Küste Hero Istock-1540337901 Michael Workman

OffChEm & OffChEm II (2017 – 2023)

Chemical emissions from offshore wind farms – Potential impacts on the marine environment and their evaluation

Aerial view of an offshore wind farm

(Photo: Sabine Billerbeck/Hereon)

The progressive expansion of offshore wind energy in the North Sea and Baltic Sea is accompanied by an increasing intrusion into the marine environment. More than 1,500 offshore wind turbines and at least 20 converter and transformer platforms have already been erected (as of December 2021). Each offshore installation represents an intervention in the marine environment. Material releases from these installations have hardly been investigated to date. The main issues here are the necessary measures for corrosion protection and the use of operational materials. Scientific knowledge about the quantities released and their distribution in the respective environmental compartments (water, sediment, biota) is currently scarce. A comprehensive assessment of the effects on the marine environment is therefore only possible to a limited extent based on current knowledge.

Focus on corrosion protection

Galvanic anodes (so-called "sacrificial anodes") are used to protect offshore installations from corrosion, as a result of which large quantities of metal compounds (especially compounds of aluminum and zinc) are continuously discharged into the marine environment during the course of operation of the installation. In addition to the main components, galvanic anodes also contain other metallic secondary components (e.g. indium, lead, cadmium as well as other heavy metals), which are also discharged into the marine environment when the anodes melt down.

Aims of the project

In the project OffChEm and its follow-on project OffChEm II, funded by the Federal Maritime and Hydrographic Agency (BSH), the Hereon investigates the following aspects in collaboration with the BSH:

  • Identification of potential inorganic (harmful) substances which could have a relevant impact on the marine environment through the corrosion protection of offshore wind farms.
  • Development of analytical methods and suitable sampling strategies to determine the emissions of the potential substances in the various compartments in the vicinity of offshore wind farms.
  • Evaluation of the relevance of the identified potential pollutants on the basis of their chemical emissions from offshore wind farms and their influence on the local and regional marine environment.

Within the framework of OffChEm and OffChEm II, offshore wind farms in the North Sea and Baltic Sea were and are sampled. Since 2016, sampling campaigns have been conducted at least once a year on research vessels from BSH and Hereon to collect water and sediment samples.
Reports on selected campaigns can be found at the following links:

Campaign 2019 in the North Sea: Measurement campaign on the "Atair" and Measurement campaign on the "Atair" - Second attempt (in German).

2020 campaign in the North Sea on the Ludwig Prandtl: Instagram highlight "Takeover"

Campaign 2021 in the Baltic Sea on the Ludwig Prandtl: Baltic Sea campaign successfully completed (in German).

25.07. – 05.08.2016: In a first survey the surrounding of different offshore wind farms in the North Sea close to the coast line were sampled with the research vessel "Ludwig Prandtl" (Hereon).

31.05 – 06.06.2017: In the course oft he BSH monitoring with the research vessel Atair first test samples were taken inside offshore wind farms and from areas that are planned to become offshore wind farms in the future.

17.07.-19.07.2017: Sampling campaign in the wind farm "DanTysk" and areas close to Sylt’s coast line. The aim was to gain insights into the influence of singles wind turbines on water currents and turbulences. In addition water samples were taken for the analysis of trace metals.

10.04.-16.04.2018: A first high-resolution sampling of different offshore wind farms in the North Sea was accomplished with the research vessel "Atair" (BSH). In total, at more than 50 sampling stations water, sediment and particulate matter samples were taken.

05.03.-14.03.2019: For insights into temporal changes in pollution load samples stations from previous sampling campaigns were sampled again. In total almost 100 water, sediment and particulate matter samples were taken in and around offshore wind farms in the North Sea. More on this campaign in these blog posts (in German):

Messkampagne auf der "Atair"

Messkampagne auf der "Atair" - Zweiter Anlauf

22.07.-25.07.2020: The corona pandemic is also messing up the OffChEm plans. Instead of going in April with the new ship "Atair" of the BSH, the Hereon's vessel "Ludwig Prandtl" will go to the North Sea in July. We drive from Cuxhaven to Heligoland under strict hygiene measures and with a thinned-out sampling plan. From Heligoland, we then test individual wind farms in day trips. In the end we bring 40 water and 30 sediment samples back to Geesthacht More about this campaign can be found in the Hereon's Instagram-Highlight „Takeover“

Impressions from sampling campaigns




Jonas Ludwig 2021
Bestimmung von Element- und Isotopenmustern in Sedimentproben aus verschiedenen Offshore Windparks der deutschen Nordsee zur Untersuchung möglicher stofflicher Freisetzung aus Korrosionsschutzsystemen, Bachelorarbeit, Hochschule Mannheim

Madita Kruse 2021
Zeitliche Entwicklung technologie-kritischer Elemente in Nordseesediment in Hinblick auf potenzielle Emissionen aus Offshore-Windparks“, Bachelorarbeit, TH Lübeck

Carlotta Pehlke 2020:
Untersuchung von Isotopensignaturen in Oberflächensedimenten aus Nordsee- Offshore-Windparks sowie deren Umfeld.
Bachelorarbeit, Leuphana Universität Lüneburg

Svenja Meers 2018:
Untersuchung der Elementverteilung in Oberflächensedimenten aus dem Umfeld ausgewählter Offshore Windparks im küstennahen Bereich der Nordsee.
Bachelorarbeit, FH Lübeck

Nathalie Voigt 2017:
Multielementcharakterisierung von Anodenmaterial für den kathodischen Korrosionsschutz an Offshore-Strukturen mittels ICP-MS/MS.
Bachelorarbeit, FH Lübeck