Energetic evaluation of high pressure PEM electrolyzer systems for intermediate storage of renewable energies

authored by: B. Bensmann, R. Hanke-Rauschenbach, I. K. Peña Arias, K. Sundmacher
Abstract: Three pathways for high pressure hydrogen production by means of water electrolysis are energetically compared. Besides the two classic paths, comprising either the pressurization of the product gas (path I) or the mechanical pressurization of the feed water (path II), a third path is discussed. It involves the electrochemical co-compression during the electrolysis. The energetic evaluation is based on a uniform model description of the different hydrogen production pathways. It consists of integral, steady-state balances for energy, entropy and mass as well as a modern equation of state. From this the reversible energy demand is used to identify the inherent thermodynamic drawbacks of the pathways. The additional consideration of irreversibilities allows for the determination of efficiency losses due to device specific characteristics. For hydrogen delivery pressures of up to 40 bar the classical pathways are out-performed by path III. Since the hydrogen is already produced at elevated pressure this eliminates the need for an energy consuming mechanical hydrogen compression and spares the additional energy demand due to the oxygen pressurization. However, with increasing pressure differences the hydrogen back-diffusion strongly decreases the Faradaic efficiency of the asymmetric electrolyzer that has to be compensated by an additional energy supply.
External Organisation(s): Max Planck Institute for Dynamics of Complex Technical Systems
Otto-von-Guericke University Magdeburg
Type: Article
Journal: Electrochimica acta
Volume: 110
Pages: 570-580
No. of pages: 11
ISSN: 0013-4686
Publication date: 2013
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General Chemical Engineering, Electrochemistry
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1016/j.electacta.2013.05.102 (Access: Unknown)