From sea to socket 50Hertz brings electricity from the Baltic Sea ashore
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From sea to socket 50Hertz brings electricity from the Baltic Sea ashore
2 50Hertz Offshore
Contents
Overview map....................................................................................................................3
Introduction........................................................................................................................4
Framework conditions.................................................................................................8
Connection, conversion and distribution......................................................10
Permits....................................................................................................................................20
Environmental considerations...............................................................................24
About 50Hertz...................................................................................................................28
Imprint.....................................................................................................................................28
Hansa
Bjæverskov PowerBridge
(HPB)
Tolstrup Gårde
50Hertz Offshore 3
Combined Grid Solution
(KF CGS) Kriegers Flak (O-3)
OWP Baltic 2
Arkonasee (O-2)
OWP Baltic Eagle Westlich Adlergrund (O-1)
OWF Wikinger
Westlich OWF Wikinger Süd
Arkonasee (O-4) OWF Arkona
OWF Arcadis Ost 1
O-5
O-6
Kontek OWF Baltic 1
Rügen
O-7 Lüdershagen
Bentwisch Mecklenburg- Lubmin
Western
Pomerania
Usedom
Siedenbrünzow
Güstrow
Areas suitable for wind energy and their grid connections
Key
Continental shelf/EEZ Operational 220-kV substation
12-nautical-mile zone/territorial waters Operational 380-kV substation
Grid connections (schematic):
Operational 400-kV substation
Operational 150-kV grid connection
380-220-kV conversion
Planned 150-kV grid connection
380-150-kV conversion
220-kV grid connection under construction
AC/DC converter
Planned 220-kV grid connection
Operational 380-kV grid connection Area for offshore wind turbines*
400-kV HVDC interconnector Planned offshore wind farm
300-kV HVDC interconnector Operational offshore wind farm
* as per the draft Area Development Plan 2019
4 50Hertz Offshore
Introduction
In the Agreement reached at the International Climate Conference (COP 21) in Paris on 12 December 2015, 196
countries committed to do more to protect the climate. After many years of intensive negotiations, the path
towards the climate-friendly transformation of the global economy was decided, with all parties duly pledging
to lower their emissions.
Germany’s federal government duly in- the Baltic Sea, before being transpor-
“Our approach is corporated the conclusions reached in ted over long distances to consumption
all about active and 2015 into its energy and climate policy, centres in central and southern Germa-
sustainable climate which seeks to transform the country’s ny. Consequently, new export cables
protection through entire energy system, replacing nuclear are required to connect offshore wind
innovative techno- energy with a mix of energy generated farms, while the onshore grid need to
logy.” from wind, solar, hydropower, biomass be converted and expanded as well.
and geothermal energy. The policy ob- This is a major task for transmission
Dr Frank Golletz, jective of generating sustainable energy system operators (TSOs) like 50Hertz.
Chief Technical Officer
of 50Hertz
goes hand in hand with an ambitious
plan to develop the supply of electricity
from renewable sources, including
steady expansion in the deployment
of offshore wind energy.
50Hertz brings electricity from the
It is clear that the energy transition Baltic Sea ashore
can guarantee secure, environmentally 50Hertz’s task is to transport electricity
friendly and stable economic growth. generated by wind farms in the Baltic
Sea to the mainland. As a TSO, 50Hertz
is responsible for the grid connections of
Grid optimisation and grid expansion: all wind farms in the Baltic Sea ensuring
fundamentals to the energy transition that every kilowatt-hour generated is
brought ‚from sea to socket‘ through the
transmission system. The framework for
Grid conversion and expansion are key,
this is enshrined in law: since December
as climate and energy policy targets 2006, German TSOs have been legally
only become attainable if the trans- obliged to build and operate the grid
connections of planned German
mission system has been adapted and
offshore wind farms.
optimised. More and more electricity is
generated in high-wind regions such as
50Hertz Offshore 5 “By 2030, 65% of the electricity con- sumed in Germany should be gene- rated from renewable sources. This is what the coalition parties agreed in 2018. Offshore wind energy will make a decisive contribution to achieving this. And we safely transport that energy ashore.” Kerstin Maria Rippel, Head of Communications and Public Affairs Wind energy: a key element in the energy transition Wind energy is the renewable energy with the largest potential. By late 2018, Germany’s onshore wind turbines had reached an installed capacity of approximately 52,931 megawatts (MW). Added to this are 429.5 MW from offshore wind turbines connected to the 50Hertz grid. In 2018, renewable energy already covered 56.5% of the electricity consumption within the 50Hertz transmission network. Centimetre by centimetre, the submarine cable for the 50Hertz grid connection is smoothly laid on the floor of the Baltic Sea.
