Energy-harvesting flags use wind and solar to power remote devices

The energy-harvesting flags have been developed using flexible piezoelectric strips that generate power through movement, and flexible photovoltaic cells.

The study, conducted by researchers Manchester University, is claimed to be the most advanced of its kind to date and the first to simultaneously harvest wind and solar energies using inverted flags. The research has been published in Applied Energy.

As well as remote sensors, the energy harvesting flags are capable of powering small-scale portable electronics which can be used for environmental sensing. The aim of the study is to allow cheap and sustainable energy harvesting solutions which can be deployed and left to generate energy with little or no need for maintenance. This “deploy-and-forget” strategy is the anticipated model that so-called smart cities will adopt when using remote sensors.

Jorge Silva-Leon, from Manchester’s School of Mechanical, Aerospace & Civil Engineering and lead author of the study, said: “Under the action of the wind, the flags we built bend from side to side in a repetitive fashion, also known as Limit-Cycle Oscillations. This makes them perfectly suited for uniform power generation from the deformation of piezoelectric materials. Simultaneously, the solar panels bring a double benefit: they act as a destabilising mass which triggers the onset of flapping motions at lower wind speeds, and of course are able to generate electricity from the ambient light.