Metocean data and tools for offshore developments

Addressing challenges with our metocean expertise

For addressing global energy needs and combating climate change offshore energy harvesting developments are crucial. However, these projects face significant challenges, including extreme weather conditions, climate change impacts, and the need for sustainable and resilient infrastructure.

To meet these challenges, comprehensive metocean studies are essential. Deltares’ studies provide critical data on atmospheric, hydrodynamic, and wave conditions, which are necessary for assessing risks, designing and maintaining offshore structures.

The accuracy of the studies is ensured by Deltares’ expertise in areas such as wave and three-dimensional hydrodynamical modelling in complex regions (e.g. with sand waves and outcrops), tropical cyclone modelling, extreme weather event assessment and climate change impact analyses. In addition, and making use of the broad expertise base of Deltares, the studies also can include marine growth, tsunami and seismic activity and ice assessments. On top of our expertise we also employ our advanced tools and models to further ensure the quality of the provided metocean data and assessments.

In summary, the scope of the metocean studies we carry out can involve:

• Validation of metocean measurement campaigns, such as those with Floating LiDAR Buoys
• Detailed high-resolution wave modelling
• Detailed high-resolution 3D hydrodynamic modelling
• Coupling of high-resolution atmospheric modelling from external parties with internally developed high-resolution hydrodynamic and wave modelling
• Operational analysis, including directional and monthly statistics, weather windows and severe sea states
• Univariate, multivariate, stationary and non-stationary extreme value analyses, including the determination of severe and extreme sea states
• Wind shear and turbulence data analyses
• Tropical cyclone modelling, including the generation of synthetic tracks and modelling of associated wind, wave and hydrodynamics conditions for hazard and risk assessments
• Marine growth assessment
• Sea State Analyses, including crest heigh, local wave breaking and slamming assessments
• Snow and ice assessment
• Tsunami and earthquake risk assessments
• Assessment of the effect of the offshore wind development on the metocean conditions
• Assessment of the effects of climate change on the metocean conditions
• Certification support
• Dashboards: digital twins for operational and maintenance support and long-term metocean data viewers for planning and design

Connection between knowledge gaps and technological needs

Most metocean assessments are carried out using methods and tools developed by Deltares. There is a circular connection between identified knowledge gaps and technological needs, and the knowledge and tools developed and improved in joint industry and research projects.

Examples of joint industry and research projects

CHASM (Coupled High-resolution Atmosphere Sea Modelling)

Which aimed to reduce uncertainty in the numerical modelling of metocean conditions at offshore wind farms by coupling the existing atmospheric GRASP model and wave SWAN model.

We are currently working on the follow-up of this study: the WHAM (Wave-Hydrodynamics-Atmosphere Model) project, a joint research & development effort focused on radically reducing uncertainties in metocean conditions for offshore wind development.

Offshore Meteo Dashboard

The installation and maintenance of an offshore wind park involve logistical challenges, which require the coordination of supply and support vessels, installation jack-ups, and transfer of personnel, which are all weather-restricted. Statistical analysis and forecasting of expected weather windows is therefore essential for the planning of marine installations.

Deltares’ Offshore Maintenance joint industry projects focused on developing an Offshore Meteo Dashboard to be used for short-term access strategy selection for offshore wind, thereby reducing the cost and risk of offshore wind operation and maintenance (O&M).

The then developed Meteo Dashboard is an integrated software system which collects, stores, and presents measured and forecasted meteo- and hydrodynamic data for each wind turbine. It is designed to include a detailed forecasting system, with high-resolution hydrodynamic modelling providing forecasts of waves, currents, and water levels at each wind turbine location in the offshore wind farm and along possible ship routes from the harbour to the farm.

Long-term and high-resolution numerical modelling

In order to determine accurate operational and extreme conditions our metocean studies generally include detailed local modelling of the hydrodynamics and waves for a period of at least 30 years and with a resolution of 1 hour. The hydrodynamic modelling is often carried out using a 3D model and the wave model spectral results are partitioned into swell and wind-sea wave systems.

State-of-the-art metocean tools

Implemented knowledge of environmental processes, field measurements, data-driven analysis, and state-of-the-art numerical models play a central role in our metocean studies. A tailored approach is determined for each study based on end objectives and the appropriateness of each tool. The main numerical tool used in our studies are:

• ORCA: tool for the validation and operational and extreme values analyses of metocean data.
• TCWiSE: highly flexible tool for estimating extreme tropical cyclone wind speeds and associated risks.
• Delft3D: open source software that facilitates state-of-the-art hydrodynamic, morphodynamic and wave modelling.
• SWAN: state of the art spectral wave model (also included in Delft3D and although not developed by Deltares, we have also contributed to it) allowing the long-term modelling of the wave spectra including depth-induced effects.
• BlueEarth: community-based open data platform, initiated by Deltares, providing global data for free.

These tools are continually developed using the latest scientific knowledge and feedback from ongoing projects.

Metocean study for the Princess Elisabeth Zone

The Belgian federal government is aiming to increase the total capacity of operational offshore wind energy from 2.2 GW currently to 5.4-5.8 GW by 2030 at the latest, through the development of new offshore wind farms within the three parcels of the Princess Elisabeth Zone (PEZ).

To be able to realise the largest possible share of additional offshore renewable electricity production at the lowest possible social cost the Belgian government requested in 2024 the metocean team of Deltares in collaboration with HKV and Haedes to perform a detailed metocean study for each of the three parcels within PEZ and to also develop an online data-portal through which the high-resolution metocean data, derived within the metocean study, is made freely available to the public.

By providing high-quality metocean data within a morphologically active area with large sand banks beforehand to the market, the costs for the development of the additional capacity and the amount of materials needed can be substantially reduced making sure that the OWFs within the three lots are not designed using overconservative environmental conditions. From this online dataset future tenderers can extract the data (timeseries and statistics) at the exact location they require and use it as input for design.

Furthermore, as the PEZ metocean dataset reaches further than the limits of the development area itself, the metocean data could also be used for a multitude of other purposes by the general public.

Metocean conditions during the incident with the MSC Zoe

In 2019, Deltares contributed to an investigation by the Dutch Safety Board into the incident involving the container vessel MSC Zoe, which lost several containers north of the Dutch Wadden Islands. Deltares provided insights into the metocean conditions (wind, waves, currents) during the accident and assessed the frequency of such conditions. This study helped understand the environmental factors contributing to the incident and led to the implementation of active traffic guidance for shipping north of the Wadden Islands.

Cutting maintenance costs for offshore wind farms using improved forecasts

Deltares developed a web-based dashboard that provides forecasts two days in advance, covering wind speeds, wave heights, and currents for individual offshore wind turbines. This operational decision-making system helps wind-farm managers make better decisions about maintenance activities, reducing costs and risks associated with offshore wind operation and maintenance.