There are vibrations occurring in the ground nearly all the time. They happen when cars pass by, when machines are operating, and from natural forces in the earth’s crust. For the most part, we don’t notice these vibrations. But they are there, and they represent an untapped source of clean energy.
Small tremors in the ground can be converted into electricity in two ways. One is by using piezoelectric materials, which produce voltages when they are bent, stretched, or compressed. The other is by electromagnetic induction, which generates a current when a magnet moves past a conductor.
The amount of electricity that can be generated by tapping into these small ground vibrations is quite small. It is not a replacement for solar or wind power. But having small amounts of electric power on hand where the power grid or a battery supply is unavailable could be very valuable.
Sensors are increasingly important in many challenging locations. They are used to monitor bridges, water systems, the environment, natural hazards, earthquake activity, water quality, and more. They might be located deep inside mines, underground in carbon dioxide storage facilities, on the seabed, or inside closed structures.
Researchers at Norway’s NINTEF, one of Europe’s largest research institutes, have been developing vibration harvesting devices in collaboration with colleagues in Sweden and Chile. Using computer simulations and laboratory testing, they have created devices based on both ways to generate electricity. The next step will be to test the devices in a variety of real-world environments. The amount of energy the devices can generate may be small, but such devices can be very valuable in many places.
