BURNABY, British Columbia., Oct. 27, 2025 — Researchers from Simon Fraser University proposed an innovative standardization framework to overcome long-standing inconsistencies in testing indoor solar technology — enabling reliable efficiency measurements and accelerating progress toward practical, sustainable indoor energy harvesting.
As smart devices become increasingly integrated into daily life, finding reliable ways to power them is becoming increasingly important. Currently, these devices rely heavily on conventional disposable batteries, which contribute to pollution through toxic chemicals and waste generation. Indoor photovoltaics (IPV) have emerged as a prospective solution. Similar to solar panels that convert sunlight into electricity, IPVs sustainably generate energy by harvesting ambient light to power smart devices.
Assessing the performance of IPVs, however, presents a significant challenge due to the complexity of indoor lighting conditions. Outdoor solar panels are tested under consistent sunlight, but indoor lighting isn't so consistent. It varies widely depending on the shape, size, spectra, positioning, and brightness of the light sources used. As a result, measurements of IPV performance are often inconsistent and can be misleading. Without reliable measurement standards, performance claims can run into issues of consumer trust, and device designers are left with little guidance.
Visual impression of indoor solar measurements. Courtesy of Simon Fraser University.
“IPV development requires accurate, benchmarkable performance data, which is currently hindered by inconsistencies in characterization and benchmarking methods," said Vincenzo Pecunia, a professor in Simon Frasier University's School of Sustainable Energy Engineering. “The field currently faces a reliability crisis, with reported advances often obscured by measurement inaccuracies.”
To address this issue, Pecunia and his team investigated how different testing configurations and protocols can skew IPV efficiency results. They found that IPV performance measurements become unreliable under scattered or diffuse light — the kind commonly found indoors. To tackle this, the team developed strategies to reliably quantify IPV efficiency under everyday lighting, while allowing fair performance comparisons across laboratories.
Another challenge the team addressed was the standardization of IPV measurements amid the vast diversity of indoor light spectra. They found that simply labelling a bulb “warm white” or “cool white,” or referring to its “color temperature,” is insufficient because there are hundreds of versions of each. Their solutions include a universal "reference cell," which acts as a translator to standardize indoor lighting conditions for consistent IPV performance comparisons across labs.
The research was published in Joule (www.doi.org/10.1016/j.joule.2025.102126).