What crops grow well under agrivoltaic solar panels?

Research consistently shows that shade-tolerant crops perform well or better under agrivoltaic conditions compared to open-field cultivation, particularly in hot climates. High-performing crops include: leafy greens (lettuce, spinach, arugula), herbs (basil, cilantro, mint), some small fruits (strawberries, some raspberry varieties), root vegetables (carrots, beets), and flowers (lavender, chamomile). Crops that require high-PAR (photosynthetically active radiation) — corn, soybeans, sunflowers, most grain crops — are more challenging under standard agrivoltaic systems and typically require elevated panel heights (12+ feet) and wider row spacing to maintain acceptable yields. Shade-tolerance data from the USDA and University of Massachusetts Amherst agrivoltaics research program provides crop-specific PAR thresholds for agrivoltaic system design.

How is bifacial energy gain calculated in PVsyst?

PVsyst calculates bifacial energy gain using a view-factor model that computes the irradiance distribution on the rear surface of each module row, accounting for: ground albedo (user-specified or measured), row spacing and height, module bifaciality factor, and shading from adjacent rows on the rear surface. The rear irradiance distribution is non-uniform — module edges exposed to open sky receive more reflected light than the center of long rows. PVsyst integrates these distributions hourly and multiplies by the BF to compute rear-side energy production. Users should input measured site albedo (from a pyranometer or albedometer) rather than using default values, as albedo variations of ±0.05 translate to 0.5–1.5% differences in calculated bifacial gain.

What is the Land Equivalent Ratio (LER) and what values are typically achieved in agrivoltaic projects?

The Land Equivalent Ratio (LER) compares the land area required for separate, dedicated solar and farming operations to produce the same combined output as an agrivoltaic co-location system. LER = (agrivoltaic solar yield / standalone solar yield) + (agrivoltaic crop yield / standalone crop yield). An LER of 1.4 means 40% less land is needed for the combined agrivoltaic system than for dedicated separate solar and farming. Published agrivoltaic research reports LER values of 1.3–1.9 depending on crop type, climate, and system design. European Fraunhofer ISE studies in Germany report LER around 1.56 for vegetable crops; Arizona State University studies for shade-tolerant crops in hot climates report LER > 1.5 driven largely by water savings.

How much does albedo affect bifacial solar production?

Albedo has a direct and significant impact on bifacial rear-side energy production. In a typical ground-mount fixed-tilt bifacial system at 20° tilt with GCR 0.40 and BF 0.70: increasing ground albedo from 0.10 (dark soil/asphalt) to 0.25 (dry grass) increases bifacial gain from approximately 4% to 8–9%. Increasing albedo further to 0.40 (white gravel) can yield 12–15% bifacial gain. Single-axis tracker systems at higher mounting heights amplify albedo sensitivity — the same albedo improvement may yield 2–3 additional percentage points of gain on a tracker vs. fixed-tilt. White reflective geotextile ground cover products (sometimes called "bifacial boosters") have been commercially deployed to increase albedo, though cost-benefit analysis varies by module BF, system size, and electricity price.

← Renewable Energy Studio

Engineering·9 min read·October 1, 2025

🌾 Agrivoltaics and Bifacial Solar Panels: Dual-Use Land, Albedo Effects, and Energy Yield

An engineering and agronomic guide to agrivoltaics — co-locating solar panels with agricultural land use — and bifacial solar module technology, including albedo optimization, bifacial gain modeling, bifaciality factors, and global deployment examples.

What Is Agrivoltaics?

Agrivoltaics (also spelled "agri-voltaics" or referred to as "agri-PV") describes the co-location of solar photovoltaic panels and agricultural activities on the same land parcel. The concept, originally proposed by Adolf Goetzberger and Adolf Zastrow in 1981 and experimentally demonstrated at the Fraunhofer Institute in 1982, has gained significant commercial momentum since 2015 as solar developers seek to reduce land conflicts, address community opposition, and create additional revenue streams from solar project sites.

Agrivoltaic systems fall into several categories:

Elevated agrivoltaics: Panels mounted at 10–18 feet above ground on raised structures, allowing full agricultural equipment access for row crops, vegetables, or small fruits beneath the array.
Inter-row cultivation: Standard-height ground-mount arrays with wider spacing between rows, allowing livestock grazing, wildflower planting, or shade-tolerant crop cultivation in the inter-row spaces.
Solar grazing: Sheep grazing beneath and between solar panels for vegetation management, eliminating herbicide use and mowing costs while generating agricultural revenue.
Pollinator-friendly solar: Native wildflower and grass plantings beneath arrays that provide habitat for pollinators (bees, butterflies) and support ecosystem services. The American Solar Grazing Association (ASGA) and Xerces Society have developed pollinator habitat certification standards for solar sites.

