Microbial Fuel Cell Energy
Excerpt from "A look to the future: USN research stretches from advanced systems to microbial power"
Publication: Jane's International Defence Review
Date Posted: 29-Sep-2017
One power technology SSC Pacific is investigating involves the transformation of sediment found at the bottom of the sea floor into energy to run sensors. The process uses microbial fuel cells to make a mud battery. It can provide the potential to have a power source that does not have to be replenished, Russell said.
The way it works is by having an anode, the negative portion of the battery, buried in sediment and electrically connected via an inexpensive carbon cloth, to a cathode, the positive part of the battery that is in the overlying water column, said Dr Y Mariah Arias-Thode, a scientist at SSC Pacific.
“Bacteria will donate their electrons to the anode and then the electrons are carried up to the cathode via some form of circuitry and an oxygen-reducing reaction occurs and that is how you get the energy,” Arias-Thode said.
Best of all, it always works, she said.
Dr Arias-Thode, a scientist at SSC Pacific, holds up a piece of carbon cloth used to obtain electrical power from sea floor sediment. (IHS Markit/Geoff Fein)
SSC Pacific is planning to conduct a demonstration for the US Southern Command using the microbial fuel cell to power a PH sensor for drug interdiction. PH sensors do not require much power. SSC Pacific would place sensors in a river environment to detect acids used by illicit drug manufactures that are dumped into the water.
SSC Pacific is also planning to do a demonstration of a larger-scale microbial fuel cell in the Mediterranean Sea as part of its Coalition Warfare Program with the Italian Ministry of Defence.
A microbial fuel cell generates about 0.4 volts of power, Arias-Thode noted. “It took us a year to do the electronics to step up the voltage from 0.4 to 12 volts; and none of the [equipment] is COTS.”
Last year during the 'Trident Warrior 2016' exercise off Hawaii, SSC Pacific attached a magnetometer to one of the microbial fuel cells. The sensor was able to track ships sailing out of Pearl Harbor.
The 'Holy Grail' would be if the microbial fuel cell could trickle charge a UUV in the future, Russell noted.
“We don't know if we would ever get that much power out. We are doing research there to explore what the limits are, what kind of microbes exist. Certain microbes are more efficient at generating power and they don't all live in the same area around the globe, and in the undersea environment, the deeper you get it tends to be cooler [so microbes would not generate as much power],” Russell said. “Understanding what the scope is, where it could be used, whether we could transport microbes, and what impact that might have – it certainly is an interesting research area that you wouldn’t normally think of for a C4ISR lab, but it is important because our products have to [operate] in various places.”
A spin off is that some of these microbial fuel cells clean up the environment, so SSC Pacific is looking at them to possibly purify water for the Marine Corps, Russell added.
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