The period of constructing a wind park is undeniably very intensive. But that doesn’t mean that nothing else happens after commissioning. Quite the contrary. It’s the start of the 20-year period in which the park must do what it is designed to do: supply reliable and renewable energy to a hundred thousand households on the mainland. This is the phase designated as O&M – Operations & Maintenance. Two concepts behind which an entire world lies. This part of the website gives a look behind the scenes by focussing on various topics. What is the general task when operating the wind park? How are ICT and data handled? How is energy supplied to the “electricity market”? And what is necessary to have the maintenance of the wind park go smoothly throughout the year?



Siemens Gamesa service contract extended

Siemens Gamesa Renewable Energy and Gemini Consortium have reached an agreement for the extension of the operations and maintenance service agreement for the 600-MW Gemini offshore wind park in the Dutch North Sea until 2036.
The original 15-year long-term service program (LTP) to service wind turbines at the Gemini offshore wind park has been extended by another five years. This new agreement builds on the service work that Siemens Gamesa has provided since 2016 including full maintenance of the 150 SG 4.0-130 wind turbines installed at the site. The LTP covers new services and different upgrades, providing greater control over operation and maintenance costs.
Paulina Hobbs, CEO of Siemens Gamesa’s North Europe and Middle East Service region, states, “We are very pleased that we have
reached such an important agreement, not only for its significant size, but also because it demonstrates that our clients trust Siemens Gamesa and our expertise in effectively, reliably and safely maintaining their fleets. It also increases our footprint in such an important and competitive market."
Gemini’s CEO Bart Hoefakker adds, “We are delighted to continue our relationship with Siemens Gamesa through this agreement. It is an example of a strong strategic alliance that will allow us to optimize the performance of our offshore wind farm while managing risk and providing extra value to our investors.”
Gemini is one of the largest offshore wind parks in the Netherlands; last year it produced 2.5 TWh of low-carbon electricity for around 800.000 households.



Gemini in full swing

With good maintenance as the basis, Gemini’s operations and maintenance (O&M) team is aiming for turbines that perform to the maximum. To achieve this, the O&M team carefully monitors the turbines so it can identify malfunctions at an early stage and predict their effect on the Gemini Wind Park production as accurately as possible.
It does this because the O&M team’s activities include a very important financial component. Gemini is a large producer which supplies electricity to the energy market on a daily basis. Therefore, accurate power forecasting is essential to Gemini’s success. Professional O&M makes all the difference in achieving that success.



Construction oyster bank in Gemini Wind Park

A unique nature restoration project has been started in the North Sea. For the first time, oyster beds are being repaired in deeper parts of the North Sea. This effort is being undertaken in order to learn the success factors for active recovery and also to 'kickstart' wild flat oyster beds.


World Wildlife Fund (WWF) and ARK Nature Development have initiated this project, and Gemini Wind Park has also made a contribution. At the park, some 1,000 kg of oysters and test cages have been placed as part of a broader programme of oyster bed repair at several locations in the North Sea. This also represents the first attempt in the North Sea of starting an oyster bank within a wind park.

Flat oyster beds used to occur on a large scale in the North Sea; until the beginning of the 20th century, about 20% of the North Sea floor was covered with oyster beds. These shellfish banks have largely disappeared due to overfishing, disease and cold winters. The banks offer a breeding ground for marine animals, support the growth of plants and animals, filter the sea water, increase fish production and contribute to coastal protection.

The richness of the species found on shellfish banks is 60% higher near sandy soils. Sharks and skates lay their eggs on the bank and small fish and shrimps can shelter and grow there. The shellfish bank is also an important breeding ground for predatory fish, seabirds and marine mammals. Shellfish banks therefore represent a fundamental, resilient and healthy North Sea ecosystem.




Windea la Cour

Proper maintenance is assured with good materials. At Norwegian shipyard Ulstein Verft Norway, the first of two support vessels to be used for wind park maintenance was launched in 2016. This ship, a service operations vessel (SOV), has been chartered by Siemens and specifically deployed for turbine maintenance in the Gemini Wind Park.
The vessel is designed to be used in a variety of weather conditions. On board there is room for more than 40 technicians who have set sail from Eemshaven in the summer of 2016. These technicians were mostly recruited in the northern Netherlands. Siemens has named the ship ‘Windea La Cour’, and with the Siemens technology of Blue Drive Plus C the ship has a durable drive system. The ship is equipped with a helideck and state-of-the-art technology. Operating from Eemshaven, this ship transfers the crew members to the wind park. It provides accommodation for 60 people in single cabins, of which 40 are
dedicated to service technicians.


The Siemens vessel Windea la Cour is

equipped with a motion-compensated

gangway system (Uptime) to transfer

technicians to the wind turbine.