UCSC Engineer Deploys Research on ‘Mud Batteries’

Assistant Professor of Electrical and Computer Engineering, Colleen Josephson, has deployed research on "mud batteries" at the UCSC farm.

By Emily Cerf via UCSC Newscenter

With growing populations, climate change, and high levels of consumption, many areas of the world can expect to face water shortages by 2050. The majority of freshwater on earth is used for agriculture, driving the need for soil moisture sensing systems that are proven to help farmers more efficiently water their crops. While this tool has the potential to minimize or avoid a water crisis, it is not widely used due to cost and difficult maintenance.

Microbial fuel cells, a method for gathering tiny amounts of energy from bacteria that live in soil, are a potential solution to provide renewable energy to power soil moisture detection systems on farms. UC Santa Cruz Assistant Professor of Electrical and Computer Engineering Colleen Josephson published new research exploring the current state of this technology and future opportunities for expanding its efficacy and impact.

The farm at UCSC currently hosts one of the only sites in the world to test this technology in the field, as Josephson’s group and her collaborators experiment with the efficacy of microbial fuel cells, also called mud batteries, outside of a laboratory.

“To our knowledge, we’re the first to be looking at how we can use these microbial fuel cells in outdoor sensor networks,” Jospehson said. “Some of our early results have been pretty exciting, showing that we can incubate these cells in a laboratory environment and then move them out to a farm field and generate power in a relatively steady state.”

Past research has shown that monitoring the levels of water in a crop field can help farmers better water their crops, maintaining yields while using 20 to 50 percent less water. But today, fewer than 10 percent of farms in the U.S. use intelligent watering systems. Josephson and her coauthors on the new research (Weitao Shuai and George Wells at Northwestern University, Pat Pannuto and Gabriel Marcano and UC San Diego, and Josiah Hester at the Georgia Institute of Technology) believe this technology can be leveraged for the resilience of food-producing ecosystems, allowing us to farm and feed ourselves as sustainability as possible while minimizing impact on the planet.

An emerging technology

While employed at Microsoft Research before joining Baskin Engineering, Josephson worked on a project to develop lower-cost sensing solutions for agriculture, an area that combined her expertise in low-power wireless communication systems and her personal interests in biology, gardening, and food systems.

A microbial fuel cell with components labeled.

After a few years of research, her team came up with technology that could monitor soil moisture at a fraction of the cost of other systems and was significantly easier for farmers to deploy and maintain. The system was designed to last five-years on a single coin-cell battery, but the researchers wanted to push for a renewable system where the users would never have to worry about their power source.