are
perhaps still in their infancy and for which it is not yet clear whether they will be able to
contribute to the energy transition on a larger scale.
All this also has consequences for the electricity grid in the Netherlands. On 8 January 2019,
the Financieele Dagblad (FD) reported that the electricity grid in the Northern Netherlands
is almost full and that no room could be offered for all initiatives in this region to install solar
panels, in particular. Another report in the FD, dated 7 May 2019, shows that an
entrepreneur had to wait more than a year for a grid connection for an electric sand motor.
Furthermore, many SDE subsidy schemes include the obligation to start the subsidy period
within a certain period of time after obtaining a subsidy decision, regardless of whether the
activity to be subsidised has been taken into use. If a timely start is not possible, it is often
impossible to postpone the date on which the subsidy-period starts. Uncertainties in this area
will, of course, be taken into account when deciding whether or not to invest in a sustainable
energy development. Think also of Amsterdam’s announcement that consideration is being
given to not allowing diesel and petrol cars into the city from 2030. To the extent that this
plan is feasible, it will also mean a major change for the network in Amsterdam.
All this shows that attention to sufficient network capacity should be an essential and integral
part of the energy transition. In the case of large(r) initiatives, the involvement of a network
operator occurs relatively quickly, so that a (more or less timely) network connection will be
available in this way. In the case of offshore wind energy, this has now been enshrined in law.
But it is expected that the smaller initiatives will become an essential part of the energy
transition. It is important to prevent these initiatives from being delayed to such an extent
that they abandon a sustainable solution. After all, it is undesirable for restrictions in the
electricity grid to result in people being forced to choose a less sustainable solution, as it were.
Sufficient
network capacity
should be an
essential and
integral part of
the energy
transition
Not only do network companies need to be closely involved in the (national, regional and
local) energy strategies so their expertise can be used as a basis for thinking about the timing
of various forms of policy. It is also important, however, that sufficient resources are available
to set the network up in such a way that it does not so much follow already known and certain
developments, but also includes (sufficient) room for the connection of new sustainable
developments. This is precisely how the network can contribute to achieving the objectives of
the energy transition.
02-2019 | 13

Grid Connection
Bart Stam
Future offshore wind farms require bold solutions
Bigger, higher
and further
The Netherlands faces an enormous challenge of producing 49 terawatt
hours of electricity from wind turbines at the North Sea by the year 2030.
The only solution seems to be ever larger turbines far away from the coast,
but how do we ensure that offshore wind energy remains competitive?
PHOTO: TENNET
This was discussed at the National Wind Energy Event
April 17 in Rotterdam. Offshore wind energy in the
Netherlands literally has the wind at its back. For
example, the 2030 Roadmap by the Ministry of
Economic Affairs and Climate Policy aims for no less than 10.6
gigawatts (10,600 megawatts) in the Dutch part of the North Sea.
Of this, 3.5 GW must be installed by 2023 and 6.1 GW by 2030.
By way of comparison: the four existing offshore wind farms have
a combined capacity of 957 MW. So, there’s work to do!
The designated zones for the third generation (2023-2030) of
offshore wind farms are ‘Hollandse Kust (West)’ (1,400 MW), ‘Ten
Noorden van de Waddeneilanden’ (700 MW) and ‘IJmuiden Ver’
(4,000 MW or 4 GW). The latter’s name (‘IJmuiden Far’) has been
chosen aptly, because the location is situated at no less than eighty
kilometres from the coast, near the British Exclusive Economic Zone.
Here, Swedish developer Vattenfall will build the Norfolk Vanguard
and Norfolk Boreas wind farms, both accounting for 1.8 GW.
Enormous distances
Such distances between wind farms and the mainland pose
considerable challenges. In the run-up to IJmuiden Ver offshore
wind farm, which is scheduled to go into production between
2027 and 2030, TenneT is already working on the development of
a new generation of 2 gigawatt (GW) transformer stations and 525
kilovolt (kV) electricity cables, in order to get the enormous
amount of electricity on land efficiently. “Offshore wind energy is
currently showing a paradox”, claims Rob van der Hage MSc,
Manager Offshore Grid Development at TenneT NL. “While the
If there’s no demand from
the industry, then there’s no
business case
costs for construction, operation and investment are steadily
decreasing, transport and connection costs are increasing due to
longer distances. This can pose a threat to the cost reduction of
offshore wind energy.”
For the upcoming wind farms in 2023, TenneT can suffice with
transformer stations of 700 MW. However, new solutions are
needed for IJmuiden Ver sized wind farms. For example, as grid
manager TenneT has calculated, from about 80 kilometres off the
coast, DC cables are more efficient than AC cables. Of course, the
Arnhem-based grid operator also takes into account the 10 MW
and 12 MW wind turbines that will make their debut in a few
years’ time. For example, General Electric is currently building the
world’s largest wind turbine, Haliade-X 12 MW, in the port of
Rotterdam. This test model will have three rotor blades of 107
metres and a rotor diameter of no less than 220 metres. A test
period of five years will start by mid-2019.
Energy islands
Together with Gasunie, Port of Rotterdam and Energinet.dk from
Denmark, TenneT has been investigating the feasibility of artificial
energy islands in the North Sea since 2016. It goes without saying
that these ‘NorthSea Windpower Hubs’ will not be realised
overnight, so TenneT and its partners are aiming for 2030 and
beyond. The aim of these islands is not only to bundle large
quantities of electricity from neighbouring wind farms and bring it
ashore in North-West Europe via an advanced network of
connectors and cables, but also to use the electricity produced on
site for, hydrogen production, for example. In addition,
maintenance and assembly of wind turbines could also take place
there. Such energy islands do require far-reaching European
cooperation. Especially, if in the distant future the entire North
Sea is likely to host 150 GW (or more) of offshore wind farms.
For Kees-Jan Rameau, chief strategic growth officer at energy
company Eneco, it is important that the price of wind energy
14 | 02-2019

Artist’s impression of IJmuiden Ver offshore substation station
continues to fall in the coming years. “At Luchterduinen in 2011,
investment costs were 170 euros per megawatt hour. At Borssele 3
and 4, December 2016, this rate had already fallen to 54 euros
and the end is not yet in sight. That’s why nowadays, we can build
offshore wind farms without government subsidies.”
According to Rameau, this cost reduction can only continue if we
succeed in balancing supply and demand of electricity from wind
farms at sea. “In 2030, most of the demand for clean electricity
will come from industry, approximately some 18 terawatt hour.
After all, for their production processes companies will have to
switch from natural gas to electrification in the coming years.”
For this view, Rameau gets support from Hans Timmers,
chairman of NWEA (Netherlands Wind Energy Association), and
Allard Castelein, CEO of the Port of Rotterdam. Rameau: “We are
currently building large-scale wind turbines, and also solar panels,
without asking if there’s a demand for this electricity by the
industry, households or the transport sector. This has to change.”
Coastal areas
According to Rameau, it is also important that the electricity
generated offshore is directly transported to the large industries in
the coastal areas. In his view, this will prevent billions of euros in
investments in new high-voltage lines and onshore grid upgrades.
With Tata Steel in IJmuiden, but also with the large petrochemical
and process industry in the ports of Rotterdam, Amsterdam,
Vlissingen/Terneuzen and Eemshaven, the Netherlands has an
excellent position.
Timmers (NWEA) also believes that the national industry is
essential for the success - or failure - of offshore wind energy. “If
there’s no demand from the industry, then there’s no business
case.” Timmers does not foresee any problems with the first 10.6
gigawatts of wind farms at the North Sea. However, the situation
will be different at around 60 to 75 GW in the year 2050. The
‘Planbureau voor de Leefomgeving’ (Netherlands Environmental
Assessment Agency) has calculated this is most likely the
maximum capacity of the Dutch Exclusive Economic Zone.
Timmers: “That’s about 20 to 25 percent of the total area. At that
stage, we have to think very carefully about what the infrastructure
at sea should look like, how we are going to get all that electricity
on land and what is going to happen with it.”
Although the Netherlands is currently almost at the bottom of the
European Union with only 7.28% renewable energy, according to
the chairman of the NWEA, we are making up for lost ground in
the field of offshore wind energy. “In 2030, The Netherlands will
be the third country in the North Sea with a capacity of 10.6 GW,
after Great Britain (30 GW) and Germany (15 GW). In addition,
we have a strong supply industry that is involved in three quarters
of all European wind farms.” Timmers mentions TenneT, SIF
Offshore Foundations, Huisman, Royal IHC, Boskalis, Van Oord
and Seaway Heavy Lifting as fine examples.
Opportunities for Rotterdam
Allard Castelein of the Port of Rotterdam also sees offshore wind
energy as an important tool to become an energy-neutral port in
2050. “We have 200 MW of wind turbines in the port area and
can still grow to around 300 MW, but unfortunately there is no
more space in our port. That is why we are looking at the North
Sea with extra interest. This must become our new national energy
province.”
According to Castelein, offshore wind can largely take care of the
electrification and sustainability of Rotterdam’s industry. “In the
future, the petrochemical and process industry will not only need
large amounts of sustainable electricity, but also large amounts of
heat of about 1400 degrees Celsius. Offshore wind farms are
extremely suitable for converting this electricity into hydrogen via
electrolysis, as source for this heat.”
Castelein is convinced that the port of Rotterdam can benefit
greatly from offshore wind energy. “Ten thousand jobs will be
created in 2020, and ten years later it will be doubled. We must
not miss this opportunity!”
02-2019 | 15

