Yes, but only a little. A microbial fuel cell (MFC), sometimes called a bacterial battery, uses bacteria to turn organic matter such as urine or wastewater into electricity. A single cell typically gives about one or two milliwatts. Pilot plants running on real wastewater manage roughly 0.1 to 10 watts per cubic metre of reactor, according to a 2026 review, which is far too little to run a treatment works, let alone a home.
Where MFCs have proved themselves is with tiny loads: lighting an LED, running a sensor, topping up a phone. They are not a rival to solar energy or wind power. Their most realistic future is in cleaning wastewater while using less energy to do it.
How it works
Certain bacteria, known as exoelectrogens, feed on organic matter and release electrons as they break it down. Normally they would hand those electrons to oxygen. In an MFC, the bacteria live on a solid electrode, the anode, and pass their electrons to it instead.
The electrons then flow through an external circuit to a second electrode, the cathode, where they usually combine with oxygen. That flow is an electric current. A single cell gives less than one volt, so practical systems stack many cells together, much as torch batteries are put in series.
So, can microbes be used as a source of energy? Yes: the energy comes from the chemical energy stored in the organic matter they eat, and the MFC simply catches some of it as electricity.
A close relative, the microbial electrolysis cell (MEC), works the other way round. It adds a small voltage from outside and, instead of electricity, produces hydrogen gas.
History and the key microbe
The idea is more than a century old. The earliest work is usually credited to M. C. Potter, a British botanist, who reported electricity from microbial decomposition in the Proceedings of the Royal Society B in 1911. The Royal Society’s archive holds his series of papers on the electrical effects that accompany the breakdown of organic compounds.
The best-known microbe in the field is Geobacter. It was first isolated from mud in the Potomac River by Derek Lovley, now at the University of Massachusetts Amherst. Geobacter can connect itself to electrodes using conductive protein filaments, often called “microbial nanowires”, just 3–5 nanometres wide. A key paper on these nanowires appeared in Nature in 2005. It is not the only microbe that can do this; any exoelectrogen can, in principle, feed an MFC.
Real-world examples
Pee Power (Bristol and Glastonbury, 2015 onwards)
The best-known field trial is Pee Power, developed by the Bristol BioEnergy Centre at the Bristol Robotics Laboratory, UWE Bristol, led by Professor Ioannis Ieropoulos. A urinal fitted with MFC stacks was trialled on UWE’s Frenchay campus from February to May 2015, then at Glastonbury Festival in June 2015, where it served about 1,000 users a day. The electricity lit the inside of the urinal.
Pee Power went back to Glastonbury for several years, powering lighting, information displays and phone charging, according to UWE. A scaled-up design, “PEE POWER urinal II”, was published in the Journal of Power Sources in 2018. The point is not the amount of energy but that it works in a busy, messy, real setting.
Plant microbial fuel cells
Plant-e, a spin-off from Wageningen University in the Netherlands, sells products that make electricity from living plants. The plants leak organic compounds through their roots, and bacteria in the soil turn some of that into current. The output is tiny, enough for small sensors or LEDs rather than anything in the home.
Biosensors
MFC-type biosensors, for example for monitoring water quality, are a more realistic niche than power generation. Here the bacteria’s electrical signal is used as a measurement: a change in current can show that something in the water has changed.
What the numbers say
Per cell
In the Pee Power urinal trials, individual MFCs gave 1–2 milliwatts each, according to the team’s 2016 paper in Environmental Science: Water Research & Technology. Earlier, a 2013 paper in the International Journal of Hydrogen Energy reported that a stack of 48 small urine-fed MFCs gave 1.5 milliwatts in total, while converting over 50% of the energy available in neat urine. That is a respectable conversion rate on a very small amount of energy.
Per cubic metre
Scaling up does not help as much as you might hope. A 2026 review of pilot studies in the journal Sustainability found that MFCs on real wastewater typically produce 0.1 to 10 watts per cubic metre of reactor, “far below levels needed for major energy generation”. The same pilots did remove much of the organic load from the water (measured as chemical oxygen demand, or COD).
