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.
An Unlikely Power Source
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
About two years ago, NXP began collaborating with
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
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
sustainability and ESG efforts.