6 50Hertz Offshore Transfer to the Andalusia platform of the Wikinger wind farm to the north of Rügen island.
50Hertz Offshore 7
Not only onshore, but especially on Energy storage: a technology of the
the high seas, wind has tremendous future “50Hertz is drawing
power, and 50Hertz is pursuing many on its strong, Europe-
offshore construction projects in the Storage facilities are important for wide commitment and
Baltic Sea to make use of this precious ensuring the optimal use of renewable extensive technical
natural resource. The first commercial energy for when there is no wind or know-how to rise to
offshore wind farm, Baltic 1, comprising there are fluctuations in the grid. Many modern-day energy
21 turbines, has been feeding electricity current research projects are refining challenges.”
into the 50Hertz grid since 2 May 2011. storage technologies. Grids could
These 2.3-MW turbines deliver a total also play a role if regions with high Dr Henrich Quick,
Head of Offshore Projects
capacity of some 50 MW, enough to storage potential, e.g. Scandinavia,
supply 50,000 households with elec- become more interconnected with
tricity. Since late 2015, another offshore their neighbours. For example, in a bid
wind farm, Baltic 2, has also been part to make use of Sweden‘s enormous
of the grid. Other projects are either hydropower storage capacity, 50Hertz
planned, already under construction or is planning the Hansa PowerBridge
in trial operation. Interconnector, together with Swedish
TSO Svenska kraftnät. This offshore
cable connection will link the electri-
city grids of both countries across the
Baltic Sea.
The 50Hertz transmission network: key figures on wind energy 2016-2018
DESCRIPTION 2016 2017 2018
Maximum feed-in from wind turbines 13,398 MW 14,266 MW 15,672 MW
Minimum feed-in from wind turbines 25 MW 5 MW 11 MW
Highest 15-minute spike from +2,130 MW/ +1,022 MW/ +918 MW/
wind turbines
–2,487 MW –702 MW –1,039 MW
Highest one-hour spike from +3,107 MW/ +2,469 MW/ +3,069 MW/
wind turbines
–3,137 MW –2,415 MW –3,042 MW
Highest day spike caused by wind turbines +8,382 MW +10,333 MW +13,220 MW
Installed capacity of onshore wind turbines 17,791 MW 17,866 MW 18,346 MW
Installed capacity of offshore wind turbines 336 MW 690 MW 1,068 MW
8 50Hertz Offshore
Framework conditions
Regulated expansion on the high seas: the legal Boosting offshore wind energy is the main purpose
framework governing wind energy generation of the Offshore Wind Energy Act, which entered
into force on 1 January 2017. The goal by 2030 is to
The many different German laws and stipulations increase installed wind turbine capacity at sea from
governing the development and connection of 6.4 (source: Association of German Offshore Wind
offshore wind energy facilities include the Renewable Farm Operators (BWO), 2019) to a total of 15 gigawatts
Energy Sources Act (Erneuerbare-Energien-Gesetz, (GW). The law provides for the promotion of offshore
EEG), the Offshore Grid Development Plan (Offshore- installations through a competitive tender process
Netzentwicklungsplan, O-NEP), Area Development and is applicable to all offshore wind turbines set to
Plan (Flächenentwicklungsplan, FEP), Federal Grid become operational from 2021. It also allows for the
Requirements Plan Act (Bundesbedarfsplangesetz, testing of innovative technologies by facilitating the
BBPIG), Energy Industry Act (Energiewirtschaftsge- construction of pilot wind turbines.
setz, EnWG) and the German Offshore Wind Energy
Act (Windseegesetz, WindSeeG). This legislation Until then, tenders during the so-called transition
determines where wind turbines are constructed, phase (from 2021 to 2025) fall under the scope of
how they are connected at sea and on land and how previously planned and approved offshore wind
they are subsidised. It also regulates the expansion and farms. As of 2026, a ‚central model‘ will apply, based
development of the electricity grid with a view to reliably on the Area Development Plan (ADP) drawn up by the
supplying consumers with the generated energy. Federal Maritime and Hydrographic Agency (BSH) in
coordination with the National Regulatory Authority
(Bundesnetzagentur, BNetzA). The FEP indicates
An eye for
detail.
potential locations of future wind farms and describes
how and when they should be connected to the
electricity grid. As such, the FEP is the key planning
instrument for offshore wind, replacing the current
O-NEP process. The first version of the FEP was
drawn up in 2018 and 2019 and will be updated
every four years or as required.
