Certification bodies play a significant role in the planning and realisation of offshore wind farms, assuming responsibility for the facilities in the process. World Wind Technology discusses the special challenges in this industry with Alexander Heitmann, head of offshore wind services at TÜV SÜD Industrie Service.

TÜV SÜD has been successfully engaged with offshore wind farms and projects for some years. How did this business area develop?

Alexander Heitmann: The company has gathered multifaceted experience and technical know-how in wind energy since the 1990s. This pioneering saw the realisation of the first large-scale onshore projects in Germany and the first wind-turbine prototypes ready for large-volume production. TÜV SÜD’s expertise dates back to this exciting era of change, when it entered this new market by offering type-testing and type-certification services for wind turbines.

TÜV SÜD has continuously expanded its portfolio of services, which now includes wind measurement, site assessment, structural analysis, geotechnical surveys, grid compatibility analysis, type and project certification.

It supports project developers, designers, turbine manufacturers and operators throughout the lifecycle of a wind farm, taking responsibility for commissioning and acceptance inspections, as well as periodic inspections.

A Hamburg location was established in 2011. This is where activities are bundled in direct proximity to the port of Hamburg, the German Maritime and Hydrographic Agency (Bundesamt für Seeschifffahrt und Hydrographie) and the offshore development areas in the North Sea and Baltic, integrating the expertise of offshore specialists, shipbuilders and inspectors. By acquiring Project Management Support Services Limited (PMSS) in 2012, TÜV SÜD significantly reinforced its wind expertise in the UK and the US. Today, it employs 160 wind professionals at 15 locations around the world.

Offshore wind energy is on the rise worldwide. On the open seas, however, this relatively new industry faces challenging environmental conditions. What is the state of play in the fields of standards, codes and regulations?

It’s not a case of ‘one answer fits all’, as regulatory approaches differ from country to country and region to region. Where standards and requirements are concerned, we must adopt a differentiated approach with respect to the individual markets. TÜV SÜD encounters both extremes: extremely strict requirements with narrowly defined processes, and relatively open procedures that offer a lot of leeway, but highly complex offshore wind projects require well-structured planning, stringent organisation, binding agreements and technical standards. There are different codes and standards throughout the world to achieve this end, but their specific details and interpretations differ greatly.

Which areas have the most catching up to do, and are most in need of improvement?

Processes in wind-turbine design and production have fully matured and largely become standardised internationally. This also applies to the structural design of turbines and substations, the design of foundations, and the relevant tests and certifications. TÜV SÜD considers the greatest need for improvement to be in relation to codes and standards that apply to entire offshore wind farms, and all their works and interfaces.

This covers design review, but also quality assurance during production, transport, erection and commissioning. Is the lifting accessory suitable for hoisting the large components? How are components transported and fixed on the installation vessel used for wind-farm erection? Are the anchorage points for fastening the lifting accessories strong enough? Can the components be transported safely through rough seas? These and other questions are frequently raised in practice, and each new offshore project will help to ensure that these practical aspects will be given more consideration during planning in the future. In the short and medium term, this will naturally also be reflected in the directives and standards, which are constantly revised and updated.

How important is the relationship between planners, manufacturers, owners and operators on the one side and the certification body on the other?

How should these stakeholders continue their cooperation throughout the wind farm’s service life?
Stakeholder cooperation is one of the key success factors for offshore projects. However, other stakeholders may tend to underestimate the role that our work plays in safe and reliable project implementation. By pointing out irregularities and errors in planning, the company runs the risk of being perceived as being obstructive. This view doesn’t do justice to the complex situation; TÜV SÜD has a completely different and very clear understanding of its activities. Its focus is on technical testing and inspections; activities are aimed at preventing future economic loss and ensuring compliance with all regulations.

Current standards and provisions are by no means carved in stone. Standardisation is more of a work in progress, and this is something of which TÜV SÜD is very aware. In practice, this means that quick and flexible solutions must be found that fit the prevailing situation and lead to successful outcomes. This applies, for example, whenever interpretations on the details of relevant provisions vary, differences in opinion exist or vulnerabilities at interfaces become obvious.

