A team of researchers from Northwestern University has introduced a groundbreaking soil-powered fuel cell, offering a potential eco-friendly alternative for underground sensors in precision agriculture. Approximately the size of a standard paperback book, this technology harnesses energy from microbes residing in the soil, presenting a sustainable option in contrast to batteries laden with toxic chemicals that contribute to environmental pollution.
The researchers conducted tests on the soil-powered fuel cell, demonstrating its capability to power sensors measuring soil moisture and detecting touch. This feature could be particularly valuable for tracking animals passing through agricultural areas. To facilitate wireless communication, the team equipped the soil-powered sensor with a small antenna for data transmission to a neighboring base station, reflecting existing radio frequency signals.
The remarkable aspect of this soil-powered fuel cell is its effectiveness in both wet and dry conditions, outlasting similar technologies by an impressive 120%. The findings of the research will be published in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable, and Ubiquitous Technologies.
Bill Yen, an alumnus of Northwestern leading the research, emphasized the significance of finding alternatives for powering the growing number of Internet of Things (IoT) devices. Yen stated that envisioning a future with trillions of devices requires moving away from using hazardous materials in batteries and embracing alternatives that provide low amounts of energy. The soil microbial fuel cells, which utilize special microbes to break down soil and generate energy, offer a sustainable solution as long as there is organic carbon in the soil.
George Wells, a senior author on the study and an associate professor of civil and environmental engineering at Northwestern’s McCormick School of Engineering, emphasized the ubiquity of these microbes in soil, highlighting the potential to capture their electricity through simple engineered systems. While acknowledging that this energy won’t power entire cities, it can efficiently fuel practical, low-power applications.
The researchers addressed the challenges posed by existing microbial fuel cells, which had been hindered by unreliable performance and low output power, particularly in low-moisture conditions. The winning design, featuring a unique geometry with perpendicular alignment of the anode and cathode, proved effective in dry and water-logged conditions alike.
With the soil-based microbial fuel cell demonstrating robust performance, the researchers aim to make the technology more accessible by using components that can be sourced from local hardware stores. They also plan to develop a fully biodegradable version of the soil-based fuel cell, avoiding complex supply chains and steering clear of conflict minerals. The study was supported by the National Science Foundation, the Agricultural and Food Research Initiative, the Alfred P. Sloan Foundation, VMware Research, and 3M.