Stabilising methane production in a series-stack of bioelectrochemical systems
Year: 2025
Type: article
Abstract: Electromethanogenesis (EMG) is a power-to-gas technology that converts CO 2 into methane in bioelectrochemical systems (BES) using electricity. Scaling up requires the stacking of multiple BES cells, often through parallel and series connections. However, series configurations can lead to voltage imbalances due to biocatalysts variability and uneven feeding, compromising performance. This work presents a simple, cost-effective cell balance system (CBS), based on commercial diodes, to equilibrate voltage across a three-cell BES stack performing EMG (2.7 V stack voltage). Cells were hydraulically connected in parallel and electrically connected in series. The stack was operated under normal and uneven anolyte feeding, with and without the CBS. Without CBS, stopping the feed to one cell dropped stack voltage by 1.45 V and reduced methane production from 0.66 to 0.23 m 3 -CH 4 m −3 cathode d −1 , while energy efficiency fell from 86 % to 44 %. With the CBS, voltage imbalances stayed below 1.15 V; methane production and efficiency increased by 57 % and 49 %, respectively, in comparison with the absence of CBS. The CBS redistributed the current, allowing a rapid recovery, after reestablishing feeding conditions. In conclusion, a simple diode-based CBS provides a robust, scalable, low-cost means to manage voltage imbalances, facilitating reliable operation and industrial upscaling.
Source: Journal of Power Sources
Authors: Maria Vega-Paredes, Daniele Molognoni, Simone Colantoni, Pau Bosch-Jimenez, Sebastià Puig, Eduard Borràs
Institutions: Universitat de Girona, Leitat Technological Center
Language: English
Subfield: Environmental Engineering
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,230
OpenAlex ID: W4413371480