B.1.7.1 Offshore Wind Parks

The construction and maintenance of huge offshore wind parks started in response to the increasing demand for renewable energy. Germany’s first offshore wind park, Alpha Ventus consists of only twelve turbines and got grid access in 2010. Within the next 5 – 10 years, it is expected that around 10.000 people will be working in the offshore wind industry. This section aims to give an idea of what it means to work in that new industry: a special working environment that is changing rapidly with the development of bigger and higher performing turbines and rapidly decreased installation time.

An offshore wind park is a cluster of wind turbines, platforms such as accommodation platforms and /or transformer platforms, manned as well as unmanned, and vessels like

  • guard vessels
  • crew transfer vessels (CTV)
  • service operation vessels (SOV)

In the different life cycle phases of a wind park there may be additional vessels such as hotel vessels, jack up barges for installation or accommodation, diving vessels, construction vessels, vessels for maintenance and many more.

The life-threatening environment makes it necessary for employers to implement EHS (Environment, Health and Safety) principles in the working environment and organize projects accordingly. Any precautions must be taken to protect people against accidents and incidents that could lead to injuries, as well as any other threats to people’s health. In addition, First Aid must be available and a rescue chain (a determined way to provide medical care from incident to hospital) must be organized.

B.1.7.2 Employees Health

Offshore employees must undergo a medical check-up at least every two years. National requirements vary, but via the so-called “Hardanger Agreement”, the United Kingdom, the Netherlands and Norway’s oil and gas industries accept each other’s national health certificates. Germany’s health certificate for wind energy offshore workers, which is based on DGAUM (German Society of Occupational and Environmental Medicine) is also accepted in the Netherlands.

Offshore workers should be physically and mentally healthy, as access to emergency care and treatment of illness are limited. Physical demands are high and include the ability to climb, to wear PPE (Personal Protection Equipment could reach 10-12 kg additional weight), and to complete training in sea survival and helicopter under-water escape training.

Fitness facilities and healthy food should be available offshore as well as leisure facilities and the possibility to stay in touch with friends and family at home.

Employers should support employee self-care and health awareness.

The ageing workforce is a challenge to both employers and employees.

B.1.7.3 The life cycle of a wind park

The life cycle of a wind park has different phases:

  1. Sea survey and planning. The construction field is determined, all applications are submitted, and all permits are obtained. The ground must be analysed, unexpected objects must be found and removed, especially remaining from wars: shipwrecks, airplane wrecks and unexploded objects.
  2. Installation phase: this starts with cleaning and preparing the construction site, laying cables, grounding foundations, erecting the top sides of different structures such as wind turbines and platforms. This phase involves a high number of personnel on site, estimated at 200-250 workers, with many different departments involved and a high workload.
  3. Operations and maintenance of all facilities: this involves less people, depending on tasks, smaller teams and less vessels. Constructions are likely to be unmanned.
  4. Decommissioning phase – removal or repowering: again, this involves a high headcount and many different professions and vessels.

B.1.7.4 Working on an offshore wind park

Working in the offshore wind industry has much in common with other jobs offshore, including exposure to and dependence on weather conditions including storms, humidity, cold and sun.

People usually work in 12hrs shift, working day and night for 14 days followed by 14 days off although this may vary in different nations. A crew change can include a long travelling time by vessel or helicopter and further travel time to reach home once ashore. 

All employees must be appropriately trained for the special working, living and transportation demands, as well as for the many specialist jobs and roles, which may differ considerably from an onshore job.

Working places offshore are diverse. The workplace and job could be an office job at a desk aboard an HVDC platform or a member of the catering crew on a SOV, or a service technician on a wind turbine in the maintenance phase.

All employees must pass a medical examination before undergoing all the necessary training that is mandatory for working offshore in a safe manner, according to the risk assessment of jobs and sites. Employees are often specialists in their trained jobs but not seafarers. Additionally, in the first years of European offshore wind Industry most of them never thought they would be working offshore when they were gaining their professional qualifications. Thus, working offshore is not suitable for everybody and the employee himself and his family etc. must be able to withstand that special work-life-balance. Phases of intense home life and leisure time change regularly to phases with very limited contact, even in times of private challenges or problems. A stable social surrounding is helpful.

B.1.7.5 Working places at an offshore wind park


These huge converter platforms are constructed onshore, brought offshore and grounded on an undersea foundation. They then need to be installed by people. The platforms have all necessary technical equipment as well as cabins, a well-equipped sick bay with the possibility of telemedical support, a restaurant, a fitness room and some facilities for leisure time. In periods with additional personnel on board, such as in the installation phase, temporary living quarters (TLCs) can be used. A medically trained person provides professional medical first and prolonged care, supported by trained laypersons and telemedical support from telemedical centres onshore - the number and their qualifications may vary, depending on the purpose of the construction, the number of workers and the construction phase.  They are prepared for Medevac to occur and telemedical support is important for them.

Usually, these platforms are located far out at sea, up to 90 km from the coast. Some of them are manned, others temporarily staffed or unmanned. Not all the functions of an HVDC platform can be carried out remotely from onshore; technical personnel are needed on the platform for its operation and maintenance.

The employer is responsible for a safe working environment, which means safe travel, safe work, and safe living quarters for the employers. Food and first aid must be provided for technical employees and other workers. Many different professionals work temporarily or permanently on board: engineers, technicians, construction site workers, divers, caterers, cooks, housekeepers, nurses/medics, crane operators, industry climbers, painters, office workers, EHS and logistic professionals and more. In addition to their original professional education some of them have more than one role at the wind park. Due to the rules and regulations, there must be dedicated personnel for positions including a helicopter landing officer, coxswain, radio operator, members of a first response team, fire fighters, and other additional responsibilities. Thus, it is likely that one person has additional, emergency tasks as well as his usual job.

