Test Plan, Post Access Report: Investigation of Opportunities for Mass Reduction and Improved Integration of Wave Energy Converter Components

C-Power (2024). Test Plan, Post Access Report: Investigation of Opportunities for Mass Reduction and Improved Integration of Wave Energy Converter Components. Report by Cardinal Engineering.

@techreport{CPower-2024-,
author = {C-Power},
title = {Test Plan, Post Access Report: Investigation of Opportunities for Mass Reduction and Improved Integration of Wave Energy Converter Components},
institution = {Cardinal Engineering},
year = {2024},
month = {mar},
url = {https://teamer-us.org/report/columbia-power-technologies-investigation-of-opportunities-mass-reduction-and-improved-integration-of-wave-energy-converter-components/},
keywords = {Wave, Point Absorber, Modeling, Hydrodynamics, Performance, Structural, Cost Assessment},
}

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TY - RPRT
TI - Test Plan, Post Access Report: Investigation of Opportunities for Mass Reduction and Improved Integration of Wave Energy Converter Components
AU - C-Power
AB - C·Power is developing the SeaRAY k20 Wave Energy Converter (WEC). This design is based on the SeaRAY k2, a patented three-body device utilizing a heave plate, dual Power Take Offs (PTOs), and single point mooring. The device is currently undergoing Pre-Installation and Test and Check Out. The 20 kW k20 is significantly larger than the 2 kW device upon which it is based but is still designed to be transportable in standard International Organization for Standardization (ISO) shipping containers or racks.The heaviest single component of the k20 system is the central nacelle. Ocean conditions at deployment sites of commercial interest require a rugged, resilient structure. This has been achieved in the demonstration design with a reinforced steel structure. However, the mass of this structure challenges the limits of ISO container maximum weight.To support continued development efforts of the k20, two design challenges were investigated in this study:The definition of a certification path for a multifunctional structure that can serve as a shipping container for land transport, a barge to tow the WEC on station for deployment, and as the heave plate for the k20 after deployment. This design approach reduces the cost of deployment by allowing the use of smaller vessels, faster tow speeds, and fewer restrictions to weather suitable for safe marine operations. This concept also reduces costs by eliminating required shipping dunnage and potentially allowing for onshore connection of the heave plate to the WEC.Improved design of the WEC center member, the nacelle, by investigating alternative materials and stiffening methods. The analysis resulting from this Request for Technical Support will inform the design of a lightweight, lower manufacturing and operating cost structure that increases energy conversion.Two major conclusions can be drawn from the analysis study:There is a clear path to developing a multifunctional heave plate/barge/shipping container. Engaging with the certification organizations early in the design process to establish unique requirements is beneficial.Variations on many metallic and composite material systems can be employed to meet international standards for structural performance. In general, investigating in proper design using composite material systems will lead to reduced weight, improved WEC performance, and reduced costs. Composites provide a very attractive alternative to metallic material systems for this application. Not only does a composite nacelle provide a cost reduction in up-front capital expenditures via reduced manufacturing costs, but there is also a reduction in operational costs that could be significant. Based on an examination at the limit of design life, the replacement of the device baseline nacelle due to corrosion is estimated to be $129,000 compared to refurbishment costs of $26,000 for a Fiber Reinforced Plastic (FRP) design. When the corrosion reduction is coupled with the estimated 25% capital cost reduction and the 107% increase in Power-to-Weight ratio, the composite material system becomes the clear choice.It is recommended to continue the design and development efforts of the SeaRAY k20 nacelle and other major WEC structural components with FRP material systems. Further analysis must be conducted to ensure compliance with all relevant load cases expected by the WEC, including the Fatigue Limit State. Analyses should be further supported by physical testing following the DNV-OS-C501 Offshore Standard, COMPOSITE COMPONENTS. The specification lays out a specific plan to ensure a robust design. Subsequentially, final updates to the Finite Element Model (FEM) properties and construction should be assessed. Per the DNV specification, the manufacturer making the test pieces should be the manufacturer of the component as consistency in the manufacturing process and workmanship are vital to the success of composite structures.
DA - 2024/03//
PY - 2024
SP - 93
PB - Cardinal Engineering
UR - https://teamer-us.org/report/columbia-power-technologies-investigation-of-opportunities-mass-reduction-and-improved-integration-of-wave-energy-converter-components/
LA - English
KW - Wave
KW - Point Absorber
KW - Modeling
KW - Hydrodynamics
KW - Performance
KW - Structural
KW - Cost Assessment
ER -

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Abstract

C·Power is developing the SeaRAY k20 Wave Energy Converter (WEC). This design is based on the SeaRAY k2, a patented three-body device utilizing a heave plate, dual Power Take Offs (PTOs), and single point mooring. The device is currently undergoing Pre-Installation and Test and Check Out. The 20 kW k20 is significantly larger than the 2 kW device upon which it is based but is still designed to be transportable in standard International Organization for Standardization (ISO) shipping containers or racks.

The heaviest single component of the k20 system is the central nacelle. Ocean conditions at deployment sites of commercial interest require a rugged, resilient structure. This has been achieved in the demonstration design with a reinforced steel structure. However, the mass of this structure challenges the limits of ISO container maximum weight.

To support continued development efforts of the k20, two design challenges were investigated in this study:

The definition of a certification path for a multifunctional structure that can serve as a shipping container for land transport, a barge to tow the WEC on station for deployment, and as the heave plate for the k20 after deployment. This design approach reduces the cost of deployment by allowing the use of smaller vessels, faster tow speeds, and fewer restrictions to weather suitable for safe marine operations. This concept also reduces costs by eliminating required shipping dunnage and potentially allowing for onshore connection of the heave plate to the WEC.
Improved design of the WEC center member, the nacelle, by investigating alternative materials and stiffening methods. The analysis resulting from this Request for Technical Support will inform the design of a lightweight, lower manufacturing and operating cost structure that increases energy conversion.

Two major conclusions can be drawn from the analysis study:

There is a clear path to developing a multifunctional heave plate/barge/shipping container. Engaging with the certification organizations early in the design process to establish unique requirements is beneficial.
Variations on many metallic and composite material systems can be employed to meet international standards for structural performance. In general, investigating in proper design using composite material systems will lead to reduced weight, improved WEC performance, and reduced costs. Composites provide a very attractive alternative to metallic material systems for this application. Not only does a composite nacelle provide a cost reduction in up-front capital expenditures via reduced manufacturing costs, but there is also a reduction in operational costs that could be significant. Based on an examination at the limit of design life, the replacement of the device baseline nacelle due to corrosion is estimated to be $129,000 compared to refurbishment costs of $26,000 for a Fiber Reinforced Plastic (FRP) design. When the corrosion reduction is coupled with the estimated 25% capital cost reduction and the 107% increase in Power-to-Weight ratio, the composite material system becomes the clear choice.

It is recommended to continue the design and development efforts of the SeaRAY k20 nacelle and other major WEC structural components with FRP material systems. Further analysis must be conducted to ensure compliance with all relevant load cases expected by the WEC, including the Fatigue Limit State. Analyses should be further supported by physical testing following the DNV-OS-C501 Offshore Standard, COMPOSITE COMPONENTS. The specification lays out a specific plan to ensure a robust design. Subsequentially, final updates to the Finite Element Model (FEM) properties and construction should be assessed. Per the DNV specification, the manufacturer making the test pieces should be the manufacturer of the component as consistency in the manufacturing process and workmanship are vital to the success of composite structures.