Connected IoT devices are pervading all aspects of our daily lives but there is a significant problem associated with the way these devices are powered, since a large proportion of them use disposable batteries. Batteries are a big cause of environmental concern; almost all batteries use toxic materials, and they are even difficult to recycle. One of the solutions to the problem is using battery-less devices that can be powered by ambient energy sources such as solar (indoor and outdoor light), kinetic (motion, vibration, pressure), thermal (obtained from temperature differences) and radio frequency/RF (obtained from ambient radio waves present from Wi-Fi, radio transmitters, cellular stations and others) and more. This technique, commonly known as ‘Energy Harvesting’ (EH), converts ambient energy sources into electrical energy so the devices, IoT devices in this context, can partially or fully work without needing battery power. Not every IoT application is suited and ready to harvest ambient power, but a growing number of devices are getting closer, especially the ones that require very low power and transfer data intermittently.
The growth of energy harvesting devices is being driven by sustainability mandates (like the EU Battery Regulation), maintenance cost savings, lower cost of ownership for powered devices, and advances in low power chips. Maintenance costs are reduced by using battery-less devices as potentially there is no cost associated with battery replacement logistics and disposal. This especially benefits industries that have devices located in hard-to-reach places or sectors that have large number of devices installed per site such as smart buildings. Additionally, improvement in harvesting modules technology is also giving a push to the market, for example, solar energy has been used for decades but in the last couple of years solar cells have become more efficient so they can produce higher output voltages for a given light intensity.
Transforma Insights recently published a report ‘The potential for energy harvesting powering IoT devices’ that includes forecasts on the number of IoT devices that can potentially make use of energy harvesting sources. The report highlights the IoT applications that represent the biggest market opportunity for energy harvesting and presents examples of battery-less IoT products that are already commercially available in the market. Some of the key players mentioned in the report include Atmosic Technologies, Dracula Technologies, Ebelong, EnOcean, E-Peas, Exeger, HaiLa, Linptech, Minew, Nexperia, Powercast and Wiliot.
This blog post presents some of the key findings from the report.
Transforma Insights identifies four categories of energy harvesting: Solar, Kinetic, Thermal and RF. Solar harvesting has the greatest potential to power IoT devices of all energy harvesting technologies, followed by RF, kinetic energy, and then thermal energy.
Transforma Insights forecasts that the number of IoT connected devices that have the potential to be powered by solar (photovoltaic) harvesting by the end of 2030 will be 7 billion, around one-fifth of total IoT connected devices in 2030.
Around 3 billion devices could potentially be powered by RF energy harvesting while kinetic energy can potentially support 1 billion IoT devices in 2030. Although kinetic energy harvesting has the potential to generate more power than RF energy harvesting, the ability of RF technology to power electronic shelf labels (ESLs), one of the largest segments of connected devices, positions it as a higher potential energy-harvesting method in terms of potential deployment volume. Thermal has less significant potential compared to other sources with 84 million connected devices in 2030.
The potential for each of the energy harvesting approaches is highly concentrated in just a few use cases. As illustrated in the graphic below, the top five IoT applications for each of the energy sources (solar, kinetic, thermal and RF) account for 70–90% of the total IoT connected devices powered through EH. For example, for RF energy, the top five applications (Inventory Management & Monitoring, Building Automation, Track & Trace, Building Safety & Security and Building Lighting) alone represent 92% of all IoT connected devices that can be powered through ambient RF. For most of the energy sources, Inventory Management & Monitoring, Building Automation, Building Lighting controllers and Track & Trace have the highest potential, especially for harvesting energy from solar and RF. The top use cases are:
The opportunity for leveraging solar energy is distributed across a wider range of IoT applications, with 38 IoT applications showing potential for solar harvesting. In contrast, the opportunities for thermal and RF energy harvesting are more concentrated, with only 10 and 13 applicable IoT use cases, respectively.
Opportunities for kinetic energy are generally smaller with 1 billion devices in 2030, but it is crucial for its application in wearables, self-powered switches, industrial vibration sensors and micromobility devices. A notable commercial example of self-powered switch is the EnOcean wireless switch, a self-powered Zigbee-compatible device that is powered by kinetic energy. Thermal has less significant potential compared to other sources but can also be important for applications in healthcare monitoring devices and wearables. Some commercial examples of wearables using thermal include early prototypes from Matrix Industries (PowerWatch) and ThermoLife, which use body heat for supplemental power. There are also ongoing trials for using thermal energy in connected scales and diabetes monitoring devices.
Solar will be the dominant energy harvesting technology with a potential 7 billion devices in 2030. It will be followed by RF (3 billion devices), kinetic energy (1 billion devices) and thermal energy (83 million devices). In terms of IoT applications, Building Automation, Track & Trace (including supply chain asset trackers), Building Lighting (wireless light control) switches and Inventory Management have been early to adopt energy harvesting and have the potential to account for maximum share. These are examples of IoT products that are already working battery-less. Asset trackers and electronic shelf labels also have great potential to use battery-less technologies as they are used to send small amounts of data intermittently, which suits harvesting perfectly.
