Wind Energy: Maintenance, Repair and Replacement: Patent Review

Summary

Wind energy is one of the most significant and successful areas of modern energy based on renewable sources. Over the past 10 years the share of wind energy in world electricity production has increased from about 1% to 5%, while its total capacity has amounted to about 50% of all renewable energy capacities. The volume of installed capacities of wind energy in 2020 reached about 100 GW, and the cumulative volume - more than 700 GW. The three world leaders in installed wind power facilities include China, the USA, and Germany. In China in 2020, the volume of newly installed capacity was about 60% of the global.

One of most important problems of wind energy is the relatively low-capacity factor, which in real practice of wind turbines rarely exceeds 30%. As a result, huge material-intensive and expensive structures of wind turbines sit idle for a considerable time without generating electricity, reducing the investment attractiveness of the industry, hindering a decrease in selling prices for electricity and limiting the competitiveness of this industry. Ensuring the maximum capacity factor of wind turbines is hampered by objective factors in the form of local natural resources, first of all, the magnitude and range of wind speed, its stability and tendency to powerful gusts.

Also, there is a large group of subjective factors that impede the extraction of the maximum possible capacity factor. These include, for example: ineffective equipment condition monitoring, especially remote monitoring; poor-quality maintenance; untimely delivery of component parts; suboptimal organization of transportation or repair work; lack of high-performance tools for maintenance, which leads to unexpected shutdowns of wind turbines.

Solving these problems can provide additional reserves for the use of power and represents the most promising way to improve the efficiency of the wind power industry in general. A selection of inventions related to the mounting, maintenance, repair and replacement of wind turbines and published by patent offices around the globe in 2000 -2020 is provided for consideration in the present review.

Key Highlights

The review includes 7095 patents and patent applications, prepared by applicants from 28 countries and registered in 43 patent offices. The patent documents mention 1386 applicants and 1402 IPC subgroups. As of the date of compilation of the present review about 550 inventions published in 2020 were found, processed, and registered, which obviously is not the all-embracing result. It should be taken into consideration that the process of publication of new patent documents in national and generally-accessible databases take certain time, while their determination and processing are comprehensive and time-consuming procedures that could not be finished by the middle of 2021. Hence, 2020 data are often excluded from the comparative analysis and only provided as a general information.

The review contains: distribution of documents by years; by bibliographical and technological indicators; by top patent offices; by lead countries for inventive activity; analysis of non-resident participation; correlation of International Patent Classification indices; analysis of activity of the most productive applicants; shares of participation of applicants in the intellectual property registry; rating evaluation of patent documents using original methodology; analysis of major manufacturing operations and equipment. For each of the patent documents selected for the examination in the present review the characteristics of unified indicators were preliminary defined, they include: technical problems, types of inventive solutions employed, belonging to one or another technological segment. This allows the internal content for each of the indicators in the aggregate array of documents to be visualized, for instance, to define the sequence and proportional correlation of technical problems the inventive solutions disclosed in the texts aim to solve.

The review provides data relating to the patenting activity in the leading patent offices, including USPTO (US), EPO (States to the European Patent Convention), CNIPA (CN), KIPO (KR), JPO (JP), CIPO (CA), IP Australia (AU), DPMA (DE), TIPO (TW), DKPTO (DK). It contains a detailed description of the results of patenting activity for the leading applicants, including Wobben Properties GmbH, Vestas Wind Systems A/S, General Electric, Siemens Group, Wobben Aloys, Mitsubishi Heavy Industries, Ltd., Senvion Deutschland GmbH, Goldwind, Samsung Heavy Industries Co. Ltd, Vestas Offshore Wind A/S. Statistical data is presented in two comparative variants - for patents granted during the entire analytical period and for applications published during the last five years.

The chapter Major manufacturing operations and equipment provides a detailed statistical and technological analysis of patent documents related to Maintenance, repair and replacement of wind turbines was conducted for individual patent groups containing documents with similar technological attributes:

• Mounting & Maintenance of towers;
• Cranes, including hoists and other lifting mechanisms;
• Transport of blades - predominantly transport of wind turbine blades;
• Mounting & Maintenance of blades;
• Offshore transport - predominantly transport of wind turbine equipment in offshore areas;
• Offshore Mounting & Maintenance - predominantly wind turbine mounting and maintenance operations in offshore areas;
• Inspection - predominantly inspection of technical condition of wind turbines;
• Working platforms - working platforms designed for repair operations;
• Robotics - robotic devices designed for repair operations;
• Other maintenance - other repair operations and equipment.

The groups were selected on a trade-off basis, taking into consideration the technological importance of a subject, its popularity with inventors, the possibility of unambiguous interpretation of technological attributes of a group, and reasonable number of the groups. For each group general statistical indicators were calculated, including breakdown of patent documents by years and by major patent offices, and also leading applicants and statistical indicator trends were provided. IPC indices, problems of inventions, technology elements, and the list of the top groups of identical unified indicators are provided as technological indicators. The patents having the highest rating in each group and the patents representing the most extensive patent families were reviewed. Identification numbers of patent documents representing the groups are provided in an annex, distributed by patent offices. A portion of indicators is provided separately for patents and patent applications for the purpose of comparative analysis. The conclusion contains comparative statistical data with the evaluation of the existing trends.

This Review serves as one of the variants to monitor advanced technical achievements in the specified industrial sector. The statistical data, rating evaluations and carefully selected patent documents provided in the Review can be of interest for inventors, engineers, researchers, students and educators, as well as for businessmen and investors, who in one way or another are concerned with the problems of the development of wind energy production technologies.