50Hertz Offshore 9
The EEG is the key funding instrument for in-
creasing the share of renewables in Germany’s
electricity supply. This law obliges TSOs to
prioritise integrating electricity from renewable
energy sources into the grid. It also determines
the remuneration that the operators of offshore
installations receive for each kilowatt-hour
(kWh) of electricity generated within a certain
period.
The EnWG is the basis for grid development in
Germany, ensuring that the supply of electricity
Inspection of gas-insulated switchgear on a wind and gas are as secure, competitively priced,
farm platform. consumer-friendly, efficient and environmen-
tally friendly as possible. It stipulates that
TSOs have to make their grids accessible to all
The Federal Maritime and Hydrographic Agency consumers under the same conditions. The
EnWG also regulates which system operator
(Bundesamt für Seeschifffahrt und Hydrographie,
is responsible for connecting offshore wind
BSH) drafts the FEP through an extensive coordina- farms. The TSO responsible for the Baltic Sea is
tion and consultation process. Applicable authorities 50Hertz.
non-governmental environmental organisations,
TSOs and members of the public are all given the
opportunity to voice their opinions. These are taken
into account when the plan is drawn up.
Further information on the legal framework conditions:
̶ Federal Maritime and Hydrographic Agency:
www.bsh.de
̶ Federal Network Agency:
www.bundesnetzagentur.de
̶ Gesetze im Internet (online laws, a joint project of the Federal Ministry of Justice and Consumer Protection and juris GmbH):
www.gesetze-im-internet.de
̶ Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railway:
www.netzausbau.de
̶ Information portals of transmission system operators 50Hertz Transmission GmbH, Amprion GmbH, TenneT TSO GmbH
and TransnetBW GmbH:
www.netzentwicklungsplan.de
www.netztransparenz.de
10 50Hertz Offshore
Connection, conversion
and distribution
From sea to socket: how 50Hertz brings wind energy ashore
Wind energy generated at sea has to travel a long way to reach our power sockets and wind farms located
a long way offshore in the Baltic Sea necessitate long distance grid connections. How? Through cables
constructed and operated by the designated TSO, 50Hertz.
A step-by-step guide to connection,
conversion and distribution:
Robust, high performance offshore and onshore
cables transport the generated electricity securely.
The starting point is an offshore substation that
bundles the cable connections of all the wind farms’
turbines and transforms the voltage from 33 to 150 or
220 kV.
Generated electricity is transported to an onshore
substation, where it is collected, converted to 380 kV
and fed into 50Hertz‘s transmission system.
This is how wind energy generated in the Baltic Sea
is brought to consumers via regional and municipal
distribution systems.50Hertz Offshore 11
“Together with our project partner,
the Danish TSO Energinet, we are
planning the first interconnector in
the Baltic Sea, including grid connec-
tions for several Danish and German
offshore wind farms. This intercon-
nector will help us make an important
contribution towards a successful
European energy transition.”
Delivery of a transformer for power generated in the
Baltic Sea to Bentwisch substation near Rostock. Elke Kwapis,
CGS project leader
Grid connection: a key prerequisite for
the European energy market
50Hertz has ensured timely grid connections since As power lines span large distances, there are trans-
2013, when the need for expansion became a binding mission losses to contend with, countries’ differing
component of the O-NEP. This guideline stipulated grid frequencies, gaps in the grid and the fact that
grid connection capacities for TSOs, and served until energy cannot be stored easily. 50Hertz rises to these
2017 as the basis for 50Hertz’s projects. Previously, challenges by finding innovative solutions.
offshore wind farms had to be built on the high seas
and be technically ready for operation before grid Kriegers Flak Combined Grid Solution (CGS):
connections could be established. Today, 50Hertz can connecting Germany and Denmark
already start working on a grid connection before the
wind farm in question has been built. The CGS connects the Danish region of Zealand with
the German state of Mecklenburg-Western Pomerania.
Such improved framework conditions mark an This project is an example of innovation for the energy
important step towards the swifter, more sustainable transition, being the first interconnector between two
development of renewable energy in the EU. After all, wind farms through which electricity can be directed
when there is a surplus of electricity or fluctuations and traded in both directions between Denmark and
in generation from renewable sources, secure grid Germany. No comparable project has ever been
connections between European neighbours are very realised anywhere in the world.