Agronomic Benefits and Crop Performance Research

Research from the University of Massachusetts, Oregon State University, and Fraunhofer ISE has documented several agronomic co-benefits of agrivoltaic co-location:

Water stress reduction: Partial shading beneath panels reduces evapotranspiration by 15–50%, decreasing crop water stress during peak summer heat. A landmark study in Arizona showed 65% water savings for shade-tolerant crops (lettuce, spinach, basil) grown beneath agrivoltaic panels with equivalent or improved yields.
Microclimatic buffering: Panels moderate ground-level temperature extremes — cooler during heat stress periods, warmer during frost risk periods — extending growing seasons in marginal climates.
Crop yield outcomes: Shade-tolerant crops (leafy greens, herbs, berries) and some vegetables show yield improvements or equivalent yields under agrivoltaic conditions. Shade-intolerant crops (corn, soybeans) require careful system design to limit shade impact; elevated panel heights and optimized row spacing maintain adequate photosynthetically active radiation (PAR).
Land Equivalent Ratio (LER): The LER metric quantifies agrivoltaic land efficiency — an LER > 1.0 indicates that agrivoltaic co-location produces more combined energy + agricultural output per unit land than separate dedicated solar and farm plots. LER values of 1.3–1.7 are commonly reported in European and US agrivoltaic trials.

Bifacial Solar Module Technology

Bifacial solar modules generate electricity from both the front (facing the sun) and rear (facing the ground) surfaces, capturing reflected irradiance (albedo) in addition to direct and diffuse sunlight on the front face. Bifacial technology has become the dominant module architecture in utility-scale solar, with bifacial module shipments exceeding 70% of global PV module production by 2023.

Key bifacial module characteristics:

Bifaciality factor (BF): The ratio of rear-side power to front-side power under identical illumination conditions, typically 65–85% for PERC (Passivated Emitter Rear Cell) bifacial modules and 90–95% for TOPCon (Tunnel Oxide Passivated Contact) and HJT (Heterojunction Technology) bifacial modules. A higher bifaciality factor means the rear side captures a greater proportion of the equivalent front-side output.
Module construction: Bifacial modules use transparent backsheets or dual-glass construction to allow light to reach the rear cell surface. Dual-glass modules (glass-glass) provide superior environmental protection and longer warranties (30 years) but add weight (~20% heavier than standard glass-backsheet modules).
Temperature coefficients: Bifacial modules, particularly HJT, offer superior temperature coefficients (-0.25% to -0.26%/°C vs. -0.34%/°C for standard PERC), which means less production loss on hot days — particularly relevant in agrivoltaic deployments where ground-level temperatures can be moderated by vegetation.

Albedo and Bifacial Energy Gain Modeling

The rear-side production of a bifacial module depends on the irradiance reflected from the ground surface below the array — the albedo. Albedo is expressed as the fraction of incident light reflected, ranging from 0 (perfect absorber) to 1 (perfect reflector):

Fresh snow: 0.80–0.95
White gravel or light concrete: 0.25–0.40
Dry grass or crops: 0.20–0.26
Green grass or crops: 0.18–0.23
Dark soil or asphalt: 0.05–0.15

Agrivoltaic sites with actively managed ground cover (grasses, cover crops, native wildflowers) typically have albedo values of 0.20–0.28, comparable to standard solar site ground cover. White gravel or light-colored surface treatments can increase albedo to 0.30–0.40, boosting bifacial gain significantly.

Bifacial energy gain (additional annual production compared to equivalent monofacial module) is typically modeled using:

Bifacial gain = BF × (rear irradiance / front irradiance) integrated over the year.
Typical bifacial gains for ground-mount utility-scale solar: 5–12% additional energy over equivalent monofacial systems, depending on ground albedo, tilt angle, mounting height, row spacing, and BF.
Single-axis trackers increase bifacial gain by 2–4 percentage points compared to fixed-tilt due to improved rear-side irradiance uniformity and higher average row heights during tracking.
Modeling tools: PVsyst (bifacial module simulation), SAM (bifacial module model), and manufacturer-specific bifacial modeling tools (LONGi, JA Solar, First Solar).

Ground Cover Ratio and Row Spacing Design

The Ground Cover Ratio (GCR) — the ratio of total panel area to ground area — affects both bifacial energy production and agricultural land availability in agrivoltaic systems. Standard utility-scale ground-mount solar uses GCR of 0.35–0.45. Agrivoltaic systems typically use lower GCR (0.25–0.35) to preserve agricultural access and reduce inter-row shading on crops.

Wider row spacing (lower GCR) in agrivoltaic systems has complex effects on bifacial gain: lower GCR improves rear-side irradiance uniformity (reducing shading of rear surface by adjacent rows) but also reduces the proportion of diffuse sky radiation captured. Optimal GCR for bifacial agrivoltaic systems is site-specific and requires numerical optimization using ray-tracing or view-factor models.

Policy, Land Use, and Commercial Deployment

Agrivoltaics is supported by federal policy through the USDA Partnerships for Climate-Smart Commodities grants and NRCS (Natural Resources Conservation Service) programs that recognize agrivoltaic practices as conservation activities. Several US states — including Massachusetts, Minnesota, and Maryland — have incorporated agrivoltaic land use standards into their solar siting frameworks, providing property tax relief for agricultural land hosting agrivoltaic systems.

Commercial agrivoltaic deployments in the US include: Jack's Solar Garden (Colorado, 1.2 MW elevated PV with multiple crop trials, research partnership with NREL and Colorado State University), Connexus Energy (Minnesota community solar with sheep grazing), and multiple projects by developer Nexamp and renewable energy company Ørsted.

Topics covered

agrivoltaicsbifacial solarbifacial gainalbedodual-use solarsolar agriculturebifaciality factorground cover ratiorear irradiancesolar grazingpollinator habitat solarbifacial PV modelingbifacial moduleagrivoltaic system design

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