Long experience offshore ensures key role for certifiersTaken from: Offshore Wind Journal June 2012
Classification societies have been ensuring that the oil and gas sector and other parts of the energy business operate in compliance with standards and have also been helping to reduce risk for decades so it is no surprise that they are gearing up to play an ever greater role in the renewables market.
As Steve Gilkes, who was appointed global wind turbine leader at Lloyd’s Register earlier this year, told OWJ, as offshore windfarms move into deeper waters, so the need for the kind of services provided by class is growing.
“With this growth come the complexities of developing new types of safer, more reliable wind turbine technologies. At the same time, the technical assurance needs of companies operating in the wind power generation sector are increasing,” Mr Gilkes told OWJ.
“A lot of new players are coming into the market, including large utilities, some of whom have experience in the offshore market, some of whom don’t,” said Mr Gilkes. “Those that have experience offshore are looking at new ways to do things and are questioning existing practices. Some have large engineering organisations internally, others don’t, but all of them can benefit from the kind of services class offers.
“They don’t have to use a third party to demonstrate compliance with standards, of course. Many conduct their own risk assessments, but it makes sense to use an independent third party, especially if you want to enhance the technical and financial bankability of a project. In the short time that I have been here, I have found that the effect of having Lloyd’s Register involved in a project is remarkable in terms of the level of confidence that it can bring. People like to have Lloyd’s Register on board.”
As Mr Gilkes noted, Lloyd’s Register has a huge amount of experience in the offshore oil and gas market. There are, he said, many similarities between offshore oil and gas and offshore renewables projects. “It’s all about industry’s attitude to risk, and the technical knowhow that a classification society can bring to a project,” he explained.
With Round 3 and Round 2 extension projects moving into the implementation phase, Mr Gilkes highlighted the role of Lloyd’s Register’s risk consultancy Scandpower, and the growing role that Scandpower is playing in the renewables market.
Scandpower has been assigned the task of developing the risk management services within the Lloyd’s Register group. As part of the development of its service offering it can also draw on the expertise in Human Engineering Ltd, a specialist in human factors with some 60 employees that recently became part of Scandpower.
Scandpower has more than 350 risk management staff, in addition to several hundred risk practitioners embedded in the Lloyd’s Register organisation. During the last 12 months it has carried out a number of joint projects for clients in the oil and gas, nuclear, renewable energy, marine and transport industries. Among the projects it has been appointed to carry out in the offshore wind sector, Scandpower is providing risk management services to the Statoil-Stakraft joint venture company, Scira Offshore Energy Limited, for Sheringham Shoal. This work has included performing several risk and hazard analyses, such as quantitative risk analysis and hazard identification (HAZID and HAZOP), concentrating on marine operations in particular. Scandpower also acted as HSE engineer to assist the subcontractor, Master Marine, in building one of the service vessels to be used for installation purposes. Mr Gilkes said that the project presented numerous health and safety challenges, including getting 88 monopiles in place, which required a firm focus on the safety of marine operations.
Another well-known class society, Det Norske Veritas (DNV), is also experiencing strong growth in the offshore wind sector and is expanding its ability to offer the kind of certification services that are necessary to keep up with global demand for type approval from turbine manufacturers, in addition to offshore wind project certification in Europe and elsewhere.
In 2011, DNV issued updated service specifications describing principles and procedures for delivering type and project certification; published an update to its standard for design of offshore wind turbines; and issued an industry first recommended practice for the use of remote sensing for wind energy assessments.
DNV notes that going through the certification process for a wind turbine or windfarm ensures that it adheres to required or expected industry standards, and reduces risk during the lifecycle of the project. However, says DNV, echoing Mr Gilkes’ comments, in a market with scarce technical resources and strong growth it is important for participants in the certification process to understand the mechanisms of the process and how to interpret the regulatory requirements, in order to save time and money.
Like Mr Gilkes, Lars Samuelsson, manager, energy development at classification society ABS, believes that classification societies’ long experience in the offshore oil and gas sector is eminently transferable to the offshore wind sector. “After all, we have been dealing with structures for the offshore industry for more than 60 years,” Mr Samuelsson told OWJ.
Offshore wind may still be in the early stages of development in the US, but ABS’s international experience in the offshore wind market is significant – ABS group was selected to perform inspections of 49 offshore foundations for RWE Innogy’s Nordsee Ost offshore windfarm off the German coast, and will inspect the welding and assembly processes for the foundations and check for compliance with the manufacturer’s design documentation according to the specifications. In addition, inspection of transition pieces, pile clusters, lattice steelwork and interface flanges will also be conducted. Speaking at the time that the contract was announced, Torsten Muuss, director renewable energy for ABS Group Ltd, said the group’s offshore experience “has proven the importance of monitoring, especially foundations, as inspection is difficult and costly after the wind turbine has been erected”.
