By Ankit SinghReviewed by Susha Cheriyedath, M.Sc.Dec 16 2024
Smart cities are quickly becoming a reality, with sensors and devices quietly working to monitor everything from traffic jams to air quality. However, keeping these systems running efficiently presents a significant challenge. Traditional battery-powered solutions aren’t scalable—they need to be replaced on a regular basis, driving up maintenance costs and undermining long-term sustainability goals.

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Energy harvesting offers a practical alternative. By capturing ambient energy—like sunlight, vibrations, or radio frequencies (RF)—devices can power themselves, significantly reducing maintenance while improving reliability. For businesses and city planners, this approach offers a cost-effective and sustainable way to scale smart infrastructure.
In this article, we’ll examine how energy harvesting works, its real-world applications, and the opportunities it presents for creating smarter, more efficient cities.
Understanding Energy Harvesting in IoT
Energy harvesting enables IoT devices to generate power from their surroundings, converting ambient sources like sunlight, heat, motion, or radio frequencies into usable electricity. This eliminates reliance on traditional batteries, which can be impractical for large-scale deployments due to their limited lifespan and high maintenance costs.
In urban environments, where thousands of sensors monitor everything from traffic flow to infrastructure health, energy harvesting delivers clear advantages. Self-powered devices can collect and transmit data, process information, and communicate wirelessly—all without human intervention for battery replacements.
By improving operational efficiency and reducing environmental impact, energy harvesting makes it feasible to scale IoT networks while keeping costs under control. It’s a practical solution for cities looking to balance innovation with sustainability.1,2
Ambient Energy Sources in Urban Settings
Urban environments are rich with untapped energy sources that can be harvested to power IoT devices. By leveraging these ambient energies, cities can reduce their reliance on batteries and enable continuous, low-maintenance operation for large-scale IoT networks.
Solar Energy
Solar energy remains the most accessible and widely used source for energy harvesting. Photovoltaic (PV) cells convert sunlight into electricity, allowing outdoor devices—like smart streetlights, air quality sensors, and surveillance cameras—to operate indefinitely. Recent advancements also enable PV systems to capture energy from artificial lighting indoors, providing power for small, low-energy IoT devices.1,2
Thermal Energy
Urban environments naturally generate thermal gradients from industrial processes, HVAC systems, and heat-absorbing surfaces like asphalt. Thermoelectric generators (TEGs) convert these temperature differences into electricity, enabling devices to monitor industrial equipment, energy efficiency, or environmental conditions without relying on external power sources.1,2
Kinetic Energy
High-traffic areas like roads, bridges, and sidewalks are prime locations for kinetic energy harvesting. By using piezoelectric materials or electromagnetic systems, mechanical energy from vibrations, motion, or pressure is converted into electrical power. For instance, sensors embedded in roadways can harness energy from the vibrations caused by passing vehicles, powering traffic or infrastructure monitoring systems.1,2
Radio Frequency Energy
Ambient RF signals from Wi-Fi routers, mobile towers, and other transmitters offer a consistent energy source for low-power IoT devices. RF energy harvesting enables self-powered applications such as smart meters, asset trackers, and sensors in urban settings, where RF emissions are always present.1,2
Applications in Smart Cities
Integrating energy harvesting with IoT is unlocking innovative applications across urban environments. From monitoring air quality to ensuring infrastructure safety, self-powered devices reduce energy costs and maintenance needs while enabling smarter, more efficient cities.
