As the world increasingly connects through the Internet of Things (IoT), engineers and system designers face a growing challenge: how to reliably power the billions of devices spread across factories, cities, offices, and even our bodies. Traditional power sources like batteries can be bulky, require frequent replacement, and often fall short in remote or hard-to-access environments.
Enter energy harvesting, a transformative approach that captures ambient energy from the surrounding environment and converts it into usable electrical power. For electrical engineers sourcing components from distributors like OLC and for procurement professionals responsible for supply chain efficiency, understanding energy harvesting is becoming essential.
What is Energy Harvesting?
Energy harvesting (also known as energy scavenging) is the process of capturing and converting small amounts of energy from external sources—such as heat, motion, light, or electromagnetic fields—into electrical energy. These harvested energy sources can power ultra-low-power electronics, like IoT sensors and wireless transmitters, eliminating or minimizing the need for batteries or wired power.
While the energy generated is typically small, usually ranging from microwatts to a few milliwatts, it is often sufficient for the needs of embedded systems, especially when paired with power-efficient components and smart-energy storage solutions.
Now, let’s explore some of the most impactful energy harvesting technologies and how they work.
TEGs operate based on the Seebeck effect, a principle of thermoelectricity where a voltage is generated across two dissimilar conductors or semiconductors when there’s a temperature difference between them. Essentially, heat flows from the hot side to the cold side of the material, and electrons move with it, creating electrical potential.
These devices consist of an array of thermoelectric materials arranged to maximize thermal gradient exposure. The greater the temperature difference between the two sides, the higher the electrical output. Because of this, that desired thermal gradient exposure should be as steep as possible – as hot as possible on one side and as cold as possible on the other. Within reason, of course.
In industrial settings, machines and equipment often generate excess heat. Instead of letting this energy dissipate into the air, TEGs can recover some of it and convert it into power for embedded monitoring systems. Similarly, in wearables or medical devices, TEGs can use the temperature differential between a person’s skin and the environment to power sensors, reducing the need for battery changes.
For engineers, this means sourcing highly efficient TEG modules and voltage regulation ICs that can work with low, fluctuating input voltages. While not common, a truly out-of-this-world application of TEGs is in space applications, where radioactive decay generates heat that powers satellites, probes, and rovers via a TEG. In their article "What is Energy Harvesting?", CircuitBread provides an excellent overview of the TEGs and gets into more detail of how they work on a semiconductor level.
Piezoelectric materials generate electricity when mechanically stressed, a result of their internal crystal structure. When these materials are bent, compressed, or vibrated, they produce a voltage across their surfaces.
Piezoelectric harvesters are typically used in environments where vibrations or mechanical movements are common. They can be embedded in shoe soles, roads, bridges, or industrial equipment. Materials commonly used include quartz, PZT (lead zirconate titanate), and newer flexible polymers.
Imagine a smart bridge that can monitor structural health through embedded sensors. Instead of running power lines or constantly replacing batteries, piezoelectric devices can harvest energy from the natural vibrations caused by traffic. In wearable tech, every step you take could be generating power. While the amount of power may not be large, it would be sufficient to maintain the charge on a watch or other small device.
TENGs are based on the triboelectric effect, where materials become electrically charged after coming into frictional contact with a different material. When two surfaces repeatedly touch and separate, such as in fabrics rubbing or skin movement, charges accumulate and create a voltage. Interestingly, even though we’ve been familiar with the triboelectric effect for centuries, there’s still argument about the underlying details of how it works. At the moment, anyway!
Unlike piezoelectric materials, TENGs can be made from a wider variety of materials, including common polymers. This flexibility makes them ideal for wearables and textiles.
Triboelectric harvesters are being explored for next-gen wearables that are entirely self-powered by human motion. From clothing that monitors vital signs to surfaces that detect environmental changes, TENGs could help unlock entirely new design paradigms.
RF energy harvesting captures power from ambient electromagnetic waves, like those emitted from Wi-Fi routers, cell towers, or even TV broadcasts. An RF harvester uses an antenna to collect EM waves, which are then converted to a DC voltage using a rectifier circuit.
The output is typically quite low, even lower than the other technologies already discussed. But for ultra-low-power applications, even small amounts of power can be enough to charge a capacitor and intermittently operate a device.
One of the most exciting examples comes from RFID tags which harvest power from surrounding RF signals. These tags can be embedded in packaging to track product freshness, location, or temperature in real time. They’re seen even more in action with the ever-more ubiquitous ID cards, generally used in security applications.
Energy harvesting is poised to revolutionize the way we think about power in electronics. From wearables and remote sensors to industrial automation and smart packaging, it’s enabling new products that are smaller, smarter, and more sustainable.
For engineers and buyers alike, partnering with a distributor that understands the full ecosystem of energy harvesting, from materials to power management to storage, will be key to successful deployment. At the end of the day, the power is out there. We just have to harvest it.
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