To put that in context, a one-cubic-metre tank (1,000 litres) would give between a tenth of a watt and ten watts. At the top end, that is roughly one LED bulb. At the bottom, it would struggle to charge a phone.
Laboratory cells running on ideal feedstocks can do considerably better per square metre of electrode, but results vary hugely with design and feed, and lab figures are a ceiling rather than a guide to the field.
| Measure | Typical figure | Source and year |
|---|---|---|
| Single cell (Pee Power trials) | 1–2 mW | Ieropoulos et al., 2016 |
| Stack of 48 urine-fed cells | 1.5 mW in total | Ieropoulos et al., 2013 |
| Pilot plants on real wastewater | 0.1–10 W per m³ | Sustainability review, 2026 |
| Voltage of one cell | Below 1 V | Standard MFC design |
Limitations
The barriers are well documented in the 2026 review and in UK pilot work:
- Low power density, which falls further as reactors get bigger.
- Costly materials, especially electrodes and membranes.
- Voltage reversal in stacks, where a weak cell drags down the others.
- Inconsistent treatment, with water quality not always meeting the required standard.
None of this means MFCs are useless. It means the honest case for them is not power generation. Wastewater treatment uses a great deal of energy, and the aim of microbial electrochemical systems is to cut that energy use while cleaning the water, not to produce surplus electricity. Claims that MFCs are “revolutionising” energy, or are ready to power medical implants, are not supported by evidence; implants remain lab concepts.
MFCs should also not be confused with anaerobic digestion, where bacteria turn sewage sludge into biogas. Digestion is a mature technology used at a much larger scale by UK water companies, and is closer in spirit to biomass energy and other waste-to-energy technologies.
The UK angle
The UK has done more than most countries to take MFCs out of the lab. Bristol’s Pee Power work is the best-known example.
In the north-east, Newcastle University and Northumbrian Water have tested microbial electrolysis cells on real sewage. A 100-litre MEC ran for 12 months on raw domestic wastewater at temperatures between 1 and 22 °C, producing on average 0.6 litres of hydrogen a day, according to a 2014 paper in Bioresource Technology. Removal of organic matter was inconsistent and fell short of the required standards. A later, larger unit with six anodes of 1 m² each made 0.8 litres a day of 93% pure hydrogen in winter, at about 11 °C, in work funded by EPSRC and Northumbrian Water.
That much hydrogen holds roughly two watt-hours of energy a day, enough to run a 10-watt LED bulb for around ten minutes. As fuel, it is negligible; the value lies in cleaner, lower-energy treatment. Newcastle University describes the partnership as being at the forefront of microbial electrochemical technology, and a spin-out, METzero, was set up to commercialise it.
Frequently asked questions
What is a microbial fuel cell?
A device in which bacteria break down organic matter and pass electrons to an electrode, creating a small electric current. “Bacterial battery” and “bio battery” are informal names for the same idea.
How much electricity does a microbial fuel cell produce?
About 1–2 milliwatts per cell in field trials such as Pee Power. Pilot plants on real wastewater typically give 0.1 to 10 watts per cubic metre of reactor, according to a 2026 review. That is enough for small lights or sensors.
Are microbial fuel cells used in sewage works today?
Only in pilots. No treatment works we know of generates its electricity this way. UK water companies do make energy from sewage at scale, but through anaerobic digestion, which produces biogas.
What is a plant microbial fuel cell?
A version that uses living plants. The roots release organic compounds and soil bacteria turn some of that into electricity. The Dutch company Plant-e sells such products, but the output is at sensor or LED scale.
What is the difference between an MFC and an MEC?
An MFC produces electricity. A microbial electrolysis cell (MEC) takes in a small voltage and produces hydrogen gas instead. Both rely on the same kind of bacteria.
Could microbial fuel cells power my home?
No. Even at the best pilot-scale figure, a one-cubic-metre tank would give about ten watts. For home electricity, established renewables such as solar panels are the realistic option.