The issue of finite energy resources and environmental pollution around the world is always mentioned as one of the main agendas. As an alternative to solving this problem, the conversion to renewable energy takes into account the aspects of the environment, safety, and efficiency. Power generation using wind power built on mountain ridges needs to be converted to offshore wind power considering the limitations of noise and areas.
In order to efficiently and stably produce and supply electricity through offshore wind power, the core elements in selecting locations are wind conditions and water depth conditions. However, considering the specificity of offshore wind farms being developed in the sea, the maritime traffic aspect should be considered. The first is that measures and standards for securing safety should be prepared to eliminate or minimize the possibility of accidents such as collisions and contact by impeding the navigation of ships due to the installation of offshore structures. Second, although the sea is a public water surface that anybody can use, changes in traffic flow such as ships having to navigate around due to occupancy and use due to the development of maritime structures are expected for a certain period of time, and there should be social consent and agreement from users.
In the offshore wind farm developed on the sea, public water that can be used by anybody, the safety of the ships should be ensured against various effects that will be caused by the installation of wind power generations in the sea where ship traffic occurs frequently. However, foreign guidelines are applied to ensure safety distances for safe navigation of offshore wind farms and ships in domestic cases. However, foreign guidelines do not take into account the size of turning characteristics according to various types of passage and status of navigation. In particular, even though the size of the tactical diameter is different depending on the type of ship, six times the length of the ship is applied equally to all ships. In addition, the scope of application of safety zones according to environmental external force factors, traffic density, wind power generator functions, and shapes was not clearly presented.
The offshore wind farms are developed in traffic separation schemes, designated channels, narrow waterways, and general water with no designated channel. Depending on the passage type, the offshore wind farms can be divided into an open sea area and adjacent to a port. In addition, it is not reasonable to apply the same standard to all situations because the traffic flow and volume of a ship are different depending on the presence or not of TSS, channel, and the size of the evacuation area is different depending on the occurrence of crossing relationship. In particular, since the size of the safety distance depends on the characteristics of external forces by water area, environmental conditions such as wind, current, and the ratio of depth and draught(h/d) should be applied, and the ship's turning characteristics vary depending on the type of ship. In addition, in terms of maritime traffic density, the size should be applied differently when considering the passage frequency of ships passing at the target route or traffic flow, the double size of the blade diameter(2D) according to the specifications of each generator should be applied as a safety zone so as not to collide with the rotating blades of wind power generators.
Therefore, this study points out the limitations of current international regulations, guidelines, and proposed guidelines by some nations and suggests offshore wind farms and models of navigation safety that apply the unique characteristics of the sea, ships, and structures in establishing safety distance. The suggested model was verified with the largest ship navigating through the waters around the offshore wind farm developed in the north sea. In addition, additional verification was carried out through the ship handling simulation for each participant by dividing into waters adjacent to the port and open sea to be developed offshore wind farms in domestic waters. As a result, in the verification of the north sea area, it was reviewed that ships navigating through 25 offshore wind farms were satisfied when applying the model, excluding one out of a total of 26 offshore wind farms according to a type of passage and status of navigation, the reliability of the model was ensured, and the satisfaction rate was found 96% in approximately. On the other hand, in the verification through ship handling simulation, the reliability of the model was ensured because the lateral size according to the turning characteristics carried out by the participants in the waters adjacent to the port was 0.1.0L different from the size suggested by the model. In the open sea area, the maximum tactical diameter of ships carried out by participants differed from a tactical diameter of type of each ship suggested by the model to less than 1.0L, but this area has not been developed yet; hence the model can be used for design arrangement.
The 'Model for the navigation safety of offshore wind farm and vessel' suggested in this study supplements and improves against the safety distance size presented in the existing foreign regulations and guidelines, as it does not reflect various parameters, including the type of passage and status of navigation. Regarding the rapid increase in the development of offshore wind farms at domestic and foreign from about ten years ago, the model developed in this study is expected to be a guideline and milestone for the safety of ships using the sea at domestic and foreign.