Microbes in Dirt Provide Electricity for African Villagers
by Matthew McDermott, Brooklyn, NY on 09. 5.08
A makeshift microbial fuel cell: a bucket, waste water and a graphite sheet. Photo: Lebônê
Providing electricity to people in countries where either the grid is not reliable, or nonexistent and unlikely ever to be built, can make a huge difference in people’s quality of life in very practical ways. We’ve written before about companies such as D.Light Design which have solar-powered replacements for kerosene lanterns , and efforts to bring small-scale solar panels to off-grid villages in Laos. Hand cranked cell phone chargers, radios and flashlights are other proven options that have received attention.
Microbial Fuel Cells Provide Enough Power for Small Devices
One option which is being investigated in a pilot project by Cambridge, Massachusetts company Lebônê Solutions is using microbial fuel cells to provide electricity to villagers in Tanzania. While the power produced by microbial fuel cells isn’t great, it does provide enough electricity for the small DC powered devices that the villagers want to run, Lebônê co-founder Hugo Van Vuuren told Technology Review. Compared to other renewable energy options such as solar panels or small-scale wind turbines they are also less expensive to produce and easier to set up.
A What Type of Fuel Cell?
Lebônê gives us a very basic rundown on how microbial fuel cells work:
These inexpensive fuel cells run on animal and plant waste and naturally occurring soil microbes, and are framed around a flexible substrate (wood, steel, etc) that can vary by geographic availability. This is truly electricity right out of the ground. These fuel cells are used to charge a battery or cheap supercapacitor, which in turn will be used to power a high-efficiency efficient LED or PLED lamp.
And Technology Review gives us a bit more detail:
To make the fuel cell, the team put graphite cloth--the anode--in the bottom of a bucket along with chicken wire--the cathode--and microbe-laden waste, either mud, cow manure, or residue from coffee crops. A layer of sand acts as an ion barrier while salt water helps the protons travel more easily. The team adds a power management board (the only device that the villagers will most likely have to import, says [Lebônê co-founder Aviva] Presser) to regulate the power and send it to a battery. Such a fuel cell can run a cheap, efficient light-emitting diode (LED) for four to five hours per evening. "We're hoping the entire system will be around $10 when we're ready," says Presser.
Namibia Next Up For Fuel Cell Trial
After Tanzania, Lebônê’s second trial, funded by a $200,000 grant from the World Bank, will be an 18-month pilot project in Namibia where the the firm will couple their fuel cell design with the the next generation of LEDs.
:: Lebônê Solutions, :: Technology Review and :: Plenty
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Anyone been to a graphite plant? Not a pretty sight. How many of the electrodes would be used over course of a year by a family? How much graphite does it consume?
TH, I can't remember, but did you cover the Wind Belt?
http://www.popularmechanics.com/technology/industry/4224763.html?series=37
This is pretty cool, but I'm skeptical. It seems like watching this is a bunch of hassle for minimal gain. I don't see how it competes well with a hand cranked flashlight. Maybe it would be more appealing if a few families could share a slightly larger system. Then again, I'm not the intended audience.
This is so fantastic. Combine it with the evaporative cooling refrigerator made of two nested buckets with a wet sand between-layer.
You might as well just ride a bike/generator.
Interesting article but another one Treehugger had seems like a more reliable and viable energy solution for these type of places. Gasification and especially at an individual level like the guy in the article was making (out of junk yard parts) could give people all the energy they could need and run large generators. Inexpensive too.
Loved the gasifier Treehugger article so here is the link for those of you who are interested:
http://www.treehugger.com/files/2008/08/build-do-it-yourself-biomass-gasifier.php
If a village doens't have to choose then why not both?
I have been exploring microbial FC design for a while now, but have had problems optaining some hardware for experimentaion. Was able to make a cheep conductive polymer composite with graphite and polystyrene using an acetone and toluene solvent mixture. Think it might be helpful for folks that have limited means to optain graphite sheeting/plate for the MFC electrodes. Don't think the polymer gell can be patented, but think it might be useful with work:
clean polystyrene foam, 10 grams
Acetone solvent, 50 ml
Toulene solvent, 20 ml
graphite powder(can be obtained from boat supply
operations as an additive to paints), 20-30 grams.
Mix solvents together, weigh polystyrene foam and dissolve into the solvent mixture. Add slowly graphite powder. This gell will coat pourous materials and with air curing makes an acceptable
conductive surface The gell can act as an conductive adhesive also.
Have tried a newspaper & waste fiberglass composite wafer coated with the gel, seems to have good conductivity, but solvent mixture needs to be manipulated to preserve porosity. The composite is very strong(helps to cast the wafers under about .5 to 1 ton PSI). Think the surface area could be improved for greater power output of the MFC.
For what its worth. Sam