Offshore+turbine+blades+require+increased+reliability+focus

As offshore wind turbine blades are getting larger, new methods to assess the integrity and remaining life time of the blades are needed. DNV has initiated a research and innovation project, and an associated Joint Industry Project (JIP), to develop best practices for composite blade integrity assessment, tailored to the needs of wind turbines operating in areas with extreme weather conditions. The industry consortium partners consist of Vestas, Energy Research Institute @ Nanyang Technological University and Instron.

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Bjørn Tore Markussen
Bjorn Tore Markussen, Managing Director of DNV’s Clean Technology Centre (CTC) in Singapore

The increasing length of offshore wind turbine blades has prompted the use of advanced composite materials, with positive operational experiences so far, but with a limited range of supporting analysis and testing methods that can be directly applied to large scale wind turbines. DNV initiated the innovation project to develop improved integrity assessment procedures for large scale offshore wind turbines in January 2011 and has joined the JIP industry consortium focusing on advanced composites for wind turbines. Leveraging the experience of Instron in bi-axial testing of composites with various flaws introduced, the expertise of DNV together with ERI@N in finite element analysis, and the knowledge of Vestas in this industry, the project aims to provide insight into composite failure in wind turbine blades. From this, DNV will develop integrity management procedures for advanced composite wind turbine blades.

“As a natural consequence of the ambitious plans and targets set for renewable energy in many countries, we are seeing increasing projections on the amount of wind power being fed into the grid”, says Managing Director, Bjorn Tore Markussen of DNV’s Clean Technology Centre (CTC) in Singapore. “The increased expectations for wind power generation have led to growth in wind turbine size, particularly in offshore wind. The technical and potential quality issues faced in such a rapid growth phase can be overcome by cross-industry collaboration to develop best practices, such as this project”.

Most offshore wind projects face the possibility of extreme weather conditions. This complicates key technical and operational issues such as material selection and blade manufacturing quality as well as the assessment of the remaining life of blades that have sustained damage due to extreme loading. The integrity management procedures developed by the DNV innovation project will utilize results from the Joint Industry Project to assess the integrity of advanced composite offshore wind turbine blades. The goal is to enable more accurate predictions of the remaining life of wind turbine blades however tough the environment.

Professor Subodh Mhaisalkar, Executive Director of ERI@N added, “In the first phase of this JIP, the research is addressing development of bi-axial testing methods and finite element analysis procedures that will enable development of test data for deriving and verifying models for flaw growth in the composites. This is required for remaining life predictions with regard to pre-existing manufacturing flaws or service induced damage. This project could be an important contribution to the wind industry, as the project can be extended to develop future standards, guidelines and procedures on the matter.”

“Vestas agrees that more work and data in this area would be valuable in helping the industry to develop better and more reliable products,” says Mr Peter Cheng, Vestas Vice President for Asia Innovation

“We are confident that this development of a set of integrity management procedures will benefit companies moving into the evolving offshore wind industry” says Mr. Markussen. “We therefore invite new participants from across the offshore wind industry to join the potential next phase of this Joint Industry Project.”


Dato: 13. januar 2012

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About DNV in the Wind industry

We have been a global leader in the wind industry for over 25 years and DNV is the largest wind energy consultancy in the U.S. as well as one of the world’s largest combined consultancies and certification bodies. More than 250 DNV colleagues are employed directly in delivering wind energy expertise while many more contribute from our other business areas such as maritime and energy.

Our wind energy offices are located in Denmark, UK, Germany, Norway, U.S., China, South Korea, Singapore, Brazil, and India. DNV offers a broad range of advisory services that support the wind industry in its critical technical and financial decision making. These include initial site selection, wind resource assessment and energy analysis to power performance testing, technical due diligence for investors and operational risk management.

DNV also provides third party type certification of onshore and offshore turbines, as well as certification of offshore wind farms. This helps to minimize late design changes and secures the confidence of manufacturers, developers, owners, financiers, insurers and the relevant authorities. Since 2001, DNV has worked in close cooperation with the wind industry to develop the state of the art knowledge that ensures transparent, cost efficient and unified approaches to building wind energy technology. This knowledge is published in our standards, rules, guidelines and recommended practices.

We are also leading international efforts to standardize design practices through active participation in the IEC and other standards bodies. Building on our role as the world’s leading classification society, DNV has supported the development of all types of installation and service vessels. This included the development of the world’s first class notations for these vessels to improve safety and promote uniform standards.

DNV in Asia
With its network of 2,000 employees in 80 offices in Middle East and Asia, DNV has the infrastructure, resources and contacts to grow further and help its customers to manage their risks in a holistic manner.
As one of the world’s leading risk management and sustainability service providers with over 40 years presence in Singapore, DNV opened in March 2010 its Clean Technology Centre to meet the growing demand for Risk Management services in South East Asia within the segments of Green Shipping, LNG & CCS as well as Power/Transmission and Renewables.

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