The optimization of vertical bifacial photovoltaic farms for efficient agrivoltaic systems[edit | edit source]
Publisher: Elsevier; Publication: Solar Energy;Year: 2021; Lifetime: ; PV Technology: ; Location: Lahore, Pakistan; PV Power: ; Energy: ; Efficiency:
- Introduction
- Objective: To develop a light distribution model that can provide esimate of the irradiation incident on the ground in AV setting and use it to determine the implication on energy and crop yield
- Methodology
- Two config: N-S oriented at a tilt and use monos, E-W vertical and use bifacials; location: Lahore, Pakistan
- MATLAB code used for irradiance modelling; irradiation received by panels and ground calculated, shadowing on the ground, LER as well as crop yield (lettuce) determined
- Results and discussion
- The two config tested with three variations in densities: p=h; p=2h and p=3h
- Similar energy and crop yields for both confi for shade intolerant crops - with half dense PV config as compared to GMPV
- Denser PV array; different yield; bi-E-W higher crop and mono-N-S higher energy
- For greater than 80% of lettuce yield, PV density varies from half to twice of GMPVs
- For greater than 80% of energy yield, crop yield varies from 65% (intolerant) to 100% (tolerant)
- High hetrogeneity observed for N-S config while homogenous for E-W under low panel densities; for high panel densities, light distribution generally homogenous for both config
- Crop yield suffers for E-W as p/h decreases; below p/h=4, crop yield for E-W are generally higher except for shade tolerant crops
- At low densities, LER similar while it gets higher for monons with increased densities
- Results related to impact of tilt angle also discussed
- Soiling can cause 2-5% loss of annual PV power for tilted arrays
- Model validation performed - model sligtly overstimates yield
The potential of agrivoltaic systems[edit | edit source]
Publisher: Elsevier; Publication: Renewable and Sustainable Energy Reviews ;Year: 2015; Location: US;
- Development of a solar PV model combined with crop and solar radiation model to ascertain the efficacy of agrivoltaic system
- 30% more economic value of agrivoltiac system when compared to agricultural systems
- In US, if lettuce fields were converted to agrivoltaic systems, more than 40 to 70 GW electricity generation can be increased
- PV System configuration: 4 meters high, half density - 3.2 m inter row spacing, full density - 6.4 m inter row spacing
- Lettuce can tolerate up to 30% shading
- 42% reduction in yeild for full density and 19% for half density agrivoltaic system as compared to control - Summer
- No significant reduction in yeild for lettuce in half density while 21% in full density as compared to control - Spring
Increasing the agricultural sustainability of closed agirvoltaic system with the integration of vertical farming: A case study on bay-leaf lettuce[edit | edit source]
Publisher: Elsevier; Publication: Applied Energy;Year: 2023;
- Increased land productivity by combining vertical farming (VF) with agrivoltaic greenhouses (closed agrivoltaic (CS) systems) - original CA had 100% PV cover ratio amd thus yield reduced significantly
- 13 times increased yield for lettuce observed as compared to CA only
- Energy required to meet the electricity needs - only 12% covered from CA
- More land required to achieve self sufficiency in electricity - 5 to 14 times higher than VF area
- Underutilized CA can be improved by integrating VF - a trade off between energy production and land consumption though exists
Increasing the agricultural sustainability of closed agirvoltaic system with the integration of vertical farming: A case study on bay-leaf lettuce[edit | edit source]
Publisher: Elsevier; Publication: Energy;Year: 2022;
- Objective: Ascertaining the potential of urban rooftop agrivoltaic system
- Case study: Shezhen, China
- Converting 854,000 rofftops can produce 9.84x105 tonnes of lettuce each year sufficient to fulfill the whole city needs
