Artificial “power plants” harness energy from wind and rain

Fake plants are entering the 21st century. Researchers developed real “power plants” – tiny leaf-shaped generators that create electricity from a breeze or raindrops – and described them in ACS Sustainable Chemistry and Engineering. The team tested the energy harvesters by incorporating them into artificial plants.

Electric energy can be produced by nature in several ways. For example, solar panels convert light energy from the sun and wind turbines convert the kinetic energy of air into motion. However, these methods generally rely on a single source and are therefore only effective when that source is available. Solar panels don’t work after sunset, for example, and a calm day won’t produce much wind power.

More recently, multi-source energy harvesters have emerged as a method to capture energy from different renewable sources in a single device, thereby maximizing potential output. So, Ravinder Dahiya and his colleagues wanted to create a multi-source energy harvester capable of producing energy from wind and rain.

The team built two different types of energy harvesters: a triboelectric nanogenerator (TENG) to capture kinetic energy from wind and a droplet-based energy generator (DEG) to collect energy from raindrops which fall. The TENG consisted of a layer of nylon nanofibers sandwiched between layers of polytetrafluoroethylene, more commonly known as Teflon, and copper electrodes.

Static charges were generated and converted into electricity when the layers pressed against each other. Teflon was also used to make the DEG, which was waterproofed and covered with a conductive fabric to act as electrodes. When raindrops hit one of the electrodes, it caused an imbalance of charges, generating a current. Under optimal conditions, the TENG produced 252 V of power and the DEG 113 V, but only for short periods.

The team mounted the DEG atop the TENG and incorporated leaf-shaped versions into an artificial plant. When the leaf-shaped generators were exposed to conditions mimicking natural wind and rain, they powered 10 LED lights in short flickers. This proof-of-concept “power plant” device could be further developed into larger power plant systems or networks to produce clean energy from natural sources, the researchers say.