Optimization and economic evaluation of a PEM electrolysis system considering its degradation in variable-power operations

Abstract

This paper investigates the economic evaluation of hydrogen production by water electrolysis, considering the impact of power fluctuations on the efficiency and durability of proton exchange membrane electrolytic cells (PEMEC). To this end, a general efficiency model and a lifetime prediction model for PEMEC with variable-power operations are proposed, leading to a life-cycle economic evaluation model considering the long-term effect of uncertain technical–economic parameters of Proton Exchange Membrane Electrolysis System (PEMES). Then a bi-level optimization model is established to balance the utilization of new-energy generation and the economy of PEMES. Three improved algorithms, i.e., the genetic algorithm (GA), grey wolf algorithm (GWA), and dragonfly algorithm (DA), are suggested to solve the optimization problem effectively. Meanwhile, a plausibility verification and correction method for optimal solutions are proposed. Finally, the economic feasibility of PEMESs coupled with four different wind power plants (WPP) and Photovoltaic power plants (PVP) are discussed. The evaluation results indicate that the economics of PEMES, neither off-grid nor grid-connected, are unsatisfactory when evaluated with the available techno-economic parameters. Besides, the average voltage growth rate (AVGR) of PEMEC at variable power operation is supposed to be much less than 10 μV·h−1 to reduce the cost of hydrogen to $2.5/kg.