Environmental Monitoring
Self-powered sensors provide continuous, real-time data on air quality, noise levels, and weather conditions, helping city planners make informed decisions. Companies like Siemens and BreezoMeter are deploying these systems to combat pollution, optimize waste management, and improve public health. For instance, air quality sensors along busy roads can detect harmful pollution spikes and trigger immediate action.3
Smart Transportation
Energy-harvesting sensors embedded in roads and vehicles can monitor traffic patterns, optimize signal timings, and identify maintenance needs. Piezoelectric sensors, for example, generate power from vehicle vibrations while simultaneously monitoring road conditions. Solutions from established companies like IBM and startups such as EcoMotion are reducing congestion and enhancing public transit efficiency.3,4
Public Safety
Surveillance systems and emergency sensors powered by ambient energy ensure continuous operation, even in remote or disaster-prone areas where reliable power is critical. Hikvision is at the forefront of energy-harvesting surveillance technologies, while startups such as SenseFly are providing innovative public safety solutions. This is particularly beneficial in areas prone to natural disasters or accidents, where reliable power is essential.3
Infrastructure Health
Monitoring the structural integrity of bridges, buildings, and other infrastructure is essential for safety and longevity. Self-powered sensors detect vibrations, stress, and material degradation, enabling early intervention before small issues escalate. Vibration-based energy harvesters provide power for these systems, with companies such as Structural Monitoring Systems advancing reliable, self-sustaining solutions for infrastructure management.3
Advantages of Energy Harvesting for IoT
Energy harvesting offers a range of benefits that make it a critical technology for IoT in smart cities, combining sustainability, cost savings, and scalability to support large-scale sensor networks.1,2
- Extended Device Lifespan: By eliminating reliance on traditional batteries, energy harvesting significantly extends the operational life of IoT devices.
- Reduced Maintenance Costs: Self-powered devices minimize the need for frequent battery replacements, cutting labor and maintenance expenses.
- Environmental Benefits: By reducing battery waste and utilizing renewable energy sources, energy harvesting aligns with modern sustainability goals.
- Scalability: With power no longer a limiting factor, self-powered IoT devices make it feasible to deploy extensive sensor networks across urban environments.
Challenges and Considerations
While energy harvesting is a highly promising technology when it comes to IoT, its practical implementation still poses some challenges. These issues range from energy availability and efficiency to scalability and environmental impact, all of which require innovative solutions to ensure widespread adoption.1,5
- Energy Availability: Ambient energy sources, such as solar or RF, are often intermittent. For example, solar energy isn’t available at night, and RF signals may fluctuate depending on the environment. Efficient energy storage solutions, like supercapacitors or advanced batteries, are essential to maintain consistent device operation.
- Energy Conversion Efficiency: Current technologies often struggle with low conversion rates, limiting the amount of usable energy captured. Improving conversion efficiency through advanced materials and designs remains a focus of ongoing research.
- Cost and Scalability: While energy harvesting reduces long-term costs, the upfront expense of integrating these systems into IoT devices can be high. Innovations in materials and manufacturing processes are key to making these solutions more cost-effective and scalable.
- Environmental Impact: Although energy harvesting promotes sustainability, the materials used—such as rare earth metals—can have their own environmental consequences. Developing eco-friendly alternatives will be critical for long-term viability.
Latest in Self-Powered IoT Research
Recent advancements in self-powered IoT research have led to significant breakthroughs in energy harvesting and smart city applications. One notable study published in MDPI Sensors introduced a self-optimizing water level monitoring methodology designed specifically for smart city IoT applications. This system was designed to enhance both accuracy and power efficiency by incorporating a multi-step measurement mechanism alongside a dynamic self-charging process.
The system was able to successfully achieve accuracy improvements ranging from 0.16 % to 0.39 %, while maintaining stable battery levels above 50 %. Equipped with an embedded control device, an ultrasonic sensor, and a Long Range (LoRa) module, this approach demonstrates high precision and energy-efficient performance, making it particularly effective for water monitoring applications.6
In another significant development, research published in Microprocessors and Microsystems proposed a self-powered garbage management system aimed at improving waste management in smart cities. This system integrates IoT technology with convolutional neural networks (CNN) to facilitate waste segregation and energy generation. It classifies household waste into organic and inorganic categories with an impressive accuracy of 98 %. The system was also able to produce biogas from 50 kg of organic waste, generating approximately 114 MJ of electricity. Controlled by a Raspberry Pi, this automated solution streamlines the processes of collection, segregation, and notifications for recycling, offering a sustainable approach to municipal waste management.7
The rapid growth of connected IoT devices—projected to reach approximately 18.8 billion globally by the end of 2024—highlights the increasing need for efficient, self-powered sensors. To address the challenges associated with large-scale IoT deployments, researchers are focusing on developing highly efficient energy harvesters that can be combined with hybrid approaches such as wireless power transfer (WPT). This exploration includes advancements in triboelectric nanogenerators (TENGs) and photovoltaic systems that can harvest energy from various environmental sources.