Grid Connection
Nadine Huiskes
Challenging site investigations for Hollandse Kust Zuid 1 & 2
Storms, sea mines
and dunes
Even though there is not so much to see, the preparatory works for the Hollandse
Kust Zuid 1 & 2 wind farm - the first subsidy-free Dutch wind farm - is in full swing.
In the coming years, Vattenfall will build a wind farm off the coast of The Hague and
Noordwijk that can supply 1 to 1.5 million households with renewable energy.
Until summer, many researchers work day and night
offshore to find out as much as possible about the location
of the wind farm. Using high-tech equipment,
they scan underwater for bombs and shipwrecks and
map the seabed. During this process they are faced with various
challenges.
The work started in February, but soon storms Freya and Gareth
disrupted the works. The two research vessels, with a total of thirty
crew members, were forced to take shelter in the Scheveningen
harbor. “Of course it’s very frustrating to have such bad weather
right from the start, but there’s not much you can do about it,”
says Daniel Jenkins, project manager at Bibby HydroMap, the
company that carries out the geophysical surveys. “The vessels are
built for worse weather conditions, but the equipment is very sensitive.
We know that if we collect data during bad weather, it will
be of poor quality. That is simply not an option.”
According to Aidan Marchand, who oversees the technical implementation
of the project from Vattenfall, it was already known upfront
that the North Sea does not always offer the best (weather)
conditions for site investigations. “That is why our original planning
already includes a number of weeks in which we cannot collect
data.” Due to the turbulent weather, the research vessels have
to make the most of the calm periods in order to catch up. Jenkins:
“The crew collects data 24 hours a day, thus also at night. In this
way, we make optimal use of the favorable weather windows.”
The mobile sand dunes at the
bottom of the sea make the construction
of the wind farm
complex
Every ten days, research vessels Bibby Athena and Bibby Tethra
arrive at the port of Scheveningen to take in supplies or to change
crew members.
Sonar and Soil samples
The seabed is examined until August, using scanning equipment
that does not disturb the environment. This research is followed by
the collection of soil samples. In addition to the geophysical surveys
by Bibby HydroMap, Fugro conducts the geotechnical surveys.
Marchand explains the difference: “The geophysical research
mainly uses scan sensors that are towed in the water behind the
vessels. This results in an image of the seabed and the objects that
are located there. This is important for the next step: the geotechnical
studies, in which Fugro drills into the seabed and takes samples
to determine the composition and strength of the seabed.”
The results are used to design the most efficient foundations as
well as the cable routing for the wind farm.
From mine to plain bomb
The North Sea contains many traces of history. Explosives can be
found in many shapes and sizes. During both World War I and II,
countless sea mines were dropped; less than a quarter of these
were cleared afterwards. Hollandse Kust Zuid is located just north
of the most important flying route of the Allied Forces. Planes often
crashed into the sea or dropped their bombs too early. In addition,
fighting took place offshore, often between Allied aircraft and
German war vessels. It was not uncommon for torpedoes, bombs,
missiles and cannons to miss their target and end up on the seabed.
Ships that were hit sank. In later times, these unexploded
ordnances (UXO) regularly ended up in fishing nets, after which
they were thrown overboard again. This often happened in the
proximity of well-known shipwrecks, which fishermen avoided
anyway.
“It is relatively easy to identify shipwrecks,” says Jenkins. “This is
more difficult for UXO. We make a list of objects and their magne-
16 | 02-2019

Bibby Tethra Photo: Vattenfall/Hans-Peter van Velthoven
tic characteristics, size, shape and depth. A specialized agency then
analyzes this data.” The next step is to dismantle explosives.
Marchand: “We share the data with the coastguard, who calls in
the Royal Dutch Navy to clear the UXO.” Many shipwrecks have
already been recorded on navigation maps, but strong currents
may have moved or buried them. Sometimes the help of archaeologists
is called in.
Predicting sand dunes
Mapping wrecks and explosives is just one part of the site investigations.
In order to optimally design the wind farm - specifically
the foundation and cable routes - it is necessary to collect as
much data as possible. Thanks to the relatively shallow water and
sandy seabed, the North Sea is a great location for wind turbines.
There are, however, a number of issues that require attention.
“The mobile sand dunes at the bottom of the sea make the construction
of the wind farm complex,” says Marchand. “In some
places there is a mobile layer of sand of up to four meters thick.
These sand dunes are moving, which can lead to problems in the
future. Not so much for the foundations, they can withstand a
changing seabed. But cables are usually buried one to three meters
deep under the seabed and we don’t want them to be exposed.”
The solution lies in the predictive power of high-tech models.
“These can predict the behavior of the sand dunes on the
longer term, which allows us to make the best possible design for
the cable routes.”
Avoiding sand dunes
Jenkins points out that the sand dunes pose another challenge: the
equipment can strike a sandbank, which can lead to gaps in the
data collection. “The vessels sail at around nine kilometers per
hour. If a large sandbank suddenly appears, that is a risk for the
equipment, which is often towed in the water a few hundred meters
behind the vessel. We want to keep the sonar as close as possible
to the seabed. And at the same level, so that the data collection
is constant. We have a Remotely Operated Towed Vehicle (ROTV)
on board that scans the seabed and automatically intervenes in
case of a sand dune. But on some occasions this does not work
so well, which means you have to adjust the equipment manually.
We need to keep an eye on this at all times.”
This attention also applies to the high waves that are also very
characteristic for the North Sea. Research vessels Bibby Athena
and Bibby Tethra sometimes have to deviate considerably from
the planned sailing direction to ensure that the equipment under
water follows the intended path.
High-tech equipment
With less than thirty meter in length, the vessels are maneuverable
and built for researching large areas. Thanks to the Small
Waterplane Area Twin Hull (SWATH) design, visible in the
characteristic hull of Bibby Athena and Bibby Tethra, they can
easily sail the turbulent sea. The vessels are also equipped with a
so called ‘A-frame’ that deploys the equipment, with a platform
specifically designed to recover equipment and with an impressive
collection of other high-tech research equipment. The collection
and storage of data is done securely thanks to cameras on deck,
cooled and soundproof units in which the data is stored, and
emergency power supply. On board there is room for sixteen people,
who can use modern conveniences such as air conditioning
and satellite TV. Every ten days the vessels arrive at the port of
Scheveningen to take in supplies or to change crew members.
eyes and ears on board
02-2019 | 17

VATTENFALL/HANS-PETER VAN VELTHOVEN
Hollandse Kust Zuid is located
just north of the most important
flying route of the Allied Forces
A Vattenfall representative is also present on the vessels. “We are
Vattenfall’s eyes and ears,” says Tom Gray from East Point Geo, a
consultancy firm for onshore and offshore geo projects. Based on
their expertise, the representatives can properly assess the ongoing
site investigations. Gray points out that the works are not only
technically very complex, but are also carried out in a high-risk environment.
“The representatives ensure that all procedures are
carried out safely and correctly. In addition, it is a working environment
where the crew and research teams operate under considerable
pressure. We therefore also keep an eye on for example
stress levels.”
When Bibby Athena and Bibby Tethra are in the harbor due to
bad weather, the representatives of East Point Geo ensure that
vessels and equipment are maintained and that the crew remains
ready to sail when the weather changes. “It is important that the
research equipment on both vessels is calibrated equally so that
data is collected in the same way,” Gray explains. “The crew is
subdivided into a crew that maintains the vessels and a crew that
maintains the research equipment,” adds Jenkins. “When the vessels
are in the port of Scheveningen, everyone stays on board.
Together they ensure that the moral remains high and that the
equipment stays ready for use.”
Design process
Until the end of 2019, Bibby HydroMap and Fugro will analyze,
test and interpret the collected data. This is essential input for designing
the cabling, foundations and wind turbines. The engineers
must take many aspects into account. Marchand: “The technology
for offshore wind is developing very fast. The wind turbines that
will be installed in 2022 will be different from the ones being produced
now. With our international experience in wind energy, we
can properly assess these developments and ensure that the infrastructure
is flexible and therefore suitable for newer technologies.”
The engineers also take environmental issues into account. By
doing so, they aim to preserve the local ecology as much as possible,
both during construction as well as during operations of the
wind farm.
Ambitions
At the end of 2022, Hollandse Kust Zuid 1 & 2 will produce its
first renewable energy. This is an important step for Vattenfall in
realizing its ambition for the future: enabling fossil-free living
within one generation. With a capacity of around 760 megawatts,
the wind farm also makes a significant contribution to the Dutch
ambition to have 4,500 megawatts of installed capacity at sea in
2023. Until then, the strong wind that makes the North Sea so
ideal for generating wind energy is an unpredictable factor for the
research teams at sea.
18 | 02-2019

