Greenhouses have been widely used to grow lettuce (Lactuca sativa) for commercial markets worldwide, but electricity is a major input cost at these facilities when supplemental lighting is needed. To improve sustainability, solar energy, especially photovoltaic technologies, is being investigated as an alternative power source. One promising solution is the use of semi-transparent perovskite solar cells, which transmit high levels of extended photosynthetic active radiation (ePAR), the light needed for photosynthesis, while generating electricity. This study quantified the effects of perovskite solar systems on lettuce photosynthetic rates under short-term exposure. Two trials that explored the photosynthetic capacity of ‘Green Towers’ lettuce underneath methylammonium lead iodide (MAPbI3), MAPbI2.25Br0.75, MAPbI1.5Br1.5, MAPbI0.75Br2.25, and methylammonium lead bromide (MAPbBr3) thin films, each with distinct energy bandgap and corresponding transmission spectra, were conducted. Light-response curves were created by exposing lettuce to increasing light intensities, and nonlinear regression was used to determine the maximum quantum yield of photosystem II (Fv/Fm) and maximum net photosynthesis rate (PNmax) under the perovskite samples. In the first trial, lettuce photosynthesis was measured under MAPbI3perovskite samples at 0.06, 0.12, and 0.24 M concentrations, with increasing concentrations producing thicker films that reduced spectral transparency. In the second trial, lettuce photosynthesis was measured under MAPbI3, MAPbI2.25Br0.75, MAPbI1.5Br1.5, MAPbI0.75Br2.25, and MAPbBr3at a concentration of 0.06 M. There were no differences inFv/FmandPNmaxof lettuce underneath the perovskite samples at the concentrations of 0.06 M or 0.12 M in both trials (P >0.05). ThePNmaxwas greater under 0.24 M MAPbI3perovskite in the first trial, highlighting its potential for agrivoltaic applications. Semi-transparent perovskites show promise as greenhouse glazing materials.
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Organic solar powered greenhouse performance optimization and global economic opportunity
Greenhouses conserve land and water while increasing crop production, making them an attractive system for low environmental impact agriculture. Yet, to achieve this goal, there is a need to reduce their large energy demand. Employing semitransparent organic solar cells (OSCs) on greenhouse structures provide an opportunity to offset the greenhouse energy needs while maintaining the lighting needs of the plants. However, the design trade-off involved in optimizing solar power generation and crop productivity to maximize greenhouse economic value is yet to be studied in detail. Here, a functional plant growth model is integrated with a dynamic energy model that includes supplemental lighting to optimize the economics of growing lettuce and tomato. The greenhouse optimization considers 64 different OSC active layers with varying roof coverage for 25 distinct climates providing a global perspective. We find that crop yield is the primary economic driver, and that crop yield can be maintained in OSC-greenhouses across diverse climates. The crop productivity along with the energy produced by the OSCs results in improved net present value of the OSC-greenhouses relative to conventional systems in most climates for both lettuce and tomato. In addition, we find common solar cell active layers that maximize greenhouse economic value resulting in guidelines for scaling up OSC-greenhouse design. Through this model framework, we highlight the opportunity for OSCs in greenhouses, uncover designs and locations that provide the most value, and provide a basis for further development of OSC-greenhouses to achieve a sustainable means of food production.
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- Award ID(s):
- 1639429
- PAR ID:
- 10380060
- Date Published:
- Journal Name:
- Energy & Environmental Science
- Volume:
- 15
- Issue:
- 4
- ISSN:
- 1754-5692
- Page Range / eLocation ID:
- 1659 to 1671
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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