The full story
A need for consistent and reliable metocean data
High quality and reliable metocean data is fundamental to the success of any marine project such as design, operation and maintenance of offshore wind farms. Inconsistent and sometimes unreliable metocean data has resulted in a more costly design of various offshore wind farm projects in Europe.
The Dutch Government has taken a unique approach in providing developers with high quality metocean data. The new approach ensures access to consistent and reliable metocean data along the Dutch offshore wind farm concession areas, which can be easily accessible. RVO.nl (on behalf of the Dutch Government and supported by BLIX Consultancy BV) commissioned DHI (who has contributed to more than 85% of all offshore wind farm projects in Europe) to provide a comprehensive and user-friendly digital metocean database.
A digital metocean database
Using state-of-the-art numerical models and advanced analysis methods, 38 years of metocean data at any given point within parts of the Dutch North Sea area was delivered in the form of a digital database.
The database includes meteorology, hydrodynamics and waves; further pre-processed data such as extreme metocean conditions, joint-probabilities, associated parameters, tidal analysis fatigue data and spectral data.
DHI established dedicated high-resolution state-of-the-art numerical models (based on MIKE Powered by DHI software package) to provide metocean conditions in the Dutch North Sea area. The models were forced by wind/pressure field data from the Climate Forecast System Reanalysis (CFSR) dataset established by the National Centers for Environmental Prediction (NCEP).
An extensive validation of the modelling result was conducted using satellite and local measurements. The validation showed very good model performance and thus ensured accurate and high-quality metocean conditions at the desired areas.
Left: The North Atlantic regional model domain and bathymetry; Right: The database area (outer red line) shown together with Hollandse Kust (zuid) and Hollandse Kust (Noord) offshore wind farms. © DHI
Normal and extreme conditions at sea
Normal metocean conditions were described in detail and were based on the 38 years of modelling results. Extreme conditions were established for wind, current and water levels for return periods up to 100 years and for waves (significant wave height, maximum individual wave height and maximum crest heights) for return periods up to 10,000 years using advanced statistical methods. Joint probability of metocean conditions is also provided with this report. The results can be directly used for design purposes.
User-friendly interface: an all-in-one approach
Users can access the modelling data and the analysis results through a user-friendly interface.
A snapshot of the metocean database software containing +10 TB of data based on the MIKE OPERATIONS platform. © DHI
Various types of analysis (rose, scatter diagrams, occurrence tables, persistence, and so on) will be available concurrently through the database software which is based on MIKE OPERATIONS technology.
Accurate and reliable metocean data
The digital database provides high quality, validated and comprehensive metocean data detailing normal and extreme conditions within the Dutch North Sea sector. It will help:
- reduce cost by delivering all the required data for the developers for their initial cost estimates and final design – which means no further metocean studies are needed
- develop the best possible metocean data basis suitable for design for the Dutch North Sea area
- provide the industry with easy access to certified, high quality and consistent metocean data in Dutch North Sea area
- support cost-effective development of future offshore wind farms for the Netherlands
The database and a comprehensive report describing the methodology used, are applicable for the design, maintenance and operation of offshore wind farms, inter-array cables, substations and their support structures. This will benefit companies submitting bids to develop projects in the Dutch sector of the North Sea.
The metocean report (in English) can be downloaded here: http://offshorewind.rvo.nl/windwaterzh.