Energy Harvesting

What is Energy Harvesting?

Process where energy is derived from external sources, captured and stored for use in electronic systems.

Energy harvesting is a process by which ambient energy is captured and converted into electricity for small autonomous devices, such as satellites, laptops and nodes in sensor networks making them self-sufficient.

Sources as lighting, temperature differentials, vibrations, and radio waves (RF energy) can be re-used to operate low-power electronic devices.

 

Where is it useful?

  • Where line power is unavailable or costly
  • Where batteries are costly or difficult to replace
  • Where energy is needed only when ambient energy is present

 

 

 

Market demand

Growth in the 2-digit range will increase the market volume by 4 within the next 5 years after 2015

 

Typical applications

  • Portable consumer electronics Calculators, toys, piezo gas lighters, electronic car keys, electronic apparel etc
  • Industrial Mainly buildings, machinery, engines, non-meshed wireless sensors and actuators
  • Wristwatches
  • Laptops, e-books
  • Wireless sensors
  • Military and aerospace excluding WSN
  • Healthcare Implants, disposable testers, drug delivery…
  • Other Research, animals, farming etc

 

Where to find ‘’free energy’’?

Typical energy harvester output power

 RF:         0.1μW/cm²

 Vibration: 1mW/cm²

 Thermal: 10mW/cm²

 Photovoltaic: 100mW/cm²

 

Typical energy harvester voltages

RF: 0.01mV

Vibration: 0.1-0.4 V

Thermal: 0.02 - 1.0 V

Photovoltaic: 0.5 / 0.7 Vtyp/per_cell

 

Power consumption

Battery powered Applications in

Body Area Networks

3μW = 1.8V * 1.7μA

 

Industrialization

  • Need for better power density
  • Ultra low power electronics
  • Small energy storage devices with high energy capacity
  • Wireless communication standards & transmission rate improvements

 

Market acceptance of energy harvesting devices is very application-dependant

This is based on several parameters:

  • Size & weight
  • Amount of power generated versus amount of power needed by the system
  • Cost: Ease of access to grid & ease of access to the module or system to power
  • Number of devices to power
  • Critical mission of the module or system to power
  • Required device lifetime: Projected lifetime for the energy harvesting device compared to the system parts lifetime
  • A major factor to be taken into account is if there is enough power harvested for a particular application from a particular environment, and if the scavenged power needs to be stored

 

Collecting Energy

Music Club

  • A dance club in Rotterdam creates energy to power the LED lighting
  • each visitor creates 20W of power by dancing on the flexible floor

 

Pedestrian Walk

  • use of piezoelectric materials to harvest electrical energy
  • from pedestrians walking over it

 

Footbridge

  • Piezoelectric materials can harvest energy from vibrations, such as the
  • slight movement of a footbridge as pedestrians walk across it.

 

Energy Harvesting

  • Energy Harvesting applications are potentially everywhere
  • Power needs of typical applications continue to drop
  • Energy source characteristics determine transducer choice
  • Reliable, regulated power achieveable with properly designed systems