Renewable energy sources have been prioritized over fossil fuels for comparatively superior sustainability, environmental and climate benefits. In particular, offshore wind farms, utilizing the large marine space with strong wind potential, have significantly developed over the past few decades. Generally, submarine power cables are used for transmitting power from the offshore wind farms to the onshore facilities. These cables have a significant impact on the navigation system and are susceptible to damages caused mainly by human factors such as fishing and shipping. To this end, an optimized submarine power cable routing selection criterion is highly desirable for better decision making in terms of technical feasibility, safety, reliability and cost of laying, operating and maintaining of the power cables.
Fuzzy logic approaches have gained a lot of interest in developing reasonable decisions through qualitative and quantitative description of various factors using fuzzy sets. However, most of these methods use traditional rules to describe the relationship between the input and output variables which may result in a loss of useful information. In an attempt to address this problem, Dr. Dan Jiang and Dr. Xuefeng Yang from Chongqing Jiaotong University in collaboration with Dr. Bing Wu from the Wuhan University of Technology and Professor Van Gelder from the Delft University of Technology developed evident reasoning approach to deal with uncertainty and incomplete information for effective submarine power cable routing selection of offshore wind farms. This approach was fundamentally based on a three-layer decision-making approach considering four major attributes; routing condition, cable reliability, navigational environment, and special zones. Their work is currently published in the journal, Ocean Engineering.
Based on the belief degree, extended IF-THEN rules were constructed for inference purposes. A three-layer decision-making framework was then established after the fuzzification of the input variables. The authors observed that evident reasoning and index value were essential items in obtaining optimal routing selection from the submarine power cable candidates. As such, this is a promising method for field application. Specifically, the proposed approach was validated by describing its application to ZheNeng offshore wind farm in the East Chinese Sea. From the analysis and comparison of three submarine power cable routings, the one with the best navigational environment and conditions for channel crossover was regarded as the best. This was also attributed to its good performance in the attributes of cable reliability and special zones. Unlike other routings, the best submarine power cable routing was less prone to damages initiated by human activities due to minimal interaction with ship navigation.
Generally, the decision made by the proposed method were in agreement with the existing results. Despite the remarkable results, the study has some limitations including limited data since the input variables are derived from the existing data sources. Consequently, the decision attributes and influencing factors need to be adjusted by specific characteristics. Altogether, the study insights provide essential information that will be of great importance in future improvement of the submarine power cable routing selection by addressing some of the inherent limitations.
Jiang, D., Wu, B., Yang, X., & Van Gelder, P. (2019). A fuzzy evidential reasoning based approach for submarine power cable routing selection for offshore wind farms. Ocean Engineering, 193, 106616.