Optimal Sizing of Battery Energy Storage System for Hybrid offshore Renewable Energy Systems: A Curtailment-Based Optimization Framework

Sammanfattning

The integration of Battery Energy Storage System (BESS) into hybrid offshore renewable energy systems offers significant potential for reducing curtailment and improving techno-economic performance. This thesis presents a computationally efficient optimization framework for sizing BESS which is connected to a hybrid offshore systems combining wind, wave, and photovoltaic energy sources. The framework employs a curtailment-based power frequency histogram to identify the BESS power rating search interval, a MILP formulation to maximize total delivered energy which is subjected to cable capacity and battery operational constraints, discrete Pareto front construction in the total delivered energy and levelized cost of energy objective space, and Fuzzy Decision Making for final solution selection. The methodology is applied to three renewable source combinations, wind-wave, wind-PV, and wind-wave-PV, at two European offshore location: WindFloat Atlantic off the coast of Portugal and Princess Amalia Park in the North Sea off the Netherlands. The analysis was done by using ERA5 reanalysis data for 2024. The manufacturer provided matrices for a 15 MW IEA reference wind turbine, a 400 kW Corpower wave energy converter, and a 700 W Trina solar PV panel are also used for the analysis. Results show that optimal BESS size is governed primarily by statistical distribution of curtailment rather than total installed generation capacity. Among all the combinations, the wind-wave-PV combination shows highest TDE with a most favourable LCOE. The FDM-selected solutions consistently identify intermediate power ratings within the curtailment range. This confirms that the histogram-based approach focuses the optimization on economically relevant configuration without sacrificing solution quality. The findings provide a guidance for pre-feasibility assessment for a hybrid renewable energy system.