important. In this regard, TSOs like 50Hertz face a
number of challenges.12 50Hertz Offshore The Kriegers Flak Combined Grid Solution (CGS) will connect the Danish region of Zealand with the German federal state of Mecklenburg-Western Pomerania. The centrepiece of the CGS is the smart control of Since the voltage levels of the Danish (150 kV) and the interconnector by a so-called ‚master controller‘, German (220 kV) grid - differ, a transformer is also a digital tool deployed from the 50Hertz transmission needed. This transformer is installed on one of the control centre in Neuenhagen, near Berlin. Danish offshore platforms. The transmission systems of Denmark and Germany The European Commission has designated the CGS are not synchronous, so the three phases of the a ‚project of common interest‘ (PCI). The European alternating current are out of phase, requiring har- Energy Programme for Recovery (EEPR) is also monisation before transiting to the other respective providing funding for the project. national grid. This is done by serially connecting two converters, one of which transforms the alternating current (AC) from the Nordic interconnected system into direct current (DC), while the other converts Further details: this DC back into AC suitable for the continental 50hertz.com/vorhaben29 European synchronous area. This so-called double converter is installed in Bentwisch, near Rostock.
50Hertz Offshore 13
Hansa PowerBridge: The Hansa PowerBridge:
two countries, one interconnected electricity grid
̶ contributes to stable market prices in both
Hansa PowerBridge will transport renewable energy countries
from Germany to Sweden via an onshore and offshore
cable connection, starting from a substation in Güstrow, ̶ generates additional trade capacity for renewable
via Fischland and through the Baltic Sea to Scandinavia. energy, while supporting the further development
This interconnector, Hansa PowerBridge, will span the of Europe‘s single energy market
overall distance of 300 km. Its purpose - to connect the
two countries’ separate grids. ̶ stabilises the European electricity system because
it can transport surplus renewable energy.
The advantages are obvious. Electricity generated in
Germany can be consumed directly in Sweden and
elsewhere in Scandinavia, leaving the Scandinavian
hydropower stations untouched. When wind condi-
tions in Germany are poor and there is little sun or
consumption is high, Scandinavian electricity produ- “50Hertz builds bridges: the Hansa
cers can call on their unused hydropower reserves PowerBridge connects the wind
to supply renewable energy to German consumers. energy generated in Germany to
Their hydropower stations serve as indirect electricity large pumped-storage plants in
storage facilities, ensuring balanced prices on the Scandinavia.”
electricity markets.
Dr Clemens Unger,
Hansa PowerBridge project leader
Design of the Hansa PowerBridge Transmission system
Transmission Güstrow Lüssow Dierhagen Hurva Hurva Transmission
system substation converter cable section converter substation system
station
AC DC DC AC
Onshore cable Submarine cable Onshore cable
Alternating current (AC) Direct current (DC) Alternating current (AC)
Germany – 50Hertz Sweden – Svenska kraftnät14 50Hertz Offshore
Hansa PowerBridge is due to have a capacity of
around 700 MW and to go online in 2026. The in-
vestment costs total roughly €600 million, with the
project partners 50Hertz and Svenska kraftnät each
contributing half.
Further details:
50hertz.com/Hansa PowerBridge
Full information on offshore projects
can be found here:
50hertz.com/netzentwicklung/projekteaufsee
Energy storage: increasingly important in the
process of the energy transition
In the next years, increasingly large volumes of
renewable energy will be fed into the electricity
grid. When this power cannot be consumed
immediately, storage solutions will – next to
flexibility options – constitute an additional fac-
tor in making the energy transition a success.
This is where Scandinavia comes into play; the
region has a sufficiently high storage capacity.
Sweden and Norway alone have over 48 GW of
power at their disposal. Sweden’s energy mix
is dominated by hydropower stations, which
can be called upon at short notice to generate
CO2-free electricity. Furthermore, the Swedish
electricity grid is closely interconnected with
its Norwegian counterpart, which also has
large hydropower stations available for storing
surplus electricity.
Schematic representation of interaction between storage facilities
in Denmark and Renewable generation in Germany (HPB).50Hertz Offshore 15
Technology
Submarine cables: lifelines between wind farms and shores
On its journey from the high seas to the shore, electricity flows through robust, high performance submarine 150
and 220 kV cables between 21 and 26 cm in diameter, weighing about 100 kg per metre. These cables connect
offshore substations to landfall points, from where onshore cables transport the electricity underground to the
nearest grid connection point. The submarine cables are three-phase cables with synthetic insulation made of
cross-linked polyethylene (XLPE). An integrated fibre optic cable transfers measurement and control data, while
a metal coating protects the cable core against damage, e.g. from ships’ anchors.
