Scientists have created flags that can generate electrical energy using wind and solar power.

The novel wind and solar energy-harvesting flags have been developed using flexible piezoelectric strips and flexible photovoltaic cells.

Piezoelectric strips allow the flag to generate power through movement, whilst the photovoltaics is the best known method of harnessing electric power by using solar cells.

The study, conducted by researchers at The University of Manchester, is 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 the journal Applied Energy.

The newly developed energy harvesting flags are capable of powering remote sensors and small-scale portable electronics which can be used for environmental sensing such as to monitor pollution, sound levels and heat for example.

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.

Dr Andrea Cioncolini, co-author of the study, added: “Wind and solar energies typically have intermittencies that tend to compensate each other. The sun does not usually shine during stormy conditions, whereas calm days with little wind are usually associated with shiny sun. This makes wind and solar energies particularly well suited for simultaneous harvesting, with a view at compensating their intermittency.”

Source: The University of Manchester