Deployment of microbial fuel cells in the marine environment where the anode is buried in the sediment has always been difficult, particularly when anode(s) have been large to maximize power output. Successful burial has required large masses, substantial horsepower resulting in  occassional fuel cell damage (Chadwick et al, 2011) and diver support during deployment, confirmation and follow-on maintenance in order to ensure the anodes are sufficiently buried. Successful deployment is never guaranteed and tends to be limited to softer sediments without surface or subsurface obstructions. These issues become more daunting when deployment in deeper water is attempted. Reimers and others appreciated these obstacles early in their field programs and have deployed fuel cell anodes in chambers, open at the bottom, which when lowered to the sediment become sealed and anoxic (Nielsen, et al 2007). Microbial metabolism at the anodes depends on organic compounds diffusing up from the enclosed sediments or even enhanced by nutritional additives.

We present the design and preliminary data from an alternate approach to these deployment obstacles with a focus on scaling. Carbon cloth, functioning as an anode, is attached to one side of a rolled rubber sheet, Carbon cloth, buoyed by small floats also functions as a cathode and is attached to the other (top) side of the sheet. As with other designs, power output depends on diffusion of organic material to the anode surface. The rubber sheet, deployed as a roll on the sediment, is unrolled on the bottom via hydraulic pressure in flexible hose attached along the length of the rolled sheet (think New Year’s Eve party makers). The roll-out is initiated with a battery-powered well pump. The rubber sheet ensures anoxic conditions around the anode(s) on the bottom side of the sheet. Anode/cathode pairs are connected by potentiastats and individual currents recorded. 

D.B. Chadwick, J.A. Kagan, A.Q. Wotawa-Bergen and W.C. Davis, "Sled for Benthic Microbial Fuel Cell Deployment with Carbon Fabric Anodes," Oceans 2011, IEEE, (2011).

Nielsen ME¹, Reimers CE, and Stecher HA 3rd. 2007. Enhanced power from chambered benthic microbial fuel cells. Environ Sci Technol. 41(22):7895-900.