All these aspects are critical, in particularly during wind farm operation, when the reliability, availability and longevity of plants and components are key factors. While there are mandatory inspections, TÜV SÜD’s advice is to take a closer look during periodic inspections. Offshore farms have only been operated for a relatively short time throughout the world, so there is no long-term empirical data on operational events and conditions that may impact on the service life of components and parts. Assessment by third-party experts may help to identify and address weaknesses at an early stage.

This sounds as if the offshore wind sector is still facing significant challenges. Which of them do you consider the most pressing? How does choosing the right certification partner help to master these challenges?

Every offshore project involves enormous time pressure. While this is not unusual for large-scale projects, wind, waves and stormy weather may cause unnoticed damage to components that are nevertheless installed, resulting in delays to the project schedule or exorbitant costs, despite even the most well-founded planning. Certification activities are also subject to time pressure. Given this, responsiveness, flexibility, speed and commitment are aspects to look out for in a certification body.

The question of what to prioritise arises time and again at sea, where unscheduled events can play havoc with project schedules. Decisions need to be made quickly and responsibly, even in specific situations that require deviation from planning, standards or provisions. Solution-oriented targeted action plays an important role. This is best implemented by integrating the certification at an early planning stage and already anticipating the need for contingencies in the run-up to the project.

At this stage, the interfaces between the individual suppliers, manufacturers, transport and construction companies should not be neglected. This calls for a holistic approach to processes and sub-projects, which also includes maritime offshore requirements. In our experience, these are key skills for successful project realisation, and TÜV SÜD is well prepared to measure up to them.

How do you ensure that TÜV SÜD will continue to be the partner of choice for offshore wind farm projects also in the future?

All signs still point to growth. TÜV SÜD’s manpower has increased in recent years, pooling relevant expertise in wind energy, structural engineering, maritime lifting systems, welding and offshore applications in its team.

For problems beyond these fields, such as issues related to fire safety or corrosion protection systems, it is possible to call on expertise from across the TÜV SÜD Group, which has long-standing experience in large-scale industrial projects, standards and international regulations. This multidisciplinary know-how is TÜV SÜD’s USP.

Your company has been on board in many offshore wind farm projects. Which was your favourite?

Within the scope of certification of the Dutch Gemini Offshore wind farm last summer, TÜV SÜD successfully completed the design assessment of the wind farm and the certification of two substations. The wind farm is situated in the Dutch exclusive economic zone (EEZ) in the North Sea, around 85km off the Dutch coast. Design assessment covered the turbines’ support structures, a total of 150 monopiles including the transition pieces and steel towers.
Certification of the two stations comprised review of the design documentation and the geotechnical report as well as checking of the substations’ support structures and topside platforms. This was a very exciting project that raised interesting issues and demonstrated good cooperation between designers, the main contractor and Gemini, which was a key factor in the successful completion of the contracts.

What future trends or events are you looking forward to most?

TÜV SÜD’s experts will accompany the construction of the new Sandbank offshore wind farm, located around 90km off the German island of Sylt, in the North Sea. The contract was won from the project company, Sandbank Offshore Wind, for the certification of the implementation phase, involving production monitoring according to the BSH standard. TÜV SÜD will check the foundations, the wind turbines, the substations and the internal cabling for the wind farm.

It’s another important milestone for the energy transition in Germany. Beyond contributing their certification experience, TÜV SÜD’s experts will also step up their focus on the aspects of health and safety and on potential areas for cost reduction.

TÜV SÜD is a premium quality, safety, and sustainability solutions provider that specialises in testing, inspection, auditing, certification, training and knowledge services. Since 1866, we have remained committed to our founding principle of protecting people, property and the environment from technology-related risks.

Headquartered in Munich, Germany, TÜV SÜD is represented in more than 800 locations worldwide. Our dedicated team of 20,000 multi-disciplinary experts are recognised as specialists in their respective fields. By combining impartial expertise with invaluable insights, we add tangible value to businesses, consumers and the environment. Working in close partnership, we support you with a comprehensive suite of services worldwide to increase efficiency, reduce overheads and manage risk.

For more information visit www.tuv-sud.com.