Description
The aim of this Project is to develop the conceptual engineering, including laboratory tests of a small-scale prototype and the conceptual design certification, of an offshore wind floating platform which will contribute to bringing down the current costs of offshore wind energy as well as increasing its deployment. The concept developed by Cobra involves the use of an active semi-submersible concrete structure to counteract the tilting moments generated by the wind and, depending on local site conditions, it could be deployed in water depths above 30-40m. Moreover, the concept offers great flexibility in the construction process, maximizes onshore works (by assembling the Wind Turbine Generator WTG on the platform in the port) and allows performing transport and installation operations by means of simple tug boats. Det Norske Veritas DNV will take part in the project as a partner in charge of carrying out the supervision and certification of the conceptual design.
Summary of project results
Conceptual & Basic engineering has been performed during 2014-2015 and currently the design is undergoing a conceptual certification by DNV-GL. The main tasks performed during this period are the followings: -Conceptual Design -Optimization Design -Seakeeping -Intact Stability -Damage Stability -Towing -Mooring Systems -Structural Analysis -Construction Process -Tank Testing of a Small-scale Prototype
Summary of bilateral results
One of the goals of the Project was to certify the technology developed by Cobra making sure that it met all the requirements set in DNV’s standards in order to reduce as much as possible the risk of this new technology and also contribute to make it bankable. DNV, by the end of 2015, finally provided Cobra a feasibility statement of its technology. Cobra’s intention is to keep working together with DNV-GL during the next phase which will be a full Project Certification. Scope of work During this project Det Norske Veritas has reviewed the conceptual design of Cobra’s floating wind turbine concrete structure. The design verification review was done against DNV Offshore Standard J103 “Design of Floating Wind Turbines Structures”, Edition June 2013. This standard covers structural design of floating wind turbine structures and their station keeping systems. The standard takes transportation, installation and inspection issues into account to the extent necessary in the context of structural design. The design principles and overall requirements are defined in the standard. Wherever possible, the standard makes reference to requirements set forth in its fixed-structures counterpart, DNV-OS-J101. The Scope of Work undertaken by DNV for the Certification of the conceptual design covered the following items: 1 -Verification of Conceptual Design Basis 1 1.-Site Conditions 1.2 -Interface Loads & Requirements from Wind Turbine Manufacturer 1.3 -Conceptual Design Basis Evaluation 2 -Verification of Conceptual Design 2.1 Conceptual Design Documentation Review