- Installed PV capcity will be 2106 MW - meets 0.2% of city's electricity needs
- PV panels coverage rate of up to 20% - checkerboard pattern - no reduction in lettuce yield
Water budget and crop modelling for agrivoltaic systems: Application to irrigated lettuces[edit | edit source]
Publisher: Elsevier; Publication: Agricultural Water Management;Year: 2018; Lifetime: ; PV Technology: ; Location: Montpellier, France; PV Power: ; Energy: ; Efficiency:
- Introduction
- Objective: To esimtate the effect of rain redistribution on crop yield and water requirement, ascertain water use and land use efficiencies, optimizng shading strategy soil water considering various factors
- Materials and methods
- Location: Montpellier, France; crop: lettuce; drip irrigation
- Four shading config; fixed tilt of 25o facing south - HD (3.2 m gap); FD (1.6m gap); ST (maximize solar interception by PV) and CT (parallel in morning and evening - max interception in afternoon)
- Radiaion, air temp and RH, wind vel and dir, rain, soil moisture content was measured; evapotranspiration, water productivity and LER calculated
- Irrigation model developed for AV considering stomatal conductance, variation of radiation and expandingo on Optirrig model
- Results
- 33% ST, 30% HD, 49% FD and 23% CT - less radiation than Control
- Actual evapotranspiration reduction: 22% ST, 26% HD, and 19% CT
- Fresh biomass reduced for all AV config - -24% on average in spring; -16% for ST and CT while -31% for HD in summers
- Reduced irrigation for both seasons for AV config
- LER>1 for all AV config for both season
- Almost similar yields are obtained with delay in harvest
Implications of spatial-temporal shading in agrivoltaics under fixed tilt & tracking bifacial photovoltaic panels[edit | edit source]
Publisher: Elsevier; Publication: Renewable Energy;Year: 2022; Lifetime: ; PV Technology: ; Location: Lahore, Pakistan; Corvallis, US; PV Power: ; Energy: ; Efficiency:
- Introduction
- Objective: To model variation in sunlight based on PV config and esimate implications on crop yield
- Methodology
- Factor-based approach used to determine shading pattern underneath PV
- Four config - N/S faced 30o fixed tilt, E-W verticals, N-S SAT and E-W SAT
- Useful PAR ratio is the PARu,AV divided by PARu,open; Y,PAR = PARu,AV/PARu,open
- Normalized PAR = PAR/PARth
- Results and Discussion
- Half density = inter row spacing twice the normal heigh and half = four times the normal height; normal height 1m
- PAR th = 213W/m2 for lettuce and tomato = 596W/m2
- Fixed tilt - N/S vs E/W
- E/W verticals have homogenous irradiation, higher PAR
- N/S fixed tilts hetrogenous, lower PAR underneat panels compared to open space b/w modules
- SAT - N/S vs E/W
- Similar PAR pattern E-W vertical and E-W SAT
- For both SAT - seasonal variation evident - higher in underneath panels in winters and lower in summers
- Normalized PAR vary significantly under N-S SAT
- Daily cummulative spatial useful PAR yield
- 30% less useful PAR in winter and 10% in summer - NS fixed tilts, lettuce
- 40-50% less useful PAR below PV modules, none in b/w spaces - NS fixed tilts, tomato
- Tomato yield not less than 20% for E/W vertical - homogenous YPAR
- Comparison with field experiment
- Corvallis, US; N-S fixed tilt
- YPAR from experiment = 0.46 and from simulation = 0.51
- Intercropping for half density solar array
- Based on threshold PAR (<80% for tomato), areas defined based on the pitch for cropping tomato and lettuce
- Different for different configurations
- E/W tracking - pitch can be segregated into 3 segments
- N/S fixed - tomatoes to be farmed near north and lettuce south; uniform YPAR along the pitch during summer but not in winters
- E/W verticals - YPAR more than 80%, hence no need for intercropping
- Intercropping increases land productivity in general
- Intercropping for full density solar array
- N/S fixed - tomato and lettuce planted alternately
- E/W vertical - same intercropping pattern as half density
- E/W vertical provide highest YPAR for tomato, lowerst E/W SAt
