The natural phone charger: The power plant of the future

The E-Kaia is a prototype phone charger that uses excess energy from a plant’s photosynthetic cycle and microorganisms in the soil to create electricity. The E-Kaia was designed by Evelyn Aravena, Camila Rupcich, and Carolina Guerro in 2009, students from Duoc UC, and Andrés Bello University in Chile. The E-Kaia works by partially burying a bio-circuit in the soil next to a plant. 

Plants take in oxygen, and when combined with energy from the sun, they go through a metabolic cycle called photosynthesis. This cycle creates food for the plant, some of which is stored in their roots. Amongst the roots there are microorganisms that help the plant take up nutrients and in turn they get some food. The microorganisms then use that food for their own metabolic cycles. In these cycles, nutrients are converted to energy and during the process some electrons are lost – absorbed into the soil. It is these electrons that the E-Kaia device takes advantage of. Not all of the electrons are harvested in the process, and the plant and its microorganisms are not harmed in the process. Best of all, this type of energy generation, although small, has no environmental impact as it releases no emissions or harmful by-products like traditional methods.

The E-Kaia output is 5 volts and 0.6 amps, which is enough to charge your phone in about one and a half hours; for comparison, the Apple USB charger output is 5 volts and 1 amp. A USB plug is integrated into the E-Kaia so most phone chargers or devices that use a USB can plug in and charge courtesy of the environment. Because the team’s patent is still pending, specifics on the E-Kaia bio-circuit are not yet available, but the team hopes that they can start distributing the device later in 2015. 

Similarly, Wageningen University in the Netherlands are developing the Plant-e. The Plant-e uses the same principle as the E-Kaia where electrons from microorganisms in the soil power the device. As the Plant-e device is patented details have been released on how it works: An anode is implanted in the soil, and a cathode surrounded by water is installed next to the soil separated by a membrane. The anode and cathode are connected to the device by wires. As there is a charge difference between the environment that the anode and cathode are in, electrons flow from the soil through the anode and cathode and into the charger. The flow of electrons generates an electric current and powers the device.