Alpha Ventus

Wind Project Site

Title: Alpha Ventus

Status:

In Operation

Project Manager:

Deutsche Offshore - Testfeld und Infrastructur

Turbine Developer:

Adwen Offshore, Senvion

Foundation Manufacturer:

Aker Solutions, OWEC Tower

Website:

External Link

Construction Start:

July 1, 2008

Operation Start:

April 1, 2010

Info Last Updated:

August 4, 2023

Contact:

Maren Engelhardt
_{(login for email address)}

Details

Technology:

Fixed Offshore Wind

Project Scale:

Commercial Farm

Turbine Model:

Adwen AD 5-116 (x6), Senvion 5M (x6)

Hub Height:

90-92 m

Rotor Diameter:

116-123 m

Number of Turbines:

Capacity per Turbine:

5 MW

Installed Capacity:

60 MW

Support Structure:

Tripod Foundation, Jacket Foundation

Inter-Array Cables:

33 kV

Export Cables:

AC, Buried Seafloor Cables

Export Cable Voltage:

110 kV

Number of Export Cables:

Cable Landfall:

Trenched

Physical Site:

Shallow Water (<60m), Marine, Soft-Bottom Habitat

Water Depth:

30 m

Distance from Shore:

45-60 km

Country:

Germany

Description

The Alpha Ventus wind farm is the first German offshore wind farm and thus has the longest operational experience of all German offshore wind farms. It is owned by Deutsche Offshore – Testfeld und Infrastructur GmbH & Co. KG, which was formed by the three utilities EWE, E.ON, and Vattenfall. In 2019, RWE AG took over the shares of E.ON. The farm consists of 12 5 MW turbines for a total of 60 MW, including six Senvion 5MW turbines on jacket foundations designed by OWEC Tower and six Adwen AD 5-116 turbines on tripods designed by OWT. Alpha Ventus went into operation in April of 2010. The wind farm is located off the coast of Germany on the North Sea near the island of Borkum, with the twelve turbines laid out in a 4x3 grid covering 4 square kilometers of ocean. The entire area of the wind farm is closed to general shipping and fishing.

Within the wind farm, the electricity is routed from the wind turbines to the offshore substation using 33 kV submarine cables. To do this, around 16 kilometers of cable were buried at least 60 centimeters deep in the seabed. In the offshore substation, the electricity is increased to 110 kV and then transported to the mainland via an approximately 60 km long submarine cable that also runs via the island of Norderney. There the electricity is fed into the Hagermarsch substation and from there it is transferred to the German transmission network. The transmission system operator TenneT TSO GmbH is responsible for the offshore grid connection.

Location

Alpha Ventus is located in the North Sea 60 kilometers off the coast of Germany, 45km north of the island of Borkum. The farm is controlled from the operations room of EWE Offshore Service & Solutions GmbH in Oldenburg. Exact locations of each turbine can be found on RAVE’s data webpage here. Request to access data here.

Licensing Information

April 2002: Likely Maritime and Hydrographic Agency, Permit for cable routing
2001: Federal Maritime and Hydrographic Agency, Permit for construction

Project Timeline

April 2010: Farm officially opened and became commercially operational
November 2009: Construction completed
September 2009: Installation begins of additional six turbines
August 2009: First six turbines operational
July 2009: First turbine installed
June 2009: Jacket foundations installed
April 2009: Tripod foundations installed
July 2008: Construction begins on substation
February 2008: Baseline surveying for Marine Mammals
2001: Permit for construction approved by Federal Maritime and Hydrographic Agency

Key Environmental Issues

Alpha Ventus is home to the research institute RAVE (Research at Alpha Ventus), which tackles open issues in offshore wind energy, and boasts the research platform FINO 1, 400 m to the west of the wind farm. Fraunhofer IWES coordinates RAVE projects. Since 2009, an extensive measurement program has been part of RAVE. Four of the twelve turbines of the Alpha Ventus wind farm have been equipped with extensive measurement technology. The marine ecosystem – marine mammals, fish, bottom creatures, sea, resting and migratory birds – were recorded for the first time two years before the start of construction and examined in detail during construction and operation.

