Scientists at Northwestern University have created a dirt-powered fuel cell that generates electricity from soil microbes and can operate underground sensors for more than 120 percent longer than comparable systems.
How the soil-powered fuel cell works
The device, about the size of a paperback book, uses naturally occurring microbes in dirt to break down organic material and release electrons, creating a small electric current. It functions like a microbial fuel cell with an anode, cathode and electrolyte, but relies on bacterial activity instead of chemical reactions. As long as organic carbon is present in the soil, the microbes can continue producing energy, potentially allowing the system to run indefinitely.
Why researchers see it as a battery alternative
Traditional batteries used in Internet of Things devices contain toxic and flammable materials, depend on complex global supply chains and add to electronic waste. The fuel cell offers a low-power, environmentally benign option for decentralized sensor networks. Researchers note that with trillions of IoT devices expected, alternatives to lithium and heavy metals are needed to avoid environmental harm.
What the fuel cell can power
In tests, the system successfully ran sensors that measure soil moisture and detect touch, which could aid monitor wildlife movement through fields. It also includes a small antenna that sends data wirelessly by reflecting existing radio frequency signals, keeping energy use extremely low. The device proved reliable in both dry and flooded soil conditions across a range of environments.
How the team is supporting wider use
The researchers have published their study in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies. They have also released their designs, tutorials and simulation tools publicly so others can build on the work. This open approach aims to accelerate adoption of the technology in precision agriculture and environmental monitoring.
How long can the dirt-powered fuel cell operate?
The system produced more sustained power than similar systems and lasted about 120 percent longer in testing.
What kind of sensors can it run?
It has been used to operate sensors that measure soil moisture and detect touch, with potential applications in monitoring wildlife movement.