Design, Operation, Modeling and Grid Integration of Power-to-Gas Bioelectrochemical Systems

Abstract

This paper deals with the design, operation, modeling, and grid integration of bioelectrochemical systems (BES) for power-to-gas application, through an electromethanogenesis process. The paper objective is to show that BES-based power-to-gas energy storage is feasible on a large scale, showing a first approximation that goes from the BES design and operation to the electrical grid integration. It is the first study attempting to cover all aspects of a BES-based power-to-gas technology, on authors’ knowledge. Designed BES reactors were based on a modular architecture, suitable for a future scaling-up. They were operated in steady state for eight months, and continuously monitored in terms of power consumption, water treatment, and biomethane production, in order to obtain data for the following modeling activity. A black box linear model of the BES was computed by using least-square methods, and validated through comparison with collected experimental data. Afterwards, a BES stack was simulated through several series and parallel connections of reactors, in order to obtain higher power consumption and test the grid integration of a real application system. The renewable energy surplus and energy price variability were evaluated for the grid integration of the BES stack. The BES stack was then simulated as energy storage system during low energy price periods, and tested experimentally with a real time system.

Integration of Membrane Contactors and Bioelectrochemical Systems for CO2 Conversion to CH4

“…Anode and cathode electrodes (170 cm 2 projected surface, each) were made of thermally activated carbon felt, 4.6 mm thick (SGL Group, Munich, Germany). This material was chosen given its mechanical and electrical properties, and its appropriate surface chemistry, suitable for biofilm growth, based on previous experience [25]. The ratio between electrodes surface and reactor volume (23.8 m 2 m −3 ) was within the range of values that could be calculated from previous EMG studies (10-40 m 2 m −3 ) [8,16,21,23,24].…”

“…Reactors were inoculated in batch mode with a mixture of 50% acetate-based mineral medium and 50% anaerobic sludge, collected from the anaerobic digester recirculation line at a local WWTP (the sludge chemical composition is shown in Table A2 in the Appendix A). The mineral medium was composed of 450 mg (Table A3, Appendix A) and 5 mL L −1 vitamins solution [25]. A constant voltage of 0.7 V was applied between anode and cathode of each EMG-BES by using a potentiostat (VMP3, BioLogic, Grenoble, France).…”

“…This represents a scalable and cheaper option than the double-chamber BES architecture. Ultimately, a voltage of 0.7-1.2 V must be applied in single-chamber EMG-BES for the process to occur at a significant rate [25]. A lower value favors direct EMG over indirect one as main CH 4 generation pathway.…”

Bioelectrochemical Systems for Removal of Selected Metals and Perchlorate from Groundwater: A Review

“…In BESs, both oxidation and reduction reactions can occur, respectively at the anode and at the cathode [45][46][47], and thus oxidized contaminants such as nitrate, vanadium, perchlorate or chromium can be reduced in the cathodic environment, while arsenic and/or organic matter can be oxidized in the anodic environment (Figure 1), with possible complete groundwater remediation due to the integration in a single treatment sequence. Energies 2018, 11, x FOR PEER REVIEW 2 of 22 as being able to produce energy from more complex substrates such as domestic and industrial wastewater: dairy [15-18], food-processing [19], leachate [20,21], pharmaceutical [22], brewery [23,24], winery [25], oil [26] and petroleum refinery wastewater [27] are amongst the principal examples.After the initial exclusive interest as possible net energy producers from organic matter degradation, which had somehow disappointed researchers' initial development expectations [28][29][30][31][32], BES technology has been used as a flexible platform for fulfilling several other tasks: brackish water desalination in microbial desalination cells (MDC) [33,34], hydrogen production in the microbial electrolysis cell (MEC) setup [35,36], microbial electrosynthesis (MES) of valuable chemicals and commodities [37,38], power-to-gas energy storage [39], nutrient recovery [40,41], and biosensing [42,43] are some notable examples.Due to the intrinsic characteristics of the technology, BES has been identified as a promising technology for groundwater bioremediation [44]. In BESs, both oxidation and reduction reactions can occur, respectively at the anode and at the cathode [45][46][47], and thus oxidized contaminants such as nitrate, vanadium, perchlorate or chromium can be reduced in the cathodic environment, while arsenic and/or organic matter can be oxidized in the anodic environment (Figure 1), with possible complete groundwater remediation due to the integration in a single treatment sequence.…”

“…After the initial exclusive interest as possible net energy producers from organic matter degradation, which had somehow disappointed researchers' initial development expectations [28][29][30][31][32], BES technology has been used as a flexible platform for fulfilling several other tasks: brackish water desalination in microbial desalination cells (MDC) [33,34], hydrogen production in the microbial electrolysis cell (MEC) setup [35,36], microbial electrosynthesis (MES) of valuable chemicals and commodities [37,38], power-to-gas energy storage [39], nutrient recovery [40,41], and biosensing [42,43] are some notable examples.…”