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DECEMBER 2011

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ABS GROUP ACQUIREs SAFETEC NORDIC AS

Safetec is one of the leading providers of safety and reliability consultancy services in Norway and around the world.

Since 1984, Safetec has been providing risk analysis, asset management, safety management and emergency preparedness services in Norway and all over the world for a variety of customers in the oil and gas, maritime, transportation, energy and health industries, among others.

Through its main offices in Oslo, Stavenger, and Bergen, Norway, and subsidiary offices in Aberdeen and London, UK, and Kuala Lumpur, Malaysia, Safetec has successfully undertaken numerous projects in both the onshore and offshore oil and gas sectors and provided a wide range of services to engineering contractors, operators and equipment suppliers. Similarly, Safetec is well-known in the maritime industry and has a long history of providing premier risk-analysis, safety and reliability services to a host of clients including ship operators and owners, maritime authorities, oil and gas companies and others.

Specifically, Safetec provides services and expertise in the following areas:

For more information, visit: www.safetec.no


Industry News

Wind Farm Trends

windfarm

The trend towards larger projects with increased energy output has spurred demand for larger capacity turbines of the multi-megawatt class. In this respect, wind turbine rated power has increased dramatically over the past two decades, which has influenced the loads that the turbines and their components must withstand. This has proven challenging not only for manufacturers but also for project financiers, developers, owners and operators.

Indeed, many lessons have been learned by all involved parties. For example, owing to the frenzied pace of market development, turbines were at times scaled up without having been adequately tested in terms of their ability to withstand the increased loads. Today, testing periods have been extended before putting newly developed turbine designs into serial production.

On the other hand, it is essential to recognise that overall performance of a turbine is not only dependent on the design stage, but also on each stage throughout its operating life. In this context, design verification, regular monitoring and condition inspections of wind turbines are essential in order to achieve the following objectives:

i. minimise down-time while predicting and limiting potential damage locally;
ii. prevent secondary damage at other components; and
iii. appropriately schedule turbine down-time due to preventive maintenance requirements.

Carrying out regular inspections on relevant turbine parts helps ensure compliance with technical design specifications and detect quality issues and deviations from the design, required manufacturing specifications and procedures which might result in the premature breakdown of components.

To be able to offer the necessary and required services ABS Consulting has developed tailor-made services and solutions for the different Life Cycle Phases.


Service Spotlight

wind farm

Can the ABS Life Cycle Benefit your Wind Project?

Conceptual Phase

This phase of the project life cycle focuses on ensuring that projects which proceed through to initial design are indeed viable. This is accomplished by verifying that due diligence has been conducted throughout the initial assessment process, wind measurements have been undertaken in an appropriate manner and there are no legal or regulatory issues which might jeopardise further development.

Verification of Design Basis and Site Assessment

The second phase focuses on the "Site Assessment" which consists of a preliminary review of the conceptual design while evaluating the site with specific attention being paid to the wind, geotechnical and environmental conditions, to ensure that relevant guidelines and conditions are considered as well. The regulations and guidelines will be reviewed to verify that, for the site in question, the codes and standards which form the basis of the project are listed. Relevant statutory requirements - which might include safety-related issues such as embarkation and rescue or decommissioning - also need to be listed.

The design of the integrated structure comprising wind turbine, tower and foundation should be based on the site-specific conditions.

Verification of Site-Specific Design

Based on the successful verification of the Design Basis, the verification of the detailed design for the specific project site involves a more comprehensive approach and covers the verification of loads and response, the wind turbine, electrical systems, installation and commissioning procedures as well as the operation and maintenance.

The verification of loads consists of a complete documentation review followed by an independent analysis of dynamic load modelling of the complete system, including the foundation. The wind turbine will then be verified to ensure compliance of the load assumptions with the design basis.

Manufacturing Phase

For this phase, information from the previous phase is essential for verifying that the approved design requirements are implemented into the manufacturing phase such that the highest quality is maintained throughout the manufacturing process. A manufacturing survey comprising inspection and audit activities is necessary to verify that the manufacturing of the wind turbines for the specific project is carried out according to the approved design and quality specifications.

The extent of inspection and audits to be carried out should be evaluated for each individual project, wind turbine type and manufacturer in question.

Transportation and Installation Phase

The transportation and installation phase of wind turbine components is a crucial stage of a wind farm project. Monitoring and supervision during this phase are important for detecting defects before commencement of construction, especially since it may not be possible or economically justifiable to rectify defects or deviations thereafter.

Commissioning Phase

During commissioning, all systems and equipment should be checked for compliance with approved documentation and commissioning procedures. The relevant systems need to be functionally tested, as practicable and in accordance with approved procedures.

