The Korea Offshore Wind Power(KOWP) is being planned to construct offshore wind energy farms with an overall rated power of 2.5GW in the south-western coast until 2019.
Hitherto, various structural types of support structures for offshore wind turbines are being proposed but these structures are the lack of study for economic analysis or not performed. So it is difficult to confirm the economical superiority compared to existing types. The offshore structure with economical efficiency means to minimize the mobilizing equipments and short offshore construction period due to application of rapid installation method. The development of new support structure with economical efficiency is then necessary in the most basically view.
Accordingly this study proposes support structure of improved jacket-type with economical efficiency based on analysis results for structural geometries and installation logistics of jacket-type applied in development work for offshore wind turbines of the south-western coast and test-bed of Jeju Wol-jeong-li. This proposed support structure was confirmed economical superiority that is possible shortening of offshore installation period and construction quality improvement through new connection method of jacket and pile.
Also, in order to compare structural adequacy of generally jacket and proposed jacket, static, modal and on-bottom analyses were carried out based on identical design data for offshore environmental and soil conditions of south western coast and aerodynamic load displayed in 5MW upwind report. In consequence, structural behaviour of generally jacket and proposed jacket is respectively showed combined and independent behaviour in accordance with connection method of jacket to pile. This result means that structural stiffness of generally jacket is better than proposed jacket from this paper. However, these support structures are satisfied with all criteria defined in design basis.
To compare economical efficiency for these structures, economic analysis was carried out based on total construction cost combined with fabrication and installation costs. As a result, the proposed jacket was able to confirmation to have economical superiority by minimization of the mobilizing equipments and reduction of offshore installation period through the introduction of new connection method of jacket to pile.
If the proposed jacket in this study is applied in development business of offshore wind energy farms with an overall rated power of 2.5GW in the south-western coast, this project will be able to save construction cost drastically. Further, this structural type will also be foundation of offshore wind turbines in the country.