The scheduling of alkaline water electrolysis for hydrogen production using hybrid energy sources

This paper presents a scheduling approach to maximize the profitability of alkaline water electrolysis (AWE) coupled with hybrid energy sources. AWE combined with solar power can produce extremely pure and green hydrogen. However, the capital investment of solar-powered AWE plant is still high, and thus its operating profitability should be carefully optimized. To this end, optimization-based operations are developed to schedule AWE productions with solar power and grid electricity supply. The AWE is modeled by computational fluid dynamics (CFD) software to obtain its polarization curve and efficiency. The solar power prediction, time-of-use (TOU) price, startup cost, and demand constraints are integrated with the AWE operational characteristics to form single-step and multi-step optimization formulas. The scheduling plan is determined by rapidly solving those formulas to global optimality. The case studies show that (i) AWE power consumption should follow the solar energy generation profile from 8 AM to 4 PM if TOU price is high; (ii) multi-step optimization with the receding horizon strategy can improve the AWE profitability; (iii) producing hydrogen is more profitable than selling PV electricity back to grid; (iv) PV capacity impacts the levelized cost of hydrogen, and thus should be carefully selected.