Decommissioning cost modelling for offshore wind farms: A bottom-up approach  

The lifespan for offshore wind farms (OWFs) is between 20 and 25 years, and with a growing demand for renewable energy, the number of OWFs approaching decommissioning phase will dramatically increase in the coming years. This paper presents a new cost model by adopting a bottom-up approach for the removal and transportation phases of OWF decommissioning projects. Based on the experience in Oil and Gas industry, a project percentage breakdown analysis is also performed to expand the model further and estimate the overall decommissioning costs. To test the efficiency of the proposed cost modelling approach, the cost estimations for four OWF decommissioning case studies with different levels of public information and data are investigated. The numerical results revealed that in addition to the proposed cost model efficiently estimating the removal and transportation costs, it can also be adapted to estimate the overall decommissioning costs, by applying percentage weightages obtained from the percentage breakdown analysis.