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REDWIN - reduce wind energy cost

REDucing cost in offshore WINd by integrated structural and geotechnical design is a R&D Project supported by The Norwegian Research Council ENERGIX program.

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The primary objective of REDWIN is to contribute to the reduction of costs in the design of offshore wind turbines (OWT) by developing soil-foundation models that will account for key geotechnical issues such as stiffness, damping, drainage, degradation, and long-term behavior, and integrate them in the OWT structural model for more optimal analysis and design.

The resulting tool will shorten the design process and will allow the designers to adopt accurate, advanced, and benchmarked foundation design tools already in the preliminary study phase. By using these methods, the uncertainties in the analyses will be significantly reduced, and unreasonably, conservative and expensive OWT design will be avoided.

Some elements of this research include:

  • Development of models for foundation stiffness and damping calibrated against full-scale prototype data
  • Library of soil-interaction models, 3DSoil, for shallow (e.g. caisson) Foundations   and deep (monopile) foundations
  • Implementation of 3DSoil in integrated aero-hydro-elastic analysis tool 3DFloat   (developed by project partner IFE)
  • Benchmarking and improving existing simplified foundation and   soil-structure-interaction models using the results of this research

Offshore wind has grown to be a significant renewable energy source during the last decade. However, there is a consensus among the operators that for offshore wind energy to be long-term sustainable, the cost of wind farms has to be reduced. Cost reduction can be achieved in several ways. To this end, optimal foundation solutions and steel tonnage are two aspects with significant potential.

While considerable research and development has been made on structural aspects of Offshore Wind Turbines (OWT) and their integrated analyses with wind and waves, conservative approaches and assumptions are often applied to geotechnical and foundation issues. Moreover, integration of suitable and validated foundation models in operational OWT design is lacking.

The coupling between load, structure, and foundation will influence OWT behavior. It is therefore believed that considerable savings in OWT construction can be made through integrated analysis of soil-structure interaction (SSI) including a profoundly increased accuracy in modeling of the foundation behavior. While several attempts have been made in this direction, (e.g. Zaaijer 2006, Damgaard et al. 2014), there is a dire need for more research to include key soil response issues including damping, stiffness, drainage, degradation, and long-term behavior. These issues not only impact the design of the foundation, but they also have an important influence on the behavior of the structure.

The goal of this research project is to develop new engineering tools for accurate treatment of the soil and foundation behavior and enable direct integrated OWT analyses. Such tools and methods may reduce uncertainty and provide a rational basis for design. This will lay the basis for a more optimal design for the OWT foundation and thereby reduce the price of renewable energy.

OWTs are designed and constructed in several different ways according to wind and wave conditions, sea currents, depths, and soil conditions. It is time-consuming to establish a complete, comprehensive wind farm under varying conditions. Advanced computational tools are therefore needed to optimize design and engineering.

Today, the geotechnical engineers working on the foundations and the structural engineers working on the construction operate within separate professional fields. There are no comprehensive tools that can combine the two areas, enabling them to jointly arrive at the best solutions.

As a consequence, both expert groups often need to repeat their calculations several times before they can arrive at a solution that satisfies all needs. The engineering phases often take longer than scheduled, and necessary, with no guarantees that the resulting solutions are the best possible. Since foundations represent 25- 30 percent of total construction costs, there is a great potential for savings.

REDWIN brings together experts from the two engineering fields, to jointly develop better methods.  The aim is to design new models describing soils and foundations that will be integrated with the computational tools used by structural engineers today. This will contribute to optimized engineering and design, resulting in less expensive offshore wind energy.

Project coordination and management

The consortium assembles research organizations (NGI, IFE), university (NTNU), and private organizations (Equinor, Vattenfall, and Dr. Tech. Olav Olsen). Each partner is keenly interested in contributing to the project and has the competence to contribute to the new developments.

In addition, research collaboration with several external universities, research institutes, and R&D centers (Danish Technical University, University of Western Australia, Perth, University of Ålborg, University College Dublin, Rambøll Denmark, and NOWITECH). These well-established institutions within OWT research have been targeted and responded to positively. The role of the external partners is elaborated below.

The project will be conducted under the leadership of NGI, and involve a range of other highly competent key specialists in each of the partner organizations.

