A study, conducted by researchers at The University of Manchester, explains how some researchers at the University of Manchester in the UK have developed the first flags that can simultaneously generate electrical energy using wind and solar power. The wind and solar energy harvesting flags have been designed with adaptable piezoelectric strips and PV cells. The strips enable the flag to produce energy through movement and the photovoltaics captures the electrical power via solar cells. The flags will be able to power remote sensors and portable electronics which can monitor pollution as well as heat and sound levels.

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. The strategy is known as “deploy-and-forget” and this is the anticipated for 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, says: “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 destabilizing mass which triggers the onset of flapping motions at lower wind speeds, and of course are able to generate electricity from the ambient light.
Co-author of the project Andrea Cioncolini explains that both wind and solar tend to have intermittencies that can compensate each other i.e. sun does not usually shine during stormy conditions, whereas calm days with no wind are usually when the sun is shining. This makes wind and solar energies particularly well suited for simultaneous harvesting, with a view at compensating their intermittency.

The team at Manchester University developed techniques such as rapid video imagery and data analysis to highlight the flags worked. The developed systems were tested in various wind speeds replicating a range of weather conditions and proved to be successful.