ABSTRACT
SOLAR AGRIVOLTAICS DESIGN: CRITICAL FACTORS AND KEY CONSIDERATIONS
Journal: Malaysian Journal of Sustainable Agriculture (MJSA)
Author: Rittick Maity, Sudhakar Kumarasamy, Amir Abdul Razak
This is an open access article distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
DOI: 10.26480/mjsa.01.2025.16.20
KEYWORDS: Agrivoltaics, solar energy, agriculture, design principles, sustainability
1. INTRODUCTION
The photovoltaic technology has been used for transition from fossil fuel energy to non-fossil fuel energy. The UN Sustainable development goals (SDGs) stresses on use of affordable clean energy to combat climate change and its impact. Several advantages due to modularity, low cost, good lifespan and market growth has promoted solar photovoltaics to be used as a decentralized form system (Toledo and Scognamiglio, 2021). The large-scale PV farms in malaysia have been encouraged to setup for lower carbon emissions by 2050 (Ya’acob et al., 2023).
Currently, land-based PV farms are facing competition with food production for land allocation. Hence, innovative solutions that minimize land use are gaining importance. Examples include building integrated photovoltaics (BIPV) utilizing existing building surfaces, floating PV on water surfaces, and agrivoltaic systems (APV) that allow dual land use for food and energy production (Agrivoltaics, n.d.).
The concept of agrivoltaics i.e. fusion of solar PV with agriculture, has led land productive for farmer and also leads to income generation (Macknick et al., 2015; Chalgynbayeva, 2023). Agrivoltaics, a promising approach that integrates solar photovoltaic (PV) systems with agricultural practices, has emerged as a compelling strategy to maximize land use efficiency and resource utilization. This integration involves the co-located use of land for both solar energy generation and agricultural activities, offering dual benefits of renewable energy generation and crop cultivation. The design of agrivoltaic systems requires careful consideration of various factors, including optimal land management, crop selection, system configuration, and environmental impacts. By strategically placing solar panels above or alongside crops, agrivoltaics not only harness solar energy but also provide shading and microclimate control that can enhance crop productivity and water-use efficiency.
A study about the dynamic prototype of a photovoltaic greenhouse with an length of 3.17m and with of 2.14m (Moretti and Marucci, 2019). Researchers proposed to keep the structural heights about 2m and interrow distance between solar panel 3 times the height of the solar (Goetzberger and Zastrow, 1982). A study on AVS system which has height of 3.3 m, tilt of 32° with a spacing of 1m (Barron-Gafford et al., 2019). Researchers studied a prototype of a mono-crystalline mounted at a height of 4m as it is the first experimental pilot project, however, was installed in France, close to the southern city of Montpellier in the spring of 2010 (Dupraz et al., 2011)
The paper mainly discusses on the different design factors and how this factors influences the production of crops and electricity generation.
2. KEY COMPONENTS IN AGRVOLTAIC DESIGN
2.1 Different Solar PV Technologies
The basic agrivoltaics model was first proposed by Akira Nagashima in Japan. He termed it as solar sharing (Doedt et al., 2023). Monocrystalline panels have higher efficiencies. It can generate more electricity per square meter. Monocrystalline panels in agrivoltaics often require less space to generate the same amount of electricity as polycrystalline panels. This can allow for more flexible placement in agrivoltaic setups, potentially minimizing shading effects on crops or livestock. Monocrystalline panels typically perform better in high temperatures compared to polycrystalline panels, which can be advantageous in agricultural regions where temperatures can rise significantly. Polycrystalline panels generally have a lower cost per watt compared to monocrystalline panels. This cost difference may influence the economic feasibility of agrivoltaic projects, especially when considering large-scale installations of agrivoltaics. Polycrystalline panels often have a bluish hue as shown in figure 5b, while monocrystalline panels appear darker and more uniform. Depending on the visual impact desired in agricultural settings, one type of panel might be preferred over the other. Integrating CdTe as it has high modularity, thin and lightweight. CdTe modules can be designed to transmit certain wavelengths of light as seen in figure 1c. that are beneficial for plant growth while capturing others for electricity generation. This spectral selectivity can enhance crop photosynthesis and productivity. Even with the unique qualities of third-generation photovoltaic devices (such as their environmental effect, cheap manufacturing costs, variety of colors and transparency levels, and flexibility), stability and efficiency are still crucial elements that need to be enhanced to promote them as an alternative to PV technologies that have become solidified at the market levels, in contrast to silicon-based PV) and the latest advancements in the field.
