Development of a whole life cost model for offshore wind farms

This paper presents a Cost Breakdown Structure (CBS) to identify the key cost drivers of offshore wind farms throughout the whole life span (∼25 years). A mathematical tool is also developed to evaluate all the costs associated with five phases of offshore wind projects, namely, Pre-development and Consenting (P&C), Production and Acquisition (P&A), Installation and Commissioning (I&C), Operation and Maintenance (O&M), and Decommissioning and Disposal (D&D). Several critical factors such as geographical location and meteorological conditions, power rating and capacity factor of wind turbines, reliability of subassemblies, and availability and accessibility of transportation means are taken into account in cost analyses. The O&M costs are assessed using the data available in failure databases (e.g. fault logs and O&M reports) and the data supplied by inspection agencies. A Net Present Value (NPV) approach is used to quantify the current value of future cash flows and a bottom-up estimate of the overall cost is obtained. Finally, the model is tested on an offshore 500 MW baseline wind farm project. Our results indicate that the capital cost of wind turbines and their sub-assemblies as well as the installation cost account for the largest proportion of LCC, followed by the O&M costs. A sensitivity analysis is also conducted to identify those factors having the greatest impact on Levelized Cost Of Energy (LCOE).