Fibre optic cables
Synthetic gap-filling elements
Protective wrapping (PP yarn)
Mixed (stainless) steel polyethylene round wire armour
(galvanised)
Outer protective sheath (PP yarn)
High-density multi-wired copper conductor,
Nominal cross section 1;200 mm²
Extruded inner insulation screen
XLPE insulation
Extruded outer insulation screen
Swelling material (strips/fleece)
Lead jacket (transverse water barrier)
Conductive single-core cable with PE outer sheath
Cross-section of an offshore submarine cable.16 50Hertz Offshore Pulling in the submarine cable at the landing point in Lubmin (Mecklenburg-Western Pomerania). Cable-laying technology: working in wind, The cable vessel then sets course for the offshore weather and waves substation, laying the cable at sea, metre by metre. Laying cables at sea is challenging work. The weather A special feed track is used to lower the cable from conditions have to be suitable and heavy cables have the drum into the water. Submarine cables can to be transported. Coiled onto large drums, cables be manufactured to have far greater lengths than are transported by ship to their planned installation onshore cables. Once made, they are directly spooled site. First, the cable is laid up to the landing point onto the turntable on board the cable vessel for at the coast. When it arrives, one end of the cable is transport to their destination. The weight and rigidity pulled onto land by ship and connected to the grid. of onshore cables means they can be spooled and Floats keep the cable at the water‘s surface during transported up to a length of 700 m (AC) or 1,000 m the process, so that a winch can be used to pull the (DC). Consequently, onshore cable ends need to be submarine cable onto land through a landfall culvert. connected with a joint every 700 or 1,000 m. As they The floats are then removed, allowing the cable to are transported by ship, the far longer submarine cable slowly sink to the bottom. can be connected with a joint about every 25 km.
50Hertz Offshore 17
Once the cable has sunk to the sea floor, depending
on the composition of the seabed different methods
and tools are used to dig the cable trench. For exam
ple, on hard and stony subsoils, a plough is utilised.
If the seabed is sandy, a vertical injector travels along
the cable to lower it. Jetting nozzles controlled from
the vessel lower the submarine cable from its position
on the seabed into the sediment, or operational
cables may be lowered to increased depths. In this
manner, the seabed underneath the cable is fluidised,
allowing it to sink deeper into the sediment under its
own weight.
A joint connects two submarine cable lengths.
The turntable can
accommodate and transport
up to 25,000 m of cable.
When cables are laid, the
sea must not be too rough
and the waves must be no
higher than 1.5 m.18 50Hertz Offshore
Once the cable laying vessel has reached the desig- Operating offshore substations is very challenging. As
nated offshore substation, the submarine cable has to sea air is very humid, the offshore substation needs
be connected to the HV switchgear. To this end, the to be carefully climate controlled and dehumidified. It
submarine cable has to be pulled onto the platform is also reinforced to enable it to withstand the severe
(a technically challenging procedure in itself) and weather conditions encountered at sea.
then painstakingly guided along the platform. It takes
about three weeks to lay a 25 km long cable section, One important component in any offshore substation
depending on the method used and the weather is its transformer, which converts 33 kV (the power
conditions. level at which the offshore wind farm (OWF) grid is
operated, to 150 kV (Baltic 1 and 2) or 220 kV (Ostwind
Offshore substations enable reliable, low-loss 1). This way, the electricity can be transported to shore
transport with the fewest possible losses. Upon making landfall,
the electricity passes through another substation, the
The centrepiece of each wind farm is its offshore sub intermediate station for electricity from the Baltic Sea,
station, which serves as a connection point. This facility where its voltage is increased once more, this time to
weighs several hundred tonnes and is fully assembled 380 kV before being transported further at this extra-
onshore before being transported offshore by ship. high voltage.
The power cables of all wind farm turbines lead to the offshore substation.50Hertz Offshore 19
Offshore substation to connect the Danish Kriegers Flak Offshore
Wind Farm (OWF), the Baltic 1, and 2 OWFs.
Inside the tower of the 50Hertz converter station at Bentwisch,
DC is converted to AC and vice-versa.
Converter stations: electricity grids‘ Interconnectors: connecting
conversion artists European grids
Direct current (DC) is experiencing a boom thanks Electricity knows no borders. Electricity always takes
to the energy transition. High Voltage Direct Current the path of least resistance. As a result, interconnec-
(HVDC) transmission enables large volumes of tors provide a means for transporting electricity to
electricity to be transported over long distances with wherever it is needed or to suitable storage facilities.
few losses. It also means electricity flows can be con- Interconnectors connect the transmission grids of
trolled in a targeted manner and provides an efficient different EU member states, thereby contributing
way of interconnecting wind energy generation areas to security of supply both in each country as well as
in the north with centres of consumption in the south. across Europe. Furthermore, they enable cross-border
The challenge here is that the current electricity grid electricity trading, which benefits everyone in the
was designed for alternating current (AC). Hence the long term.
need for complex AC to-DC converter stations.