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Interview
Sabine Lankhorst
Hans Schwirtz & Mario Loi of Prysmian
Stepping up to serve
the future grid
Future grid capacity is currently a hot topic in the Netherlands. With the wind
projects becoming larger, especially at sea, what are the requirements in terms
of cable designs?
Wind Energy Magazine spoke to Mario Loi and
Hans Schwirtz at the Delft production facility and
head office for the Nordics of international energy
and telecom cable and system provider Prysmian.
Hans Schwirtz, Commercial Manager Projects of Prysmian
PowerLink S.r.l., is responsible for the company’s subsea activities
in the Nordics. “After the telecom boom, following the
introduction of the internet, we now see a huge hype in power,
both onshore and offshore, in interconnecting countries,
connecting wind farms but also in optimising the grid”, he tells.
While the Netherlands is moving away from gas towards a more
electricity-based energy system, with large influx from renewable
energy in the future, this will have a big impact on the current
national distribution network, for both the national Transmission
System Operator and distribution network operators.
Mario Loi, as Business Manager Utilities Netherlands responsible
for the onshore market, explains: “There are already difficulties in
keeping up with the current renewable energy influx, especially
with solar energy.” We are currently working on several highvoltage
networks to keep up but it seems that already in the near
future this won't be enough, he stresses. All parties involved are
still debating on this topic.
“Nobody wants wind farms in their backyard but they neither
want these huge high-voltage pylons. Something has to happen.”
Prysmian is taking this very serious, he stresses, regular meetings
have been set up with all parties involved to discuss this topic.
When you step up to 220 kV, the
present cable designs need a
fundamental change
"Where are we headed in the electricity market, what is the desired
capacity and how does this affect our company? Should we and
when do we adapt our production process is one continuous
question we ask ourselves."
Bigger and longer
One thing is sure, cables will become bigger in size and capacity
and larger. For one, clients opt for cables with better efficiency.
This generally means cables will be larger in diameter. Another
reason is the growth in wind turbine size. Schwirtz elaborates: “20
years ago, we talked about kilowatts and now we are talking about
megawatts. Old turbines are being replaced by modern, more
powerful turbines. As voltages and currents increase, these require
higher transmission powers. This has an impact on the size of
cables and the installation components.” Offshore, he sees not only
an increase in turbine size but also in wind farm size and wind
farms being built further offshore. “We are now already building
700 MW wind farms. After 2025 we will see 2 to 4 GW wind sites.
These are no longer wind farms but proper power plants!”
With regards to the inter-array cables, 66 kV cables are becoming
the standard. “The 33 kV inter-array cables will still be used for
smaller wind farms or nearshore, such as Fryslân Wind Farm. The
turbines in the range of 9.5 to 12 MW that are currently being
developed already require 66 kV cables. Those in the range of 15
to 20 MW will even need 132 kV cables. We are already designing
these.” After that, he warns, it will become a challenge. When you
step up to 220 kV, the present cable designs need a fundamental
change. Because of the continuous force on the cables, caused by
the movement of the wind turbines, the cables need to be light and
very flexible. Lead sheaths or aluminium sheaths cannot stand
much movement although they are still the best solutions to keep
the cable dry. The company is already talking to a number of
parties in the offshore wind to look into this. Also, the bigger the
offshore turbines, the bigger the distance required between the
turbines. This means longer inter-array cables are needed.
20 | 02-2019

66 kV subsea cable
for offshore wind
Schwirtz sees examples of wind farms where they require interarray
cables of 15 km.
The size and the far away location also affects the length and size
of export cables. Schwirtz: “We already produce export cables with
a diameter of 30 cm that weigh around 170 kilos per metre. That’s
almost a redoubling from the first 33 kV cables used at one of the
early Dutch offshore wind farms.” The current standard is 220 kV
AC but the market is moving towards 275 kV AC and 320 to 500
kV DC. AC cables loose efficiency on longer distances. DC cables
are cheaper but require expensive converters. However, these pay
themselves back with each kilometre of cable. There is a grey area
around 700 MW and 70 km in which, on a project-by-project
base, the optimum AC-DC solution has to be evaluated, he
explains. As to the capacity of the export cables, Prysmian recently
showed with the contract for the 600 kV Western HVDC link,
connecting the Scottish and the English/Wales power grids, that it
is able to provide high capacity cables.
Onshore, Loi also sees an increase in size and length of the cables.
“Take Fryslân Wind Farm, we are talking about one complete
connection of at least 55 km! This has an impact on the grid but
also on the permitting process.” The latter, he explains, is much
more complicated than offshore as it involves many more players,
both governmental and private, especially if a cable route is
intersecting multiple municipality borders. In the case of Fryslân
Wind Farm, the situation is even more complicated as a large
section of the cable will be installed in the Afsluitdijk, at the same
time as the Ministry of Waterways and Public Works is working on
a dike reinforcement project. He also sees a shift towards the use
of DC connections. When DC is used for connecting offshore
wind farms to the land station it means that parts of the onshore
track will also consist of DC cables. Due to the high capacity, less
cables (2 instead of 3), and thus less space, are required.
Growing focus on sustainability
Sustainability is a focus area for Prysmian. Until 30, 40 years ago,
Prysmian still produced paper insulated, lead covered (PILC)
02-2019 | 21

cables. However, pressure was placed on the cable manufacturers
to look into more cleaner solutions. This lead to the introduction
of XLPE (crosslinked polyethylene) and EPR (ethylene propylene
rubber) cables. These materials are not easy to recycle though.
Around ten years ago, Prysmian developed their P-Laser
insulation material. P-Laser is an eco-friendly cable, manufactured
using thermoplastic materials. Its production process utilises ‘zerogas’
technology, reducing CO2 emissions. It is also capable to
perform at higher temperatures, allowing for higher voltages.
Prysmian currently only produces P-Laser cables for onshore use
but is already in the process of developing them for subsea use
also.
“We were pioneers in this field. Unfortunately the use of
sustainable materials currently only takes up around a small
percentage of our market”, Loi says, “in fact, European tender
regulations even prevented us back then to include the product in
a tender on grounds of preventing a level playing field!”
Nowadays, as the interest and sense of necessity for sustainable
solutions is growing amongst clients, there is more competition in
the market. For most clients, however, cost is still a deciding
factor.
QA, monitoring and prediction
Schwirtz: “Cables are a critical product. They take up a relatively
small percentage of the total value of a wind farm but if they are
not functioning, there is no revenue. This becomes even more so
important with subsidy-free wind farms.” Extreme QA is applied
to the cable production, especially to subsea cables. “Half of the
time is spent on testing. With each new production step the entire
cable is tested again”, he adds. Prysmian has test labs in the UK,
Italy and the Netherlands. The company also decided to invest in
their own mobile diagnostic and testing facilities from the Delft
facility. With mobile road-transportable equipment, high voltage
cables can be tested under extreme voltages. It is currently the
only mobile diagnostic and testing facility where very long export
cables can be tested before being put into operation. The export
cable for the Gemini offshore wind farm was tested for this reason,
even though Prysmian did not provide the cable itself.
However, he explains, an offshore cable generally does not get
damaged because of production errors but due to external
elements; by trawling and sometimes by errors made during
installation. Most of the time, a cable breaks down when it is
operating at its highest capacity, when there are strong winds. This
is also the worst weather situation to pick up the broken cable,
repair it and install it again. It also depends on the availability of
the required equipment at that time. “When an onshore cable is
damaged it will take between 2 to 7 days to repair the cable.
Offshore, this could take a few months.”
It is for this reason that monitoring of subsea cables is extremely
important. The quality of a cable can be determined by measuring
the temperature. This is done by making use of the optical fibres,
sending a thin light-pulse and wait for the reflection. Schwirtz:
“We can measure the temperature and location with a precision of
up to a few metres. By correlating current and temperature, we
can see if a cable is heating up disproportionally or is not heating
up as expected. These situations can be caused by a cable part that
was buried too deep or a cable being exposed. Both scenarios can
put a cable at a risk.” This method is now also used for inter-array
cables.
The most important indicator of the quality of the cable, however,
is the insulation. Prysmian has developed its own system based on
partial discharge sensoring. Schwirtz: “Damage on the insulation
leads to small electrostatic discharge. We can, say with some
restrictions, measure these discharges. By integrating this add-on
system with temperature measurement we can not only determine
the actual quality of a cable but also predict future quality. This
way we can plan repair activities at a more convenient time, for
example during planned maintenance activities, better weather
windows, or when the required equipment is available. This leads
to better cost-efficiency.”
Future outlook Prysmian
In the offshore wind market the two Prysmian men see a trend
towards project developers using less contracts. Schwirtz
elaborates: “For the UK Gwynt y Môr offshore wind project, our
client managed around 120 contracts. For the Westermeerwind
Wind Farm, only one contractor was assigned for the complete
wind farm installation.” Prysmian can perform both supply only,
as is the case for Borssele 3 & 4, or turn-key projects, as required
in for instance TenneT’s tenders for the 220 kV offshore
connections. Playing a different role can at times create tension.
Schwirtz: “Sometimes you are a supplier and sometimes a
competitor. You have to carefully consider each project because
there can easily be a conflict of interest.” Fortunately he sees the
market becoming more mature.
Even though the power market is booming, it does not mean it
necessarily is a growth market. Schwirtz: “Due to cables becoming
more efficient, the cable market itself in general is not growing
substantially, not in volume nor profit. We use less cables and
therefore need less volume per megawatt. To survive in this
market, it is necessary to scale up your business. Prysmian’s
strategy is to acquire other healthy cable companies that
complement our existing activities. With the acquisition of Draka
and General Cables we showed that we have been able to do so
successfully.”
When an onshore cable is
damaged it will take between 2 to 7
days to repair the cable. Offshore,
this could take a few months
22 | 02-2019

Prysmian Group
Prysmian Group is active in both the
onshore and offshore wind markets.
The company provides all the required
cables for the wind industry, low, mid
and high voltage cables, inter
connectors, optical fibres and -cables,
auxiliary equipment, testing and
monitoring and maintenance. On land,
Prysmian doesn’t perform the civil
work itself but works with external
partners. Offshore, it is able to supply
cables or deliver turn-key projects.
There is a strong focus on large interconnection
projects and to a lesser
extent the inter-array installation.
At the Delft facility, originally the head
office of Nederlandse Kabelfabriek, all
land cables for the Dutch market are
produced. Although Prysmian is
specialist in large cable drums, due to
limited storage space and no proper
access for the large cable laying
vessels, the production of subsea
cables is taking place outside the
Netherlands; in Finland, Germany,
Norway and Italy. The company owns
3 cable laying vessels; Ulisse, Giulio
Verne and Cable Enterprise. All with a
minimum load capacity of 7,000
tonnes and the Giullio Verne with
capability to install at water depths of
up to 3,000 metres. A fourth one is on
its way.
Cable laying vessel Cable Enterprise
5,000mt carousel in Drammen loaded with cables for an offshore wind farm
02-2019 | 23

