Structural Integrity of Offshore Wind Turbines: Oversight of Design, Fabrication, and Installation - Special Report 305 (2011)

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7 Summary of Key Findings and Recommendations The charge of this committee was to review the proposed approach of the Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEMRE) in overseeing the structural safety of offshore wind turbines. It was to consider the design, fabrication, and installation of these turbines. Specifically, the committee was charged with providing findings in three areas: standards and practices, the role of certified verification agents (CVAs), and the qualifications needed by CVAs. Specific findings and rec- ommendations in these areas are given at the ends of Chapters 3, 4, 5, and 6 of this report. Those chapters should be consulted for details. The sections below summarize the committee’s key findings and recommendations. During its review, the committee noted that the U.S. government, hav- ing committed to exploiting the offshore wind energy resource, has an interest in industry performance for reasons beyond its statutory mandate to ensure the safe, orderly, and environmentally responsible use of the outer continental shelf (OCS). For policy reasons, it also wants to foster the growth of the nascent U.S. offshore wind industry (see the Chapter 4 section “Regulatory Options and Policy Considerations”), which will require setting clear regulatory expectations soon and encouraging the innovation that will help make offshore wind power generation more eco- nomically competitive with other sources of electricity. FINDING: SAFETY AND THE ENVIRONMENT The risks to life safety and the environment and the consequences associ- ated with those risks are much lower for offshore wind plants than for off- shore oil and gas platforms, ships, and land-based civil structures such as buildings. Oversight of offshore wind development should take this into 127 

128 Structural Integrity of Offshore Wind Turbines account but will also need to reflect the importance of successful and reli- able operation of offshore wind turbines to policy goals. FINDINGS AND RECOMMENDATIONS: STANDARDS AND PRACTICES (TASK I) The committee was tasked with reviewing the applicability and adequacy of existing standards and practices for the design, fabrication, and instal- lation of offshore wind turbines. In response to this charge, the commit- tee reviewed the standards and guidance documents (the latter including guidelines, recommended practices, and similar documents) that have been developed or are under development by nongovernmental organiza- tions, classification societies, standards-development bodies, and govern- ment entities. It also considered ways in which BOEMRE might address deficiencies in existing standards and guidance documents. Applicability and Adequacy • In reviewing existing sets of standards and guidance documents, the committee found that many could be applied in the United States but that no one set was complete. Many sets of standards and guidance documents for offshore wind turbines are available from standards organizations, classification soci- eties, and at least one government. Many, if not most, have elements that are relevant to the United States and can be applied to installations in U.S. waters. Most of these standards and guidance documents—notably, those used in continental Europe—are detailed and prescriptive. However, they are incomplete in that no one set covers all aspects of structural design, fabrication, and installation. All existing standards and guidance documents have shortcomings that will have to be overcome if they are to be applied in the United States. The following are some of the most important areas where existing standards need more work for use in the United States: – Environmental site conditions for the United States, especially storm and hurricane conditions for the Gulf of Mexico and the East Coast. These and other conditions—such as ice loading (for the Great 

Summary of Key Findings and Recommendations 129 Lakes) and seismic activity (especially on the Pacific coast)—would need to be covered appropriately. – Transparency. Methodologies for strength analysis1 differ among the standards and guidance documents and are not always fully delin- eated, making it difficult to compare the standards and guidance documents against one another to determine whether they provide equivalent safety levels, especially when applied to novel concepts. The methodologies, assumptions, and data used for strength analy- sis must be laid out clearly to provide the necessary transparency. • BOEMRE’s own regulations (published in 30 CFR 285) and accom- panying guidance are inadequate in that they do not identify spe- cific criteria that a proposed project must meet to be approved and gain the necessary permits. Although regulations2 promulgated by BOEMRE require that detailed reports for design, construction, and operation of offshore wind turbines be submitted for BOEMRE approval, they do not spec- ify standards that an offshore wind turbine must meet. Rather, a third party (CVA) is asked to comment on the adequacy of design, fabrica- tion, and installation and provide reports to BOEMRE indicating the CVA’s assessment of adequacy. Moreover, when a general level of per- formance such as “safe” is stipulated, no guidance is provided on how to assess whether this level of performance has been met. • The United States urgently needs a set of clear and specific standards to reduce uncertainty in the requirements that projects must meet, facilitate the orderly development of offshore wind energy, and sup- port the stable economic development of a nascent industry. States and private companies are developing plans for offshore wind energy projects in state waters and on the OCS. Well-defined U.S. reg- ulations for development on the OCS are needed (a) to provide a resource for states as they develop requirements for projects in state waters and (b) to supply industry with sufficient clarity and certainty on 1 Some standards and guidance documents are based on strength or limit states design; others are based on allowable stress design. The philosophies underlying these methods are fundamentally different. See Chapter 4. 2 30 CFR Part 285, 74 FR 81, pp. 19638-29871. 

