Author Options:

Generating a Couple of Watts Using Urine? Answered

I recently came across a paper written by a researcher from a Scottish University about generating electricity directly from urine in a fuel cell and I was wondering if a larger version could be built to generate around 2 watts.  The power per square cm is around 1.5mW so even at 1mW I would need 2000 cm-sq so I think it would be easier to build a stack of cells instead of one or 2 large cells.

I'd like to attach the paper but it's one which you need to pay for though I got it for free, could a moderator let me know what to do?  It was written by a Shanwen Tao and called 'A Direct Urea Fuel Cell' DOI: 10.1039/b924786f

Another idea I had was to use a small PV setup to generate hydrogen from urine and then store the gas so that it can be used in a hydrogen fuel cell.  I've had some difficulty in trying a to find a cheap fuel cell but then I came across this page: http://www.mtmscientific.com/fuelcell.html
Are there any really simple ways of building a fuel cell?

I'm posting this here to see if anyone can help me come up with a viable design and maybe even build it for me.  I can pay you for your time and effort; though as a student I do have a tight budget to stick to.

Any help, advice and ideas will be very much appreciated.


Most fuel cells use precious metals that are innately expensive,.otherwise anyone could build one for a few bucks. A multicavity simple homemade battery might work better. a 555 chip could be used to convert the dc to ac.

Most fuel cells use precious metals that are innately expensive,.otherwise anyone could build one for a few bucks.

The important parts of the fuel cell are the Anode and Cathode materials. What you use to facilitate the chemical reaction can vary. There are much better options than using urine in a fuel cell.

Fuel cells will never be cheap due to the materials needed to make it worth while as a power source to start with. This is why we don't have a fuel cell in every home or cars running off fuel cells. It seems like a great idea being able to just fill it up with water or come other fluid to facilitate the chemical reaction but the cost of materials is the issue.

The anode and cathode for the direct urea fuel cell are Ni/C and MnO2/C respectively. I understand the price issue but I don't intend to start a business or anything, this is just something that I'm interested in.

Did you take a look at the mtmscientific link, that fuel cell design doesn't seem to have any expensive materials in it's list.

After posting this thread I had an idea on building a very simple storage cell and this is a drawing of my idea but the credit for the image goes to user LiquidLightning. In my version a platinum coated and nickel mesh would be used instead of plain wire. Now here comes the part I'm not sure about, if I use a solar cell to generate the hydrogen can I store the gases within the test tube for an extended period of time so it could be used later. For example, if I have a 20W input and ran it for an hour can I come back after a couple of days and run the cell to produce electricity and if that is possible what will the efficiency be like?

The link you gave is a cheap and basic science experiment for school children. It's a nice demonstration of electrolysis and a fuel cell but your using more power to separate the hydrogen and oxygen then the actual fuel cell produces.

Your looking at a problem with diminishing returns. Yes better anode and cathode materials like Platinum and Nickle (which the platinum is quite expensive and will need to be replaced from time to time) will give you more power. The down side is you'll still be generating more power with the solar panel than you'll produce from the fuel cell. But your looking at this as a fun project not an actual source of energy correct?

Storage is you main issue. A tube or empty soda bottle isn't going to hold very much hydrogen gas. If you want to collect it over a period of time you'll need a way to pump it into a pressurized container or you'll need to constantly replace the tube/bottle. Which isn't very practical.