In collaboration with semiconductor company NXP, Plant-e has successfully developed an energy-harvesting strategy, using electronics from NXP designed specifically for Plant-Microbial Fuel Cells (P-MFCs), including an efficient algorithm for Maximum Power Point Tracking (MPPT). The voltage-regulated algorithm has proven to be highly effective and easy to implement, undergoing extensive testing in varying environmental conditions to ensure reliability. Additionally, Electrochemical Impedance Spectroscopy (EIS) provided insights into internal resistances and capacitances, leading to a better understanding our P-MFCs, that we can use for an improved design and energy extraction strategy.

Our exploration of MPPT algorithms revealed that impedance-regulated and voltage-regulated methods outperformed current-regulated approaches. The voltage-regulated algorithm’s simplicity and efficiency make it the preferred choice for P-MFCs.

NXP also contributed to the prototyping of a harvester-IC on an evaluation board, which was used in a demonstration setup in partnership with Waterboard de Dommel. This setup used a reliable pressure-based water level sensor of which readings were wirelessly transmitted to an online dashboard, all on the power of our P-MFCs.

In collaboration with SODAQ, a company that develops low-power IoT solutions, Plant-e introduces two innovative low-power wireless sensors that can be efficiently powered by Plant-Microbial Fuel Cells. These two proof-of-concept sensor setups, a rain gauge and a soil-moisture sensor, are now entering final validation at Plant-e, having shown very promising performance so far.

The two environmental sensors add another layer to our growing portfolio of sustainable, plant-powered remote sensors. Previous demonstrations included air -temperature, -pressure and -humidity, water level and phenology sensors. The expansion with the SODAQ sensor setups offers additional market opportunities for our pre-commercial product lineup.

With the help of electronics development partner IRNAS, Plant-e has successfully developed hardware for monitoring and harnessing energy from Plant-Microbial Fuel Cells (P-MFCs). This piece of hardware, which we call the harvester, effectively harvests energy from P-MFCs, stores it on a supercapacitor or other storage element and regulates the voltage to a practical level (3.6V for powering wireless sensors). The hardware also transmits status data via a low-power Bluetooth interface, enabling the monitoring of P-MFC conditions and performance, as well as soil conditions and battery status (energy balance).

The IRNAS harvesters, coupled with P-MFCs, offer a unique solution for powering wireless sensors by energy from nature. A vertical low-power P-MFC module we name the PowerStick is under development, featuring the Bluetooth Low Energy Monitor (BLEM) to keep track of the P-MFC conditions and energy availability, via an app on your mobile phone. The BLEM enables comprehensive monitoring of P-MFC performance, energy/battery status and also facilitates a diagnosis for troubleshooting.