130 Structural Integrity of Offshore Wind Turbines how projects will be evaluated as companies seek the necessary financ- ing. Further delays in developing an adequate national regulatory frame- work are likely to impede development of offshore wind facilities in U.S. waters. Moreover, developments in state waters could proceed in the absence of federal regulations, possibly leading to inconsistent safety and performance across projects. Filling the Gaps • Performance-based standards are a regulatory framework that best meets two government objectives: (a) fulfilling BOEMRE’s mission of overseeing the safe, orderly, and environmentally responsible devel- opment of the OCS and (b) fostering innovation and competitiveness. Improvements in the efficiency of offshore wind turbine installations and reductions in capital and operating costs are needed if offshore wind energy is to become a highly competitive renewable energy source. Performance-based (goal-based) standards, which are gradually replac- ing prescriptive standards in other industries (such as civil infrastructure, offshore oil and gas, and shipping), provide the flexibility needed to accommodate new technologies. They can be administered and modi- fied by the regulatory bodies in a straightforward way, they clarify the responsibilities of industry in meeting project goals, and they result in the transparency that comes with the delineation of goals and objectives. Recommendations To enable timely development of U.S. offshore wind energy within a robust regulatory framework, the following approach is recommended: 1. BOEMRE should proceed immediately with development of a set of goal-based standards governing the structural safety of offshore wind turbines and power platforms. These regulations should be risk- informed (see Appendix A) and should cover design, fabrication, and installation. Offshore wind energy is an emerging technology; there- fore, the standards should be crafted to allow and encourage introduc- tion of innovative solutions that improve the safety, environmental performance, reliability, and efficiency of offshore wind facilities. BOEMRE should either develop these regulations within the agency 

Summary of Key Findings and Recommendations 131 in a timely manner or facilitate development through, or with the advice of, an outside group of experts. In any case, it is essential that BOEMRE take responsibility for the process and the final product. 2. Because offshore wind projects are already under way, BOEMRE should provide industry with a well-defined regulatory framework as soon as practical. The U.S. offshore wind turbine regulations should be promul- gated no later than the end of calendar year 2011, and a specific plan for meeting that target should be established as soon as possible. 3. On request of a rule development body, BOEMRE should review the rules and guidelines proposed by that body for compliance3 with BOEMRE’s goal-based standards and identify any deficiencies. Once BOEMRE deems a set of rules to be in full compliance with the goal- based standards, it should approve such rules for application to U.S. off- shore wind facilities. Examples of rules and guidelines that could be considered are those that have been developed by Germanischer Lloyd, Det Norske Veritas, and the American Bureau of Shipping. Pre- approved rules should have the benefit of expediting the regulatory review process. However, BOEMRE should be prepared to review stan- dards and guidelines proposed by a developer and accepted by a CVA for compliance with its goal-based regulations on a case-by-case basis. 4. BOEMRE should take a leading role in promoting awareness of lessons learned in the offshore wind and offshore oil and gas industries among project developers, industry professionals, and standards development bodies. The goal is to help industry avoid mistakes that have been encountered elsewhere and to promote practices that have proved to be successful. FINDINGS AND RECOMMENDATIONS: ROLE OF THE CVA (TASK II) 1. The responsibility for proposing a comprehensive set of standards, guidelines, and recommended practices should rest with the develop- ers. The CVA’s role should be to review and comment on the adequacy 3 A set of rules is deemed compliant if meeting those rules will be taken as sufficient evidence that the performance-based goals have been met. 