Interview
Sabine Lankhorst
Jaco Lemmerzaal, Managing Director of HSM Offshore
The beating heart
of a wind farm
In 2002, HSM Offshore built the offshore substation for the first offshore wind
farm, the Danish Horns Rev A. Almost 17 years and several wind farm
generations later, the Dutch manufacturing company is still building offshore
platforms for the wind energy industry.
The latest being the Borssele Alpha and Beta platforms.
Wind Energy Magazine spoke to Jaco Lemmerzaal at
HSM Offshore in Schiedam.
You won the contracts for both the Borssele Alpha and
Beta substations, how are the activities developing?
The contract for the Offshore High Voltage Substations include
the jackets and the topsides. At the moment, we just completed
the topside of Borssele Alpha. We signed the contract for this 700
MW offshore platform in March 2017. In the Summer of 2018 we
already installed the jacket. We are now waiting for the right
weather window to transport it to the site. The installation is
contracted to Seaway 7. Once the topside is installed, it will take a
few months to organise and connect everything. The whole
platform should be operational by the end of August.
You also made a start on the construction of the Borssele
Beta platform. Are there any differences to mention?
We have also just completed the jacket for Borssele Beta. Like with
the Borssele Alpha topside, we are currently waiting for it to be
transported. We now continue focusing on the construction of the
topside for Borssele Beta which is planned to be installed spring
2020. Borssele Alpha and Beta are the first platforms to be built
following TenneT’s standardised offshore connection design. The
hearts of the platforms are the same but the full design is adapted
to the site specific requirements such as water depth. Alpha is a
pilot, so most work went into this platform. Due to the time
At the peak of construction
activities there are over 400
persons involved
pressure, we had to start the construction while we were still
optimising the design. There are, of course, always some lessons
learned when you build a first platform but nothing major in this
case. For example, for Borssele Beta, we researched how we could
make the construction process for the jacket more efficient. We
didn’t change anything in the jacket design itself but we did
change the construction method.
What are the main challenges in building an offshore
platform?
TenneT holds the responsibility to ensure that an offshore
platform is operational at all times in order to guarantee a
continuous electricity supply to its clients, the energy companies.
Therefore, the platform needs a high availability. Great care and
attention is paid to this, both in the design and during the
construction of the platform, to prevent future failure of the
systems. All this requires a well thought design and a properly
organised coordination. At the peak of construction activities there
are over 400 persons involved. These are our own people and
temporary contracted personnel like welders and fitters. We have
also subcontracted several activities, including electrical and
instrumentation, piping and HVAC. And then you have the
representatives from TenneT and our vendors and the inspection
people. You can imagine the coordination it requires to ensure that
everything is working smoothly!
Will the other OHVS’ also work with the same design?
Tennet has become the owner of the design. This design was
included in new tender packages and was used as the basic design
for the next platforms. The builders of these platforms will
probably add their own design elements and remain responsible
for the total design, as EPCI Contractor. For example, for the
Borssele Alpha and Beta platforms we introduced our own HVAC
design to prevent overheating of the system which may lead to a
system break down. The builders of the next platforms might have
a different view on this.
24 | 02-2019

u Borssele Alpha & Beta
Dimensions
Topside: 58 x 32 x 26 m
Jacket Alpha: 50 x 28 x 55 m
Jacket Beta: 50 x 28 x 57.5 m
Piles: 61 m each
Weight
Topside: 3,700 t
Jacket: 2,900 t (including
cable deck and J-tubes)
Piles: 1,400 t
Capacity
Total power: 700 MW
(2 x 350 MW)
Intake: 66 kV
Export: 220 kV
Jacket Borssele Alpha installed
02-2019 | 25

Load-out topside Borssele Alpha at HSM Yard, Schiedam. Photo: Robert Nagelkerke
How have offshore platforms developed over time?
Our first offshore platform for offshore wind, the Horns Rev
Alpha, looked completely different! At that time, our client did not
have any offshore experience yet and thought a simple case of
‘copy - paste’ of their onshore experience would suffice. So instead
of installing a topside on a jacket foundation, like we are doing
right now, we had to pile the platform on location in a frame.
When we were awarded the contract for Horns Rev B and later C,
it was already a different situation. And it doesn’t stop, offshore
turbines are getting bigger and more powerful, wind farms are
getting larger, and so will the offshore substations. Our challenge is
to build platforms in a most efficient manner and at the same time
in a cost-effective way. But also, how can we install the platforms as
economically as possible? Perhaps the use of suction buckets instead
of piling could become more of an option. The engineers will also
be challenged in designing a large platform that is not too heavy.
What you also see is a new way of looking at the accessibility and
maintenance of platforms. Modern platforms need to be lowmaintenance
and in principle unmanned. Borssele Alpha and Beta
will not have a helideck. A helideck might look simple. However,
there’s a lot to take into consideration with regards to safety
requirements, fire protection, navigation, etcetera. By means of
state-of-the-art technology, the platform can be monitored from a
land-based office. Even though we do not design own products,
we do keep an eye on the market in order to be able to offer stateof-the-art
platforms to our clients.
Borssele Alpha and Beta are only the first of a
standardised offshore grid connection introduced
by TenneT. Would it not have made sense
to have one party build all platforms?
In total, there are 8 standardised platforms to be built. TenneT
decided to split the purchase of the platforms in 4 phases.
We won the contracts for the two first standardised platforms.
Unfortunately we did not win the next two, those for Hollandse
Kust Zuid 1 & 2. These contracts were awarded to Petrofac Norge
BV. The platforms will be built in Dubai. The contracts for the
next three platforms (Hollandse Kust Noord and West) are now
being tendered. For these substations we know that we are
confronted with global competition, including India and China.
TenneT is a state-owned company, therefore it has to comply with
European tender policies. To be honest, this can be quite frustrating
to us at times. In the Netherlands, our Government advocates an
open market and therefore also an open economic policy. This
means that contracts are put out to tender internationally. Let me
be clear, we do not mind competition but there should be a level
playing field. Here we are, a country with an open market yet
surrounded by countries that apply protectionism as their economic
policy. Take for example France, this country is developing a large
domestic market for offshore wind. For a company outside of
France it is practically impossible to compete on this market. The
UK also applies a certain level of protectionism. Here, you must
meet high requirements in the area of local content. This could be
up to 60% of the work. In general, the more South you go, the more
difficult it becomes to get foothold on a market.
In addition, as our market is open to international businesses, we
have to compete in our own market against offers from companies
based in low-wage countries such as the aforementioned Dubai,
India and China. It is not so much that we are competing for
component costs. What makes their offering more attractive is the
low labour cost. We would be happy to have the same people
working here in The Netherlands for a comparable wage. With the
living conditions here, they would probably even prefer to work
here. However, this is not possible because in the Netherlands, all
wages need to be in line with the market to protect our national
26 | 02-2019

Installation jacket Borssele Alpha, photo: Izak van Maldegem
workers and provide equal opportunities. There is a paradox here.
We are visited on a regular base by representatives of the
Government and TenneT, praising us for the work we do here.
They are proud of this piece of local economy and national
strength. We do our best to participate in everything, from providing
guest lectures, offering apprenticeships, etcetera. However,
that same Government that is concerned about protecting our
national workforce is happy to outsource a contract to low wage
countries which means a lost opportunity for more jobs.
Do you think we will see a more protectionist approach
being introduced by the Dutch Government in the near
future?
We have been lobbying for some time now to achieve a situation
where a level playing field is achieved but it is difficult. Over time,
our ‘partners in crime’ Heerema Zwijndrecht and Hollandia
Offshore have pulled back from the offshore wind market so we
are fighting this battle almost alone now.
Do the low wages make up for the fact that there are cost
involved having to transport the platform from across the
world back to the Netherlands?
At first glance they do. Prices from companies in de Middle or fast
East are competitive because the wage component, and we
Everyone thinks wind is
booming but the energy demand
for oil and gas in particular is
still growing
estimate this on approximately half of the total costs, is much
lower. In China, the wages are almost a tenth of what we are
paying. It is clear that this is very attractive indeed. However, if
you look at the carbon footprint of building a platform on the
other side of the world it is starting to make less sense. Besides the
obvious factor, the transportation of the completed platform, there
is also the transportation of a lot of equipment and parts that are
produced here in the Netherlands or Europe which have to be sent
to China or Dubai. In addition, numerous flights back and
forward are necessary to perform the necessary inspections.
Where do you see HSM Offshore going in the next years?
We have always focused on several markets, being civil
construction for HSM Steel Structures, such as the construction
of bridges, the traditional offshore OiI & Gas sector as well as the
offshore wind sector. The past years, wind has been one of our
main focus areas and when we look at the national roadmap for
2030 we are confident that we will get our share. We mainly look
at the North Sea, Irish Sea and Baltic Sea. Denmark is going to
invest again in offshore wind. We also participated in a tender for
two offshore platforms in Belgium recently. In this case, the
Belgian Government chose to only tender out this contract to
North Western European companies with fabrication facilities in
the European Union, to keep better control of the process.
Fortunately we see that experience is becoming more valuable
while before, as a company you only needed to show that you were
financially able to perform an activity. We have no ambition to look
outside Europe.
For the future we expect a healthy mix again. Everyone thinks
wind is booming but the energy demand for oil and gas in
particular is still growing. Prices are going up again and new
investments are expected to be made.
02-2019 | 27

