Model-based economic analysis of off-grid wind/hydrogen systems
Abstract
Hydrogen has emerged in the context of large-scale renewable uptake and deep decarbonization. However, the high cost of splitting water into hydrogen using renewable energy hinders the development of green hydrogen. Here, we provide a cost analysis of hydrogen from off-grid wind. It is found that the current cost evaluation can be improved by examining the operational details of electrolysis. Instead of using low-resolution wind-speed data and linear electrolysis models, we generate 5-min resolution wind data and utilize detailed electrolysis models that can describe the safe working range, startup time, and efficiency variation. Economic assessments are performed over 112 locations in seven countries to demonstrate the influence of operational models. It is shown that over-simplified models lead to less reliable results and the relative error can be 63.65% at most. Further studies have shown the global picture of producing green hydrogen. Based on the improved model, we find that the levelized cost of hydrogen ranges from 1.66$/kg to 13.61$/kg. The wind-based hydrogen is cost-competitive in areas with abundant resources and lower investment cost, such as China and Denmark. However, it is still costly in most of the studied cases. An optimal sizing strategy or involving a battery as electricity storage can further reduce the hydrogen cost, the effectiveness of which is location-specific. The sizing strategies of electrolyzers differ by country and rely on the specific wind resource. In contrast, the sizing of batteries presents similar trends. Smaller batteries are preferred in almost all the investigated cases.