Cadmium telluride vs. crystalline silicon in agrivoltaics

Canadian researchers investigated how the transparency of cadmium telluride and crystalline silicon solar panels affects lettuce growth in agrivoltaic systems. They found that 69%–transparent silicon panels increased lettuce yield by 3.6%, whereas cadmium telluride panels led to a reduction in yield.

October 16, 2025 Lior Kahana

Image: Western University, Solar Energy, CC BY 4.0

From pv magazine Global

Researchers from Western University in Canada have examined how the transparency of photovoltaic panels influences lettuce cultivation in agrivoltaic systems.

The team grew valley heart lettuce under different lighting conditions: uniform illumination from cadmium telluride (CdTe) thin-film PV panels, and non-uniform illumination from bifacial crystalline silicon (c-Si) PV panels.

“The goal of this study was to assess the impact of the type of PV transparency on the physiological and yield responses of lettuce, and to evaluate the potential of agrivoltaics as a sustainable solution for lettuce production in Canada,” corresponding author Uzair Jamil told pv magazine. “Experiments were conducted using CdTe modules offering uniform transparency at 40%, 50%, and 70% transparency and bifacial c-Si modules offering non-uniform transparency at 44% and 69% transparency.”

Experiments took place in a controlled-environment biome designed to replicate summer conditions in London, Ontario. Daytime temperatures were maintained at 25 C and nighttime temperatures at 15 C. A 16-hour light period (6:00 a.m.–10:00 p.m.) was provided by four 600 W high-pressure sodium lamps, followed by an 8-hour dark period.

The setup included 14 lettuce plants under each c-Si module, six plants under each CdTe module, and a control group of eight plants grown without panels. Each plant was cultivated in an isolated 1.5-gallon pot, initially seeded with three plants and later thinned to one per pot. Researchers measured parameters such as chlorophyll fluorescence, leaf area, gas exchange, plant height, leaf count, and fresh weight.

Results showed that lettuce grown under 69% transparent c-Si modules achieved a 3.6% yield increase compared to open-field controls, while CdTe modules of similar transparency caused a 6% yield reduction. According to Jamil, these results highlight how non-uniform light distribution in c-Si systems can improve plant growth.

“Scaling agrivoltaics across all lettuce farms in Canada with 69% transparent PV modules could potentially generate 1,200 MW of clean energy, nearly doubling the current solar PV installations in Ontario,” Jamil said. “With 44% transparency, the capacity could approach 2,300 MW, representing nearly 40% of the current PV capacity in Canada.”

The study also estimated substantial economic benefits. If all Canadian lettuce farms adopted the 69% transparent c-Si modules, they could collectively generate CAD $342 million (USD $245 million) in additional electricity revenue. Using the 44% transparent panels could raise this to CAD $629 million. A modest 3% boost in lettuce yield would push total revenue to more than CAD $737 million—around $20 million higher than conventional farming methods.

“These findings demonstrate that spatial light heterogeneity – characteristic of c-Si systems – can enhance crop performance, presenting an opportunity for sustainable intensification,” Jamil concluded.

The tests were presented in “Transparency effects in agrivoltaics lettuce cultivation using uniform/non-uniform semitransparent photovoltaic modules in controlled environments,” published in Solar Energy.

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