Thermoeconomic Comparison of Alkaline, Solid Oxide and Anion Exchange Membrane Electrolyzers for Power-to-Gas Applications

Francesco Calise, Francesco Liberato Cappiello, Luca Cimmino, Laura Cutolo and Maria Vicidomini

Renewable and Sustainable Energy Reviews, 2025, vol. 224, issue C

Abstract: This study presents a comparative thermoeconomic analysis of three Power-to-Gas (PtG) systems operating under dynamic conditions, each integrating a different electrolysis technology: solid oxide electrolysis cell (SOEC), alkaline electrolysis cell (AEC), and anion exchange membrane (AEM) electrolysis. Each system converts excess electricity from a photovoltaic (PV) field into hydrogen via electrolysis. The hydrogen is then combined with carbon dioxide – captured from the exhaust gases of a combined heat and power (CHP) unit – within a three-stage catalytic methanation reactor to produce synthetic methane. This system supplies energy to mixed-use facilities. The methanation reactor is modelled as a three-stage fixed-bed catalytic reactor using Ni/Al2O3 as the catalyst, cooled by liquid water. Both the electrolyzer and methanator models incorporate temperature-dependent reaction kinetics and simulate realistic transient behaviour. Dynamic simulations were carried out using TRNSYS, while advanced components are modelled in MatLab. Energy results show that the SOEC-based system outperforms the AEC and AEM-based systems in terms of overall conversion efficiency (0.56 vs. 0.48 and 0.49), primary energy savings (46.90% vs. 43.90% and 43.96%), and CO2 emissions avoided (74.16% vs. 71.77% and 71.84%). To further assess system scalability and investment viability, a multi-objective optimization was carried out on the SOEC configuration. The optimization identified two Pareto-optimal configurations: the first achieves 56% primary energy savings (PES) with a simple payback period (SPB) of 5.41 years, while the second reaches 57% PES with a slightly longer SPB of 5.52 years. In both cases, curtailment of excess electricity was kept below 8%, and electrochemical chain costs remained under 45% of total investment. The results confirm that optimal system sizing – particularly of the electrolyzer and methanation units – is crucial to achieve a cost-effective and energy-efficient PtG deployment.

Keywords: Power-to-Gas; solid oxide electrolysis; alkaline electrolysis; anion exchange membrane electrolysis; methanation reactor; renewable energy systems (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S1364032125007889
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:rensus:v:224:y:2025:i:c:s1364032125007889

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/600126/bibliographic
http://www.elsevier. ... 600126/bibliographic

DOI: 10.1016/j.rser.2025.116115

Access Statistics for this article

Renewable and Sustainable Energy Reviews is currently edited by L. Kazmerski

More articles in Renewable and Sustainable Energy Reviews from Elsevier
Bibliographic data for series maintained by Catherine Liu ().