Key takeaways:
DNV released 2 new standards covering structural float components and mooring systems for floating PV projects
The standards provide guidance on material selection, safety factors, corrosion protection, design loads, and stability assessment
DNV-RP-0584 continues to serve as a guideline for the installation, operation, maintenance, and decommissioning of FPV systems in sheltered water bodies
Land is one of the major contributors to the balance-of-systems (BoS) costs of utility-scale PV installations, with 1 MW of capacity requiring around 4-5 acres of land. One way to reduce the burden on agricultural land is floating PV (FPV).
FPV installations on water bodies must meet certain technical standards for materials, design, safety, and testing.
Det Norske Veritas (DNV), a Norway-based company, recently published 2 new standards for FPV systems. The first one, DNV-ST-C108, outlines the technical requirements and provides guidance for the design and testing of structural float components used in FPV. It includes the selection of appropriate safety and consequence categories, qualified materials, and appropriate safety factors for metallic and non-metallic materials. It also covers the minimum content for the design basis, identification, and testing of failure mechanisms for non-metallic materials. Finally, the standard also provides requirements for the design of structural parts and coatings or corrosion protection systems.
The second standard, DNV-ST-E309, provides principles, methods, requirements, and recommendations for the design of mooring equipment used for FPV projects. A mooring system consists of anchors, chains, cables, or connectors that keep the FPV platform in place and prevent it from drifting or twisting in the wind or water currents. The standard covers how design loads and load combinations should be derived, as well as the analysis procedures for evaluating the reliability and stability of the mooring system.
Neither of these standards addresses the installation, inspection, maintenance, operation, or decommissioning. A recommended practice (RP), DNV-RP-0584, released in 2021, provides a comprehensive set of recommendations and guidelines from installation to decommissioning of FPV systems. This RP, however, is intended for water bodies sheltered inland and near-shore water bodies that are located close to a shoreline, with a maximum wave height of 3 m. Harsher conditions than these will be out of scope for this RP.
With floating PV deployment increasing globally, dedicated standards for structural integrity and mooring design are becoming important to support reliable and safe system installation on water bodies.