- 30% less radiation in full-density vs half-density
- YPAR higher in half density than full density
- Daily cummulative temporal useful PAR
- N/S fixed tilt or tracking provide useful irradiation in mornings/evenings in summers; may be more useful for lettuce (shade tolerants)
- In winters, useful radiation same for different configuations
- Solar power output analysis
- E/W tracking highest prodcution, N/S fixed tilt and tracking similar, E/W vertical the least
- E/W provides highest useful PAR though
Productivity and radiation use efficiency of lettuces grown in the partial shade of photovoltaic panels[edit | edit source]
Publisher: Elsevier; Publication: European Journal of Agronomy;Year: 2012;
- Implication on crop yield and plant morphology/physiology of two different PV densities causing 50% and 70% shading
- Four types of lettuces experimented for two seasons
- Compared with the available relative radiation, the lettuce yield was either equal or higher
- FD:1.6m and HD: 3.2m inter row spacing, south facing and 25o fixed tilt
- 58% of contorl in FD and 81% for HD - in summers 2010; 79% and 99% of control for FD and HD in spring 2011
Agrivoltaic Pretrial Experiment Report[edit | edit source]
- Transparent modules used with optimcal micro-tracking technology from insolight to experiment lamb's lettuce
- 70% transmittance of incident light from modules; in trials 2 and 3 15% light transmission mode selected during mid day (12 to 2 pm)
- Chlorophyll content higher for crop under the modules - no difference between contorl and crop grown behind modules
- Leaves longer and wider under modules when compared to control and crop behind modules for trials 1 and 3, in the 2nd trial - not much difference
- Averaging all three trials, fresh weight under and behind modules increased by 17% and decreased by 8%, respectively, compared to the control
- Impact of seasons on fresh weight also observed
Agrivoltaics for Farmers with Shadow and Electricity Demand: Results of a Pre-feasibility Study under Net Billing in Central Chile[edit | edit source]
- Technoeconomic evaluation of lettuce agrivoltiac performed in Chile as lettuce is adversely affected by high irradiation
- Two scenarios: Either and AV plant will provide 30 to 40% shading or a separate GMPV is installed with nets providing the shading
- Both config fixed tilt, GMPV - modules 1m high while for AV module 2.4 m high
- Pitch distance 4m for GMPV while for AV, it will be determined based on light distribution simulation
- AV - azimuth: 310, panel tilt: 22; GMPV - azimuth: 0; panel tilt: 28
- Annual shading in AV between 30 to 40%
- AV presents a positive NPV; 7 years pay-back period
Lettuce Production under Mini-PV Modules Arranged in Patterned Designs[edit | edit source]
- Location of trial: Almeria - Spain
- Lettuce agrivoltaic tested under three different arrangements: concentrated shade (CS), scattered shade (SS) and full sun (FS) and in two season - spring and summer 2021
- With same shading cover area (22%), using mini PV modules arranged in pattern improves productivity in both seasons
- PAR was higher for SS than CS for all months of experiment
- Fresh weight of lettuce: SS - 46.4% more than CS and 68.8% more than FS; in summers even more - 61.2% and 87.6% more than CS and FS respectively
Crop-Specific Optimization of Bifacial PV Arrays for Agrivoltaic Food-Energy Production: The Light-Productivity-Factor Approach[edit | edit source]
- Agrivoltaics systems installation for improved sunlight sharing between PV arrays and crops
- Height of PV modules kept between 4 - 7 m above crops
- Low density - p/h ratio 2 to 3 times of standard PV
- Paper introduces Light Productivity Factor (LPF) - factor that determines efficacy of light sharing between PV modules and crops
- For PV only - LPF=1; with Agrivoltaics methodology 1 < LPF > 2
- Used lettuce, turnip and corn
- Land Equivalent Ratio (LER) - factor that provides food-energy performance
- Uses crop yield and electrical output
