Dung and bacteria - power sources of the future?
Batteries powered by nothing more than cow dung or rotting plants might sound like the dream of a delirious eco-warrior, but fuel cells that harness bacteria to produce energy are being developed to make this dream become a reality.
Biological batteries use bacteria to convert chemical energy into electrical energy. Known as microbial fuel cells, the bacteria feed on cellulose and release hydrogen that is oxidized within the fuel cell, creating electricity. The only byproduct is water.
Using cow dung as a power source is not a new idea. For one, it's plentiful and for millennia it has been dried and used as a fuel to burn. More recently methane has been captured to power lighting and machinery, although this process requires expensive equipment.
Ann Christy, associate professor of food, agriculture and biological engineering at Ohio State University, has taken cow waste as a power source a step further. She lead research into using the bacteria in cow dung to create electricity. The bacteria release electrons when "digesting" cellulose in the form of undigested plant matter in the cows' waste.
Resembling two buckets filled with effluent with some electrodes attached, the fuel cells created by Christy's team managed to only produce half the voltage needed to power an AA-size battery.
"While that's a very small amount of voltage, the results show that it is possible to create electricity from cow waste," said Christy.
Large and low-powered, the dung batteries may not represent an immediate solution to clean, renewable and portable energy. However other efforts to create smaller and more efficient microbial fuel cells are being made elsewhere that could go some way to addressing the problem of global energy poverty.
With only 22 percent of Africa connected to an electrical grid, lead acid car batteries remain an important source of power across homes on the continent and in other less economically developed countries.
However, chemical batteries use valuable resources and their disposal can contaminate the environment. Sparing the world of lithium or lead-acid batteries would not only have environmental benefits, but create the potential for clean, abundant and renewable power.
A team of students at Massachusetts Institute of Technology (MIT) have created a microbial fuel cell that runs on plant waste. Called BioVolt they won a prize at MIT in September for their fuel cell that was designed to tackle the problem of energy poverty in rural areas of less economically developed countries.
Most microbial fuel cells use platinum as a catalyst, but BioVolt's prototype uses a non-platinum catalyst which greatly reduces its cost. The team said that the parts needed for one of its devices would only cost $2.
However, like the cow dung powered batteries, there is the persistent problem of size and power output from microbial fuel cells.
"You can always make a fuel cell that has a large amount of power, but you have to ask how large will it be and how much will it cost. Currently the economics and power to size ratio don't scale up so well," said Dr. Anthony Kucernak of Imperial College London.
Professor Phil Bartlett from Southampton University has been skeptical of some of the claims made by others working on microbial fuel cells. He calculated that to create two watts of power for a mobile phone fuel cell the electrode would need to be four square meters.
"The downside with microbial is that they're not liable to give a high power output. It will never achieve the same kind of performance as fuel cells that you actually pull out the enzyme," said Kucernak.
The BioVolt device isn't yet ready to be part of a portable mobile phone charger - it looks like a jar of murky liquid. However more commercial applications of biological batteries might not be too far away.
Sony unveiled its own portable battery that generates electricity from sugar, using enzymes as a catalyst. The company claims its bio battery produces enough power for a portable MP3 player, but it's still more than double the size of the Walkman it is powering. While Sony has committed itself to developing the technology to create bio batteries with longer lives and greater power output plenty of challenges remain.
"It's going to be exceedingly difficult to produce a biological system that can provide the microbial activity and energy needed to power mobile devices," says Kucernak, "but never say never."
What do you think. Have your say and join the debate.
Good technology but you missed the other by-product. The cells should be able to produce good quality organic fertiliser as a biogas plant does. If they don't the designers will loss out to a unit that does.
Bio-battery technology seems a very feasible option to call for in future, but at the rate of advancement of technology I believe that having batteries filled with a greenish liquid to power you sports -car is not impossible for the near future - time will tell.
I believe in the near future, human beings can find other energy to substitute traditional energy, but use the animal dung to generate the energy, maybe right now is incredulous, because it is very expensive and ordinary people can't bear it.
The use of cow dunk is a promising product if developed properly. Raw material is available and it could minimize environmental pollution. On the other hand collection centers can be set up to provide job opportunities for villages.
There will always be a way to accomplish it. The primary thing is to take one step at a time and to give it a try as we are doing. The more ideas we catch up with, the more sources of energy we will discover.
I love biological power, much better to use dung than leave it on open grassland or as manure for the farmers. We should put more efforts in search for better, clean and safer microbial fuel, instead of drilling more oil, gas and fuel around the world.
Although this is not a topic emphasized enough, I believe fuels such as dung would play a major role, especially in villages such as ones located in South Africa that tend to produce excess dung if I may use the phrase. But a major issue is the capital costs, transportation of materials and mainly skilled labor to these remote areas, making the task almost a loss in most cases. I believe the idea does have a potential with more research and thought.
Even if it is not economical enough to use bio-batteries at present, such an attempt will bring our future to a more environmentally friendly society. We have to support this kind of effort on reducing waste from our planet.
This sounds like a bunch of bull to me. Of course that is probably exactly what the government and the oil industry has fed us for years. The government to gain outrageous taxes on fuel and the oil industry for outrageous profits.
It seems we have come full circle. The very thing that was seen as backward and uncivilized by western society is now being looked on as the thing that will save money and the planet.