Offshore
Wind Farm News
1
© GE
4
© TENNET
1
IJmuiden Ver
TenneT announced it will deploy
two 2 GW direct current
connections for the far offshore
wind project IJmuiden Ver.
These will consist of converter
stations and cables. The cables
have a voltage level of
525 kV. Due to the large capacity
only 2 instead of 6 cables
will be required. The 4 GW
IJmuiden Ver site is located
some 80 km from the coast
and is part of the Roadmap
2024-2030.
2
Fryslân Wind Farm
The first construction activities
have started on the 382.7
MW nearshore wind farm in
the IJsselmeer, to the south of
the Afsluitdijk. In total, 14 cable
pipes, with a total length of
around 4.2 km were installed
at Breezanddijk. By the end of
2020, the infield cables will be
pulled through here.
Zuiderzeewind, a consortium
consisting of Van Oord and
Siemens Gamesa Renewable
Energy, is responsible for the
construction of the wind farm.
It will comprise 89 SWT-
DD-130 wind turbines with a
capacity of 4.3 MW and a rotor
diameter of 130 metres each.
The wind farm is intended to
be fully operational by 2021.
3
Hollandse Kust Zuid 1 & 2
Vattenfall has selected
Siemens Gamesa to supply 76
of its 10 MW wind turbine. The
turbine, the SG 10.0-193 DD,
has 94 metre blades and a
rotor diameter of 194 metre.
Seaway 7 is contracted for the
transport and installation of
the monopile foundations and
the laying of the inter-array
cables. The port of IJmuiden
will be used as O&M base. A
new service hub will be constructed
here for this purpose.
Commissioning of the wind
farm is planned for 2023.
Physical preparatory works
have already started. See p.16.
4
Haliade-X 12 MW
Royal HaskoningDHV has
been contracted to design the
foundation for the Haliade-X
12 MW prototype, the world’s
biggest wind turbine. The design
is based on a piled foundation,
with a large concrete
block on top that has a diameter
of 28 metres and thickness
of 4 metres in the centre. GE
Renewable Energy and
FutureWind (a Joint Venture
between Pondera
Development and SIF Holding
Netherlands) will build the
prototype of the 12 MW
offshore turbine at the SIF
premises at the Maasvlakte in
Rotterdam.
5
Borssele 1 & 2
HSM Offshore (see p.24) completed
the topside for TenneT’s
700 MW Borssele Alpha
offshore substation. It will be
installed at the Borssele 1 & 2
site sometime during May. In
April, Boskalis already laid the
first of two 61 kilometre export
cables (from NKT Cables) that
connect the offshore station
with the onshore station in
Borssele. The second is due to
be installed in May. Borssele 1
& 2 is a project by Ørsted. It
will comprise 94 wind turbines
from Siemens Gamesa with
each a power of 8 MW. The
commissioning of the 752 MW
wind farm is scheduled for the
end of 2020.
© ROBERT NAGELKERKE
3
5
© SIEMENS GAMESA
28 | 02-2019

1
2
3
4
5
Read the full news
on www.windenergymagazine.com
(EN) or
www.windenergienieuws.nl
(NL)
02-2019 | 29

Grid Connection
Martijn Bongaerts
The electrical grid in the Netherlands
Solving
the gridlock
On March 13, the Netherlands Environmental
Assessment Agency (PBL) published their
assessment of the Draft Climate Agreement.
Though the PBL has second thoughts as to the
feasibility of the climate goals, distribution network
operators have noticed in practice that the energy
transition is in full swing.
The continuous growth of in particular land based
renewable energy generation makes the effects on the
electrical grid already noticeable during operations. In
January, newspaper headlines gave it a lot of attention:
‘Shortage of power cables impedes transition to green energy.’
‘Electrical grid squeaks and creaks under growth of solar panels.’
And: ‘Energy from solar panels clogs electrical grid.’ Just a few of
the many recent headlines in the media. What is the matter with
the electrical grid in the Netherlands? And what are, if needed, the
solutions?
In the growing economy, the demand for electricity and power increases
fast, especially by industry. Also, there is an acceleration of
the energy transition: in more and more places, renewable energy
is being produced. Onshore wind energy generation is growing
steadily, but recently the growth of solar panels installed on rooftops
and in fields is remarkably fast. This supply of renewable energy
requires extra capacity of the grid.
The last two years, for instance, about € 10 billion has been committed
to subsidies for solar projects, and that has led to solar
parks booming. Especially sparsely populated areas, where the price
of land is low, are interesting for developers of solar fields.
Many solar panels and wind
turbines are installed in areas
with a reduced demand for
electricity
Take for instance the province of Friesland. Distribution network
operator Liander takes into account that in Friesland until the year
2050 about 6,100 MW of solar installations must be fitted into the
grid. To put this into perspective: at the end of 2018 the total installed
solar power was about 300 MW. This means that during the
next thirty years the supply of solar power in Friesland will grow
twentyfold.
The electrical grid (see also Box) was designed a century ago to
transport electricity from fossil power stations, especially those fuelled
by gas and coal, to the customers. It concerned a centralised
system, where most capacity resided ‘up’ in the grid, to transport
the electricity from the power stations. The more one moved towards
the ‘capillaries’ of the grid, the lower the required capacity,
and therewith a smaller diameter of the power cables. Many solar
panels and wind turbines are installed in areas with a reduced demand
for electricity, and where subsequently the grid is rather
30 | 02-2019

Electrical substation. Photo by Liander
‘thin’. However, those wind turbines and solar roofs and fields require
a high capacity, and in general the grid has not been constructed
to deal with that. By investing in new cables and stations,
the electrical grid can be extended, but that will be expensive, will
put strains on the public space and takes time.
Difference between wind turbines and solar
panels
During the last approximately twenty years, quite a lot of wind
turbines have been installed on land in the Netherlands, and generally
connecting them to the electrical grid created no serious problems.
Why are there now problems arising with the current
growth of solar panel installations?
The main difference lies in the length of the trajectory towards a
wind turbine or wind farm and the more central directing that has
been applied here in the past, as described in the so-called structural
vision document Windenergie op Land. Installing a wind turbine
leads to extensive procedures for amongst other things planning
and permits. The procedures can take many years, and this provides
the distribution network operators with sufficient time to make
those investments in the electricity grid that are required for the
transport of wind energy. Thus, the distribution network operators
know in advance where the grid capacity would need extension.
Nowadays, the time required for procedures that lead to the installation
of large solar roofs and fields is substantially shorter. There
are solar parks that are fully operational within a year. When the
grids are inadequate, their upgrading may take a considerable longer
time than the installation of the solar project itself. The current
electrical power of solar installations requires investments in the
high voltage substations that are the responsibility of both the distribution
network operators and TenneT. It takes several years to
expand a station, let alone to build a new station. That could require
easily five years or more. Thus, the time scales of projects on
02-2019 | 31

Sometimes, the distribution
network operator is forced to
put a limit on the transport
volume
the one hand and the adaptation of the grids on the other hand, lie
far apart.
The investments of the distribution network operator are fully paid
(through the tariffs) by the end users. The supervisor requires efficacy
of the distribution network operators, so that upgrades of the
grid will be performed once the investments are justified.
Therefore, an investment will be made (or the upgrading will be
started) once the distribution network operator is certain that the
capacity will be required. Because of the difference in time scales
between realisation of solar parks and expansion of the electrical
grid, the distribution network operator often cannot be informed
in due time of the precise location of the solar park.
Joint planning
Because of the long process times, the high costs and the impacts
on spatial development, an important direction to solve the problems
as sketched above lies in more control and coordination during
the planning of renewable energy generation. By formulating
local energy ambitions and making plans for the numbers and locations
of installations for generating solar and wind energy, the
local municipalities (province, town) should take the required
energy infrastructures in consideration. By incorporating the grids
in the plans right away from the start, procedures may well take
place at an accelerated pace.
If early on the distribution network operator is involved in the
planning, it is possible to quickly gain awareness of possible issues
that may arise as far as the capacity of the grid is concerned and
of what is required to solve those difficulties. Authorities can then
assist to make sure that procedures such as zoning plans, permits
and others issues are handled more quickly. An important tool to
make this joint scheme feasible, are the Regional Energy Strategies
(RES), that are now drawn up in every region of the Netherlands.
By incorporating in these RES’s both the impact and the capacity
of the electricity grids, it is easier to estimate beforehand the possible
expansions of the infrastructure.
u The lay-out of the traditional electrical grid
The electrical system in the Netherlands consists of
three parts: power stations, transmission grid and
distribution grids.
Power stations
In the power stations, electricity is generated. The locations
of the power stations are spread across the country, but
mostly near sea ports (Eemshaven, Borssele, Maasvlakte).
The main power supplying companies in the Netherlands
are, amongst others, Vattenfall, Essent, Electrabel, Intergen,
Delta and E.ON.
Apart from large power stations, there is an increasing
amount of small renewable power sources where electricity
is generated (wind farms, biogas plants, cogeneration, etcetera).
This power is also transported to consumers through
the transmission grid.
What is the transmission grid?
The transmission grid is necessary to transport electricity
from those power plants to the regions where it is used. The
transport of large amounts of electricity requires a high voltage
grid. The 220 kV and 380 kV connections form the
main transmission grid. They serve as the highway for the
transport of electrical power. They are meant for large-scale
transregional transport. The 110 kV and 150 kV grids can be
seen as trunk roads, responsible for the regional distribution
of electricity. Transmission system operator TenneT oversees
the operation of the complete high-voltage grid, from
380 kV to 110 kV, throughout the Netherlands.
What is the distribution net?
Distribution network operators such as Enexis, Liander and
Stedin are responsible for the transport of electricity at voltages
lower than 110 kV. This grid starts at the electrical
substations where high voltage is transformed to medium
voltage. The electrical substations are the shared responsibility
of both the respective regional utility company and
TenneT. The grids at medium and low voltage are the distribution
nets to which end-users, both consumers and industry,
are connected. Before electricity leaves the power point,
the voltage has been reduced to 230 V. That is accomplished
in distribution transformers.
Source: www.randstad380kv-zuidring.nl
Else…
Thus, the distribution network operators are facing a considerable
challenge, an interesting complex puzzle comprised of technology,
uncertainty, costs, distribution of costs, spatial consequences and legislation
and regulations. Unfortunately, the result is that at the moment
a local grid does not always contain on time the desired capacity
to accommodate for the fast growing demand for electricity.
Sometimes, the distribution network operator is forced to put a limit
on the transport volume. In that case, the distribution network
operator is not able to grant all requests for electrical power by major
energy users. New customers will be connected to the grid, but
with a minimal power capacity. Existing customers that require additional
electrical power will have to wait until the expansion of the
grid has been realised. In the concerning region, the limited electrical
power transport has no impact on small consumers, such as residences,
and the power consumption by existing customers.
Innovative solutions
But maybe the large investments and the amount of work in the
grids can be reduced or even prevented by using innovative solutions.
A possible solution is the setting up of a flexibility market.
Liander already implements that in Nijmegen-Noord. This distribution
network operator carefully adjusts there the balance of supply
and demand to prevent both peak loads well as the associated
32 | 02-2019