Research partners

NGI (Norwegian Geotechnical Institute) is a national center for geo-related research, With a long experience in R&D in geotechnics and geosciences. NGI has a wide experience with WT design, installation, and monitoring through numerous projects. NGI will carry out the majority of the R&D work related to OWT soil and foundation modeling, soil-structure-interaction, model validation, signal processing, and data analysis.

IFE (Institute for Energy Technology) has driven the development of the integrated model 3DFloat, which is considered to be a state-of-the-art model. IFE is leading the activity on integrated analysis within the FME NOWITECH project. 3DFloat has advanced models for sea environment description, sea loads, and structure. In the present project, IFE will be involved in the implementation and testing of integrated soil-structure-interaction models.

NTNU (Norwegian University of Science and Technology): The research group at NTNU on the topic of foundation for offshore wind turbines presently consists of five PhD candidates and one full professor. The research is founded by a joint academia-industrial initiative in the field of Renewable Energy at the faculty. NTNU hosts the PhD student funded by the project, as well as the PhD student (Kristoffer Skau) provided in-kind by NGI.

OO (Dr. Techn. Olav Olsen) is a structural engineering company that has been involved in numerous R&D projects within OWT through in-house and industry initiatives. OO will be involved in research activities related to OWT redesign and cost analysis using the new foundation models.

Industrial partners

The two industrial partners Equinor and Vattenfall represent significant international industry organizations within offshore wind energy. Their extensive knowledge and insight will be valuable for project decision-making. The experiences of Equinor and Vattenfall stem from many relevant areas including offshore wind R&D and offshore wind farm ownership.

Equinor and its offshore wind energy R&D team in Bergen have high-level knowledge and will take an active part in the project. The offshore wind energy team of Vattenfall has a wide knowledge of OWT ownership, management, and research.

The partners were chosen based on the knowledge needed to address an important missing element in OWT design. NGI has a long and broad experience within the field of soil/foundation. IFE has top expertise within wind turbine technology and fluid dynamics. NTNU has focused research on OWT and provides PhD education in the project. Olav Olsen is a structural engineering firm with valuable experience in practical design in offshore wind.

Finally, Equinor and Vattenfall represent significant international industry organizations within offshore wind. Collaboration with the various international R&D centers (see below) will ensure the use of the most recent international development in the project.

External partners

The project will collaborate with the following institutions on the following topics stated for each of them:
1.    Danish Technical University, DTU - Centrifuge data on monopiles
2.    University of Western Australia, Perth - Centrifuge data on monopod
3.    University of Ålborg - Full-scale OWT data in Fredrikshavn
4.    University College Dublin - member of OWT project PISA - Access to data on pile testing.
5.    Rambøll Denmark - Permanent deformation of OWT Foundations
6.    The project will be carried out in close collaboration with NOWITECH. The project parties IFE, NTNU, Equinor, and Vattenfall are all central partners in NOWITECH and will Ensure knowledge exchange between the two projects and that complementary research is performed in them.

It is intended that the Technical Advisory Group (TAG) will include one member from each of these institutions. TAG will meet once a year to review the progress of the project and give advice on the subject.

WP2 - Processing and assessment of prototype measurement data

A significant element of this research is the compilation of measured data available through the industrial partners of the project and through the cooperating international partners.

WP 3 - Development of 3DSoil: library of soil interaction models for different foundations

The main objective is to develop soil interaction models to be implemented in integrated analyses for OWT. This work package is the most research-extensive WP in the project, involving one Ph.D.-student at NTNU funded by the Project, and one Ph.D. supported in-kind by NGI.

Work Package 4 & 5

WP 4 - Integrated dynamic analyses of OWT WP 5 - Model calibration and verification

WP 6 - Re-design of OWTs and estimates of cost saving

This WP will investigate possible cost savings from design using improved integrated analyses including soil interaction models compared to the traditional methods.

For inquiries related to REDWIN models and results from the REDWIN project, please send an e-mail to redwinmodels@ngi.no.

