Heat Stress Tolerance in Organic Romaine Lettuce Using Crystalline Silicon and Red, Blue & Green-Colored Thin Film Agrivoltaic Systems
Climate destabilization is increasingly disrupting global agriculture. Agrivoltaics is an emerging solution to this challenge that simultaneously uses land for solar photovoltaic (PV) electricity generation and crop cultivation. This study investigates the performance of the heat sensitive crop of organic romaine lettuce under a broad range of agrivoltaic conditions outdoors alongside un-shaded controls. Twelve agrivoltaic configurations of varying crystalline silicon wafer-based and thin-film solar PV modules, differed in magnitude and spectra of light transmittance, shading patterns, and spatial coverage. During high-temperature stress conditions, the results show agrivoltaic treatments increased lettuce fresh weight by over 400% compared to unshaded control plants and by over 200% relative to the national average yield. Notably, 60% transparent colored thin-film PV modules and 44% transparent crystalline silicon-based PV modules delivered the highest productivity gains, underscoring the critical role of optimized shading intensity and spectral quality in promoting plant growth. Morphological traits such as plant height and leaf number exhibited strong positive correlations with biomass accumulation, validating the physiological benefits of partial shading and spectral filtering. The economic value of lettuce is roughly four times the value of agrivoltaic-generated electricity on equivalent land area. Overall, the results demonstrate that agrivoltaic systems can enhance romaine lettuce production during hot summers while simultaneously contributing to climate-smart agriculture and sustainable energy generation. If scaled to protect Canada’s entire lettuce crop, agrivoltaics would result in major emissions reductions as well with the total carbon dioxide emission reduction being between 2.5 Mt (thin-film PV) and 6.4 Mt (silicon PV).
Highlights
[edit | edit source]- Agrivoltaics boosted lettuce yield up to 483% under heat stress.
- 60% Cd-Te and 44% c-Si modules delivered the best productivity gains.
- Partial shading improved plant height, leaf number, and biomass.
- Agrivoltaics could add CAD $68B value and 6.3 Mt CO2 cuts in 25 years.
- Crop-specific spectral design is key for agrivoltaic system success.
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, Joshua M. Pearce |
|---|---|
| License | CC-BY-SA-4.0 |
| Organizations | Free Appropriate Sustainable Technology, Western |
| Cite as | Uzair Jamil, Joshua M. Pearce (2025). "Heat Stress Tolerance in Organic Romaine Lettuce Using Crystalline Silicon and Red, Blue & Green-Colored Thin Film Agrivoltaic Systems". Appropedia. Retrieved June 17, 2026. |