In June 2010, according to WWEA's statistics, China's new installed capacity and total installed capacity have leapt to the world's largest wind power. When overseas countries are pleasantly surprised by the rapid development achieved in China, and the people are worried about the lack of core technologies in the development process, the EU has been discussing more about how to better develop offshore wind power. In today's ever-changing new energy technology revolution, we must attach great importance to the next important wind power technology field - offshore wind power.

Development Status of Offshore Wind Power in the World With the experience of land wind power development and the exploration of offshore wind energy utilization, the development of offshore wind power in the world has developed rapidly in recent years. According to statistics, the cumulative installed capacity of offshore wind power in the world reached 2,110 MW in 2009, an increase of 48.5% over 2008, accounting for 1.2% of the total installed capacity of wind power in the world. In 2009, the newly installed capacity of offshore wind power in the world reached 689MW, an increase of over 100% over the same period of last year. The EU is the region with the fastest development of offshore wind power and the most advanced technology. It has 90% of the installed capacity of offshore wind power and 80% of offshore wind farms under construction.

Compared with the relatively mature technology in the land wind power market, the development of offshore wind farms has not yet been scaled up and is largely constrained by the site environment and technical conditions. Strictly speaking, at present, offshore wind power development is essentially the development of offshore wind power projects.

The development time of offshore wind power in the EU is not more than 20 years old, but it is also the case that offshore wind power projects have gradually matured and applied in the past three years. The United Kingdom and Denmark accounted for 44% and 30% of the world's share of offshore wind power. New offshore wind projects in 2009 were concentrated in the United Kingdom (283,000 kW), Denmark (2.3 million kW), Sweden and Germany (all 30,000 kW) and Norway (2300 kW). In May 2010, Germany established a wind farm with an installed capacity of 60,000 kW and an offshore line of 50 km, becoming the first deep-sea wind power development country.

Offshore wind turbines are basically based on offshore wind conditions and operating conditions to improve land-based aircraft models. Their design and operational specifications are based on land wind turbines. According to the particularity of offshore wind power projects, the design of offshore wind turbines places greater emphasis on reliability and focuses on improving the utilization of wind turbines and reducing the maintenance rate.

In addition, the main differences between offshore and onshore wind power development are wind turbine basic design and large-capacity fan manufacturing. In order to withstand strong wind loads, seawater corrosion, and wave impacts at sea, the foundation of offshore wind turbines is far more complicated than land, with high technical difficulties and high construction costs. Offshore wind turbines tend to be large-scale. Offshore wind turbines produced by major foreign wind turbine manufacturers are mainly concentrated in the range of 2 to 5 MW, and fan blades diameter is 72 to 126 meters.

Offshore wind power projects are often dominated by companies with experience in manufacturing and operating wind turbines because of their high technical difficulty and high investment scale. Currently, wind turbine manufacturers with experience in commercial development only have Vestas in Denmark and Siemens in Germany. . In order to avoid risks, project developers and owners more use project certification to control quality and standard management. It can be said that offshore wind power certification is a necessary part of offshore wind power development.

China began trialing offshore wind power projects in 2009. Shanghai Donghai Wind Power Co., Ltd. invested 3 billion yuan to build a 100,000-kilowatt Donghai Bridge offshore wind farm and installed 34 Huarui 3MW wind turbines. It is estimated that the annual grid-connected electricity will be 250 million kilowatt-hours. As early as in the “Eleventh Five-Year Plan” for renewable energy development, China has already deployed offshore wind power R&D and pilot projects, and it is expected that offshore wind power management policies and bidding projects will gradually deepen in the next five years.

Offshore wind certification standards In order to promote and standardize offshore wind power development, some foreign technology research institutes have established standards for offshore wind turbines, either spontaneously or with government funding, and third-party agencies have conducted tests and certifications on wind turbines, foundations, and environment in accordance with standards, and have increased Wind power project development reliability and expected risk capabilities. Certification management has become a common practice for offshore wind developers to evaluate projects and control risks. The strong wind power countries with strong technological capabilities, such as Denmark and Germany, have already imposed mandatory certification on their offshore wind projects.