Report

Publications

Presentations

REDWIN final workshop 8 November 2018 at SALT (www.salted.no), Oslo

Webinar

 

  • The primary objective of REDWIN is to contribute to the reduction of costs in the design of offshore wind turbines (OWT) by developing soil-foundation models that will account for key geotechnical issues such as stiffness, damping, drainage, degradation, and long-term behavior, and integrate them in the OWT structural model for more optimal analysis and design.

    The resulting tool will shorten the design process and will allow the designers to adopt accurate, advanced, and benchmarked foundation design tools already in the preliminary study phase. By using these methods, the uncertainties in the analyses will be significantly reduced, and unreasonably, conservative and expensive OWT design will be avoided.

    Some elements of this research include:

    • Development of models for foundation stiffness and damping calibrated against full-scale prototype data
    • Library of soil-interaction models, 3DSoil, for shallow (e.g. caisson) Foundations   and deep (monopile) foundations
    • Implementation of 3DSoil in integrated aero-hydro-elastic analysis tool 3DFloat   (developed by project partner IFE)
    • Benchmarking and improving existing simplified foundation and   soil-structure-interaction models using the results of this research

  • Offshore wind has grown to be a significant renewable energy source during the last decade. However, there is a consensus among the operators that for offshore wind energy to be long-term sustainable, the cost of wind farms has to be reduced. Cost reduction can be achieved in several ways. To this end, optimal foundation solutions and steel tonnage are two aspects with significant potential.

    While considerable research and development has been made on structural aspects of Offshore Wind Turbines (OWT) and their integrated analyses with wind and waves, conservative approaches and assumptions are often applied to geotechnical and foundation issues. Moreover, integration of suitable and validated foundation models in operational OWT design is lacking.

    The coupling between load, structure, and foundation will influence OWT behavior. It is therefore believed that considerable savings in OWT construction can be made through integrated analysis of soil-structure interaction (SSI) including a profoundly increased accuracy in modeling of the foundation behavior. While several attempts have been made in this direction, (e.g. Zaaijer 2006, Damgaard et al. 2014), there is a dire need for more research to include key soil response issues including damping, stiffness, drainage, degradation, and long-term behavior. These issues not only impact the design of the foundation, but they also have an important influence on the behavior of the structure.

    The goal of this research project is to develop new engineering tools for accurate treatment of the soil and foundation behavior and enable direct integrated OWT analyses. Such tools and methods may reduce uncertainty and provide a rational basis for design. This will lay the basis for a more optimal design for the OWT foundation and thereby reduce the price of renewable energy.

    OWTs are designed and constructed in several different ways according to wind and wave conditions, sea currents, depths, and soil conditions. It is time-consuming to establish a complete, comprehensive wind farm under varying conditions. Advanced computational tools are therefore needed to optimize design and engineering.

    Today, the geotechnical engineers working on the foundations and the structural engineers working on the construction operate within separate professional fields. There are no comprehensive tools that can combine the two areas, enabling them to jointly arrive at the best solutions.

    As a consequence, both expert groups often need to repeat their calculations several times before they can arrive at a solution that satisfies all needs. The engineering phases often take longer than scheduled, and necessary, with no guarantees that the resulting solutions are the best possible. Since foundations represent 25- 30 percent of total construction costs, there is a great potential for savings.

    REDWIN brings together experts from the two engineering fields, to jointly develop better methods.  The aim is to design new models describing soils and foundations that will be integrated with the computational tools used by structural engineers today. This will contribute to optimized engineering and design, resulting in less expensive offshore wind energy.

  • Project coordination and management

    The consortium assembles research organizations (NGI, IFE), university (NTNU), and private organizations (Equinor, Vattenfall, and Dr. Tech. Olav Olsen). Each partner is keenly interested in contributing to the project and has the competence to contribute to the new developments.

    In addition, research collaboration with several external universities, research institutes, and R&D centers (Danish Technical University, University of Western Australia, Perth, University of Ålborg, University College Dublin, Rambøll Denmark, and NOWITECH). These well-established institutions within OWT research have been targeted and responded to positively. The role of the external partners is elaborated below.

    The project will be conducted under the leadership of NGI, and involve a range of other highly competent key specialists in each of the partner organizations.

