power from raindrops

Researchers at Europe’s Atomic Energy Commission, in France, have shown that vibrations from raindrops can generate enough energy to operate certain low power wireless sensors. The findings could help improve networks of wireless sensors that measure conditions like temperature, pressure, or the presence of pollutants. These networks provide early warning systems for dangerous air quality, severe storms, or disease outbreaks, by continually monitoring the environment. Comparable existing networks currently use batteries that need to be regularly replaced. To be completely reliable and sustainable, sensor networks should ideally be able to power themselves.

To address this shortfall, researchers are now focusing their efforts on capturing and storing energy directly from the environment. “We thought of raindrops because they are one of the still- unexploited energy sources in nature,” Chaillout told the New Scientist.

Chaillout’s team is using a piezoelectric plastic material that translates mechanical energy from the impact of the raindrop into electric energy that powers a sensor. During a rainstorm, the material ‘dribbles’ electrical energy to a battery for storage.

Piezoelectric sensors are commonly used in cars to trigger airbags and some devices capture vibrational energy from ocean waves and humans – for example, people pushing turnstiles, and pedestrians climbing stairs. In the future scientists hope the technology will be able to power implantable biomedical devices which rely on batteries.

It is a very recent development that wireless sensors have become sufficiently low-powered and affordable enough to benefit from piezoelectric energy generation techniques.