Slashdot Mirror
Bacteria Powered Batteries
Agent Provocateur writes "SpaceDaily reports on
a battery that is powered by chemical reactions caused by bacteria.
A Pentagon-backed project, University of Massachusetts researchers Swades Chaudhuri, an Indian, and Derek Lovley, an American, say the battery's source is an underground bacterium that gobbles up sugar and converts its energy into electricity.
Their prototype device ran flawlessly without refuelling for up to 25 days and is cheap and stable." The chemistry behind this thing isn't really that complex - keeping the bacteria alive and kicking during that time is prolly the tougher part - you can read more on Al Jazeera, and USA Today. Now, what about replacing this battery?
Right movie, wrong reference. You're thinking of "Mr Fusion", the thing Doc threw trash (banana peels, beer, and the can itself) into to power the Delorean.
Flux Capacitor was inside the car, in the back seat area, and was shown as a Y shape.
Similar to this Vehicle?
http://www.howstuffworks.com/news-item107.htm
http://www.ias.uwe.ac.uk/goto.html?c-melhui
Mr Fusion doesn't feed the DeLorean, it powers the Flux Capacitor, as the whole plot of episode 1 revolved around the lack of plutonium. The DeLorean itself is powered by gas (which again is the whole plot in episode 3)
The reason raw sugar won't work, is because it will kill the ecoli. The water content in the bug is much higher than that in the surrounding media(pure sugar in this case). The water will will move towards the region of the high sugar content (following the gradient of high water concentration to low). This will dessicate the ecoli and kill them.
There was an article on this nearly a year ago. As soon as I saw this, I assumed I was looking at a dupe. However, the earlier battery was developed in England, and part of the goal was to eventually have the battery run not off of pure sugar, but rather garbage. As you can imagine, witty comments about Mr. Fusion and the general cleaniness level of geeks ensued.
Karma: Chevy Kavalierma.
Many people have genetic pre-disposition to diabetis. I'm one. Exercise will and does help, but the big problem is the trauma to my system (cancer) has caused some of my system to start to slow down. Net effect is diabetis.
My brother had part of his pancreas burned out, thus causing diabetis. This was much better than periodic temporary paralysis.
So, before you spout off on "diet and exercise", you might check into the facts.
Oh, and my mother was a type I diabetic, from age 10 onwards. Her diabetis was brought on by German Measles, as best as current medical science can tell. The immune system was thrown out of wack by the GM and attacked her pancreas. This is one method that can cause diabetis.
According to the article the bacteria grow at a maximum of 30C (86 F). That means the bacteria battery won't be operative during long stretches of July and August.
You don't need a chemist for that. Simply take the Calories per gram of sugar (google: 2.44 Calories (kilocalories) per gram).
83% of that is ~2 Calories.
1 kilowatt is equivalent to 14.34 kilocalories per minute, which is about 7 grams per minute.
So, about 420 grams of sugar (a bit under a pound) is needed to produce 1 kilowatt.
However, as the article states, it takes a long time to produce the energy (how long i don't recall, nor feel like looking), so essentially to charge up a chemical battery for the potential of 1 kilowatt, you would need to have the bacteria metabolize around a pound of sugar. But this is a function of the number of bacteria, and probably the efficiency of getting the sugar distributed to the bacteria depending on size.
You can't compare the two - a car engine, ie. internal combustion engine, works on a heat cycle and so it's thermal efficiency (which is different from mechanical efficiency) is limited by what is known as the carnot cycle efficiency (=[Th-Tc]/Th; google for "carnot cycle" if interested further). The carnot cycle efficiency for internal combustion (petrol/gasoline for the Americans ;-) !) engines is about 59% (going from a hazy memory here), average car engine efficiency is more like ~32% so the efficiency of a car engine is not as bad as everyone thinks.
On the other hand your bacteria are working on chemical processes, where the chemical conversion processes (should be) much much more efficient. I've got no numbers to back it up, but my feeling is that 83% is not a particularly high efficiency for a chemical conversion process.
"Because it's there." - George Mallory, when asked why he wanted to climb Mt Everest, March 18, 1923 (New York Times)
Well done, I was waiting for you to spot that.. :-)
The 83% does not include the loss in any electric motor, nor in any of the other circuitry/mechanics..
I suppose where you live as to the % you get out of a car engine - manufacturers figures are usually very optmistic. In some citys you spend a lot of time in jams, with the engine idling over. Someone commputed the average speed in London of traffic to be about 11 mph. I would guess 32% is rarly achieved by a normal petrol car user in London.
THen we get into the whole electric vs petro-electric vs hydrogen/electric etc.. Electric hybrids seem best in cities, as you can switch off the big petrol/hydro/fuel cell an idle around on batteries at low speeds, and recharge using regenerative braking..
But if the efficiency v size/weight is good, no reason why the power cell cant be bio. Biggest problem is that you can just switch it on/off - big run up/down time..
"You lied to me! There is a Swansea!"
Arthur C Clarke talked about this years ago in one of the Rendezvous with Rama trilogy - technology from the giant spiders IIRC.
It was the episode where Homer became an astronaut. He was up on the shuttle, and he ended up breaking an ant farm and releasing all the ants. So the ants were floating around in the microgravity, and when Kent Brockman was relaying the story on the news, the picture that came in from the shuttle was an ant on the camera, and many floating around in the background.
(A page on the episode, with the quote)
So Kent Brockman says:
"Ladies and gentlemen, er, we've just lost the picture, but, uh, what we've seen speaks for itself. The Corvair spacecraft has been taken over -- "conquered", if you will -- by a master race of giant space ants. It's difficult to tell from this vantage point whether they will consume the captive earth men or merely enslave them. One thing is for certain, there is no stopping them; the ants will soon be here. And I, for one, welcome our new insect overlords. I'd like to remind them that as a trusted TV personality, I can be helpful in rounding up others to toil in their underground sugar caves."
Great episode. A very good one to watch, if you get a chance.
*honks*
This is my sig. It's prescription, I swear. I need it for reading things... on the other side of things
Of course, this was the concept behind the Dracucell, which theoretically will be able to extract about 100W from the bloodstream (though actual efficiencies will be quite a bit below that).
I suspect Dracucells will do wonders for the diabetic population.
--Dan
I built a bacterial fuel cell (from their description, identical except for the bacterial species) as a high school science project in 1964! We just used some bacteria from the Kansas River.
It worked... dump in sugar, get out current.
I think what is new here is the high level of efficiency.
The only good weather is bad weather.
(from http://members.nuvox.net/~on.jwclymer/rq/)
The molecular weight of glucose is 180 g/mol. The calculated heat of combustion is 2830 kJ/mol, or 3.8 kcals/g.
2830 kJ/mol / 180 g/mol * 0.83 = 13 kJ/g
1 kWh = 60 min * 60 s/min * 1000 J/s = 3600 kJ
3600 kJ / 13 kJ/g ~= 280 grams of sugar for 1 kWh or power
Can't find a good price for sugar, but 1 kWh of electricty is not more than 10-15 cents in the US. I have a feeling that half a pound of sugar is way more than that...
The Intelligent Autonomous Systems Lab at the University of the West of England has demonstrated a robot doing phototaxis, powered entirely by a microbial fuel cell.