The increasing use of bifacial photovoltaic (PV) modules has created a need for accurate measurement of ground-reflected solar radiation, known as albedo. Commercially available albedometers are generally based on either pyranometers or silicon irradiance sensors. Pyranometer-based albedometers are widely used but are relatively expensive and have a spectral response that differs from that of PV modules. Silicon sensor-based albedometers provide better spectral matching but are affected by measurement errors caused by temperature differences between the upward- and downward-facing sensors, as well as by unequal degradation during long-term outdoor use.

The device consists of two identical, calibrated solar cells encapsulated within a single glass-to-glass structure, with one cell facing the sky and the other facing the ground. NCPRE's fabricated back-to-back dual solar cell albedometer along with the assembled electronic unit used for short-circuit current measurement is shown below. Albedo is calculated directly from the ratio of the short-circuit currents generated by the two cells. Since both cells are integrated into the same structure, they operate under nearly identical conditions.

Experimental validation showed that this design minimises errors caused by temperature mismatch and differential degradation. In addition, the use of solar cells as sensors provides a spectral response that closely matches that of PV modules, making the measurements more relevant to bifacial PV applications. The compact and robust design provides a cost-effective alternative to conventional albedometers while maintaining accurate and reliable measurements in outdoor conditions. The technology can support bifacial PV site assessment, performance monitoring, and energy yield estimation, helping improve the deployment of bifacial solar energy systems.

This work resulted in the grant of an Indian patent titled "A Dual Solar Cell Albedometer and a Method of Manufacturing the Dual Solar Cell Albedometer" (Patent No. 588491), granted on 6 May 2026, and a Chinese patent application has been filed. The work was carried out by Pavan Fuke, a PhD student at NCPRE, under the guidance of Prof. Anil Kottantharayil.