A review on energy harvesting for sustainable IoT monitoring systems

Autonomous condition monitoring is essential for advancing intelligent systems in both industrial and domestic Internet of Things (IoT) applications. However, continuous long-term condition monitoring is challenged by the limited energy availability for wireless sensor nodes (WSNs). Therefore, energy harvesting offers a promising approach by converting ambient or host energy into electrical power to sustain WSN operation. To bridge the gap between energy harvesting and condition monitoring, this review provides an overview and synthesis of recent advances in energy harvesting technologies tailored for condition monitoring applications. State-of-the-art developments in energy harvesting are categorized into six domains: healthcare, ocean, machinery, grid, railway, and infrastructure. The characteristics of these energy sources and their domain-specific monitoring requirements are analyzed. Furthermore, this review examines harvesting transducers, structural designs, and optimization methods employed in energy harvesters. Finally, the review discusses current challenges and future prospects for energy-autonomous condition monitoring systems, aiming to support the deployment of sustainable IoT sensing solutions.