Let’s be honest, it’s always just matter of time before someone’s solution to a novel problem was to pee on it. I’m sure you know about getting jellyfish stings on the beach; the common advice would be to pee on the stings (here’s hoping your jellyfish didn’t embrace you in the face). Of course, it doesn’t actually work, and this is something left to professionals. I’m talking about medical treatment, not urinating on you. Oh, don’t be gross.
We humans seem to have this thing about wanting to solve problems using urine, and it’s not a new fad at all. I know there will be some that would say ‘don’t knock ’til you try it, ‘ but unless I see some studies confirming that they work, I’m going to continue knocking it since there’s really no reason to try it. Also, ew.
However, a study recently published in Applied Energy proposes – based on some research the same group has done before – that one could use a little bit of electrochemical know-how to power your phone by having yourself a pee. Since the authors released the paper under a Creative Commons license (what a great thing, the CC license), you don’t need to buy access to this paper. You don’t have to give it a read if you don’t want to, but at least check out the “Graphical Abstract” to get an idea of how they propose this works (I don’t know my full rights to use their graphics, so I’ll link it). I’ll wait.
Science, everybody. The whole thing is based on the concept of ‘microbial fuel cells’, or MFCs. Short story; these use bacteria to convert organic matter into electricity, mostly thanks to electrons moving from one place to another. The authors wanted to create MFCs that use urine as fuel, but it must be able to be or do quite a few things:
- Charge up a smart phone and a basic (so, ‘dumb’?) phone
- No electricity required to run the cells themselves
- Powered by one person’s urine, or 600mL
- Low maintenance (because who wants to?)
But why do this? MFCs tend to have low power, and they wanted it to be more efficient. Also, this can use organic matter; when I organic, I mean literally and not the popular definition often associated with high-end (overpriced) supermarkets. MFCs also have low maintenance costs and robust enough that it can “power telecommunication devices in remote areas.” So I guess it’s good for if your phone bails in the middle of nowhere (and hopefully not in the middle of, say, a central business district of a major city).
So how they go about this? Well, they would regularly collect urine and rigged a system where their urine tank would ‘take a leak’ at regular intervals. The urine would cascade through the 6 MFCs stacked on top of each other. However, they couldn’t just plug the phones directly into this without monkeying around with the phone charging circuitry, which deals with the incoming electricity used to charge your phone. This is interesting, as the authors mention that these often take a huge chunk of power when charging anyway (as they do so your phone doesn’t explode). Anyway, the pump and the various instruments had to be powered by things other than urine (can’t help that), but the MFC stack itself had to only be powered by what is essentially a peeing robot.
Did it work? Well, the output dipped by half after 4-5 months, but then it went back up to the normal level by itself – they didn’t (couldn’t?) explain why it did, but at least it works. One of the key findings that it can give it a good amount of charge in 107 minutes (longer for a smart phone); this doesn’t mean that you’re going constantly for an hour and 47 minutes (what on earth is wrong with your bladder?), it just means that go have a pee, wait for about a couple of hours, and there. Of course, it works better if your leave your phone off. They suggest for best results, don’t let the battery drain completely. Presumably, this would go around how some phones have a circuit that trips if there isn’t enough charge, and you can’t turn it back on until there’s enough (this way, you can turn it back on ASAP). The whole setup costs (by the authors’ reckoning) £360 (US$475), but I’m guessing your phone would have to have some modifications into it. I’m not sure if there’s any pee-to-DC chargers out there in the market.
So there you have it, some energy research so you can play some Pokémon GO after you go. Now wash your hands.
Featured article: Walter XA, Stinchcombe A, Greenman J, Ieropoulos I. (2016) Urine transduction to usable energy: A modular MFC approach for smartphone and remote system charging. Applied Energy. 10.1016/j.apenergy.2016.06.006
Featured image credit: Wikimedia Commons (CC-BY-20, author: Ulybug)