Alternative fuels like solar and wind are expected to grow in importance to meet the immense power demand of 75 billion mobile and edge devices expected to be in use by 2030. NXP is looking ahead to innovate ways to harvest electricity from alternative renewables and recently tested an integrated circuit (IC) powered by bacteria in soil.
Plants excrete organic matter into the soil as a natural byproduct of their growth, which is then broken down by bacteria that release small amounts of electrons. This can be captured in a process similar to the way batteries are charged, which entails transferring the charge to a carbon electrode (anode) and then transferring it to a counter electrode (cathode). The amount of energy that this technology can harvest, called a plant microbial fuel cell (P-MFC), depends on parameters like fuel cell size, type of soil and temperature (it’s harder to capture charges in winter, for instance). Still, under typically temperate weather conditions, a single P-MFC could produce enough electricity to run a smart sensor like those already used to monitor the environment.
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About two years ago, NXP began collaborating with Plant-E, a small startup composed of environmental engineers dedicated to designing and building the electronics that would harvest and then deliver that energy.
After quickly coming up with the silicon necessary for a demo of the potential, the NXP team set up a field test at our headquarters in Eindhoven, The Netherlands, which involved connecting sensors and sending wireless updates approximately once every four hours (six updates/day), which was sufficient to monitor physical qualities such as water levels. This success prompted more innovation and development and led to an advanced model demonstrated at the 2022 Consumer Electronics Show that could power updates every five minutes, producing 290 readings/day and thereby suggesting a range of additional sensing and connectivity possibilities that included powering an edge node.
P-MFC technology still faces significant innovation challenges, including overcoming operational difficulties harvesting electricity in cold climates. But the potential opportunities for a “Bio-IoT” are vast. Imagine farms in rural areas without reliable electricity using their soil to power sensors that monitor crop conditions or using P-MFCs that harvest electricity in warm months so that it can be stored for use in colder seasons. You may never be able to plug your smartphone into a nearby potted plant to charge it, but continued innovation could lead to breakthroughs in low-power chips that open new frontiers in what, where and how we use the many millions of smart devices that await us in the future.
The idea of a Bio-IoT that runs on a power source that is not only renewable but recycled is as promising as it is intriguing. Keep following NXP for more about our sustainability and ESG efforts.
Arjan Leeuwenburgh is Sr. Director managing CTO Design Center at NXP and is based in Eindhoven (NL). He has 30 years of experience in semiconductor industry and has held several positions in R&D management. In his current role, passionate about innovation and with his engineering heart still beating, he is responsible for IC Development R&D activities enabling new product introductions for various business lines in NXP.
