# Maximum Safe Parameters of Outbound Loaded Vessels for Wind Turbine Installation
## 2 Offshore Wind Turbines and Vessels for Their Installation--Current Status and Development Trends  
No offshore wind turbine with a unit capacity greater than 10 MW has yet been installed in the world (as of December 2021). Currently, the largest OWT installed onshore is a Siemens Gamesa Renewable Energy (SGRE) prototype named SG 14-222 DD, whose generated power in boost mode can reach 15 MW. It was installed for testing in \(\mathcal{O}\)sterild in November 2021 [1]. Offshore installation of such a turbine is planned in 2025 at the Sofia farm [2]. SGRE has thus overtaken the previous, leader General Electric (GE), whose prototype offshore wind turbine named Haliade-X with a capacity of 12 MW was installed for testing in the port of Rotterdam in 2019. According to GE's statement, the first installation of this type of OWT is scheduled at the Dogger Bank Teesside A and B farm in early 2022, followed by the installation of a modified version with a capacity increased to 13 MW at the Sofia farm in 2023 [3]. The largest model of the Haliade-X turbine, with a capacity of 14 MW, is expected to be used at the Dogger Bank Teesside C farm in 2025 [4]. By November 2021, the largest offshore wind turbine whose prototype has been submitted for testing is the V236-15 MW from Vestas capable of generating a nominal 15 MW. It will be installed at \(\mathcal{O}\)sterild in the first half of 2022 [5]. An analysis of global trends in the size of installed OMTs (resulting from an increase in the power they generate) clearly indicates that wind turbines with a capacity of more than 10 MW, referred to as 4 th-generation turbines, will be used to build offshore wind farms. A predictive analysis of the increase in the number of installed OMTs in the coming years shows that compared to the global market, the European offshore wind market will use the newest and largest 4 th-generation wind turbines for the construction of offshore wind farms (Figure 1). As of the end of 2021, a concept for a future offshore wind turbine larger than 16 MW has not yet been published, but literature analysis indicates that we can expect such a solution in the next decade. This is indicated by annual reports and analyses of the wind power market [7; 8; 9; 10] and by the start of planning and construction by ship owners to install 20 MW+ OWT vessels with wingspan lengths up to 130 m.  
The drive to reduce average energy costs has resulted in a significant increase in wind turbine size, but larger rotors face significant technical and logistical challenges. The largest published design for a 25 MW offshore wind turbine rotor has a diameter of 260 m [11]. However, an analysis of the publications indicates that from a materials engineering point of view, a 50 MW turbine with a wing panel length of more than 250 m and a weight of about 502 tons is feasible [12]. Figure 1: Predicted trend of wind turbine capacity growth [6]. Additionally, it should be taken into account that offshore wind farms being built in the Baltic Sea in the Polish economic zone will have a total generated capacity of 6 GW by 2030 [13]. In order to obtain such power, the construction of about 430 offshore wind turbines with a unit capacity of 14 MW or more is planned. In recent years, the momentum of the 4 th-generation OWT design and construction process has significantly outpaced the pace of technological development of vessels capable of offshore installation. The offshore wind industry is just beginning to respond to the lack of WTIV impacts capable of installing the latest generation of offshore wind turbines, but there is still uncertainty about the capacity of the global fleet to support planned offshore investments [14,15]. Determined in 2020, the estimated number of WTIV vessels in the global fleet capable of installing OWT categorized by generated capacity is shown in Figure 2. In late 2021, the actual number of vessels capable of installing 14 MW turbines slightly exceeds the estimates.