Business

Microbes for Off-the-Grid Electricity

(Page 2 of 2)

  • Thursday, September 4, 2008
  • By Kristina Grifantini

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 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.

"The beauty of it is it's a self-sustaining system," says Derek Lovley, a professor at the University of Massachusetts Amherst, who is not involved in the work and who published initial studies on microbial fuel cells in 2002. Using LED lights is "a nice, practical application for this, if they can get it to be simple and inexpensive," says Lovley. "This is actually, as far as I know, the only current practical application of [microbial] fuel cells." Right now, most microbial fuel-cell work is research based, although there have been attempts to use microbes in fuel cells to treat waste water.

How much power the microbial fuel cell can generate depends on the area of the graphite sheets. About one square meter of fuel cell yields one watt, which could recharge a cell phone, according to Van Vuuren. Five square meters can power a portable stereo, fan, or small light.

For the next test, due to launch in December in Namibia and funded by the World Bank, the team plans to couple a new fuel-cell design with conventional high-efficiency LED lights. For that trial, Lebônê will make 100 fuel cells and ultimately hopes to reach up to 3,000.

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Guest (Thoms)

  • 1256 Days Ago
  • 09/05/2008

How is this better?

How is this better than hand cranked generator devices? My hand cranked flashlight was less then $10, lasts for hours and powers 1 to 3 LEDs. Similar devices are available for cellphones, TVs, radios, etc. This is proven, cheap, scalable technology. So how is the microbe technology better then hand cranked generators?

Reply

DJTal

154 Comments

  • 1256 Days Ago
  • 09/05/2008

Re: How is this better?

Well , i guess it's better because the microbes are doing the work , which saves human power . But , compared with having to walk 5 miles to a  generator , hand cranking would use less energy . Trust a bunch of highly intelligent Harvard students to come up with the most difficult way to generate power ........ poor Africans!! But , its a good thing now that we've been educated about microbial fuel cells .

Reply

mkogrady

423 Comments

  • 1253 Days Ago
  • 09/08/2008

Re: How is this better?

On a broader scale, these MFC's can use the waste water from a sewage system, or sediment from brackish ponds and lakes. In essence recycling waste for energy. The bacteria used in water treatment plants is an active culture that can be easily and readily sourced. The muck...well...it's easily sourced too I imagine.

Reply

myrightfoot

1 Comment

  • 1256 Days Ago
  • 09/05/2008

How is it better?!

It's better in a lot of way. First, these generators can be built out of common items. The only non local resources that you might need are the carbon filaments and power control.  If these items can be sourced at a low enough cost then thousands, if not millions of households could have their own bio generators. They can charge lots of items, have few mechanical parts that break down overtime, and everyone has waste that they can fuel the generators with. I think its brilliant in its simplicity and could be a great tool for million worldwide.

Reply

mkogrady

423 Comments

  • 1253 Days Ago
  • 09/08/2008

How Scalable is this?

If a bucket of muck and sand, one square meter of Graphite some chicken wire and sodium solution as a carrier is all it takes to power up a cell phone, how big of a system is needed to power up a house?

Can a fuel cell the size of a VW bus be created to run a home, assuming you can route it through an inverter? Or - can the DC power be used to split water into hydrogen and power a gas generator directly?

Once the muck is spent, is it tossed out and all the inner workings rinsed out with fresh water and a new system built with fresh muck? Does it pose any envirmental challenge?

What muck works best or what would you look for as a base?

Reply

kgrifant

12 Comments

  • 1253 Days Ago
  • 09/08/2008

Re: How Scalable is this?

Because this fuel cell yields about 1 watt per meter squared of anode, it would take quite a bit of surface area to power a house. Instead, the team hopes to provide small amounts of power to farmers. Waste from the fuel cell can be used as fertilizer--there are no hazardous byproducts. Soil, manure from domestic animals, and other organic-rich waste works best.

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jackbrack

1 Comment

  • 345 Days Ago
  • 03/05/2011

MFC update

big boys are getting involved.  Just search, and you will find several folks that want to get rich on this with IPO's.  This is serious stuff bros and babes

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