132 Structural Integrity of Offshore Wind Turbines of the proposed standards and rules in meeting the objectives defined in the BOEMRE goal-based standards. Although BOEMRE should con- sider the documentation provided by the developer and the report of the CVA, the responsibility for approval of the proposed standards and guidelines and for determination of their conformance with the goal- based standards should rest solely with the agency. 2. The scope of the BOEMRE third-party review process should include the following: – Blades, – Blade controls (if reliance on active controls is required for load reduction), – Tower and structural support, – Foundation and station keeping, – Infield cables and connectors, – Other structures—structural and electrical systems, and – Export cables. The third-party review should ensure the following: Design: The design adheres to good industry practice, the basis of the design is applicable for the location and stated objectives of the project, site-specific conditions have been appropriately addressed, and the identified codes and standards are adhered to. Fabrication and manufacturing: Quality assurance/quality control processes are in place to ensure that fabrication and manufacturing comply with the design and the identified codes and standards. Installation: All transportation and field installation activities are performed in a manner ensuring that the facility meets the design intent. The third-party reviewer should provide periodic reports to BOEMRE with regard to the review findings and should note any devi- ations or concerns. 3. Type certification of a wind turbine may be substituted for portions of third-party design review if the type certificate is appropriate for site conditions [e.g., the International Electrotechnical Commission (IEC) wind class]. 4. BOEMRE should retain responsibility for final approval. It is essential that BOEMRE have staff who are competent to select qualified third parties (see Task III) and to approve projects. 

Summary of Key Findings and Recommendations 133 FINDINGS AND RECOMMENDATIONS: CVA QUALIFICATIONS (TASK III) Findings The committee’s key findings with regard to CVA qualifications, which are based on a review of the implementation of the CVA process for offshore oil and gas facilities, the proposed Code of Federal Regulations language for an offshore wind CVA, and how other engineered systems implement third-party reviews, are as follows: 1. A qualified CVA must be a. Independent and objective, with no involvement in the scope of work being reviewed (i.e., design, fabrication, or installation); b. Experienced in performing scopes of work similar to that being reviewed, with detailed knowledge of the codes and standards being applied; familiarity with the approaches proposed by the developer; and the technical expertise and engineering judgment to verify assumptions, conclusions, and results independently; and c. Directed by a registered professional engineer (or international equivalent). 2. A CVA for the design stage must have expertise in a. Identification, specification, and implementation of design limit states; b. Fatigue and strength design approaches, including the effects of coupled wind–wave dynamics; c. Determination of the adequacy of proposed design environmental condition for the site; d. Evaluation of foundation design; e. Evaluation of interaction between the foundation and the turbine system; f. Determination of the adequacy of the geotechnical assessment; and g. Performance of design calculations similar to those provided in the design reports. This is not a requirement that independent calcu- lations be performed but that the CVA be able to perform them as necessary. 3. A CVA for the fabrication stage will need expertise in a. Fabricator quality control, b. Material quality evaluation, 

134 Structural Integrity of Offshore Wind Turbines c. Welder qualifications, d. Nondestructive testing, e. Destructive testing (e.g., full-scale blade tests), and f. Blade materials and fabrication. 4. A CVA for the installation stage will need expertise in a. Evaluation of installation plans and procedures; b. Witnessing of installation operations including loadout, towing, launching, uprighting, submergence, and so forth; c. Marine operations; d. Subsea cabling activities including trenching, burial, and connections; e. Offshore construction activities; and f. Installation equipment. 5. The CVA for design, for fabrication, and for installation need not be the same organization or person, and it is unlikely that a single person would have sufficient expertise to lead an effective CVA for all phases. 6. It would be beneficial, though not essential, for a CVA to have experi- ence in third-party reviews and in interacting with regulatory agencies. 7. Given the variety of controlling environmental loads (e.g., hurricanes, seismic activity, ice loads) and installation requirements (e.g., mudslide areas, tidal erosion effects) in U.S. waters, the CVA’s experience should be related to the installation location. 8. Experience with the use of project-specific CVA approval in the offshore oil and gas CVA industry indicates that project-specific approval of CVAs is better than maintenance of a list of BOEMRE-accepted CVAs. Recommendations The committee recommends the following with regard to CVA qual- ifications: 1. In evaluating potential CVAs, BOEMRE should seek organizations and individuals that a. Are independent and objective; b. Have experience, technical expertise, and engineering judgment suf- ficient to verify assumptions, conclusions, and results independently; c. Have experience with the dominant environmental effects for the project location (e.g., earthquake-resistant design experience for offshore West Coast locations); 

