This bacteria-powered battery can generate electricity from soil
Scientists at the University of Bath have developed affordable technology that harvests electrons produced by bacteria in soil and turns them into electricity.
Picture a battery with two components: a fuel cell-like device to capture the electrons underground and a power management system that extracts energy from the soil. The idea is based on the PhD research of Conception X alum Jakub Dziegielowski, who recently launched spinout Bactery.
“You’ll have naturally occurring bacteria in soil, and they’re constantly eating up different molecules, releasing electrons,” Dziegielowski says. “They’re a catalyst that converts the energy stored in organic matter into electrons, and we can capture these and make them flow to generate electricity.”
Bactery aims to initially use the technology to power sensors and Internet of Things (IoT) devices in agriculture — to make it easier for farmers to monitor the state of their crops in real time.
Poor energy infrastructure on farms has been a major barrier to the digitalisation of the sector, and has slowed the shift towards precision agriculture, forecast to grow rapidly in the next decade. Single-use chemical batteries are the current go-to solution, but they have short lifespans and require frequent replacements, posing a significant and costly challenge when managing thousands of sensors across vast areas.
Regular power outages caused by batteries running out, animals chewing through wires or farmers accidentally cutting through them while operating their equipment also result in signal loss and unreliable data.
The team’s soil rechargeable battery offers a more practical alternative, with a lifespan of more than 25 years, low maintenance needs and a cost of around £25 per unit.
Dziegielowski says at the moment the technology can harvest enough electricity to charge a phone once per day, but could be scaled by increasing its size.
“Sensors and IoT electronics normally don’t require much power at all, so we can use small systems to sustain their operation, and we can already meet their power demand without any issues,” he says.
Back in 2019, the team tested a larger prototype in northeast Brazil to help clean up the drinking water supply of a remote fishing village.
“In Icapui, the main solution for securing drinking water is through rainwater harvesting tanks. To ensure the water is safe to drink, locals mix in large amounts of chlorine to disinfect it,” Dziegielowski says. “This can be toxic to human health if done in an uncontrolled way — the water there smelled stronger than pool water. We offered a much safer electrochemical water treatment, and the local population helped us build it.”
At the time, the novel purification system could only treat about three litres of water per day, and the main goal was to prove that the technology worked outside of the lab. Over the course of Dziegielowski’s PhD, which focused on water purification applications, the research team managed to scale its volume output tenfold — to 30 litres of water per day.
Bactery aims to offer more than just a sustainable energy source for low-power devices, and eventually develop a device to enhance crop growth and resilience to harsh weather conditions caused by climate change.
Dziegielowski developed the initial plan for his startup on the Conception X programme, which he says exposed him to “the early stages of trying to turn research into practice” and helped him diversify his skills as a PhD student — from speaking to customers to considering value propositions and building relationships with experts.
“I knew I wanted to turn this into a business to have an impact outside of academia, but I had no clue where to start,” he says.
“Conception X helped me so much across different areas. All of a sudden, I was chatting to founders of large organisations, had VCs reach out to me about my idea, and I quickly learnt how to speak their language. I even managed to get a term sheet, which helped massively in negotiations with the university while spinning out.”
