Digitized IoT systems are now part of daily life, spanning smart cities and homes, supply chain management, retail, agriculture, wearables, medical applications, and more. IoT provides easy access to information from anywhere, at any time, on any device. According to a recent MarketsandMarkets report, the global IoT market size was valued at USD 64.8 billion in 2024 and is expected to grow at a CAGR of 18.8% from 2024 to 2029. This rapid growth makes sustainability a key consideration to reduce-or even eliminate-excessive battery waste.
Batteryless energy harvesting is an ideal solution for earth-friendly IoT devices. Energy harvesting captures and converts energy from various ambient sources into usable electrical power, enabling maintenance-free and long-lifetime IoT deployments.
Light: The power generated by a solar panel depends on the amount and type of light, as well as the solar cell technology. On average, earth’s irradiance is around 1000 W/m², resulting in 20 mW/cm² from high-quality monocrystalline solar cells and 8–10 mW/cm² from more affordable amorphous silicon cells. Indoors, artificial lighting reduces output to a few μW/cm² under typical living room conditions and tens of μW/cm² on an office desk. As a result, relatively large solar panels are needed, and they must be placed on well-lit surfaces.
Presto collaborated on a project featuring a solar-powered sensor.
Read more about this innovative application: Solar-Powered IoT Sensor Collaboration
Temperature Differences: The thermoelectric effect enables the conversion of temperature differences into electrical current. Small thermal differences of a few degrees can generate a few mW/cm², while differences of 100°C may generate up to 400 mW/cm². Thermoelectric generators are promising for powering wearable devices and industrial sensors.
Managing power is one of the main challenges in IoT design. Typical IoT products are small devices that require compact energy harvesters. This means energy must be harvested, stored, and used only when a sufficient amount is available. Each step in the energy harvesting process-including storage and usage-must be optimized to provide the most efficient operation.
Different energy harvesters have unique output characteristics, so each requires a customized electronic circuit for optimal function. Effective energy harvesting is achieved by matching the power management circuit’s input impedance to the generator’s output, ensuring maximum power transfer. As the amount of available power changes, the maximum power point will shift, so the power management system must adapt dynamically to continue operating at maximum efficiency-a process known as maximum power point tracking.
Once power is extracted, it is accumulated in intermediate storage, either on a capacitor or a battery. The choice of storage depends on the product’s requirements, such as the amount of energy required, peak current consumption, expected lifetime, and operating temperature.
Importantly, the product itself must be designed to operate within the constraints of a replenishable energy source, rather than a limited but always-available battery. This is achieved by effective scheduling and taking into account when power is available. Energy harvesting is not a simple battery replacement: with careful consideration of circuit elements and good low-power practices, an energy harvesting-powered system can be a viable approach to creating a maintenance-free, long-lifetime solution.
Since 2009, Presto has supported customers in designing and implementing energy harvesting-powered systems.
Explore a real-world use case: Energy Harvesting ASIC Case Study
We help you navigate the design space of different harvesters, select the right power conditioning modules, and optimize energy storage.
Our team can also help design algorithms that ensure stable power supply and operation for your IoT product. We manage the entire ASIC procurement process, from initial design to IC delivery.
Our power management IP is designed to manage energy harvested from light and thermal sources. The on-chip module controls efficient power storage, load operation, and sleep duration, helping your product achieve energy-neutral operation. With intelligent features that support power conservation and simplify system design, you can reduce product size, lower system cost, and accelerate your time to market.
➡️ Learn more about our IP for energy harvesting: Power Management IP