Gemini Wind Park reaches ISO 55001 certification

In December 2016, Gemini Offshore Wind Park started the process to develop and implement an asset management system for the operational phase of the 600MW project.  Target was achieving ISO 55001-asset management certification.
The scope included developing a tailor-made Quality Management System (QMS) and a structured, risk-based approach towards asset management to be followed by the Gemini team organization throughout the operations phase, which the project just entered.
UK based consultancy Aeolus was selected to lead this process and the system was developed in close cooperation with the Gemini management team and engagement of CMS, an ISO 55001 consultancy, to ensure that the system would serve Gemini’s work culture and would be fully compliant with ISO 55001 requirements.
Only 1 year and 2 months after its official inauguration on 8 May 2017, Gemini has achieved ISO 55001 certification by Lloyds Register making it the first single purpose offshore wind park project to achieve such accreditation. The success of this story lies on strong involvement of both the management team and the team of Gemini that embraced this target. The result is a QMS system that helps the Gemini team to stay focused on the most important aspects of Gemini business and prioritise the day-to-day business accordingly. It helps Gemini to be on top of potential risks and opportunities following a risk-based decision-making approach, which leads to making better-informed decisions.


The ISO accreditation provides a means to conform to an excellent asset management system and continuously improve the Gemini performance. The system will ensure that risk awareness and continuous improvement are embraced for the project’s lifetime. Gemini is already producing renewable electricity for 1.5 million people, while reducing CO₂ emissions by 1.25 million tonnes per year.
About Gemini
With a total capacity of 600 megawatts, Gemini is one of the world’s largest offshore wind parks in the Dutch North Sea, both in size and in production. Gemini Wind Park has four project partners: Canadian independent renewable energy company Northland Power (60% project interest), wind turbine manufacturer Siemens (20%), a fund held by Alte Leipziger – Hallesche (10%) and renewable energy and Dutch utility HVC (10%).
About Aeolus
Aeolus is an independent offshore wind energy consultancy based in UK. It supports projects, lenders and investors worldwide on technical and commercial aspects and helps de-risk projects.
ISO 55001
ISO 55001 is an internationally accredited asset management system standard that enables an organization to achieve its objectives through the effective and efficient management of its assets.


‘First single purpose offshore

wind park project to achieve this accreditation.’

On this page you find information on the key elements of the Gemini Wind Park. Some general facts are introduced, as well as a sum-up of the main figures of the project. The introduction concludes with an important aspect of Gemini: the ecological monitoring. At Gemini, preserving the flora and fauna in the North Sea and the Waddenzee is highly valued. The monitoring helps in keeping this aspect under close scrutiny.



General facts

Gemini is one of the world’s largest offshore wind parks, both in terms of size and production.
Gemini is located in the Dutch North Sea, 85 kilometres north of the Dutch coast
and is not visible from the shore. This location offers some of the highest and most
constant wind speeds on the Dutch part of the North Sea.
The construction of the Gemini Wind Park took place between 2014 and 2017.
The project was fully operational by 2017.
Four companies joined forces to create Gemini: Northland Power (60% project share),
Siemens (20%), Van Oord (10%) and HVC (10%).
The project provided over 500 jobs during development and construction, as well as an additional 75 to 100 operational jobs over the coming years.


To get an idea of the size of Gemini

we have made a drawing of the wind

park and projected it on a map of the Amsterdam city centre.




Gemini in figures

600 megawatt production capacity

2.6 terawatt hour electricity generated per year

€ 2.8 billion project financing (loan capital and equity) pooled in record time

6 months to Financial Close - an unprecedented timescale for a project of this size

36 kilometres per hour - the average wind speed in the area

85 kilometres from the Groningen coast

68 square kilometres of wind park in the North Sea

28-36 metre water depth at the site of the wind park

5 years between obtaining the Water Act licence and the financial close in May 2014

24-36 months needed to complete the environmental surveys and obtain the required project licences

1.25 million fewer tons of CO₂ emissions per year because of Gemini

500 local jobs to be created during construction

1 land station has been constructed in Eemshaven

59-73 metres - length of the monopiles; each monopile has been adjusted to the installation depth required by the conditions at the various locations

7-11 centimetres - wall thickness of the monopiles; this varies to give additional support to the construction in areas in which the sea exerts most pressure

5-13 revolutions per minute - range of the nominal rotor speed

88.5 metres - height of the turbine hub above sea level

990 tons - lifting capacity of the crane on offshore installation vessel Aeolus

2 offshore high-voltage substations

5,000 tons - weight of a full cable carousel on installation ship Nexus

110 kilometres of export cable from each offshore substation to land (approximately)

33 - nominal kilovoltage of the thinnest infield cable (108 mm diameter) that connects the

turbines with the substations

230 - nominal kilovoltage of the thickest export cables (267 mm diameter) that can each

transport up to 75% of the electricity that Gemini generates.

450 turbine blades, each weighing 18 tonnes, to complete the wind park

1,347 tons - total weight of the heaviest installed turbine (including monopile, transition piece,

nacelle and rotor with blades)



Ecological monitoring

Gemini executes a research program which is aimed at monitoring possible ecological effects on marine life. This program started a few years before construction of the wind park and continues during construction and a number of years into operations. This monitoring program is specifically aimed at determining distributions and behavorial responses of birds, fish, seals and harbor porpoises in the area of the wind park site.



Offshore wind

A wind park needs wind in order to perform. This illustration shows where that wind can be found in the North Sea area. It makes sense: the further away from shore, the higher the average wind speed. The countervailing factor is the length of the export cables needed to convey the energy from the wind park onshore. The optimum for Gemini in this case was found in the area where winds reach an average speed of 10.2 to 10.4 metres per second.