For more information on the technology used at
Since 1996, 50Hertz has operated a 170-km-long 50Hertz, see: www.50hertz.com
HVDC connection together with the Danish TSO:
Energinet. The Kontek cable in the Baltic Sea
connects the German and Danish grids. The two
converter stations are located in Bjaeverskov (DK)
and Bentwisch (DE).20 50Hertz Offshore
Permits
Approval of offshore wind farms
If a planned offshore installation is located in the
Exclusive Economic Zone (Ausschließkiche Wirt-
schaftszone, AWZ), the Federal Maritime and Hydro-
graphic Agency (Bundesamt für Seeschiffahrt und
Hydrographie, BSH) is responsible for the permitting
process. Permits for facilities within the 12 nautical
mile zone are the responsibility of the corresponding Turntable with submarine cable for a grid
federal state(s); this is Mecklenburg-Western Pome- connection.
rania for the Baltic Sea within the area covered by
50Hertz’s grid. also involved. The federal state’s spatial planning au-
thority then draws up a regional planning assessment
How grid connections and extra-high in which it determines whether (and which) planned
voltage lines are approved routes are compatible and meet spatial planning
requirements. Its objective is to find and determine a
50Hertz is responsible for connecting offshore wind suitable corridor between the offshore wind farm and
farms in the Baltic Sea to the German electricity grid. the most favourable onshore grid connection point.
This makes 50Hertz the project developer, who needs
to consider a host of different regulations throughout The next step involves detailed planning, following a
the entire process (from planning to implementation), plan approval procedure (Planfeststellungsverfahren,
submit applications and obtain permits from the PFV). Within a corridor previously deemed suitable at
state authorities. The applicable legally prescribed the ROV stage, 50Hertz plans the route at building plot
procedures differ, depending on where in the Baltic level. This entails submitting an extensive application,
Sea construction will take place: defining which technology will be used and where
exactly the cable is to run. Human, environmental, tech-
Scenario 1: an offshore wind farm situated inside nological and economic interests are always taken into
the 12 nautical mile zone account. All stakeholders - authorities, municipalities,
Responsibility lies with the corresponding federal state(s) associations and members of the general public - are
involved in the procedure. Any advice they offer is taken
Under the regional planning procedure (Raumord- on board where possible and their views are considered.
nungsverfahren, ROV), public agencies check the The exact plan is available for public consultation by all
alternative routes drawn up by the project developer. interested parties. The procedure aims to provide fair
The competent authorities and general public are consideration of all interests.50Hertz Offshore 21
Exclusive Economic Zone (EEZ)
In the Baltic Sea, the German EEZ is adjacent to the EEZs
of Denmark, Sweden and Poland. Coastal nations can build
artificial islands, installations and structures in their EEZ. Since
2017, the German Marine Facilities Act (SeeAnlG) has regulated
the approval of structures and installations in the German EEZ,
replacing the previously applicable German Marine Facilities
Ordinance (SeeAnlV).
Open sea
Continental shelf
At the end of the process, the decision on whether or
not to issue planning permission is taken, considering
the technically and economically viable route that
promises to have the least impact on human beings Exclusive
Economic Zone
and the environment. This permit constitutes the legal
(200 nautical miles)
basis for constructing extra-high voltage lines and
entitles 50Hertz to build them. 200 nautical
miles
Connection zone
Example 2: an offshore wind farm situated in the (12 nautical miles)
Exclusive Economic Zone (EEZ) Coastal waters (territorial waters)
(12 nautical miles)
The responsibility for approving such facilities lies
with the Federal Republic of Germany Internal waters
Baseline
If an offshore wind farm is located in the EEZ, the
authorities carry out an additional planning approval
procedure for the section between the wind farm Mainland
and the 12 nautical mile zone, based on the Marine
Facilities Act (SeeAnlG) or, for facilities commissioning
after 31 December 2020, the Wind Energy at Sea Act The EEZ is the area of sea stretching from the so-called baseline,
(WindSeeG). through the coastal waters, up to 200 nautical miles out to open
sea. This area is governed by international maritime law.22 50Hertz Offshore
Human and environmental interests:
Federal Immission Control Act (BImSchG)
Four State Agencies for Agriculture and
Environment (StALU) are competent
to issue regulations under federal, Human beings, nature and the environment are given
state and EU law in the agricultural and special consideration within the framework of large
environmental domains. They mainly
address challenges affecting different
construction projects and 50Hertz aims to minimise
areas that require specialist know-how, its impact on all three. This applies not only to the
including domains such as nature, water construction of actual cables, but also to substations
and soil conservation, immission control
and converter stations. Many criteria are already
and climate protection. The StALU
responsible for Middle Mecklenburg is checked in advance of the approval procedure, based
also in charge of basic coastal defence on the Federal Immission Control Act (BImSchG),
measures and promoting the supply of
which sets out legal guidelines for safeguarding
renewable energy on behalf of all four
agencies.
against such potential impacts as air pollution, noise
and tremors. Audits are performed by the State
Agency for Agriculture and Environment of Middle
Mecklenburg (StALU MM).
