The term 'energy harvesting
' is most typically applied to powering small electronic devices using say sunshine, vibration or temperature. However, the same technologies are used in heavy engineering, such as large construction vehicles converting the rotational and vertical braking energy of their implements into electricity.
There are the very successful forms of energy harvesting and there are the basketcases of negligible commercial success - little more than research curiosities. However, many new developments are being made to enable high power energy harvesting which will result in an industry worth $3.4 billion in 2020 for energy harvesting transducers.
The research finds that energy harvesting is increasingly using the same technology, often from the same companies, whether it is generating one microwatt for sensors to vehicle battery
charging from harvesting that can reach many kilowatts. It is all one business now but, for the coming decade, the largest addressable value market lies in the range of one watt to 10 kW.
It has always been true that the favourite technologies are electrodynamics and photovoltaics. However, the users for low versus high power were different and the other harvesting technologies were rarely capable of generating high power. No more. Major recent advances move them firmly into the high power sector.
Recent announcements concerning electret and elastomeric capacitive harvesting promise up to one kilowatt. Thermoelectric generators up to 1.5 kW are being tested and performance improvement boosted by the new skutterudites. Transparent thermoelectrics capable of wide area also promises high power levels
. The new perovskite photovoltaics has suddenly achieved efficiency of almost double that which organic
photovoltaics has struggled up to after about 20 years.
As for the users, the increased focus on vehicles and off-grid buildings means that a given user is interested in everything from providing micro-grid electricity to wirelessly powering a plethora of sensors and actuators in situ.
Top image photos source: IDTechEx