From the lab to the field: Self-stratifying microbial fuel cells stacks directly powering lights. (1st November 2020)

• Record Type: Journal Article
• Authors: Walter, Xavier Alexis; You, Jiseon; Winfield, Jonathan; Bajarunas, Ugnius; Greenman, John; Ieropoulos, Ioannis A.
• Is Part Of: Applied energy. Volume 277(2020)
• Publication Date: 2020-11-01
• Subjects: Self-stratifying microbial fuel cell -- Urine treatment -- Scaling-up -- Power source -- Practical applications; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2020.115514
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Urine fed microbial fuel cell stacks were used as a direct power source. Maintaining individual cells at high potential enables stable series connections. A stack continuously and directly powered LED spotlights in the field. A stack was connected to the lights through a LED-driver to limit cell reversal. Directly connecting LEDs to a stack is more stable than using LED drivers. Abstract: The microbial fuel cell (MFC) technology relies on energy storage and harvesting circuitry to deliver stable power outputs. This increases costs, and for wider deployment into society, these should be kept minimal. The present study reports how a MFC system was developed to continuously power public toilet lighting, with for the first time no energy storage nor harvesting circuitry. Two different stacks, one consisting of 15 and the other 18 membrane-less MFC modules, were operated for 6 days and fuelled by the urine of festival goers at the 2019 Glastonbury Music Festival. The 15-module stack was directly connected to 2 spotlights each comprising 6 LEDs. The 18-module stack was connected to 2 identical LED spotlights but going through 2 LED electronic controller/drivers. Twenty hours after inoculation the stacks were able to directly power the bespoke lighting system. The electrical energy produced by the 15-module stack evolved with usage from ≈280 mW (≈2.650 V at ≈105 mA) at the beginning to ≈860 mW (≈2.750 V at ≈300 mA) by the end of the festival. The electrical energy produced by the LED-driven 18-module stack increased from ≈490 mW at the beginning to ≈680 mW toward the end of the festival. During this period, illumination was above the legal standards for outdoor public areas, with the 15-module stack reaching a maximum of ≈89 Lx at 220 cm. These results demonstrate for the first time that the MFC technology can be deployed as a direct energy source in decentralised area (e.g. refugee camps).