For more information, see:
̶ State government of Mecklenburg-Western
Pomerania’s regional planning agencies
www.afrl.mv-regierung.de
̶ State government of Schleswig-Holstein
www.schleswig-holstein.de
̶ Federal Ministry of Justice and Consumer Protection
Gesetze im Internet (online laws)
www.gesetze-im-internet.de
̶ State Agency for Agriculture and Environment
of Middle Mecklenburg
http://www.stalu-mv.de/mm/
̶ Information about the legal approval procedure can be
obtained from the federal states‘ regional planning and
approval authorities and the Federal Network Agency
https://www.netzausbau.de/5schritte/de.html
Residents receive
first-hand information.50Hertz Offshore 23 Occupational safety and health protection are top priorities at 50Hertz. Rescue drills are regularly held with a view to ensuring safety.
24 50Hertz Offshore
Environmental considerations
Grid development in harmony with nature and ̶ restrictions on construction time and the most
environment environmentally friendly construction methods,
whenever work has to be carried out in sensitive
Grid development at sea is implemented with the areas.
utmost care, to provide maximum protection for
nature and the environment. Whenever possible, 50Hertz pays close attention to environmental
50Hertz uses: impact studies
̶ bubble curtain technology for quieter construction, Already at the project planning stage, 50Hertz
to protect, fish, harbour porpoises and seabirds; balances technical requirements and the protection
of flora and fauna within the scope of the approval
̶ the most modern cable-laying methods that procedure. For example, the company conducts
involve no dredging; environmental impact studies and area surveys to
ascertain the current situation and identify the route
̶ water-friendly substances and materials; corridor with the lowest impact. This includes per-
forming environmental impact studies of FFH areas,
̶ Insulated cables to prevent heating of the seabed; special EU areas requiring plant (flora), animal (fauna)
and habitat protection.
̶ precise planning in accordance with the Offshore
Grid Development Plan, to limit the number of Sometimes, additional experts‘ reports are needed,
cables to the absolute minimum required and, for instance to assess shipping, raw material extrac-
where possible, steer well clear of nature conserva- tion, fishing or military interests. In addition, 50Hertz
tion areas, natural parks and moors, and applies draws up extensive technical documents, for instance
on local oceanographic and meteorological condi-
tions.
“We interfere with the environment
as little and as carefully as possible
and compensate any unavoidable
impact.”
Olivier Feix,
Head of Nature Conservation and Permits50Hertz Offshore 25
The sea eagle breeds in areas where
submarine and underground cables
are connected. If breeding grounds
have been established, construction
time restrictions apply for the duration
of the brood.
Marine compensation as a prerequisite for an
environmentally friendly energy transition at
sea
When 50Hertz connects offshore wind farms,
this has an inevitable impact on the marine
habitat. For these and other types of impact,
compensation has to be provided within the
12 nautical mile zone of the coast. 50Hertz
prefers to implement compensation measures
in the affected area and avoid any need to
make compensation payments. This is why it
is so important for 50Hertz to build on its vast
experience in marine compensation measures
in Germany and to develop new and effective
ones.
50Hertz carries out these studies together with exter-
nal environmental planners, route planning experts
After all, initial experience has already been
and other scientific and conservation experts. Only gained internationally in implementing and
then does actual construction work start, in which successfully balancing compensation options
at sea, including through studies on possibi-
external ecologists are also involved, among other
lities for developing marine biotopes (such as
things to monitor protection, avoidance and mitigation sea-grass beds or artificial reefs). 50Hertz is
measures and make sure that the conditions set out in continuing intensive exchanges with all stake-
the planning approval decision are respected during holders on the implementation of technically
feasible compensation measures. In this regard,
construction.
the company is counting on cooperation
within the Renewable Grid Initiative and is a
co-signatory of the Marine Grid Declaration,
among other things.26 50Hertz Offshore
What are compensation measures?
If 50Hertz has to intervene in nature, the environment
or habitats, the company minimises this impact by ta-
The dam is gone. Görmitz is once again an island.
king appropriate measures. One such example is the
project to dismantle the man-made causeway and ar-
tificial backwater between the mainland and Görmitz
island (Usedom), which was built in the 1960s, and
restore the location to its original state. This project
is one compensation measure for the construction of
the Ostwind 1 power cables, transporting electricity
from the offshore Wikinger and Arkona wind farms,
north-east of Rügen island, to Lubmin.