High Voltage pylon. Photo byTenneT
necessary reinforcement of the grid. For the time being, this seems
to be a temporary solution, as in this flexibility market the distribution
network operators must buy available capacity from customers
in a market that has not yet matured.
Another solution is cable pooling, in which user and producer use
the same cable. In that case, a higher capacity utilisation of existing
grids and connections is achieved that prevents the need for
new grid investments.
Dutch distribution network operators also investigate the occurrence
of situations where when connecting renewable electricity
sources they can relinquish the principle of redundancy.
Redundancy means that there are extra cables and installations in
the electrical grid that make restoring power after an outage easier
and quicker. This also enables maintenance of the grid without leaving
large groups of customers without power. By relinquishing
the redundancy for wind and solar parks, less cables are required.
Easing the redundancy requirement for new, renewable ‘infeeders’,
those can be connected at an earlier stage. This results in a more
efficient use of the available capacity of the electrical grid. To realise
this, it is necessary to put in writing that during outages and
maintenance, these infeeders of renewable energy cannot rely
upon the usual transport service. The current legislation and regulations
makes no distinction between users and producers of
electricity.
Furthermore, it is considered whether distribution network operators
could be allowed to invest in a more anticipatory way, which
means that they take more financial risks when they are allowed to
invest without hundred percent certainty that the grids will be
used. Nowadays, distribution network operators are not allowed to
lay cables under the ground if they are not certain that those cables
will be used.
In short
The energy transition is not just an issue of supply and demand of
energy, because the electrical grid forms a crucial part of it. With
an integrated consideration of the problems and incorporation of
solutions in the plans, many issues that could arise in the future
when connecting renewable generated electricity to the grid may
be prevented.
u This articled was originally published in Dutch in WindNieuws 02, 2019.
02-2019 | 33

Interview
Mirjam Tielen
Chris Westra and Ernst van Zuijlen of Offshore Service Facilities
An island at sea,
from dream to
reality?
Chris Westra and Ernst van Zuijlen – two old hands in wind energy – have been
working on their plan for building an island at sea for a long time. The two men of
Offshore Service Facilities are now prepared to unveil their plans.
Often during the interview, the replies go astray or they
both burst out with laughter about all their
experiences. Clearly, they harbour a great enthusiasm
for ‘their’ island.
What does your plan comprise of?
Van Zuijlen: “Basically, it consists of a simple island with room for
one or more substations, where the transformation of electrical
power generated by wind farms at sea to direct current as well as
the transport of the power to mainland is controlled. When that is
just all that you do there, an island with a size of about 50 hectares
or 120 acres is sufficient.”
Westra: “Once you start building such an island, however, it
becomes increasingly interesting if there are additional uses for it.
A hotel for maintenance personnel is a very attractive alternative
to the service operation vessels on which those people now have to
stay. The island can also become a convenient location for coastal
guard operations, to rescue people and vessels, and for yachting it
can be a safe port of call. Maybe we can produce hydrogen gas
there, use it as a base for seaweed farms and the reintroduction of
oyster reefs, or it may even offer the opportunity to build data
centres there…”
Building islands at sea is like
a new kind of Delta Works,
co-operation with partners is
crucial
Van Zuijlen: “Obviously, such things cannot happen just like that –
funds need to be available, and it has to be permittable. We are
talking about a project that could easily be worth a couple of
hundred million euros. But… all those additional options are very
inspiring and a motivation to realise this island.”
Westra: “To some people, it may seem very easy, building an
island, but such an achievement has not been accomplished yet.
To manage that for the first time in the North Sea will probably
be difficult, but we are certain that in the future there will be an
even greater demand for such islands, also for other purposes, and
then such a pilot project is required to obtain the necessary
experience.”
How does your island relate to the floating islands of
MARIN?
Westra: “That project is about experimental, large floating
elements in the ocean. It is a very nice research project, but it will
require much more knowledge before it can be marketed.”
Van Zuijlen: “A real island is much ‘easier’; the Dutch dredging
companies are well capable to build islands. There are existing
examples, for instance in Dubai, though building an island in the
middle of the sea will be quite a different story and that makes our
plan so interesting. For the first array of substations for offshore
wind farms, a solid instead of a floating island is for now a
relatively safe choice.”
When did you start making these plans to build an island
at sea?
Westra: “It started in 2004, the idea came up during the We@Sea
project. With a group of people, we made some first sketches.
Many parties were already enthusiastic; it was called HEDEN,
34 | 02-2019

Chris Westra
Ernst van Zuijlen
‘HavenEiland Duurzame Energie Noordzee’, (Port Island
Renewable Energy North Sea). Former Minister of Economic
Affairs, Maria van der Hoeven, wished to pledge a million euro for
a feasibility study, but with the fall of the Fourth Balkenende
cabinet, that pledge evaporated. Due to the financial crisis,
moreover, the support for the project subsided.”
You have both worked for a very long time in the wind
energy sector. How did that come to be?
Van Zuijlen: “I started in the wind sector as consultant, and then
became project developer, lobbyist, R&D manager and now again
a project developer, but in this case of an infrastructural project.
Until now, I have been more busy with the generation of wind
power, but these days enough people are involved with that. An
island is the next challenge.”
Westra: “For me, it started with the Amsterdam politician Roel
van Duijn, who asked me to build a small wind turbine. I
considered wind energy a democratic form of energy, in fact good
for all and everything. But solar energy made me enthusiastic as
well. I did various solar energy projects in Africa. Furthermore, I
am always ready to take on crazy, new things, and this island is
right in line.”
It seems an exceptional step to want to build an island.
Isn’t that a strange step for you?
Westra: “I think it is a very logical step, because we cannot afford
to lose time with the energy transition, and reduction of costs and
safer working conditions are very important to offshore wind
power generation. Wind energy is also a lot of fun because all the
time new aspects come up. First there was only wind power on
land, then followed offshore wind power with many new aspects to
consider, such as shipping routes, safety, personnel transfer, the
growing number of wind farms. A next logical step is: how to get
there once all those wind farms are built, without repeating the
building platform trick that the oil and gas industry used. How on
Earth are we going to accomplish that with all those offshore wind
turbines?”
Van Zuijlen: “Right from the starting days of the renewable
generation of electricity, everyone said that storage and
controllability would become an issue. In fact, it was obvious that
up to 2020 there would be no problem, but now the time to act
has really arrived. On an island, things can be done about it, for
instance by using wind energy to produce hydrogen gas, or by
connecting offshore wind farms to both the Netherlands and
England. But it is especially ‘the human factor’ that makes an
island at sea important. What spatial organisation of the North Sea
is required when so much wind power must be generated? I find it
hard to imagine that in about twenty years hundreds or thousands
maintenance workers stay for weeks at service operation vessels, a
kind of floating hotel ships. Conditions at sea can be harsh and
then it can be really enjoyable to be able to stand regularly with
both feet firmly on the ground. The island at sea makes working at
sea also more safe, requiring less sailing to and fro and thus
reducing the traffic on shipping routes that become increasingly
crowded.”
Westra: “Platforms and boats are not a good match to a renewable
solution for offshore wind power generation. Imagine being a
maintenance crew, you first need to sail a long distance, arrive
sick, be able to step onto the platform and then have to climb up
carrying heavy things, and only then the work there can finally
begin. That is not how it should be done, and in fact it is
irresponsible.”
02-2019 | 35

