Energy harvesting is the process by which energy is derived from external sources. It is a very important technology for wireless networks. I already mentioned it in a previous post about EnOcean, but I think it is a really interesting subject.
If devices can harvest energy from their surroundings, batteries might never get low. For example, in our thesis, we use a solar panel. Getting energy from the sunlight is a form of energy harvesting. I will discuss some of the most important energy harvesting technologies.
- Kinetic energy can be converted into electrical power. The movement of a magnet in an electromagnetic field provides a rate of change of flux. This results in an induced electromagnetic force on the coils. The induced voltage can be used to power a battery.
- Like mentioned before, photovoltaic panels also generate electrical power and can be used in WSN’s.
- Wind energy can be converted into electrical power by wind turbines. This is a well-known technique and used a lot for green energy. It is a little less common for use in WSN’s, but it stays an important energy harvesting method.
- A change of temperature can also be converted into electrical power by thermoelectric generators.
- Vibrations can be converted into electrical energy by piezoelectric crystals. They generate a small voltage when they are mechanically deformed.
In times of austerity and environmental awareness, this is a very important subject. Personally, I think there should be more investments in research, to improve these techniques. Maybe in several years, they can also be implemented in devices that we use every day, like a smartphone. Batteries will live much longer or maybe they will not be needed anymore.
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