2.2 Crops
The basic idea of crops being kept under solar panel is to effectively use the light saturation point and the temperature saturation point. The maximum light intensity at which a plant may achieve its highest rate of photosynthesis. Above this threshold, more light either doesn’t speed up photosynthesis or might even lead to photoinhibition. The amount of shade tolerance exhibited by different crops varies. The way that plants function in partially shaded environments, such agrivoltaic systems, is influenced by the saturation point of light levels. The C3 plants adapted to wet and moist temperature condition were photosynthesis rate increases to 20 μmol-2s-1around 25 °C leaf temperature, while the C4 plant adapted to dry and high temperature condition as the photosynthetic rate is optimum in between 30°C to 35°C. The fig 2. shows the operation of C3 and C4 plants with leaf temperature.
Agrivoltaic systems using different panel technologies as shown in table 1 employing monocrystalline and polycrystalline photovoltaic technologies offer varied benefits for different crops. Monocrystalline panels, with their high efficiency, are well-suited for crops like wheat and maize, potentially enhancing growth by reducing heat stress. In contrast, polycrystalline panels, which are more cost-effective, align well with rice and sorghum cultivation by providing beneficial partial shading and managing water use. The integration of Dye-Sensitized Solar Cells (DSSC) with polycrystalline panels further innovates the approach, particularly benefiting soybeans and sugarcane by optimizing light conditions and energy efficiency. For organic farming, while monocrystalline panels offer superior performance, polycrystalline panels provide a more economical choice, though their impact on soil and crop quality needs careful assessment. Overall, the choice of technology should balance efficiency, cost, and the specific needs of the crops to maximize both agricultural and energy outputs.
3. PERFORMANCE MATRICS
3.1 Land Equivalent Ratio
Since the APV system integrates PV modules with farmland, the impact of land use intensity on the system’s energy performance is a crucial factor in determining the overall feasibility of the solution. In this context, land use energy intensity can be quantified using metrics that measure land area per unit of energy generation (ha/kWh) and/or land area per unit of capacity (ha/kWp). Meanwhile, performance can be assessed as the amount of energy produced per unit of capacity over a typical or actual year (kWh/kWp/y), a standard metric used for solar systems. to evaluate the performance of the APV system, the authors recommend using the Land Equivalent Ratio (LER) indicator. This metric allows for a comparison between the traditional approach (separate PV and farming setups) and the integrated solution on the same land area (Chalgynbayeva et al., 2024). LER assesses whether the combined benefits of agricultural yield and solar energy are equal to or greater than those achieved through the separate use of the land.
3.2 Height of Module from Ground
The elevation of the systems above the ground (the space between the modules and the ground surface) is a crucial design factor. Higher structures, typically found in APV systems, can enhance the uniformity of radiation distribution beneath the PV modules, improve connectivity, and accommodate taller plants. Conversely, if the modules are positioned closer to the ground, the variability in radiation across crops within the same land area increases (excluding effects on surrounding areas). Complex factors contribute to the visual impact of PV systems on areas like recreation and tourism. Using higher mounting structures not only affects social acceptance but also significantly impacts installation costs and environmental consequences. In Germany, the additional expenses associated with elevating PV modules—including mounting, installation, and site preparation—are estimated to be more than double those for ground-mounted systems, rising from 0.3 EUR/kWp to 0.7 EUR/kWp (Trommsdorff, 2016).
The height of the system can also be an indicator of sustainability. Larger structures used to elevate the modules are associated with higher emissions. For instance, the LCA study reveals that an integrated PV parking lot (222 kWp) requires 72 tons of steel, resulting in 82 tons of CO2 emissions—eight times more than a conventional galvanized steel PV mounting system (Serrano et al., 2015). Additionally, in PV greenhouses (PVG), gutter height is a critical design factor as it positively impacts the total global radiation inside the greenhouse. Each additional meter of gutter height can increase the annual global radiation by 3.8% compared to a conventional greenhouse (Cossu et al., 2018). While higher APV systems can enhance solar energy collection for plants, the literature also highlights potential concerns regarding their ecological impact
3.3 Spatial Configuration between PV and Crops
A module’s height and spacing can be adjusted to cultivate different types of crops based on their light, humidity, temperature, and space needs. This allows for the identification of optimal growth zones. For ground-mounted PV installations combined with low-height crops, three distinct zones can be identified: zone 1 with low irradiance and high humidity, zone 2 with moderate light exposure and sufficient soil moisture, and zone 3 with the highest irradiation and lowest humidity (Schindele et al., 2012). Similarly, APV systems for orchards or grapevines require designs with tilt-mounted structures and PV modules placed at higher elevations to accommodate tree growth and allow farm machinery to pass underneath. Even in cases where there are no appreciable output losses, the presence of PV modules might affect quality attributes including fruit color, size, and sugar content. Tomatoes produced in a PV greenhouse with 9.8% PV coverage had smaller and less colorful fruits, according to Ureña et al. [68], but yield and cost were unaffected. In a similar vein, tomatoes with 50% PV coverage yielded inferior quality characteristics (Bulgari et al. 2015). Grapes planted in Korea under PV modules had decreased weight and sugar content (Cho et al., 2020) . This resulted in a harvest that was delayed by roughly 10 days, and the sugar levels were similar to those at the control location. On the other hand, certain species, such as strawberries, responded well in terms of yield and quality (increased chlorophyll content).