Island at Sea, photo TenneT
You will not build yourselves. Which partners are
important for you?
Van Zuijlen: “The project requires a lot of different knowledge,
thus apart from contractors, we have been in contact with applied
scientific research institutes, environmental organisations,
electricity companies, the government and we consider the public
opinion. Building islands at sea is like a new kind of Delta Works.
Co-operation with several partners is crucial and together we are
going to start something that is new. That is the way we want to
develop it, as a project that will make everybody happy and proud.”
Westra: “A main wish is that all Non-Governmental Organisations
will find common ground in this. That will not be easy. However,
building an island as such is quite easy; it requires just moving a
huge amount of sand. Such an island has never been built before,
and everyone has an opinion ready. Apart from technical issues,
our work will for 80 percent consist of stakeholder management.
The technology we leave for a large part in the hands of others; the
whole bunch of issues around that, that is where we are of
importance, and good at.”
What additional benefits can an island offer?
Westra: “A huge benefit is that by building an island, you create a
stable area for maintenance, storage, transit of renewable energy,
and in due time possibly the additional opportunity to offer a
guaranteed security of supply. The idea is to combine various
kinds of things.”
Van Zuijlen: “There will be a lot of energy arriving from the sea,
but possibly also sustainable produced food and there are many
opportunities to improve the environmental conditions in the
North Sea. The combination of offshore wind energy generation
and the idea of an island at sea make those other options a lot
more realistic. Therefore, an island at sea offers a great
opportunity.”
What are the drawbacks of an island at sea?
After some joking (‘There aren’t any!’ and ‘The sea is an
obstacle!’) follows a moment of silence… Van Zuijlen: “Building
an island at sea is an intervention in the ecological system. We are
very aware of that, and therefore we find it imperative that we can
also make use of the ecological opportunities that an island offers,
such as oyster reefs, restoration of the marine ecology and for
instance the farming of seaweed. An island at sea can easily be
regarded as a translocation of activities from the main land to the
sea, or even as a colonisation of the sea. That image we wish to
avoid as much as possible.”
Westra: “Another drawback could be that quite a lot of sand will
be required and sand is becoming scarcer, though that applies
mainly to sand extraction near the coast. Not so much a
disadvantage but a wrong approach is to view the building of an
island as a wish to tame the sea.”
What is your drive to undertake this artificial island
venture?
Westra: “It is addictive to do something that has never been done
before. To go all the way for it because you like it. I am not solely
driven by technology. Technology is beautiful, but the real issue is
that we really should tackle the energy transition now, the sooner
the better, if we want to keep conditions on earth somewhat
liveable for future generations.”
Van Zuijlen: “I strongly believe that we need very quickly drastic
technological measures to save the environment as much as
possible. Offshore wind turbines and islands at sea are both
technological solutions that contribute to the energy transition.
Human behaviour is important as well, but changing that is a lot
harder when all you do is telling people that things are going
wrong. Behaviour is strongly influenced, I think, by political
choices, for instance taxation policies and legislations.”
When should the island be realised on ‘your’ spot, near the
designated wind farm zone IJmuiden Ver?
Van Zuijlen: “The island IJVER should be ready in 2025 to be
useful when in 2027 transmission system operator Tennet wants to
connect a substation to the new wind farms in the area. That
means we have just six years to realise it, as building the substation
will also take time, to make sure that two years later the power
cables can be connected.”
u This articled was originally published in Dutch in WindNieuws 02, 2019.
36 | 02-2019

Duurzame energie voor en door iedereen
Veiligheid als
sluitstuk
Ynso Suurendonk
en Jesse Don
www.duurzameenergie.org
Probeer WindNieuws nu vrijblijvend met een
proefabonnement van twee nummers voor € 10,-
ontwerp-
energiestructuurVisie
coöperaties
wind op Zee
stomen door!
Ad. Littel
Siward Zomer
nr.3 | 2014
windpark
Duurzame energie voor en door iedereen
noordoostpolder
Frans A. van der Loo
EEn goEdE basis dE wind
Wouter Pustjens in drEnthE
Mirjam Tielen
www.duurzameenergie.org
nr.5 | 2014
waardEvollE aanbEvEling
wind
wind op zEE
Frans A. van der Loo van nii
Linda Wes
Friesland
reactie
in de Wind op essay
Mirjam Tielen pieter Boot
Krispijn Beek
www.duurzameenergie.org
Windenergie
is kinderspel
Evert Kuiken
nr.6 | 2014
WindturBines
en externe
veiligheid
Tom van der Linde
en Jeroen Eskens
Zuid-Holland:
Van woorden
naar daden
Mirjam Tielen
GedraGscode
onder de
juridiscHe loep
Aaldert ten Veen
en Derek Sietses
de waarde
Van een
onafHankelijk
windrapport
Erik Holtslag, Bob
Schulte, Rolf de Vos
nr.1 | 2015
wind op land
en de proVinciale
staten
Verkie ZinGen
Ad. Littel
VRIJDENKEN
OVER HET
ELEKTRICITEITS-
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VERMINDEREN
VAN EFFECTEN
VAN WIND-
TURBINES OP
VLEERMUIZEN
PARTICIPATIE
BIJ WIND OP ZEE
WINDDAGEN
2018
BEURS EN
PRESENTATIES
The international leading event
on Offshore Wind and
Marine Renewable Energy
www.seanergy2019.com
ode windnieuws
ode WindnieuWs
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nr.3 | 2017
ode windnieuws
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Innovation
Sabine Lankhorst
Ocean Grazer
When supply and
demand meet
With the upscaling of renewable energy production, there is
an increased demand for flexibility in the electricity
network. The University of Groningen developed the Ocean
Grazer Concept, a hybrid modular offshore system that
combines wind, wave & storage and potentially other
sources of renewable energy.
Frits Bliek got involved with
Ocean Grazer in 2018.
Trained as physicist, he has
a long track record in innovation
management and energy management
consultancy, guiding startups.
He explains how the whole idea
emerged. “In 2011, Wout Prins, teacher
at the Engineering and
Technology institute Groningen, got
inspired to develop a more efficient
technology for harvesting the energy
created by waves at high seas than
available at that time.”
This resulted in Ocean Power, a patented
wave energy converter that consists
of individual floater elements that, together,
form a blanket. By means of
sensors, connected to a monitoring
system, real-time decisions can be
made on the optimal configuration of
the floater elements for each wave
height and period so a wide spectrum
of waves can be covered simultaneously.
The next step was to develop a storage
system where the energy, produced
by the Ocean Power, could be
stored. The Ocean Battery functions
like a floating reservoir where use is
made of the pressure at the bottom of
the seabed. To store energy it pumps a
fluid via pistons through a pipe into
flexible bladders that are deflated by
the pressure of the ocean. This fluid is
based on fresh water enhanced with
biological additives. In combination
with Ocean Power, the floaters power
the adaptive pumps.
Later on, the idea was created that the
storage system could also be a perfect
solution for storing energy created by a
wind turbine at times when the demand
for energy on land is low. The
Ocean Foundation, a new multi-functional
foundation type, was designed
which could also house the Ocean
Power and Ocean Battery. The three
together form the Ocean Grazer, an
integrated energy system that combines
wind and wave energy and storage.
Balancing supply and
demand
The Ocean Grazer offers advantages in
many areas. When used at wind farms,
it is the Ocean Battery that offers the
main advantage as it responds to the
demand for flexibility in the electricity
system. When there are high winds,
thus high energy production, but low
demand, the surplus energy can temporarily
be stored in the Ocean
Battery. At peak hours, the stored
energy can be released and fed into the
grid. This creates a balance between
supply and demand.
Bliek: “Based on calculations we made
at our test lab, an Ocean Foundation
with a diameter of 60 metres could
have a storage capacity of up to 7
MWh per wind turbine.” The Ocean
Grazer could potentially lower the
LCOE with 1 ct p/kWh,” he adds, “all
depends on the water depth. The
deeper, the more efficient.” These are
preliminary figures, he stresses, prototype
testing will have to determine
more definite numbers.
38 | 02-2019

The Ocean
Battery could
also be used as
a stand-alone
device
Multi-use of wind farms
Another advantage is the multi-use of
the system. He explains: “With a growing
demand for electricity, how can
we upscale the energy production?
There is only limited space on land.
The North Sea still offers space
for the development of renewable
energy but we have
to use this space efficiently.
I can see an added
value in smarter
cooperation. It is important
for the different
North Sea users to
look at, and learn from,
each other; what does the
other want? How can we
work together? Multi-use of
wind farms is a good example.”
“Research centre MARIN is already
working on a project for multi-use of
spatial area in wind farm. We can use
the complete Ocean Grazer system at
wind farms, including the Ocean
Power wave converter. In case of high
wind speeds, when the wind force is
12 for example, the floaters of the
Ocean Power system will be pulled
down. We could do the same when
maintenance has to be performed on a
wind turbine”, he explains. In the future,
Ocean Grazer could combine
even more renewable energy sources,
such as floating solar. The system is
very flexible and modular and, depending
on the project needs, one could
use the integrated hybride system or
only a combination, he adds. The
Ocean Battery could also be used as a
stand-alone device.
Sustainability
The Ocean Grazer offers several advantages
in the area of sustainability.
The foundation surface allows for marine
life to grow, potentially creating a
new underwater habitat. In addition,
the foundation is quicker to install as it
can be assembled in the port, towed
and installed at the wind farm site in
once piece. There is no need for piling,
so there is no effect of noise on marine
mammals. Bliek: “We are also looking
how to remove the foundation in the
most efficient way.” There is still research
required to determine the lifespan
of the system, which is currently estimated
to exceed 25 years. Because the
pressure inside the system is the same
as that on the outside, there is not
much wear and tear.
Leaving the lab
Following years of intensive research
and testing at the university’s own laboratory,
with over 60 students involved,
the university is now ready to take
Ocean Grazer to the next step of prototyping,
followed by commercial deployment.
As this is beyond the capabilities
of the university, a
special-purpose company, Ocean
Grazer BV, was set up in 2018 to take
the technology out of the laboratory
and onto the market. Bliek joined the
start-up to help guide this process.
“When you try to develop everything
at the same time, you’re bound to face
some setbacks. Therefore each technology
was developed separately before
we would integrate them into one
well-functioning system. We are now
ready to look for partners and investors
to work towards a prototype that
can be tested outside.”
The technologies comprise proven
technologies. The uniqueness is in the
configuration. This makes it easier to
find the right partners to build a prototype.
“There are, for example, already
experienced gravity-based foundation
builders in the market. We
would also have to look into scour protection.
Partners like Deltares can help
us to develop this. We demonstrated in
the lab that the technology works.
Now the question is, how can we scale
up and make it cost-efficient to
build?”, he explains.
Next year, the company will install a
prototype in Eemshaven. “Here we can
perform sea trials in a relatively protected
and easy accessible environment.
A next step would be to install a
prototype in a true offshore environment,
perhaps near an oil platform.”
u www.oceangrazer.com
The Ocean Grazer offers a solution for multi-use at wind farms and enables balance in energy production and demand
02-2019 | 39

