A future without batteries for sustainable IoT growth

At Twin4Green, sustainability is at the heart of our solutions. Even if pilot projects can validate operation in energy savvy ways, scaling to reach massive IoT will require new ways of thinking about powering devices, whether sensors, actuators or gateways.

Of course, over the last few years there has been many collaborative research projects or review papers about energy harvesting for IoT but thanks to innovative companies, it is now possible to design end to end IoT solutions using off-the-shelf products.

This has been made possible by the convergence of many domains: Progress in edge computing, IC design, Moore’s law (lower operating voltages), better capacitor or battery materials, antenna designs or amplification/signal denoising.

We will look at some of the most recent announcements and try keeping the list the list of solutions up to date over time.

Solar energy powered LoraWAN devices

The new thermostat from MClimate (measuring temperature/RH/PIR/Light) is one of the latest off-the-shelf solar powered LoraWAN devices. In a webinar organized by The Things Network today, Lyubomir

Yanchev presented the new MClimate solar powered thermostat with the Epishine solar cell. (Wienke Giezeman is on the edge of his seat imagining all the possibilities….)

MClimate is already working on a second version which will also have an additional CO2 NDIR sensor.

The Twin4Green team started looking into more efficient ways of deploying end to end IoT solutions back in 2021 when we deployed a LoraWAN enabled picture frame sending temperature, relative humidity, light levels and barometric pressure data to our Digital Twin. (https://peafowlplasmonics.com/applications/)

Peafowl Plasmonics ambient comfort monitoring with LoraWAN

There is a lot of information made available to properly size the various elements needed.

Source: https://youtu.be/0SYreAVrXOE

Solar powered LPWAN is not just for sensors and it is now also applicable to gateways as the recent announcement of SPTel in Singapore shows. (https://sptel.com/first-sensor-network)

RF energy

For some use cases, solar power might not be feasible. This is where RF energy might be handy/complementary. The recently released AirFuel standard (https://airfuel.org/) for free space wireless charging might find applications with high ROI in Industry 4.0 for example.

In the same way that devices open 2 receiving windows for messages from gateways, one could imagine that the Energous Power Bridges would transfer energy to sensors on demand or on pre determined schedules.

Whether powered via RF or light/TEG harvesting, IoT devices still need some form of Energy storage:batteries or capacitors or a combination of both.

https://electronics360.globalspec.com/article/19116/supercapacitors-vs-battery-energy-storage-systems

Software evolution

In parallel to hardware becoming more frugal, new protocols are also having a great impact on power consumption. This is particularly true for the very innovative SCHC (Static Context Header Compression).

As an SCHC pioneer, Acklio’s worldwide reference implementation spans across five continents for LoRaWAN, NB-IoT, RF-MESH, and satellite technologies. The company has demonstrated significant optimizations, achieving 40-90% less data traffic, 30-70% longer battery life, and up to seven times more devices per cell.

It is now being extended to any wireless technology and more excitingly will enable seamless integration with any platform and service on the market via SCHC-over-Webhooks or SCHC-over-MQTT

https://www.ackl.io/blog/schc-everywhere-the-new-extended-ietf-roadmap

Conclusions

We are only at the beginning of a shift in the LPWAN world. In the meantime we hope that the list below will help you next time someone asks you ‘What is your battery lifetime optimization strategy ?’ you can respond ‘Ours is not to have batteries at all’.

TO GO FURTHER

The information provided should be viewed as an initial answer to ‘where do I start’ rather than a commercial endorsement.

Useful links:

SOLAR POWERED DEVICES

Solar gateways

RAK Battery Plus | The Solar Battery Kit for LoRaWAN Gateways

https://tektelic.com/products/gateways/kona-photon/

LoraWAN devices

MClimate Solar Powered Thermostat

MClimate Wireless Thermostat LoRaWAN

Milesight solenoid valve

https://www.milesight-iot.com/lorawan/controller/uc51x/