Stories tagged fuel cells

Jul
10
2009

Turn the arrows around, and you've got the right idea!: Feels like clean energy, doesn't it?
Turn the arrows around, and you've got the right idea!: Feels like clean energy, doesn't it?Courtesy bre pettis
Just kidding! The burning sensation is probably just one of the many symptoms you’ll experience during your bout with gonorrhea. It may feel like electric fire, but, really, it’s only inflammation somewhere in your urinary tract.

But while we’re on the subjects of urine, electric fire, and the future, check this out: your bladder is full of rich, savory hydrogen fuel, and some Ohio scientists have found a great way to get at it.

Using urine in power storage/production devices has been explored before, and, naturally, Science Buzz has been all over it. The story that was on Buzz before, however, was about using urine as an electrolyte medium in batteries, so it’s just there to allow the passage of electrons from one material to another. (That’s how I understood it, anyway—I couldn’t get to the original article.)

What we have here is something entirely different. With this technology, it’s the urine itself that could supply power, instead of just activating a chemical reaction in other materials.

Hydrogen, as we all know, is awesome. It’s easy to remember where it is on the periodic table (somewhere near the beginning, I think), it’s light, so it can lift stuff like zeppelins up in the air, it’s super flammable, so it can run the internal combustion engines we love so much, and it can be made to undergo a chemical reaction in a fuel cell, producing electricity. Unfortunately, hydrogen is also kind of... not awesome. Its otherwise delightful explosiveness also means that riding a hydrogen-filled zeppelin isn’t a great idea, it’s tricky to store, and despite being the most common element in the universe, it’s a pain to get a hold of.

We can get hydrogen out of water, because every molecule of water has two hydrogen atoms for each oxygen atom. But those hydrogen and oxygen atoms don’t like splitting apart, so we have to run electricity through water to get them to break up, and depending on how we produced that electricity, it sort of defeats the purpose; we’re using a lot of some other kind of fuel to make hydrogen fuel.

These clever Ohio scientists, however, realized that by using the right materials, they could get hydrogen and nitrogen to split apart from each other with a lot less electricity. (It takes them .037 volts to split hydrogen and nitrogen, compared to 1.23 volts for hydrogen and oxygen.) Where, then, is a cheap plentiful source of nitrogen bound with hydrogen? Where indeed…

You know where this is going: urine, or as I call it, yellow gold. Urea, one of the main components of urine, has four hydrogen atoms bound to two nitrogen atoms. If you put a nickel electrode into some urine and run electricity through it, that hydrogen gets released, and you can do with it what you will.

One cow, claim the scientists, could produce enough hydrogen to supply hot water for 19 houses. A gallon of urine could theoretically power a car with a hydrogen fuel cell for 90 miles. A refrigerator-sized unit, they say, “could produce one kilowatt of energy for about $5,000.” Someone might have to help me out on that last one. That can’t be per kilowatt, or “kilowatt-hour” (how we usually measure electricity usage), because a kilowatt-hour costs about 10 cents these days. I’m assuming that it would cost about $5,000 to build a unit like that, and the cost to run it would largely fall upon your kidneys. (Maybe?) Commercial farms, required to pool their animal waste anyhow, could power themselves with all the spare hydrogen.

It’s a pretty neat idea, and one that I actually had a long time ago. I have to give it to the scientists, though—they definitely advanced on my original idea. See I was just trying to burn urine straight up, and, frankly, it wasn’t working. Nothing about it was working.

I’m wondering, also, what the byproduct of urine-produced hydrogen would be. Fuel cells should just produce water vapor, but what’s happening when the hydrogen is separated from the urea? The chemical formula for urea is (NH2)2CO, so after the hydrogen leaves you’ve got two leftover nitrogen atoms, a carbon atom, and an oxygen atom. Laughing gas, or nitrous oxide, is N2O, but what about that carbon? We don’t like carbon just wandering around unsupervised these days.

Can anyone help me out here? When we remove the hydrogen from (NH2)2CO, what’s left over?

May
29
2008

The law of unintended consequences, part 4,937: Fuel cells don't pollute. But the process of making the fuel that goes in to them does.
The law of unintended consequences, part 4,937: Fuel cells don't pollute. But the process of making the fuel that goes in to them does.Courtesy geognerd

Fuel cells are sometimes promoted as a clean energy alternative. They work by combining hydrogen and oxygen to create water, with some left over energy that can then be turned into electricity. The only waste products from a fuel cell are water and heat.

Two small problems:

  • Water vapor, it turns out, is a major greenhouse gas.
  • Getting hydrogen to go into the fuel cell requires either zapping water with electricity, or treating natural gas with steam. Both of these processes require power, which currently comes from—burning coal.

So, while the fuel cell doesn’t pollute, the process of making the fuel for it does. (Though that could change if a hydrogen plant could be designed to run on wind, solar or other clean energy.)