Micro energy harvesting
Devices that gather tiny amounts of power from motion, heat, friction, radio waves or humidity.
Capture · Emerging · No. 48
- Capture
- Output: Small amounts of electricity
A wristwatch powered by body heat converts just 0.1% of the warmth flowing through it, enough for 22 microwatts.
Chart: Illustration: Micro energy harvesting
Where it comes from
Footsteps, vibration, body heat, radio signals and even damp air all carry stray energy. Crystals, semiconductors, antennas and films catch a trickle of it, from microwatts to watts.
Pavegen has over 250 floor-tile installations, Betavolt sells a 100-microwatt nickel-63 cell and NASA flies plutonium RTGs; the whole market was about USD 0.61 billion in 2025.
Three things to know
- A road harvester in a California test captured about 10% of passing vehicles' motion, some 7 to 17 J per vehicle.
- NASA's MMRTG turns plutonium-238 decay heat into about 110 W at launch, falling to about 72 W after 17 years.
- A film of bacterial protein nanowires can draw electricity from humid air, at most about 8.5 microwatts per cm².
The journey
- 1 Ambient energyMotion, heat, radio waves or moisture
- 2 HarvesterCrystal, semiconductor, antenna or film
- 3 ConversionTiny voltage rectified by a circuit
- 4 StorageCapacitor or battery holds the trickle
- 5 UseSensors, wearables, tags and space probes