USA — For scientists have not only confirmed that trees produce electricity they’ve also discovered how much they generate and even a novel way to put it to good use.
The fact that trees produce a tiny amount of electricity has been known for a while, but a new study has nailed down how the energy is produced. Initially it was thought that possible sources might include tapping into emissions from power lines or broadcast radio waves.
The answer, however, is that trees generate electricity from an imbalance in acidity between the tree and the soil.
As researchers at the Massachusetts Institute of Technology (MIT) noted, this is the same simple process that generates electricity from a potato or lemon at school science fairs.
The study was carried out at MIT and the researchers say the trees’ current could recharge battery operated sensors that can detect forest fires.
Reporting in PloS ONE, an online journal from the Public Library of Science, they say the system generates enough electricity to allow the temperature and humidity sensors to wirelessly transmit signals four times a day.
It also can send an alert if the device detects a forest fire.
Each signal hops from one sensor to the next until it reaches an existing weather station. From that location, the signal is beamed by satellite to a forestry command centre in Boise, Idaho.
The US Forest Service uses a sparse network of automated weather stations to monitor forest condition which help in predicting fire dangers.
A wider, denser network of tree-powered sensors that didn’t need periodic battery replacement would be a major improvement.
The system developers, Andreas Mershin and Shuguang Zhang, have launched a spin-off company Voltree Power based on the technology. The pair say they expect to begin pilot tests next spring on a 10-acre plot of land provided by the US Forest Service.
It’s estimated it will need one instrument for every four trees on an acre of land.
Dr Zhang explained that, while tree power is weak, it can supply a “trickle charge” that “just like a dripping faucet, can fill a bucket over time.” Thus trees can be a reliable power source to recharge batteries in embedded sensors.