“low-power” energy harvesting PV
PV together with small batteries can power wireless sensors or actuators, including in the home.
Rationale for supportSensors or actuators in dim places (e.g. indoors, or receiv- ing only artificial or diffuse light) may be powered by a combination of a suitable PV cell and battery.
Mass-market PV technology, tuned to the solar spectrum and bright light, is not adapted to dim conditions. Current- ly, amorphous silicon PV is widely used for indoor and port- able applications with commercial efficiencies of around 10 % on devices fabricated on glass. Although compound semiconductors have achieved higher power efficiencies, their cost limits their commercial rollout for commercial products. New generations of PV technologies have shown great potential in harvesting energy in low light conditions and lab demonstrations up to 30 % efficiency values have been shown for artificial indoor illumination.
Targets, Type of Activity and TRL
There is no specific standard for performance quantifica- tion under low-light conditions. The efficiency and hence the power density output is strongly dependent on the spectrum, especially since the calibration is usually done in lux. The variability of the light conditions implies the development of efficient electronics that could gather all the energy produced by the light harvesting system. At the same time, integration with a device integrated or system integrated storage element can provide the power conti- nuity needed in some low power applications such in IoT or remote monitor sensor. The pervasiveness of low pow- er PV energy harvesting requires green non-toxic material and an appropriate waste management/recycling. In this context, one can define some specific KPIs:
KPIs that can be utilised for capturing progress in the above identified R&I fields are:
|Design and Fabrication|
Identification of PV materials and PV architecture for the specific low power applications depending on the light intensity, light spectrum and application itself (2025)
Module/cell design and fabrication process that enables easy tailoring of the PV device to products specifications (2027)
Power and energy yield PV performance to meet application specific power and energy requirements (2027)
Reproducibly achieve 25 % efficiency or more over module level in the 200 lx-500 lx under white light illumination (2027)
|Manufacturing||Cost of the PV energy harvester compatible/comparable with the cost of low power electronics (2027)|