Metadata Documents

Data on benthic species assemblages and seafloor sediment characteristics in an offshore windfarm in the southeastern North Sea (Teschke et al. 2023)
Generalized changes of benthic communities after construction of wind farms in the southern North Sea (Coolen et al. 2022)
Ecological research at the offshore test site "Alpha Ventus" to be used in an evaluation of the BSH's Standards for Environmental Impact Assessments (StUKplus) (Beiersdorf et al. 2014)
Acceptance of offshore wind energy use: Final Report (Research initiative RAVE - Research at Alpha Ventus) (Hübner and Pohl 2014)
Offshore Test Site Alpha Ventus Expert Report: Marine Mammals (Final Report: from baseline to windfarm operation) (Diederichs et al. 2014)
Ecological Research at the Offshore Windfarm Alpha Ventus: Challenges, Results and Perspectives (Beiersdorf and Radecke 2014)
Effects of Pile-Driving on Harbour Porpoises (Phocoena phocoena) at the First Offshore Wind Farm in Germany (Dähne et al. 2013)
Effects of Offshore Wind Turbine Foundations on Mobile Demersal Megafauna and Pelagic Fish - Research at the Alpha Ventus Offshore Wind Farm (Krone and Krägefsky 2013)
Operational Noise: Measurement of the operational underwater noise emission of wind turbines at the Alpha Ventus offshore wind farm (Radecke and Benesch 2012)
Research into the noise reduction measure "Little Bubble Curtain" in the Alpha Ventus Test Field (Raimund et al. 2012)
Life Cycle Assessment of the Offshore Wind Farm Alpha Ventus (Wagner et al. 2011)
Welcoming the Wind (UVP Report 24) (Lüdeke and Koeppel 2010)

Phase	Stressor & Receptor	Design and Methods	Results	Publications	Data
Baseline	Marine Mammals	Aerial and Boat Based Surveys, Passive Acoustic Monitoring Three methods were used: line-transect observation by aerial and vessel surveys, and passive acoustic monitoring (PAM) via porpoise detectors (PODs). Surveys were done before construction, during construction, and during operation.	Complete Porpoise activities close to the windfarm were lower in the first two years after construction and then returned to and even exceeded the level of the baseline survey by 2012.	Diederichs et al. 2014	No data publicly available.
Operations	Noise Marine Mammals	Study of operational underwater sound emission of 5MW offshore wind energy converters Signals were collected with 5 hydrophones and acceleration sensor s above and below water. Measurements were taken 3x/day for a period of 300 seconds each and took place between 2008 and 2011.	Complete Overall in the wind farm it became quieter with increasing power, especially with increasing wave height. The reason is that the background noise was of the same order of magnitude as the turbine noise, the background noise decreased with increasing wind and more than compensated for the increase in turbine noise.	Radecke and Benesch 2012	No data publicly available.
Operations	Avoidance Fish	Hydroacoustic Surveys, Net Catches, Fish Stomach Content Analysis The effects of Alpha Ventus on pelagic fish were investigated though hydroacoustic surveys, sampling with net catches, fish stomach content analysis.	Complete A relative decline in the abundance of pelagic fish was observed during construction at Alpha Ventus.	Krone and Krägefsky 2013	No data publicly available.
Construction, Operations	Habitat Change Physical Environment	Van Veen Grab Samples Van Veen grab samples taken annually over four years beginning in 2008 in order to study the benthic community and seafloor sediment characteristics.	Complete Predominant sediment composition was fine sand, followed by medium sand. This was consistent across all 4 years of sampling.	Teschke et al. 2023	Teschke et al. 2022
Construction, Operations	Habitat Change Physical Environment	Seabed and Fouling Sampling Seabed and fouling samples were taken from turbine foundations and surrounding seafloor from three wind farms between 2003 and 2012.	Complete The water depth was the most important structuring factor for fouling communities while seasonal effects were driving most of the observed changes in soft-sediment communities.	Coolen et al. 2022	No data publicly available.
Operations	Noise Marine Mammals	Static Acoustic Monitoring, Visual Monitoring Monitoring was conducted between 2008 and 2011 to explore the effect of pile driving on harbour porpoises.	Complete Lowest densities of observed porpoises occurred during construction in 2009. Strong avoidance response is correlated with pile driving.	Dähne et al. 2013	No data publicly available.
Operations	Noise Marine Mammals	Passive Acoustic Monitoring In May 2009 a closed bubble curtain surrounding a monopile was used during pile driving at Alpha Ventus and hydro sound measurements were recorded.	Complete The bubble curtain’s mitigation effect is strongly dependent on tide and related flow speed and direction. For future applications, there is strong need to direct the bubbles in such a way that their lateral drift is minimized.	Raimund et al. 2012	No data publicly available.
Construction, Operations	Habitat Change Physical Environment	Van Veen Grab Samples Van Veen grab samples taken annually over four years beginning in 2008 in order to study the benthic community and seafloor sediment characteristics.	Complete Predominant sediment composition was fine sand, followed by medium sand. This was consistent across all 4 years of sampling.	Teschke et al. 2023	Teschke et al. 2022
Construction, Operations	Habitat Change Physical Environment	Seabed and Fouling Sampling Seabed and fouling samples were taken from turbine foundations and surrounding seafloor from three wind farms between 2003 and 2012.	Complete The water depth was the most important structuring factor for fouling communities while seasonal effects were driving most of the observed changes in soft-sediment communities.	Coolen et al. 2022	No data publicly available.