ABS also recently completed the technical review and survey of the first offshore wind turbine operating in open Atlantic waters. After being towed 350km off the coast of Aguçadoura, Portugal, Principle Power’s WindFloat prototype demonstration unit is the first example of the deployment of a semi-submersible structure supporting a multi-megawatt wind turbine. ABS design review engineers in Houston and ABS surveyors on site at the Lisnave shipyard in Portugal worked together during the design, fabrication and installation phases of the project.
Recent months have also seen ABS complete a report on design standards for offshore windfarms for the US government’s Bureau of Safety and Environmental Enforcement (BSEE). The study focused on the governing load cases and load effects of bottom-founded offshore wind turbines subjected to hurricanes on the US outer continental shelf. Existing methods of calculating the breaking wave slamming load exerted on an offshore wind turbine support structure were also evaluated, and recommendations were made to support future enhancement to the relevant design criteria for offshore wind turbines.
ABS is also participating in a number of research and development projects awarded by the US Department of Energy. The aim is to develop simulation methods and software for the next generation of offshore wind turbines.
The first study, ‘Bottom Fixed Platform Dynamics Models Assessing Surface Ice Interactions for Transitional Depth Structures in the Great Lakes,’ led by the University of Michigan, will examine the interaction of freshwater ice loads with offshore wind structures in the environmental conditions of the Great Lakes to develop a simulation tool. ABS will support development of the ice-load models and provide assistance in applying its Guide for Building and Classing Offshore Wind Turbine Installations.
The second study, ‘Subsurface Mooring and Anchoring Dynamic Models,’ led by Texas A&M University, will draw upon more than 40 years of mooring systems experience from the oil and gas industry to develop a robust and efficient mooring dynamics program that can be interfaced with an existing dynamic analysis program for floating offshore wind turbines. ABS will participate in the development of the mooring dynamics programs and anchor database.
At the 2012 Offshore Technology Conference in Houston in April, representatives of ABS presented a paper looking at design load cases for wind turbines in hurricane-prone regions. The influence of extreme weather such as hurricanes and cyclones on wind turbine design is also being studied at Germanischer Lloyd (GL) group.
As representatives of GL Renewables Certification (GL RC) explained in a presentation at the European Wind Energy Association (EWEA) conference in Copenhagen in April, as wind energy production expands around the world, an increasing number of offshore windfarms are being proposed in cyclone-affected areas, such as in China, Korea and Japan. A properly designed windfarm should be able to withstand the tropical storms that are likely to affect it during its lifetime, said Andreas Schroeter, managing director of GL RC. Together with Mike Woebbeking, vice president of GL RC, Mr Schroeter addressed the question of how extreme weather events might influence wind turbine design. Together, they have been examining how the understanding of cyclone/hurricane loading-related issues in the wind industry can be improved and how wind turbine design methods and standards might need to evolve to ensure robust operation in tropical storms.
“The lack of clear guidance for categorising the risk a site faces of being hit by a tropical storm and the extreme variability with which such storms affect windfarm structures, means that developers are left with the uncertainties as to the fitness of their developments to deal with extreme weather conditions,” they explained.
“There are a number of factors to consider,” said Mr Woebbeking. “For example, the category of the cyclone faced, assessment of the site and climate forecasts, predicting wind speeds at their extremes, the ultimate load on the turbine, and turbulence wind conditions in tropical storms.” In due course, GL RC is planning to develop guidelines for wind turbines in tropical storms. This guidance will be a supplement to GL RC’s guidelines for the certification of wind turbines.
Bureau Veritas, another well-known classification society, is also beginning to develop services for the offshore wind sector. In 2012, it issued guidelines for the classification and certification of floating offshore wind turbines. Noting what it called the growing demand for offshore wind turbines which can be safely installed in deepwater, Bureau Veritas noted that the structures involved will use one or more types of floating platform to mount the turbine and that the lifetime of the units was comparable to offshore oil and gas projects.
“Operators and authorities need to know these platforms are safe and will be up to the job. Although this is a new way of generating energy out at sea, it builds on proven technology and experience in offshore energy,” said Bureau Veritas, noting that its guidelines bring together its experience with and rules for offshore floating units and moorings, and marries them with the internationally accepted standards for wind turbines.