Denmark started offshore wind farm construction in 1991. It is a country that formulated wind power standards and enforced certification earlier. It has accumulated more wind power technologies and development experience. The Danish government formulated the plan for wind power development very early and established a strict certification system, which guarantees the development of large-capacity fans. Denmark's certification standard is "Danish model license and wind turbine certification technical specifications", Denmark's energy authority is responsible for supervising its implementation, Denmark's national laboratory as its information support and R & D center.

The German classification society (GL) has published standards for certification of offshore wind turbines since 1995 and has since gained considerable experience through the design, certification and operation of offshore wind farms. The latest edition of the "GL Offshore Wind Turbine Certification Guide (2005)", It can be used for the design, evaluation and certification of wind turbines and wind farms, covering both wind turbine type certification and electric field project certification. It is worth mentioning that this guide focuses on the design and manufacture of wind turbines, covering everything from the scope of certification to the entire range of loads, materials, structures, machinery, rotary blades, electrical, safety and environmental monitoring systems, not at sea. Environmental and basic design guidance, and therefore more applicable to wind power equipment suppliers.

The International Electrotechnical Commission (IEC) announced in 2009 the latest “Design Requirements for Offshore Wind Turbines”, IEC 61400-3, which details the basic design requirements to ensure the integrity of offshore wind turbines in order to provide an appropriate level of protection. To avoid any damage that the wind turbine may encounter during its design life.

In IEC 61400-3, load assumptions and safety level determination are highlighted, where detailed information on site assessment and load assumptions can be found, but on materials, structures, mechanical components and systems (safety systems, electrical systems), etc. There is no or simply a reference to the content.

IEC 61400-3 should be used in conjunction with appropriate IEC/ISO standards. It is particularly pointed out that this standard is basically consistent with the requirements in IEC 61400-1, but it is not completely copied, and IEC 61400-1 is a globally recognized standard for fan safety.

Although our country has just started in the development of the sea, domestic experts and scholars have drawn lessons from the experience of China's onshore wind power development and foreign offshore wind power standards, and completed the formulation of offshore wind turbine standards. In 2009, China Classification Society (CCS) formulated the "Offshore Wind Turbine Specifications", which covers the whole process of environment and load, material manufacturing, structure, electrical system, installation and commissioning, monitoring and maintenance. The standard has passed the review of experts and is expected to be announced in 2011. The standard will further standardize the development of offshore wind power equipment manufacturing enterprises in China, improve the safety and reliability of offshore wind power projects, and provide reference for domestic certification work.

NV's offshore wind certification management has a huge investment in offshore wind power development and is more risky than land-based wind farms. Therefore, effective measures must be taken to manage risks. In order to protect the interests of investors and control project risks, owners, investors and insurers seek technical certification through the search for experienced intermediaries to assess whether a wind farm can successfully operate within its useful life. DNV relies on the practice of exploration and certification management of offshore wind power development to form a relatively complete reference for technical certification and risk management system.

DNV is a third party engaged in offshore wind power certification earlier and has representativeness and influence in the field of international offshore wind power certification. It has independently developed DNV-OS-J101: Design Standard for Offshore Wind Turbine Structures (2007). Since 1991, it has provided certification services for more than 40 offshore wind farms around the world, such as London Array (1 GW), Greater Gabbard (500 MW), Thanet Offshore Wind Farm (300 MW) offshore wind projects and Denmark Horns Rev ( 369 MW) offshore wind power project.

DNV mainly provides project certification for wind farm development of wind turbines, type certification of wind turbine manufacturing, risk management of offshore wind power projects, and risk management of project safety, health and environmental risk (SHE), etc., in offshore wind certification. service.

Project Certification System: The core of the DNV project certification system consists of six stages. Each stage represents the period from the design basis verification to the online inspection. The DNV project certification is based on a step-by-step approach and reduces the total project risk through the following major steps: the first phase, which considers the design basis for external conditions; the second phase, the detailed design; the third phase, manufacturing; and the fourth phase, Installation; Stage V, commissioning; Stage VI, online.

