Chinese Invention Uses Lotus Leaves to Power Small Electronic Devices

Chinese scientists have developed a transpiration energy generator capable of creating electricity using lotus leaves. The generator could turn nearly all leaves on the planet into a continuous and sustainable source of energy.

The researchers said their discovery of the leaf transpiration’s hydrovoltaic effect provided “fresh perspective for advancing green energy technologies,” as the South China Morning Post reported.

The research team said their lotus leaf transpiration generator (LTG) had the ability to power small electronic devices. It could also be used to create electricity networks using plant power.

Hydrovoltaic electricity is reliant on the movement of water and its interaction with solid surfaces. A steady supply of water is often required for current devices, which creates geographic limits, since the devices need to be close to bodies of water like rivers.

“Hydrovoltaic electricity generation, being demonstrated through various forms of water movement, holds great promise for advancing green energy technologies. However, the natural transpiration of plant leaves, as the largest water flux on land accumulating immense latent energy, has rarely been directly harvested,” the scientists wrote in the study. “Here we present a living leaf transpiration generator using a lotus leaf, enabling direct harvest of latent energy via leaf transpiration. The leaf transpiration generator demonstrated sustained all-day electricity generation, featuring an open-circuit voltage of 0.25 V and a short-circuit current of 50 nA, which was effectively amplified in series or parallel connections.”

The study, “Hydrovoltaic electricity generation induced by living leaf transpiration,” was published in the journal Nature Water.

Transpiration in plants involves water moving through the roots to their leaves before evaporating.

“Transpiration is basically evaporation of water from inside plant leaves. Studies have revealed that transpiration accounts for about 10% of the moisture in the atmosphere, with oceans, seas, and other bodies of water (lakes, rivers, streams) providing nearly all of the remaining amount,” the National Oceanic and Atmospheric Administration said. “During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year.”

The team estimated that the harvesting of transpiration energy from plants has the potential to produce 67.5 terawatt hours of power globally each year, reported Interesting Engineering.

The researchers said that with technical advancement and continued research, the power generation method could become widely used and commercially viable.

Though the process is still in its early stages, the research team is working on understanding the role of plant transpiration in power generation, enhancing the contact between electrode and plant and integrating LTG with renewable sources of energy like solar and wind.

The authors said the study “uncovers the unprecedented hydrovoltaic effect of leaf transpiration,” as the South China Morning Post reported.