ROSAP – Ramboll Offshore Structure Analysis Programs

Dr.-Ing. Tim Fischer

Vice Director, Wind Energy

T: +49 40 302020-132

Ronnie Refstrup Pedersen

Senior Chief Consultant

T: +45 5161 4574

Optimise design and reduce capital expenditure

The global wind industry continues to break records for new investments and capacity, but high costs remain a major challenge to continuing the green transition.

As the fastest-growing part of the sector, the offshore wind industry still needs to find new ways to optimise designs and accommodate costs related to planning, fabrication, installation and operation. In many cases, optimisation is not only about reducing the steel weight, but also about securing an operational friendly design. 

Ramboll’s design software ROSAP (Ramboll Offshore Structural Analysis Package) provides indispensable tools for designing operational friendly wind turbine foundations.

The software includes a complete package for static and dynamic analyses of spatial framed structures, covering all phases from transport and lifting to in-service. Loads, such as hydrodynamic, wind, constant force and accelerations, are intuitively defined and processed according to recognised theories and standards. Typically, more than 10,000 different combinations of loads are calculated to secure the optimal design. 

Global and cross-sector application

ROSAP has been originally developed by Ramboll’s Oil & Gas division back in the 1980s. It has been used for the analysis of most jackets, topsides, offshore bridges and risers within the Danish sector of the North Sea, and for several studies in the Middle East, UK, US, and Norway.

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Around 2000, Ramboll has started utilising ROSAP for the design of offshore wind turbine foundations, introducing new features for the more dynamic systems. Overall, ROSAP has been used for the design and documentation of more than 3250 individual foundation designs for wind turbines with 14 GW distributed on offshore wind farms around the world.

Designs critical for cost-effectiveness

The measurements ROSAP performs have in some cases resulted in a significant reduction of capital expenditures compared to other competitive designs. 

In 2015, Ramboll became the first foreign advisor to design one of China’s largest offshore parks – SPIC Binhai North H1 in Jiangsu province – and since then, Ramboll has become active on the Japanese and Taiwanese markets.

Mr. Zhang Yi, project manager with the Chinese State Power Investment Cooperation, explains that the total price was a decisive factor in choosing Ramboll for the SPIC Binhai North H2 contract.

“Ramboll could supply a solution that was 20% cheaper than what the competitors had to offer and could deliver a better thought-out solution owning to its wide palette of competencies” says Zhang Yi.

Further optimising designs

It is becoming increasingly evident that measurements are a key element in lowering not only capital expenditures but also operating expenses. 

Ronnie Pedersen, Senior Chief Consultant at Ramboll, emphasises that: 

“Offshore wind turbines and foundations will be strategically monitored in the future and Ramboll has the knowhow and numerical framework to utilise the measurement data by updating the ROSAP model to a True Digital Twin, which can be used to facilitate decisions on life-time extensions or inspections. This can be used to offer new real-time insights into the health of the structure and further optimise future structural designs”. 

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