What is Energy Harvesting?
Energy harvesting is the process of capturing ambient energy from the surrounding environment and converting it into usable electrical power. Heat differentials, mechanical vibrations, light, and electromagnetic waves — energy that would otherwise go to waste — can power IoT devices indefinitely, enabling self-sustaining sensor systems that operate for decades without a battery change.
The global IoT device market is projected to exceed 25 billion devices by 2030. Supplying and replacing batteries for all of these devices is physically, economically, and environmentally unsustainable. Energy harvesting addresses this problem at the root, enabling a battery-free, self-sustaining IoT infrastructure that scales without the burden of maintenance.
Why Energy Harvesting is Gaining Momentum
Carbon neutrality goals and tightening ESG regulations are pushing companies to reduce the carbon footprint of their entire IoT infrastructure. Producing and disposing of a single lithium battery generates approximately 70–100 kg of CO₂. For large factories with thousands of IoT sensors, battery management alone can account for tens of tons of annual carbon emissions.
Battery replacement also requires production downtime and places skilled workers in hazardous environments — a significant operational burden. Energy harvesting IoT nodes eliminate this problem entirely. Once installed, they operate autonomously for 5–10+ years, making them a cornerstone of smart factory and smart infrastructure deployments worldwide.
Primary Energy Collection Methods
Energy harvesting is broadly categorized by energy source: thermoelectric generation, vibration harvesting, photovoltaic harvesting, and RF energy collection. Each method has distinct output characteristics and is suited to different deployment environments. Combining multiple sources in a multi-source architecture provides more stable and reliable power.
Thermoelectric Generation (TEG) — Heat to Electricity
Thermoelectric Generators (TEGs) exploit the Seebeck effect to convert temperature differentials directly into electrical energy. They are especially effective around industrial piping, high-temperature equipment, and cooling system surfaces. A 5°C differential yields a few milliwatts; differentials above 50°C can produce tens to hundreds of milliwatts — more than sufficient to power a low-power MCU and wireless communication module.
Steam pipes, heat exchangers, and electric motors are ideal TEG environments because they continuously generate heat during normal operation. As long as the equipment runs, power is continuously supplied — making TEG an exceptionally reliable energy source for predictive maintenance sensors.
Piezoelectric Harvesting — Vibration to Electricity
Piezoelectric elements generate voltage when mechanically deformed. Vibrations from motors, pumps, compressors, and conveyor belts are collected and converted into electrical power. In the 10–1000 Hz vibration range, outputs range from a few microwatts to several milliwatts. Because power is generated only when equipment is running, piezoelectric harvesting is naturally synchronized with equipment operating state.
A piezoelectric vibration sensor is powered by the very vibration it is sensing — meaning the sensing target is also the power source. This makes it possible to build completely self-sustaining vibration monitoring systems that require no external wiring or batteries whatsoever.
Photovoltaic (PV) — Light to Electricity
Photovoltaic harvesting using solar and indoor lighting is the most mature energy harvesting technology. Outdoor environments yield several to tens of milliwatts per cm², while indoor fluorescent or LED lighting can produce tens to hundreds of microwatts per cm². It is particularly effective in smart buildings, logistics warehouses, greenhouses, and other environments with abundant light sources.
System Architecture of an Energy Harvesting IoT Node
An energy harvesting system consists of four core blocks: ① Harvester — converts ambient energy into a raw electrical signal. ② Power Management IC (PMIC) — regulates the irregular input voltage into a stable supply suitable for MCU operation. ③ Energy storage — supercapacitors or thin-film batteries store surplus energy to maintain operation during energy gaps. ④ Processing & communication — an ultra-low-power MCU paired with BLE or LoRa handles measurement, decision-making, and data transmission.
Power management design is the critical determinant of system performance. Since wireless transmission consumes the majority of harvested energy, duty cycle optimization and intermittent transmission design are essential. Qintelligence has developed an ultra-low-power firmware architecture that drives the entire system on an average consumption of under 100 μW.
Key Industrial Applications
TEG harvesting is used for steam pipe temperature monitoring, electric motor overheating detection, and heat exchanger efficiency measurement. Piezoelectric harvesting is well-suited for bearing wear detection in pumps, fans, and gearboxes, pipeline leak detection, and structural health monitoring (SHM) of buildings and bridges. Photovoltaic harvesting is widely applied in smart building occupancy detection, warehouse asset tracking, and agricultural temperature/humidity sensing.
In one documented case, a large domestic chemical plant deployed 300 thermoelectric harvesting-based temperature sensors and reduced annual battery replacement costs by approximately KRW 50 million, cutting maintenance interventions by over 90%. Energy harvesting IoT is not just a technology — it is a fundamental shift in how industrial operations are managed.
Qintelligence's Multi-Source Harvesting Platform
Qintelligence has developed a multi-source energy harvesting architecture that simultaneously utilizes thermoelectric, piezoelectric, and photovoltaic sources within a single platform. By operating all three sources in parallel, stable power is maintained even when any individual source is intermittent or insufficient. This enables IoT nodes that operate continuously across indoor/outdoor, day/night, and active/idle equipment environments without interruption.
The self-sustaining predictive maintenance solution built on this platform satisfies the 3-Zero principle: Zero Battery, Zero Installation Cost, Zero Cloud Cost. It enables smart factory transformation at 1/10th the cost of conventional wired systems. Combined with On-Device AI, it delivers a fully autonomous predictive maintenance infrastructure that detects and alerts on equipment anomalies directly at the edge — no cloud required.