General news
IHC IQIP invests in further
development BLUE Piling
Technology
IHC IQIP is investing in the BLUE Piling
Technology, a way of driving piles for offshore
wind using hydropower. It joins forces with
Jasper Winkes, the developer of the hammer
with the BLUE Piling Technology.
The technology enables larger monopiles to
be installed, reduces fatigue in the pile and
reduces noise by tackling the noise at the
source. Tests with the hammer using the
technology have demonstrated the potential
of the technology. IHC IQIP will start working
with a modernised, slightly adjusted version
of the BLUE Piling technology and expects to
achieve positive results soon.
Research into effects of
large-scale offshore wind farm
implementation in the North Sea
Large-scale implementation of offshore
wind farms in the southern North Sea can
have a large impact on the functioning of
the North Sea. This is the conclusion from
an exploratory study performed by knowledge
centre Deltares, in cooperation with
KNMI, Whiffle and Wageningen Marine
Research, by order of the Department of
Waterways and Public Works
(Rijkswaterstaat). The study is part of the
multiannual Wind at Sea Programme (Wind
op Zee Programma). The preliminary results
show that already the wind speed is affected
near the water surface at existing wind
farms and dozens of kilometres downwind.
This is also applicable to the wave height,
the turbidity and stratification of the water
and the tide dynamic. This affects the bio
diversity. More study in cooperation with
neighbouring countries is required.
Offshore Wind Innovation
Challenge 2019
The Offshore Wind Innovation Challenge is
an initiative of Offshore Wind Innovators and
aims to accelerate applied innovations in the
offshore wind industry. On 13 May, the kickoff
for the second edition of the Challenge
took place. On this day, companies that take
part in the challenge presented their technical
challenge to the Offshore Wind
Innovators community. Interested start-ups
and SME’s have 4 weeks to submit their solution
to one of the presented challenges.
During the summer months, the companies
and entrepeneurs with solutions will participate
in a Masterclass and Bootcamp.
The finals will take place on September 12.
Last year’s finalists were Ridderflex (winner),
with a new fender for SeaZip Offshore
Service. Skeye and Prodrone with blade inspections
at night, and Mel Systems and
Filtertechnik with on the spot oil analyses.
Van Oord and AdBm demonstrate new noise
mitigation system
PHOTO: VAN OORD
The DP2 Walk to Work vessel Acta
Centaurus was built by Ulstein Verft in
Norway. It is 93 m long and has a load capacity
of 3,200 t and 6 m draft. It is
equipped with hybrid battery packs and
hull designs X-BOW® and X-STERN®
for better performance in heavy seas. It features
a motion compensated gangway
Van Oord and AdBm Technologies have
successfully demonstrated the new AdBm
Noise Mitigation System (NMS), with support
from TNO. Van Oord will be deploying
the system at Borssele 3, 4 & 5.
The NMS system reduces underwater noise
resulting from offshore pile driving activities
for wind turbine foundations. It uses
special acoustic resonators designed and
produced by AdBm Technologies which reduce
the noise from pile driving. As a result,
specific frequencies can be targeted
which produce the most noise. The system
was designed and built at Van Oord.
Acta Marine welcomes Acta Centaurus
PHOTO: ACTA MARINE
and a 3D motion compensated knuckle
boom crane by SMST which can handle 6
t cargo in sea conditions up to Hs 2.5 metres.
The vessel has accommodation for up
to 120 persons and cargo areas of 1,000
square metres in total, indoors and outdoors.
It joins the Acta Auriga and Acta
Orion.
40 | 02-2019

General news
WindDays 2019
On 12 & 13 June, the annual WindDays
will take place at the World Trade Centre in
Rotterdam. This annual event, consisting of
a conference and exhibition, connects all
stakeholders within the Dutch wind sector,
thereby giving an important impulse to the
development of wind energy both on- and
offshore.
‘Without demand, no supply?
This is the theme of WindDays 2019. At
the opening session on 12 June, three speakers,
Giles Dickson (CEO WindEurope),
Dorine Bosman (Vice-President Wind at
Shell) & Medy van der Laan (Chairperson
Energie Nederland), will address this topic
from their area of expertise.
During the two-days event, other current
topics in the Dutch onshore and offshore
wind energy market are discussed through
sessions, debates and masterclasses. At the
end of the first day there will be a conference
dinner at the Harbour Club at the
foot of the Euromast.
At the exhibition, up to 50 companies, including,
amongst others Vestas, DNV-GL,
Siemens Gamesa, Enercon, Lagerwey and
Deutsche Windtechnik, will be showcasing
their products or services. Dedicated areas
are allocated for lawyers and bankers and
for start-ups.
Climate neutral
To provide a good example, the
WindDays event will be organised for the
first time in a climate-neutral way. The
event location already has taken climate-friendly
measures. To compensate for
the remaining CO2 emission, the organisers
of WindDays invest in a wind energy
project in India. It is doing so in cooperation
with Groenbalans.
Wind Energy Magazine will be available in
the media corner.
www.winddays.nl
SDE+ Spring 2019
During the SDE+ Spring 2019 subsidy application
round, RVO.nl received applications
for 43 wind energy projects with a combined
power of 143 MW. The total subsidy claim for
these projects is 309 million Euro.
SDE+ Autumn 2018
The budget for the SDE+ Autumn 2018
round was fully used. 4,618 projects, with a
budget claim of 6 billion Euro, received a
positive decision. Of these, 143 are wind
energy projects, with a combined power of
758 MW. The budget claim for these wind
projects is 1,874 million Euro.
Subsidy ‘Proeftuin op de
Noordzee’
Off the coast of The Hague, just outside
the port of Scheveningen, a unique test
area of 10 by 10 nautical miles will be developed
where companies, universities,
SME’s and start-ups in the maritime or watersports
industry can test and demonstrate
their innovations at open sea. A subsidy
(MKB Stimuleringsregeling Proeftuin
op de Noordzee) has been made available
for start-ups and SME’s. The total available
budget is € 375,000. Each interested party
can apply for max. € 25,000 (against a
personal contribution of the same
amount). The subsidy runs till 31
December 2021 and is only available for
SME’s and start-ups from the The Hague
region or for innovations that will have direct
effect on this region.
Smart Maritime Technology
13 June, Rotterdam
On 13 June, the second edition of the Smart
Maritime Technology event will take place at
the VNAB centre in Rotterdam.
Disruptive technologies
Smart Maritime Technology is a conference
that discusses disruptive technologies for
the maritime industry. What are the technologies
that the maritime sector should focus
on to stay/become future-proof?
Engineers and (innovation) managers will learn
about the latest developments in 3D
printing, artificial intelligence, augmented
reality and smart maintenance.
Confirmed speakers include, Toine
Cleophase of Damen Shipyards, Diederick
Nab of WAGO NL, Egbert Ypma of MARIN,
Robert Hekkenberg of TU Delft, Lucas
Janssen of CEAD, and others.
Wind Energy Magazine subscribers receive
discount. More information can be found at:
smt.maritiemnederland.com
02-2019 | 41

Page 06 - 09
nieuws
Page 20 - 23
Page 30 - 33
2019
magazine
Agenda
2019 Publication dates
2019
WindDays
12 & 13 JUNE, ROTTERDAM
www.winddays.nl
OCTOBER EDITION
Theme: Operation & Maintenance
Distribution at Offshore Energy
NOVEMBER EDITION
Theme: Combining Energies
Distribution at WindEurope Offshore
Smart Maritime Technology
13 JUNE, ROTTERDAM
smt.maritiemnederland.com
Global Offshore Wind
25 & 26 JUNE, LONDON, UK
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Wind Energy Magazine Vol. 6 | 02-2019
energy
Grid
Connection
When wind farms become power stations
Wieringermeer Wind Farm
Va tenfa l is cu rently working on one
of the largest Dutch onshore wind
projects. What are the cha lenges
building in an area of around 300 km²?
magazine
Interview Prysmian Group
Future grid capacity is a hot topic in
the Netherlands a the moment.
What are the requirements in terms
of cable designs?
Solving the gridlock
The acceleration of the energy
transition requires extra grid
capacity. Is the grid ready for the
future influx of renewable energy?
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42 | 02-2019

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