Exploring alternative paradigms for piezoelectric energy harvesters

Electricity is typically produced by large-scale power plants generating megawatts of power for residential and commercial use. Increasingly, however, researchers are exploring small-scale energy harvesters that draw power from kinetic fluctuations in their environment like gusts of wind or structural vibrations. These devices rely on either electromagnetic or piezoelectric effects to produce electricity, but in recent years the electromagnetic approaches have demonstrated clear advantages.

Looking forward to the future of piezoelectric energy harvesters, Yang Bai discussed an alternative paradigm for the technology that could make these devices more economically viable.

“After two decades of development, the piezoelectric method is obviously falling behind in the commercialization of kinetic energy harvesting,” said Bai.

Unlike electromagnetic energy harvesters, piezoelectric devices exhibit extreme sensitivities to specific resonance frequencies, resulting in large power outputs when exposed to those frequencies. This can make them useful in sensors that monitor structural health or environmental changes. However, the intermittent nature of the generated electricity is often not enough to compensate for the power required for sensors and computers to collect and analyze the data.

Instead of this typical use case, Bai argues that piezoelectric harvesters could themselves act as sensors, with carefully chosen excitation frequencies to provide data in the form of the energy they generate.

“The harvested energy within a certain period can be interpreted as a history of the data reflecting the change of the device’s working environment,” said Bai. “The feasibility of the Energy-as-Data concept supports its application in many Internet of Things (IoT) devices that deliver critical information instead of massive data.”

Source: “Exploring challenges and potential for a commercially viable piezoelectric energy harvesting system - Can Energy-as-Data concept thrive?,” by Yang Bai, Applied Physics Letters (2024). The article can be accessed at https://doi.org/10.1063/5.0193134 .