Summary of Key Findings and Recommendations 135 d. Have experience in the areas described in the findings section above for the CVA tasks (i.e., design, fabrication, and installation) for which they are nominated; e. Have clearly defined roles and responsibilities with adequate oversight by a registered professional engineer (or international equivalent); and f. Have an auditable quality plan for the processes and record keep- ing involved in the CVA activities. 2. BOEMRE should hire sufficient staff with adequate technical expertise (as described in Chapter 4 in the section “Implementation: Capacity and Expertise”) to oversee the development of offshore wind farms in U.S. waters. 3. BOEMRE should approve CVAs on a project-specific basis as opposed to maintaining an approved list of qualified CVAs. 4. BOEMRE should actively manage the CVA process for offshore wind facilities by disseminating lessons learned from the CVA process to pro- mote best practices to the industry. 5. BOEMRE should actively participate in the IEC Wind Turbines Certi- fication Bodies Advisory Committee as a means of staying informed on issues relating to wind turbine certification and the accreditation of CVAs. FINDINGS AND RECOMMENDATIONS: IMPLEMENTATION • In the committee’s view, unless BOEMRE’s staffing levels and expe- rience are substantially enhanced, the agency will be unable to pro- vide the leadership and decision-making capability necessary for development of U.S. offshore wind facility standards. • It is essential that BOEMRE establish a substantial core competency within the agency with the capacity and expertise to lead the develop- ment of the goal-based standards, review the rules and guidelines submitted by the third-party rule developers, and review the qualifi- cations of proposed CVAs. The committee’s findings and recommendations on standards and practices, the role of the CVA, and the qualifications needed by a CVA call for BOEMRE to take a leadership role in developing new, goal-based 

136 Structural Integrity of Offshore Wind Turbines standards; to review sets of standards and guidance documents put for- ward by industry for preapproval, identify gaps and deficiencies, and determine whether they have been sufficiently addressed; to review the full set of standards and guidance documents submitted for specific projects; and to select CVAs who can take part in all these functions as necessary. The expertise required to carry out these tasks is substantial. More- over, the critical advisory roles that the CVA could play in these tasks could require that BOEMRE make a more detailed appraisal of CVA nominations than in the past, which also implies in-depth expertise. BOEMRE will likely be asked to apply this expertise extensively and in the near future, both because regulatory expectations need to be estab- lished soon and because several offshore wind projects are already being developed and many more will likely be entering the pipeline for review and approval. • As a means of filling the experience gap for both industry and regula- tors, BOEMRE should consider creating an expert panel to provide it with guidance and feedback for the development of goal-based standards, for the review of proposed standards and guidelines for compliance with the goal-based standards, and for the initial wind development projects. Such an expert panel could help BOEMRE in developing goal-based standards expeditiously. It could also advise BOEMRE on how CVAs can assess compliance with goal-based standards and on how the agency and industry can learn from the deficiencies and other concerns that CVAs identify in projects. Finally, for the initial offshore wind develop- ment projects, such an expert panel could help BOEMRE review the packages of Guidelines—standards, rules, industry guidelines, and rec- ommended practices—submitted for application to a particular project or submitted for preapproval for use in future projects. • BOEMRE should be fully engaged in the national and international process for developing standards for offshore wind turbines, and it should be represented on the International Electrotechnical Com- mission’s technical committees and on other relevant national and international committees.