In addition to services, DNV also offers zero-phase (feasibility study phase) activities. A zero-phase feasibility study may include one or more of the following services: conceptual design verification, validation of field status through measurement plans, investigation of wind energy fields, verification of environmental impact assessment (EIA), and review of permits and effectiveness.

Project certification process: Phases 1 and 2 include the final design verification steps, and detailed on-site audits of the integrated structural system with wind turbines, foundation and soil, and site-specific environmental conditions. This verification will be carried out according to the DNV Offshore Standard DNV-OS-J101 Design Standard for Offshore Wind Turbines (2007) or similar standards required by the customer. In addition to the review of the Phase 1 and Phase 2 design documents, the certification body must also conduct an independent analysis of key details. The independent analysis tools commonly used by DNV are commercial finite element software and aeroelastic deformation specifications. Structural design verification may also include fan foundations and other structures such as offshore substations.

The third to fifth phases involve all the follow-up verification and on-site inspections related to project implementation. It includes the manufacture of support structures, substations and fans, and their commissioning.

In the sixth phase, the online phase means a periodic inspection of fans, supporting structures, substations, J-type fittings, and cables throughout the entire service life and until it is abandoned. In order to verify whether the actual conditions of the wind farm meet the required standards, DNV has adopted a regular inspection system to collect, analyze and diagnose the operational status of wind power projects.

After each phase of the project task is completed, DNV issues a certificate of conformity with the actual requirements to the owner. After the completion of the first phase to the fifth phase of the task, it is necessary to obtain the DNV certificate. The project certificate is valid from the commissioning of the offshore wind farm. For the sixth phase, the validity of the project certificate is based on the results of annual inspections and inspections.

Recommendations for offshore wind certification in China First, with reference to overseas development experience and offshore wind power in China, at this stage, our government and scientific research institutions should conduct targeted assessments of wind resources, hydrology, and meteorological resources in the offshore and deep seas of China. Impact of Wind Power Project on Marine Ecological Environment. According to the characteristics of China's coastal areas, develop a phased, sustainable development strategy. Offshore wind circuit lines should be different from the scale and speed of wind power development on the road.

Secondly, a project data acquisition system represented by pilot projects such as the East China Sea Bridge was established to collect the parameters of on-line wind turbine operation, analyze the conformity of the actual indicators and design requirements of the wind turbines, and monitor the electric field generating capacity and on-grid electricity, etc., which are the standards for offshore wind power in China. Perfection and project redevelopment, providing basic data and reference cases. Considering that the owners of the pilot projects are mainly governments, the system should be responsible and guided by the government, and it should be executed by the public institutions or commissioned by professional companies.

In addition, the research and development of offshore wind power foundation and platform design standards will be started early. One important difference between offshore wind power and land wind power is that the foundation of wind turbines is different. The cost of the basic projects of offshore wind power projects accounts for about one-third of the total wind power project construction costs. Foreign countries attach particular importance to the basic research of offshore wind power, and usually use wind turbines and foundations. Think as a whole structure. With the maturity and cost reduction of land-based wind turbine technology, the design and construction of foundation projects will inevitably become the key to offshore wind power development.

Finally, explore offshore wind certification models that subdivide security levels. By studying the standards of IEC, GL and DNV, we have found that the concept of “safety level” is proposed in these standards. A reasonable level of security will have important and long-term significance for project development. Maritime certification should implement a more detailed level of security. Different levels of security and design requirements are applied to different projects to ensure that the structure is sufficiently safe to withstand potential or sudden shocks. Offshore wind power in China can explore project certification models that subdivide safety levels based on the requirements of owners and environmental requirements.

After the extraordinary rapid development of land wind power during the “11th Five-Year Plan” period, China needs to treat the future development of offshore wind power with a more rational attitude. In addition to drawing on existing technical data from abroad, more basic data, design methods, and operational experience require China’s project developers and equipment suppliers to continue to accumulate. Forward-looking regulators should realize that when the company's independently-innovated Clippers are fitted with certification management rudder, China's wind power Clippers can really sail.