Photosynthetically active radiation complexities in agrivoltaic policy mandates: Insights from controlled environment yields under semitransparent photovoltaics
Agrivoltaics, which integrate photovoltaic (PV) energy generation with crop production, can enhance land use efficiency but reduces photosynthetically active radiation (PAR) essential for plant growth. While some studies report increased yields, the relationship between PV transparency, PAR, and crop productivity remains complex and underexplored—especially for shade-tolerant crops like lettuce. This study addresses this gap by experimentally evaluating romaine lettuce yield under cadmium telluride PV modules (offering uniform partial transparency) with seven transparency levels (10–80 %) in a controlled environment simulating outdoor summer conditions. PAR levels ranged from 43 to 419 micromol/m2-s (43–131 micromol/m2-s underneath the modules), using artificial light and natural light. Fresh weight data were collected for each treatment and compared to an unshaded control. In parallel, a review of agrivoltaic regulatory frameworks across Europe was conducted to contextualize results. Lettuce yields ranged up to 102 % relative to control conditions. Statistical analysis confirmed significant differences among treatments. Strong correlations were observed between PAR and fresh weight, and between PV transparency and yield, supporting the hypothesis that optimal PAR and transparency conditions can be identified. These relationships were expressed using mathematical trendlines for future modeling use. The findings suggest that minimum-yield-based agrivoltaics regulations offer a more effective policy framework than fixed-area limitations. Due to the inherent variability in crop yields, Germany's flexible approach of setting minimum yield requirements aligns best for maximizing agrivoltaic benefits while minimizing detriments. Establishing dynamic mandates with periodic review cycles will allow future agrivoltaic policies to remain adaptable to technological progress and regional agricultural variability.
See also
[edit | edit source]The Western Innovation for Renewable Energy (WIRED) system is currently under construction to test out new open source methods to reduce PV systems costs and enable novel forms of agrivoltaics including the world's first agrivoltaic agrotunnel.
- Coal with Carbon Capture and Sequestration is not as Land Use Efficient as Solar Photovoltaic Technology for Climate Neutral Electricity Production
- Dual use of land for PV farms and agriculture literature review
- sheep
- Israeli white plastic reflectors
- A Farmer's Guide to Going Solar (NREL)
- German guidelines: https://www.ise.fraunhofer.de/content/dam/ise/en/documents/publications/studies/APV-Guideline.pdf
- 2021 review
- Miskin, C.K., Li, Y., Perna, A., Ellis, R.G., Grubbs, E.K., Bermel, P. and Agrawal, R., 2019. Sustainable co-production of food and solar power to relax land-use constraints. Nature Sustainability, 2(10), pp.972-980.
- Retrofitting solar parks for agrivoltaics
- Shading PV
- Alexis' talk at American Solar Grazing Association2021
In the News
[edit source]From: Financial Analysis of Agrivoltaic Sheep: Breeding and Auction Lamb Business Models
- Raising sheep for grazing under solar panels makes everyone clean, green money - Western News
- Sheep Grazing Under Solar Panels Yields Green Profits Mirage News
- Agrivoltaics paired with sheep production makes nearly 100% of land grazable TechXplore
- Agrivoltaics paired with sheep production makes nearly 100% of land grazable MSN
- Grazing ’solar’ sheep offer lucrative solution for farmers My Science
- Global Renwable News
- Rinnovabili
- Education News Canada
- How agrivoltaics and “solar” sheep are redefining profitable farming in Canada PV Buzz
- Nature’s best lawnmower: How solar grazing is changing the photovoltaic landscape Euronews
- Yahoo NewZealand
- Bundle
- Photos: Sheep grazing boosts solar farms and soil health in the US and Europe Interesting Engineering
- O melhor cortador de relva da natureza: como o pastoreio solar está a mudar a paisagem fotovoltaica EuroNews
- La meilleure tondeuse à gazon de la nature : comment le pâturage solaire change le paysage photovoltaïque - Observatoiredeleurope
- Solar sheep grazing under agrivoltaic arrays can maximise land use News9
- El mejor cortacésped natural: ¿Cómo el pastoreo solar está cambiando el panorama fotovoltaico? Yahoo Spain
- ‘Solar shepherds’ earn big by grazing sheep on solar farms — and they benefit everyone involved Modern Science
- Sheep farmers are crazy about solar power plants: “Salaries are higher than lawyers” Central asia Climate Portal
- Researchers make unexpected discovery about sheep raised in nontraditional environment: 'There is an enormous opportunity' The Cool Down
- ‘Solar shepherds’ earn big by grazing sheep on solar farms — and they benefit everyone involved The Conversation
- Får och solparker - en vinst för både lantbruk, får och klimat Energinyheter (se)
- Researchers make unexpected discovery about sheep raised in nontraditional environment: 'There is an enormous opportunity' Yahoo
- Une étude révèle un duo gagnant : moutons et panneaux solaires, “un potentiel immense” Le Energeek
- ‘Farming Sunshine’ Brings Food, Power Producers Together for Local Baaa-nefit The Energy Mix
- Bùng nổ ngành nông nghiệp quang điện Saigon Online
- Solar sheep make better wool? The Carbon Almanac
- How to use sheep to manage vegetation at solar farms, boost agriculture Farm Progress
- Tarımsal Voltaik Sistemler ve Koyunlar Tarim Gundem (Turkish)
- Les « moutons solaires », un mariage lucratif entre agriculture et énergie propre Radio Canada
Agrivoltaics in Canada
[edit source]- Solar Sheep, Alberta (https://www.solarsheep.ca/)
- Sun Cycle Farms, Alberta (https://suncyclefarms.com/)
- Golden Leaf Agrivoltaics, Ontario (https://goldenleafagrivoltaics.ca/)
- The Lara Cost Farm, Ontario (https://thelaracosta.com/)
- Arnprior Solar, Ontario (https://www.edf-re.com/project/arnprior-solar/)
- Lewis Land & Stock, Ontario (https://solargrazing.org/asga-call-29-don-lewis-from-lewis-land-stock-of-ontario-canada/)
- Nanticoke Solar, Ontario (https://www.opg.com/stories/hundreds-of-grazing-sheep-helping-to-keep-opgs-nanticoke-solar-facility-in-trim-shape/)
- Western University’s Western Innovation for Renewable Energy Deployment (WIRED) (https://www.appropedia.org/Western_Innovation_for_Renewable_Energy_Deployment_(WIRED))
- Orchard, Middlesex, Ontario
- Solar Grazing Map https://solargrazing.org/map/
| Authors | Uzair Jamil, Md Motakabbir Rahman, Joshua M. Pearce |
|---|---|
| License | CC-BY-SA-4.0 |
| Organizations | Free Appropriate Sustainable Technology, Western |
| Cite as | Uzair Jamil, Md Motakabbir Rahman, Joshua M. Pearce (2025–2026). "Photosynthetically active radiation complexities in agrivoltaic policy mandates: Insights from controlled environment yields under semitransparent photovoltaics". Appropedia. Retrieved June 10, 2026. |