Torre e fundação de aerogeradores onshore e offshore: uma revisão bibliográfica abordando tipos, materiais empregados e principais características

Abstract

The production of electricity from renewable sources has become an alternative to minimize environmental problems resulting from greenhouse gas emissions. In search of solutions to this issue, kinetic energy from wind has been used as an alternative for electricity generation. With technological advancements and to meet growing demand, wind turbines have become more powerful, larger, and more efficient. As a result, towers and foundations have been subject to greater demands, playing a key role in the proper functioning of the wind turbine. Using a systematic bibliographic review, this paper addresses topics related to wind turbine towers and foundations, and the interaction between both in onshore and offshore environments. The sources consulted included databases, technical books, specialized journals, among others, comparing the advantages and disadvantages inherent to each installation environment for wind turbines. In this context, several relevant themes were covered, such as: main types of foundations and towers; structural performance of towers based on the type of material used; logistics and main challenges for transporting the towers; techniques used in the tower-foundation interaction in onshore and offshore environments; maintenance; common pathologies and the useful life of the components studied. Through data analysis, it was found that among the types of foundations commonly used in the onshore environment in Brazil, deep foundations account for 56.7% of wind turbine installations. Although there are no offshore wind farms in Brazil yet, globally, the monopile foundation (for depths less than 30 meters) was the most used in 2022 (70%), showing the challenges for sector expansion due to the complexity and costs associated with the offshore environment. The need for larger and more powerful turbines, combined with the conditions imposed by the installation environment, requires a robust design that considers the structural performance of the tower. By comparing wind towers built with different materials (reinforced concrete and steel), it was observed that reinforced concrete towers, due to their higher inertia, are less susceptible to fatigue wear and exhibit lower deflections. Regarding transportation, steel towers require complex logistics, while concrete towers can be produced on-site, helping to reduce costs in this phase. Tower maintenance must occur regularly, as it extends the tower's lifespan, minimizes repair costs, and allows for early detection of pathologies. In this context, among the pathologies that affect towers throughout their lifespan, corrosion is the most frequent, especially in offshore environments, due to the aggressive conditions. At the end of the towers' and foundations' useful life, as well as other wind turbine components, two alternatives can be considered: decommissioning or repowering. Regardless of the installation site or material used, understanding the stages involved in the design of towers and foundations is crucial for the wind turbine's performance and must therefore be considered.