A hybrid flowing water-based energy generator inspired by a rotatable waterwheel

The ever-increasing global demand for low-carbon energy underscores the urgency of water energy harvesting. Despite intensive progress, achieving continuous and efficient water energy harvesting—particularly from abundant, distributed, and low-frequency water flows such as rain, streams, and rivers—remains a critical challenge. Herein, inspired by the classical waterwheel that spatially decouples the gravitational force of flowing water into orthogonal directions for continuous rotation, we report a hybrid, rotatable flowing water-based energy generator (R-FEG) capable of continuous and efficient water energy harvesting at both low and high frequencies. The R-FEG device consists of transistor-like multilayer blades to harvest the kinetic energy of water at the liquid–solid interface via the bulk effect which is favorable at low frequency, and a magnetic rotor on a symmetrical blade array to harvest rotational energy via the electromagnetic effect at high frequency. As a result, the R-FEG device enables self-sustained operation in a wide range of flow rates, collectively delivering an enhanced power of 1131.3 μW at a typical flow rate of 2.0 L min⁻¹. Moreover, the R-FEG exhibits potential versatility as a battery-independent power solution for environmental sensing and outdoor electronics by harvesting water energy across fluctuating flow regimes. This work provides a prospective prototype for water flow energy harvesting, paving a new avenue for scalable, maintenance-free power solutions for applications in remote, offshore, and distributed water energy harvesting. © The Royal Society of Chemistry 2025.