    Research partners

    NGI (Norwegian Geotechnical Institute) is a national center for geo-related research, With a long experience in R&D in geotechnics and geosciences. NGI has a wide experience with WT design, installation, and monitoring through numerous projects. NGI will carry out the majority of the R&D work related to OWT soil and foundation modeling, soil-structure-interaction, model validation, signal processing, and data analysis.

    IFE (Institute for Energy Technology) has driven the development of the integrated model 3DFloat, which is considered to be a state-of-the-art model. IFE is leading the activity on integrated analysis within the FME NOWITECH project. 3DFloat has advanced models for sea environment description, sea loads, and structure. In the present project, IFE will be involved in the implementation and testing of integrated soil-structure-interaction models.

    NTNU (Norwegian University of Science and Technology): The research group at NTNU on the topic of foundation for offshore wind turbines presently consists of five PhD candidates and one full professor. The research is founded by a joint academia-industrial initiative in the field of Renewable Energy at the faculty. NTNU hosts the PhD student funded by the project, as well as the PhD student (Kristoffer Skau) provided in-kind by NGI.

    OO (Dr. Techn. Olav Olsen) is a structural engineering company that has been involved in numerous R&D projects within OWT through in-house and industry initiatives. OO will be involved in research activities related to OWT redesign and cost analysis using the new foundation models.

    Industrial partners

    The two industrial partners Equinor and Vattenfall represent significant international industry organizations within offshore wind energy. Their extensive knowledge and insight will be valuable for project decision-making. The experiences of Equinor and Vattenfall stem from many relevant areas including offshore wind R&D and offshore wind farm ownership.

    Equinor and its offshore wind energy R&D team in Bergen have high-level knowledge and will take an active part in the project. The offshore wind energy team of Vattenfall has a wide knowledge of OWT ownership, management, and research.

    The partners were chosen based on the knowledge needed to address an important missing element in OWT design. NGI has a long and broad experience within the field of soil/foundation. IFE has top expertise within wind turbine technology and fluid dynamics. NTNU has focused research on OWT and provides PhD education in the project. Olav Olsen is a structural engineering firm with valuable experience in practical design in offshore wind.

    Finally, Equinor and Vattenfall represent significant international industry organizations within offshore wind. Collaboration with the various international R&D centers (see below) will ensure the use of the most recent international development in the project.

    External partners

    The project will collaborate with the following institutions on the following topics stated for each of them:
    1.    Danish Technical University, DTU - Centrifuge data on monopiles
    2.    University of Western Australia, Perth - Centrifuge data on monopod
    3.    University of Ålborg - Full-scale OWT data in Fredrikshavn
    4.    University College Dublin - member of OWT project PISA - Access to data on pile testing.
    5.    Rambøll Denmark - Permanent deformation of OWT Foundations
    6.    The project will be carried out in close collaboration with NOWITECH. The project parties IFE, NTNU, Equinor, and Vattenfall are all central partners in NOWITECH and will Ensure knowledge exchange between the two projects and that complementary research is performed in them.

    It is intended that the Technical Advisory Group (TAG) will include one member from each of these institutions. TAG will meet once a year to review the progress of the project and give advice on the subject.

  • WP2 - Processing and assessment of prototype measurement data

    A significant element of this research is the compilation of measured data available through the industrial partners of the project and through the cooperating international partners.

    WP 3 - Development of 3DSoil: library of soil interaction models for different foundations

    The main objective is to develop soil interaction models to be implemented in integrated analyses for OWT. This work package is the most research-extensive WP in the project, involving one Ph.D.-student at NTNU funded by the Project, and one Ph.D. supported in-kind by NGI.

    Work Package 4 & 5

    WP 4 - Integrated dynamic analyses of OWT WP 5 - Model calibration and verification

    WP 6 - Re-design of OWTs and estimates of cost saving

    This WP will investigate possible cost savings from design using improved integrated analyses including soil interaction models compared to the traditional methods.

  • For inquiries related to REDWIN models and results from the REDWIN project, please send an e-mail to redwinmodels@ngi.no.

    Report

    Publications

    Presentations

    REDWIN final workshop 8 November 2018 at SALT (www.salted.no), Oslo

    Webinar

     

Portrait of Ana Page

Ana Page

Head of Section Advanced Modelling ana.page@ngi.no
 +47 406 98 328

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