Researchers in Canada found that semi-transparent solar panels with cadmium telluride and crystalline silicon with low transparency can increase turnip root and leaf yields in agrivoltaic systems by optimizing light quality, distribution and heat stress. Their research highlights that PV module type, transparency and spectral transmission must be carefully matched to plant physiology to maximize both crop productivity and renewable energy generation.
Researchers from the University of Western Ontario in Canada have investigated the effects of thin-film cadmium telluride (CdTe) and crystalline silicon (c-Si) solar panels on agricultural yields in agrivoltaic environments and found that PV transparency and spectral transmission are crucial for shaping optimal crop-atmosphere interactions.
“We took a closer look at agrivoltaic turnips and discovered several semi-transparent treatments that yielded significantly more food while providing solar energy,” said Joshua M. Pearce, the study’s lead author. pv magazine.
In particular, the team examined turnip growth under thirteen types of PV modules with varying transparency and spectral properties. Experiments were conducted outside at the Wired facility, Western University Field Station in Ilderton, Ontario, using pole-mounted PV racks for field-scale agrivoltaic trials.
McKenzie Turnip seeds were sown on May 21, 2025, initially with two plants per pot, later reduced to one after germination. The PV modules include three semi-transparent c-Si types with transparency of 8%, 44% and 69% respectively, and ten CdTe thin-film modules with blue, green and red spectral filters ranging in transparency from 40% to 80%. While CdTe modules provided relatively uniform light distribution, c-Si modules produced non-uniform patterns due to their intermittent solar cell arrangement.
During the growth period, important variables such as photosynthetically active radiation (PAR), spectral irradiance, plant height, leaf count and fresh biomass were measured. These data were analyzed to compare turnip growth under PV treatments and to assess the potential economic impacts of agrivoltaic energy adoption in Canada.
The analysis showed that turnip fresh weight varied significantly among the thirteen PV treatments, with the highest yield observed under the 60% CdTe module of 176.5 g, followed by the 80% CdTe panel of 130.6 g and the 8% c-Si module of 118.9 g. Moderate yields were recorded among CdTe modules with 50%, 40% and 70% transparency, as well as the 44% c-Si module.
Leaf biomass reflected root trends, with 60% CdTe reaching 367 g, and intermediate values were observed under 8% c-Si, 40% CdTe, and 80% CdTe. Weekly measurements of plant height and number of leaves reinforced these patterns and PAR measurements indicated that light alone did not drive the growth differences, as the 60% CdTe treatment achieved the highest yield at moderate PAR, while CdTe modules with similar PAR produced negligible biomass. Overall, CdTe modules with moderate transparency, together with c-Si modules with low transparency, provided optimal conditions for turnip root and leaf development.
The scientists explained that both low-transparency c-Si modules and moderately transparent CdTe modules improved crop growth by reducing heat stress and providing optimal light distribution. Non-uniform shading of c-Si modules performed better at lower transparencies, while uniform thin-film CdTe modules were most effective at 50–60% transparency.
“These results underline the importance of synthesizing PV module type with plant physiology when designing agricultural voltaic systems,” they also emphasized. “Rather than selecting PV modules based solely on energy yield or transparency rate, system designers should also consider the way light is delivered to the plant canopy – uniform or non-uniform – and how this interacts with plant morphology and stress tolerance. Furthermore, there is clearly a wide range of potential future work to optimize the spectral transmission of agrivoltaic PV modules.”
“Agrivoltaic energy simply makes technical and economic sense,” Pearce concluded. “As the climate warms, putting pressure on even relatively robust crops such as turnips, the agrivoltaic sector offers a realistic path to a sustainable food system. More work is needed to ensure that the optimal agrivoltaic module, color and shelving meet the needs of farmers, crops and our society as a whole to decarbonize.”
This content is copyrighted and may not be reused. If you would like to collaborate with us and reuse some of our content, please contact: editors@pv-magazine.com.