- Crop yield is directly proportional to useful photosynthetically active radiation (PAR)
- Crops have a threshold PAR above which the process of photosynthesis saturates
- Custom tracking; combination of standard and reverse tacking maximizes PAR requirement
- Results indicate:
- For shade tolerant crops, full density PV arrays may be utilized
- For shade sensitive crops. reduced density PV arrays may be utilized
- E/W faced vertical PV orientation - preferable fixed tilt scheme
- Benefits: Low elevation mounting, ease of operation of farm machinery and reduced soil loss
Emergent molecular traits of lettuce and tomato grown under wavelength-selective solar cells[edit | edit source]
Publisher: Frontiers; Publication: Frontiers in Plant Science; Year: 2023; Lifetime:; PV Technology: Organic Solar Cell (OSC) ; Location: ; PV Power: ; Energy: ; Efficiency:
- Abstract
- Semitransparent OSC effect electricity output as well as crop growth
- Three different OSC filters used; lettuce and tomato grown
- Lettuce yield not affected by AV; instead benefitted in terms of nutrient content and nitrogen utilization
- Introduction
- 70% increase in food demand until 2050
- Greenhouse more productive for crop growth, less water requirements, less pesticide/fertilizer use, provide shelter to plants from drought/heat/flood
- Field crops damage due to weather in US in 2021 - 8 billion USD
- Greenhouses are energy intensive, carbon footprint negative when compared to conventional crop if fossil fuels used in greenhouses
- OSCs impact light spectrum as well as intensity
- Blue and red light spectrum more efficiency used by plants for photosynthesis
- Objective: To determine the impact of OSC on shade tolerant lettuce and shade intolerant tomato under simulated OSC greenhouse condition
- No adverse impact on biomass
- Results
- Light use: similar spectra as natural light
- Biomass remained unaffected by different OSC filter
- Photosynthesis improved in OSC when compared to control for lettuce, tomato same but transpiration rate decreased
- Anthocyanin content for OSC in lettuce increased
- Discussion
- The physiology of the plants changed with variation in light quality under different OSC filters
SHADING ANALYSIS OF AGRIVOLTAIC SYSTEMS[edit | edit source]
- Four scenarios considered, with varying parameters including latitude, azimuth, slope, and inter-row spacing between photovoltaic (PV) modules
- Two crops studied - potato and lettuce - potato more suitable to AV than lettuce considering its sensitivity to solar intensity
- Simulation based study using PV-syst and excel equations
Implementation of Agrivoltaic Systems under Operating Photovoltaic Park Conditions[edit | edit source]
- Lettuce and anthurium agrivoltaics showed 0.5 - 4.9oC decreased in module temperature resulting in upto 1.6% PV panel performance improvement
- Lettuce better than anthurium to boost efficiency of PV modules
Improving Productivity of Cropland through Agrivoltaics[edit | edit source]
Objective - Review existing literature of Agrivoltaics and ascertain its applicability in Australia
- Land equivalent ratio (LER) - parameter used for this study
- Electrical output of PV system modelled via System Advisory Model
- Crops (lettuce and silverbeet) grown without shading and under shade (using black tarps) for the study - solar panels not installed
- Yield produced in Agrivoltaics setting: 72% of lettuce yield compared with traditional farms; 60% of silverbeet yield compared with traditional farms (based on fresh mass)
- Reduced crop yield most probably due to increased shading
Increasing the comprehensive economic benefits of farmland with Even-lighting Agrivoltaic Systems[edit | edit source]
- Introduction
- Inter-row distance in AV - thrice the height of panels
- In dry climates, AV have shown to reduce drought stress, maintain higher soil moisture and imporved biomass
- In suitable climates, reduction in crop yield and quality observed under AV
- Objective: Propose Even-lighting Agrivoltaic System (EAS) for high yield/quality and eff. electrical output
