Techno-Economic Assessment of an Offshore Wind Turbines-Underwater Compressed Hydrogen Energy Storage System

For achieving energy storage of offshore wind farms, a OWTs-UWCHES (Offshore Wind Turbines & Underwater Compressed Hydrogen Energy Storage) concept is proposed. The OWTs-UWCHES system is mainly composed of three parts: offshore wind turbines, a hydrogen production platform, and underwater compressed hydrogen storage units. Hydrogen is generated via water electrolysis with offshore wind electricity and is stored in low-cost underwater storage accumulators. A techno-economic analysis of the proposed OWTs-UWCHES system is conducted in this study. The simple payback period (SPB), discounted payback period (DPB), net present value (NPV), and levelized cost of hydrogen (LCOH) are investigated to evaluate the economic performance of the system. The one-at-a-time (OAT) local sensitivity analysis is conducted to determine the influence of various parameters on the economic performance. The results show that SPB and DPB were 6.4∼11.3 years and 8.7∼23.1 years, respectively. NPV is 23.78∼69.28 M$. LCOH without discount rate is 1.77∼5.76 $/kg. LCOH with discount rate is 3.39∼11.10 $/kg. SPB, DPB, and NPV are all most sensitive to the price of hydrogen and the total capital expenditure (CAPEX) of OWT. LCOH is most sensitive to OWT CAPEX and discount rate. Overall, the proposed OWTs-UWCHES concept is viable.