“The Dirt Battery”
Photo from depositphotos.com: A pile of used batteries.
By Scott Hamilton
Can you say wow? I have thought for a long time that our ancestors had more technology than we gave them credit. I wrote a couple of times in the past about ancient batteries and other strange archeological findings that pointed toward much more advanced civilizations. However, with all the new technology, especially in the area of batteries, most people think we have made great progress. This week I learned about a research project at Northwestern University focused on a fuel cell that is powered by dirt.
The fuel cell is powered by microbes living in the dirt and is about the size of a standard paperback book. It produces enough power to operate a majority of remote sensors in use today and can be used to power future technology. These soil-powered fuel cells offer a sustainable, renewable alternative to batteries, which contain toxic and flammable materials and often leak these materials into the ground. Batteries are not safe to use in sensors placed in or near our food supply, making them a poor option for monitoring soil in agricultural commercial farming operations. These dirt-powered fuel cells offer a great alternative.
What I found even more surprising than a battery alternative that was powered by dirt was the fact that this alternative was able to perform not only equally to the batteries in the test scenario, but out-performed the existing battery technology by nearly 120 percent. The test involved placing the battery in a sensor array designed to detect touch and measure soil moisture levels. It was also connected to a wireless radio antenna to transmit data to a nearby base station.
The other amazing thing about this study is that the authors of the study have released all the designs, tutorials and simulation tools to the public, making the technology open-source. This means that we can all build our own dirt-powered fuel cells and devices.
Bill Yen, Northwestern alumni and leader of the work said, “The number of devices in the Internet of Things (IoT) is constantly growing. If we imagine a future with trillions of these devices, we cannot build every one of them out of lithium, heavy metals and toxins that are dangerous to the environment. We need to find alternatives that can provide low amounts of energy to power a decentralized network of devices. In a search for solutions, we looked to soil microbial fuel cells, which use special microbes to break down soil and use that low amount of energy to power sensors. As long as there is organic carbon in the soil for the microbes to break down, the fuel cell can potentially last forever.”
The microbes already live in soil everywhere and the technology was designed to simply capture the electricity these microbes already produce. They will never produce enough energy to power a city, but they can power several IoT devices that use low level power. In recent years, farmers have increasingly adopted technology to increase the precision and improve crop yield. Among this technology are arrays of sensors to measure soil composition, moisture levels, temperature and contamination. Being able to monitor the conditions around the crop allows them to prevent over-watering, over-fertilizing and reduce costs.
Solar panels don’t work well in the dusty environment of a farm and batteries create a challenge because they go dead and must constantly be recharged or replaced. Farmers don’t want to take the time to go around their 100-acre farms dusting solar panels and replacing batteries. The technology developed by Yen and his collaborators can overcome these challenges. They can harvest energy directly from the soil the farmers want to monitor.
What is even more surprising is that this team is not claiming to have discovered something new. Soil-based microbial fuel cells (MFCs) first appeared in 1911, and rather than relying on a chemical reaction to produce electricity, MFCs harvest electricity produced by bacteria that naturally donate electrons to nearby conductors. However, there is one difficulty in MFCs – they need to remain hydrated and oxygenated, which can be difficult once they are buried under the ground within dry dirt. The team tested several designs to optimize the moisture level in the fuel cell and landed on a design that produced 68 times more power than needed by their sensor array and was built with products you can purchase at any local hardware store. I may be making a trip later this week to get the parts to build one. You can get more information at https://news.northwestern.edu/stories/2024/01/dirt-powered-fuel-cell-runs-forever/.
Until next week stay safe and learn something new.
Scott Hamilton is an Expert in Emerging Technologies at ATOS and can be reached with questions and comments via email to sh*******@te**********.org or through his website at https://www.techshepherd.org.