In-Service Phase

In-service inspections are considered crucial for ensuring the condition of the turbine and its operational availability throughout its service life. During the in-service phase the wind turbine, tower and foundation are regularly surveyed. A variety of inspections exist, which may take the form of periodic inspections, gearbox analyses, rotor blade inspections, coating inspections and condition monitoring.

Periodic inspections performed at regular intervals can help assure the safety of the wind turbine's operation as well as that of the public. Such inspections should not be considered a substitute for necessary maintenance of the turbine but rather as an additional measure to ensure its safe operation and to evaluate its technical condition.
It may be helpful and/or necessary to broaden the scope of a typical inspection by applying other techniques. These may include vibration measurement, analysis of gear oil, video-endoscopy of the gearbox, and inspection before the end of the warranty period. These additional procedures can enhance a more generic inspection process by creating a more detailed portrait of the turbine's condition.

Conclusion

Carrying out Life Cycle Services is critical not only to assure financially viable and operating wind turbines, but also to reduce down-time due to detectable failures. The Life Cycle Services allow for the adequate certification, verification, testing and inspection of wind turbines by using information gathered in each stage of development of the wind farm project.

These Life Cycle Services begin during the conceptual phase and continue throughout the design, manufacturing, installation, and commissioning phases and into the in-service phase, the longest period of all.

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Project Profile

swedishflag

Technical Consulting Enabled Vattenfall to Repower the Yttre Stengrund Offshore Wind Farm

ABS Consulting Renewable Energy was approached by Vattenfall Vindkraft AB - a Swedish utility - to perform a feasibility study for the repowering project of Vattenfall’s offshore wind farm Yttre Stengrund in Sweden.

This offshore wind farm was designed, installed and commissioned around 10 years ago. It consists of five NEG Micon 2 MW wind turbines with a hub height of 60 metre. The turbines are located approximately 5 km off the south east coast of Sweden in a water depth of 9 metre.
Today three of five wind turbines are in operation and Vattenfall is looking to repower all five turbines while keeping the five monopile foundations.

The intention is to reuse the monopile structures already built at the site and to investigate the possibility of using larger wind turbines on the existing foundations. If successful, this would mark the first repowering of an offshore wind farm in the world.

The assessment philosophy was divided in different phases. The history of the foundation structures should be established to identify potential areas of concern due to design limitations, structural deterioration or damages. ABS Consulting reviewed historical weather and operational information and performed surveys and inspections of the wind turbine support structures. In addition, ABS Consulting reviewed the design documentation that was considered for the project. Detailed visual inspections were undertaken for all five monopiles as well as manual UT and automated TOFD of the critical welds.

As part of the project, the ABS Consulting team analyzed the structures for ultimate and fatigue capacity, with a focus on the remaining fatigue life of the support structures using 10 years of historical meteorological data and actual load and performance data as input into the structural analysis scheme. The design study documented the current condition of the structures and helped to understand critical design aspects of using larger turbine units for the facility.

ABS Consulting's analysis showed that the original design of the Yttre Stengrund monopile foundation structures allowed for longer and more effective utilization of the wind farm.

In the next phase ABS Consulting will carry out a Preliminary Design verification and look into different wind turbine types and configurations to find the best solutions in terms of technology, power performance and life time for this site. Based on these results, a decision will be made to choose the "best fit" wind turbine-foundation configuration and ABS Consulting will do a Final Design Verification.

Finally ABS Consulting will give guidance to Vattenfall on outlining and establishing a Condition Monitoring Strategy.

Based upon the ABS Consulting evaluation, Vattenfall will be able to install even larger wind turbines on the monopile structures. Reusing the current foundations will save time and money in repowering the Yttre Stengrund offshore wind farm and will prolong the life of the wind farm.


other abs consulting NEWS

ABS Consulting leads towards consensus in permitting of U.S. wind energy structures

Dr. Rolando Vega, Technical Manager in ABS Consulting Renewable Energy Services, who leads a national joint-committee for the American Wind Energy Association (AWEA) and the American society for Civil Engineers (ASCE), achieved a major milestone with the MOU signing ceremony held on Friday, Dec. 9, 2011 in the ANSI offices in Washington D.C. Signed by executives Denise Bode, CEO of AWEA, and Pat Natale, Executive Director of ASCE, the MOU was established with the purpose to jointly develop recommended practices and in the future standards for large land-based wind turbine towers and foundations.

"Producing a roadmap that will inject our professional workforce with a consistent message of safety, risk and integrity in engineering practices is a great step forward", said Rolando Vega, "and with the release of the Recommended Practice for Compliance of Large Onshore Wind Turbine Support Structures our committee will reach a second milestone that I hope will serve as the foundation for our nation's engineers to expedite the permitting process as well as improve the wind turbine structural integrity and further reduce the cost of wind energy."


 

 

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