- Materials and methods
- From PV panel area, 1/3 area replaced with grooved glass plate; so area of glass plate is 1/3 the light receiving area of the system
- PV density remains the same as conventional PV
- Glass plate scatters the sunlight thus providing irradiation uniformly
- Tilt considered 23o; height of PVs = 2.5m; model of glass developed in Solidworks and coupled with Zemax 12 to give the light patter/illimination
- Two experiments:
- smaller and semi-natural in Hefei; lettuce; four config: Control T1, Conventional AV T2, EAS T3 and EAS with additional lighting T4
- larger in Fuyang; broccoli, shallot, garlic sprouts, garlic, broad bean, Jerusalem, rape; two config: control and EAS
- PAR, crop growth, yield, LER, comprehensive eco benefits of EAS were measured
- Results
- 47.38% improved irradiation with grooved glass as compared to conventional AV; crops growth rate similar to control
- 5% yield reduction for all crops except broccoli and rape while Jerusalem artichoke increased 23%
- EAS increases farmer income by 5.14 times and LER was 1.64
- Uniform light scattering under grooved glass
- Under conv AV, PPFD was v less when compared to control or EAS
- 3.87% more irradiation received on panels than on ground; compared to control EAS received 40.87% less irradiation while conv AV 88.25% less
- Lettuce: Similar fresh and dry weight in T1, T3 and T4; 53.5% and 60.5% reduction in T2
- Large Scale Experiment: Reduction in broccoli 9%, rape 11%, shallot 2%, garlic sprouts 6%, garlic 4%, broad bean 6% and Jerusalem artichoke increased 23%
- Protein content similar in 4 treatments, higher nitrate in T2 and T3 than T1 and T4
- soluble sugar content in lettuce was T2> T4> T1>T3; for vitamin C, it was T2> T3> T1> T4; for nitrate content, it was T1 = T4 < T3 =T2
- Farmer's income increased by 5.14 times for EAS
- LER always greater than 1 - average 1.64
The potential of agrivoltaic systems in the conditions of southern regions of Russian Federation[edit | edit source]
- The simulation performed on 1 ha - lettuce and sugar beetroot crop targetted
- Two different configuration - 3.2 m row spacing and 6.4 m row spacing
- Assuming 30% reduction of sunlight for 3.2m spacing and 10-20% reduction of sunlight for 6.4m spacing; expected yield of crops is supposed to be 70-80% of normal yield
- Increased land productivity by 45-70%
- With 6.4m spacing - 70% incident radiation; 3.2m spacing - 50% incident radiation available to crop
- Plant relative yield assumed to be 0.7 and 0.9 for 3.2 m and 6.4 m
Residential Agrivoltaics: Energy Efficiency and Water Conservation in the Urban Landscape[edit | edit source]
Objective: Evaluate the impact on water use for residential agrivoltaics and typical roof-mount residential solar panels
- Ascertain water use, temperatures, power production of PV panels for agrivoltaics and a typical roof-mount installation
- Less irrigation requirement for agirovltaic vs control configuration
- Weights and leaf count lower for agrivoltaic system
- Roof-mount PV moduels have higher temperature - 3.6% decrease in power
- 19% drop in maximum air temperature and 17% for soil temperature
- 328g of lettuce under full sun vs 167g for agrivoltaic
- No. of leaves - 53.6 vs 31.1 while leaf length 5.9 vs 6.9 for agrivoltaics system
Agrivotlaics Regulations/Standards[edit | edit source]
France:
- Maximum of 10% reduction in yield
- Maximum of 40% land coverage through PVs
https://www.pv-magazine.com/2024/04/09/france-issues-new-rules-for-agrivoltaics/
https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000049386027
Italy:
- 70% of surface area of the plot must be dedicated to agricultural activity
- Total area covered by the modules - 40% max
- Minimum 60% of electrical output compared to a standard PV system
Germany:
- Land loss due to construction of AV system: up to 15% max
- Min 66% yield as compared to control
Agri-photovoltaic systems – Requirements for primary agricultural use English translation of DIN SPEC 91434:2021-05