Looking ahead, the integration of artificial intelligence (AI) with IoT is also emerging as a key trend that promises to enhance safety, accuracy, and efficiency across various sectors. Researchers are making strides toward creating self-sustained IoT systems capable of operating autonomously without relying on external power sources. These developments underscore the rapid progress in self-powered IoT research and its potential to pave the way for more sustainable and efficient solutions within smart cities.
Future Prospects and Conclusion
The shift toward energy harvesting in IoT represents more than just a technical advancement—it reflects a necessary step in addressing the real challenges of scale, cost, and sustainability that come with building smart cities. By enabling devices to draw power from their surroundings, energy harvesting reduces our reliance on disposable batteries, offering a smarter way to keep essential systems running without interruption.
However, its potential goes beyond efficiency. It opens the door to smarter infrastructure, cleaner environments, and more resilient cities—cities that are not just "connected" but also sustainable and adaptable to future needs. While challenges remain, the rapid pace of research and innovation signals a clear direction: the future of urban technology lies in systems that power themselves.
As energy harvesting continues to evolve, its success will depend on collaboration between researchers, businesses, and policymakers. Together, they can turn this emerging technology into a foundational tool for building cities that are both innovative and responsible—places where technology works quietly, efficiently, and sustainably for the people who live there.
Check out this article for more on IoT and Smart Sensor Technologies!
References and Further Reading
- Eunice, A., & Carvalho, N. B. (2021). Energy Harvesting Mechanisms in a Smart City—A Review. Smart Cities, 4(2), 476-498. DOI:10.3390/smartcities4020025. https://www.mdpi.com/2624-6511/4/2/25
- Elahi, H. et al. (2020). Energy Harvesting towards Self-Powered IoT Devices. Energies, 13(21), 5528. DOI:10.3390/en13215528. https://www.mdpi.com/1996-1073/13/21/5528
- Rohini, A. et al. (2024). Self-powered wireless solution towards the smart city: Use cases and its applications. Self-Powered Sensors, 237-250. DOI:10.1016/B978-0-443-13792-1.00009-2. https://www.sciencedirect.com/science/article/abs/pii/B9780443137921000092
- Izadgoshasb, I. (2020). Piezoelectric Energy Harvesting towards Self-Powered Internet of Things (IoT) Sensors in Smart Cities. Sensors, 21(24), 8332. DOI:10.3390/s21248332. https://www.mdpi.com/1424-8220/21/24/8332
- Famitafreshi, G., & Afaqui, M. S. (2020). A Comprehensive Review on Energy Harvesting Integration in IoT Systems from MAC Layer Perspective: Challenges and Opportunities. Sensors, 21(9), 3097. DOI:10.3390/s21093097. https://www.mdpi.com/1424-8220/21/9/3097
- Chi, T. et al. (2020). A High-Accuracy and Power-Efficient Self-Optimizing Wireless Water Level Monitoring IoT Device for Smart City. Sensors, 21(6), 1936. DOI:10.3390/s21061936. https://www.mdpi.com/1424-8220/21/6/1936
- Thamarai, M., & Naresh, V. S. (2023). Smart self-power generating garbage management system using deep learning for smart cities. Microprocessors and Microsystems, 98, 104816. DOI:10.1016/j.micpro.2023.104816. https://www.sciencedirect.com/science/article/abs/pii/S0141933123000625
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