B.1.7.6 Offshore wind turbines

Over the recent years, turbine manufacturers such as Siemens Gamesa have improved the design and installation of wind turbines in terms of the quality, performance, and time. The strategy is to keep most of the construction work onshore at preassembly sites and reduce the offshore workload and complexity to a minimum. Hence it can be seen more and more as “plug’n play”.  Nowadays the overall timespan from the start of installation until the first power is produced is less than a day for one turbine.

The installation is done by huge installation vessels operating 24/7. These vessels carry multiple wind turbines and all kinds of personnel needed to bring the turbine alive: technicians for the installation, to link the high voltage connection and several supporting profiles like engineers and technicians, stock keeper, painters, crane operators, industrial climbers, and catering staff in addition to their original nautical crew. Depending on the vessel, the crew can be in the range of 20-30 seafarers 30-40 offshore workers. During commissioning employees must use big and heavy tools, such as hydraulic screwdrivers, which can weigh up to 20 kg. Each screw is between 7-8 kg and 140 of them must be tightened and controlled. Every day, all tools and equipment needed by the workers must be carried to their current location of work. The maximum load they can carry is 30 kg, so this can involve many trips.

Grid access is mostly done by personnel from service operation vessels with commissioning teams and service teams on board and using direct access systems to turbines such as ‘Ampelman’ CTV (Crew Transfer vessels). Ampelman was the first model of hydraulic bridges which made it very easy to step over to a turbine without the need to climb.  Here, heavy, and sometimes uncomfortable personal protective equipment must be worn most of the time.

Later in the maintenance phase, the service to turbines can be provided by land based CTVs which can carry 12 to 24 technicians in daily service or by SOVs. SOVs can carry around 70 people, about 40 technicians and additional engineers, office personnel, stock keepers, catering crew, housekeepers and nautical crew as needed. They usually serve one park up to one cluster of parks with maintenance. A cluster is a huge offshore area which could contain several wind parks owned by different companies, they conduct their generated energy to one or more Transformer Platforms, usually in the centre of the cluster. Before transmitting the electric current ashore, the current is transformed to direct current. Shifts are 12hrs per day for 14 days on duty after which a crew change is done by helicopter or in a harbour. Modern SOVs offer leisure facilities such as a gym, cinema, and Wi-Fi connection. Every technician has a single cabin with en-suite bath and access to daylight. Still people sometimes suffer from seasickness.

If employees are working at heights or transferring from vessel to turbine, they must wear personal protection equipment such as a harness against falling, survival suit or dry suit, different tools, helmet, boots and sometimes eye protection depending on the risk assessment. This means an additional 10kg to carry.

Vessels for different work tasks

Different vessels are needed in the different phases of constructing a wind park.  In the very beginning, special vessels are required to support diving operations. Divers usually need special equipment including availability of medical assistance and a decompression chamber. Other vessels provide cable layers and equipment. Big installation vessels carry foundations and rams to ground foundations and piles of transition pieces. Specialized workers are needed in addition to the vessel’s crew. For the installation of turbines, the installation vessel carries the components for up to 12 turbines including the tower, nacelle and blade. Installation time and manpower is decreasing following the fast development of preassembly possibilities and changing design. 

Installation vessels working as jack up vessels (Jack up Barges or Vessels are floating boats or constructions which can self-elevate above sea level with long legs able to be grounded). They carry around 70 people of whom up to 30 would be seafarers. The vessel offers cabins for installation technicians, often shared with others, and only limited leisure facilities. Seasickness is a minor problem as soon as the vessels are jacked up. Such vessels are clearly a working vessel and work continues through day and night shifts, often with a high level of activity and therefore with an elevated noise level. All working activities are dependent on weather conditions and if there is high wind and rough sea, no installation can be done.

The commissioning and service part is usually done from SOV’s. These vessels continuously hold a dynamic position in the wind park close to the turbines. Therefore, the engines are operational 24/7 and create a noise level for all staff aboard.

Crew transfer vessels (CTVs) are smaller vessels with big engines and high mobility to move personnel inside a park or from port to park. The carry up to 24 passengers with a nautical crew of 3. PPE must be worn. People on board often struggle with sea sickness, sometimes tiredness, boredom, and a limited individual space to move. These problems may increase on vessels that were originally built for different purposes and restructured as SOVs, such as ferries or offshore supply vessels.

Other Types of vessels found within a wind farm include:

  • Guard vessels are needed to secure the park. They usually carry ship’s staff only.
  • Supply vessels ensure provision of all areas with drinking water, food, fuel and more.

These vessels do not host offshore wind related employees.

In a normal operational phase, less people are needed within the cluster and turbines and some platforms stay unmanned. Monitoring and control is done remotely from onshore control centres.

Access to work

Access to work can be provided in different ways. Crew Transfer vessels and smaller boats offer direct access to the constructions and climbing is needed. SOVs mostly offers more comfortable access via motion compensated gangway systems. They provide a very easy daily commute. The use of all systems is limited by wave height.

Helicopter transfer may also be an option. Manned platforms, as well as some of the unmanned platforms have a helicopter landing deck where helicopters can land during daylight and sometimes during darkness as well. Wind turbines are only accessible by winch operations. Thus, additional training and PPE for offshore employees is needed. Helicopter under water escape training and sea survival training is mandatory, both of which are challenging.

Undergoing these conditions working offshore is not a job for everybody, but most offshore employees do like their jobs.

The Wind Energy Industry will provide a lot of interesting and safe jobs now and in a sustainable future.