The causeway’s demolition means that more oxygen
can once again reach the formerly cut-off area and
Bird of prey aviary: the steel cage for the aviary has been
that otters are no longer hampered by an artificial
assembled.
barrier. On Görmitz island itself, a habitat for ground-
nesting birds is also being restored.
Compensatory measures also include projects like
supporting the stork sanctuary in Papendorf. By con-
structing aviaries for birds of prey, 50Hertz is rolling
out an exceptional and unique species protection
project in Mecklenburg-Western Pomerania. 50Hertz
will also maintain and look after these newly created
facilities for 10 years. The facility is run on a daily basis
by employees of the Papendorf stork sanctuary,
sponsored by 50Hertz.
Baltic Sea soil survey with a
remotely operated vehicle (ROV).
These are the eyes through
which the pilots on board can see
whether any action is required.50Hertz Offshore 27
Compensation measures for line construction are
regulated by the Federal Nature Conservation Act
(Bundesnaturschutzgesetz, BNatSchG), as are other
nature conservation interests. Under BNatSchG,
project initiators are obliged to prevent or absolutely
minimise damage to nature and landscapes.
Hidden on the seabed: a lot for 50Hertz to take into
consideration when constructing cables
The Baltic Sea is full of unpleasant remnants of the
past: 300,000 t of conventional ordnance and about
5,000 t of chemical ordnance. When carrying out its
work, 50Hertz has to take account of such wartime
remnants, being the project developer responsible for
surveying the soil as part of the approval procedure.
Any hazardous waste discovered has to be document
ed and reported to the permit-issuing authority. To
prevent any risks to the general public, specialist ROV pilots survey the seabed.
service providers remove any unexploded ordnance
discovered, deciding on-site whether it can be re
moved or undergo a controlled detonation onshore.
If detonation has to take place at sea, so-called bubble The seabed also harbours archaeological treasures
curtain technology is used. This involves laying from the past, like the remains of a Swedish ship
compressed-air hoses around the site of the planned barrier. These, too, have to be taken into account and
detonation. Air is forced through uniformly distribu- avoided as far as possible. Measures 50Hertz is taking
ted openings in the hose, creating a bubble curtain in this regard include foregoing laying cable joints
that significantly dampens the diffusion of the noise. in these areas as well as implementing anchoring
This measure is intended to protect sea creatures, and prohibition zones.
the procedure is continuously monitored by taking
noise measurements and sediment samples. More information is available on the information
portal of the Federal Ministry for Economic Affairs
and Energy:
www.erneuerbare-energien.de.About 50Hertz Imprint
50Hertz operates the electricity transmission system 50Hertz Transmission GmbH, Heidestrasse 2,
10557 Berlin, Germany
in the north and east of Germany, which it expands T +49 30 5150 0
as needed for the energy transition. Our extra-high- F +49 30 5150 4477
voltage grid has an electrical circuit length of about info@50hertz.com
10,200 kilometres: the distance between Berlin and
Concept
Rio de Janeiro. 50Hertz
The 50Hertz grid area covers the federal states of Design
Heimrich & Hannot GmbH
Brandenburg, Mecklenburg-Western Pomerania,
Saxony, Saxony-Anhalt and Thuringia, as well as the Picture credits
city states of Berlin and Hamburg. Within these Jan Pauls, Christian Brehm, Jens Regiment,
visavis Filmproduktion GmbH, ewg3D – iStockphoto.com
regions, 50Hertz ensures grid and system stability,
with some 1,100 employees ensuring that about 18 Printing
million people are safely supplied with electricity copy print Kopie & Druck GmbH
around the clock.
Interesting links
50Hertz: 50hertz.com
50Hertz is a pioneer in the field of securely inte BNetzA / grid development: netzausbau.de
grating renewable energy: in our grid area, more than Offshore Grid Development Plan (O-NEP)
Grid Development Plan (NEP): netzentwicklungsplan.de
half the electricity consumed is already generated
BESTGRID: bestgrid.eu
from renewable sources, and this share is constantly Renewables Grid Initiative (RGI): renewables-grid.eu
rising. The shareholders of 50Hertz are the Belgian Federal Office for Radiation Protection (BfS): bfs.de
Information platform of the four German
transmission system operator Elia (80%) and the KfW
transmission system operators: netztransparenz.de
Bankengruppe (20%). As a European TSO, 50Hertz is European Network of Transmission System
part of the Elia Group and a member of the European Operators for Electricity
association ENTSO-E. (ENTSO-E): entsoe.eu
Date
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