A feasibility study carried out by a team of welding engineers at TWI on behalf of Offshore Group Newcastle (OGN) has examined the potential for volume assembly of a new wind turbine jacket. As a result of the study, which focused on the applicability of automated and robotic welding for the new jacket design, OGN will shortly begin assembly trials using full-scale replica parts, with a view to establishing a specialised manufacturing facility at its Wallsend yard.
OGN currently makes large process modules and jackets for the offshore oil and gas industry at its waterside yard in Wallsend. In investigating opportunities for expanding production for offshore wind applications, the company accessed the government-funded Offshore Wind Technology Transfer project, which is providing free consultancy and advice from welding and engineering experts at TWI for companies seeking to move into the field. As a result, OGN was able to work with TWI to assess welding and fit-up options for high-volume manufacture of node connections in its new design of tripod jacket.
The fabrication volumes required by OGN dictated that automated and/or robotic welding should be used as far as possible. The project team at TWI agreed that a standardised design of jacket would allow this, making sure that stub-to-can or node connections were minimised.
The team looked at methods of manufacture, first conducting a high level review of robotic welding of the connections, considering gas shielded flux cored arc welding (FCAW) and gas shielded metal active gas (MAG) welding processes, and consumable types and compositions. It then turned its attention to the fabrication assembly/welding sequence, the type and size of robot and the optimum grouping of robots and robot stations. Specific welding focuses included weld metal volume, process deposition rate, welding time, and joint completion time in relation to each node weld and the time taken to complete an assembly.
This first stage of work is now complete, and has presented OGN with a clear approach and detailed set of procedures to progress its plans to introduce jacket manufacture for offshore applications. The next stage will be to develop a prototype robotic welding station and full-scale node section replica parts for comprehensive trials. OGN will also consider the use of electron beam welded prefabricated sections of nodes for simple incorporation. The new venture is expected to result in a number of new jobs at OGN's Wallsend fabrication yard.
This feasibility study was carried out by TWI as part of the Regional Growth Fund's Offshore Wind Technology Transfer project, managed by the National Renewable Energy Centre (Narec).
National Renewable Energy Centre (Narec)
Narec has invested over £150 million of UK Government, private sector and European Union funding to create a unique integrated portfolio of research, testing and demonstration facilities for the offshore renewables industry, operated on an open-access, commercial basis in Blyth, Northumberland, England.
For more information visit: www.narec.co.uk
Offshore Wind Technology Transfer Project
TWI has been enabling the provision of free technical support and consultancy in offshore technology transfer on behalf of the Offshore Wind Technology Transfer Project - presenting a valuable opportunity for UK companies to access a unique and independent combination of materials, fabrication and inspection expertise gained through practical experience, and an unparalleled record of working in specialist areas including fatigue assessment of welded and bolted structures and wind-turbine towers.
From advanced, high productivity fabrication technology and the specification of corrosion protection standards, to structural integrity assessment and failure investigation, TWI has given participants support and advice on welding procedures and fabrication standards. Its specialists have also helped to troubleshoot production and quality problems, explore more effective technologies and processes, define requirements for training and development of new skills, increase the effectiveness of supply chains and accelerate innovation to bring new products to market.