3.4 Orientation of Agrivoltaics System
The orientation of solar panels affects their exposure to sunlight throughout the day. In most cases, panels are tilted towards the south (in the northern hemisphere) to maximize exposure to sunlight, as this direction typically receives the most sunlight over the course of a day. The orientation influences how much shade is cast on the ground below. Proper orientation can minimize shading during critical growing periods, ensuring crops receive sufficient sunlight for photosynthesis. In terms of orientation of module they are oriented to south in landscape or portrait layout.
3.5 Tilt of the Agrivoltaics System
The tilt angle of an agrivoltaic system is a critical design factor that significantly influences both solar energy production and agricultural productivity. The optimal tilt angle is often determined by the latitude of the installation site, with a common practice being to set the angle equal to the latitude to maximize annual solar energy capture. Additionally, seasonal adjustments to the tilt angle can further enhance efficiency, with steeper angles in winter and shallower angles in summer. The tilt angle also impacts the shading patterns cast on the crops below, which can vary in intensity and distribution. Different crops have unique light requirements and tolerances to shading, necessitating tailored tilt angles to optimize growth. Moreover, the tilt angle can influence the microclimate beneath the panels, affecting temperature regulation and reducing heat stress on the crops during peak sunlight hours. Properly angled panels can also improve water management by directing rainwater more effectively toward the crops. Therefore, finding the right balance in tilt angle is essential for maximizing both solar energy production and agricultural yields, and ongoing research continues to refine these parameters for various crops and regions.
3.6 Heggelbach farm, Germany (APV-Resola Project)
One of the projects in which the height of the solar modules affected the solar PV design is the Heggelbach farm in Straßkirchen from APV-Resola project. This project integrated photovoltaics with crop farming, and the height of the modules was a critical factor in the system’s design and success.The agrivoltaics system covered about 0.3 hectares with an installed capacity of 194 kWp. The module height was kept at 5m. The height of 5 meters was selected to balance solar power generation and crop yield. This height allowed sufficient sunlight to reach crops while still providing shading during peak sunlight hours.The crops chosen for this project were wheat, potatoes, clover, and celery. Each crop responds differently to light and shading, and the height allowed for enough light penetration, especially for taller or shade-tolerant crops. The high placement minimized extreme shading, which can otherwise stunt the growth of some crops, allowing them to grow with less competition for light. The elevated modules enhanced airflow under the panels, reducing humidity and creating a cooler microclimate beneath the panels. This helped mitigate heat stress on crops during hot summers, contributing to better crop yields. The airflow also helped reduce the risk of fungal diseases that thrive in damp conditions, promoting healthier crop growth. By raising the modules 5 meters off the ground, farmers were able to access the fields with traditional farming equipment (tractors, plows, etc.). This was a significant advantage, as it meant that normal agricultural activities could continue without major changes. The crops chosen for this project were wheat, potatoes, clover, and celery. Each crop responds differently to light and shading, and the height allowed for enough light penetration, especially for taller or shade-tolerant crops. The high placement minimized extreme shading, which can otherwise stunt the growth of some crops, allowing them to grow with less competition for light. The elevated modules enhanced airflow under the panels, reducing humidity and creating a cooler microclimate beneath the panels. This helped mitigate heat stress on crops during hot summers, contributing to better crop yields.The airflow also helped reduce the risk of fungal diseases that thrive in damp conditions, promoting healthier crop growth. By raising the modules 5 meters off the ground, farmers were able to access the fields with traditional farming equipment (tractors, plows, etc.). This was a significant advantage, as it meant that normal agricultural activities could continue without major changes. The agrivoltaic system showed that, in some cases, crop yields (especially shade-tolerant crops like clover) increased under the panels due to reduced heat stress. However, crops like wheat experienced a slight reduction in yield due to reduced light levels. The land’s productivity improved, with an estimated increase of over 60% in combined land-use efficiency (agriculture + energy). The study highlighted that certain crops (e.g., potatoes, clover) perform better than others in agrivoltaic systems due to their adaptability to shading. The height of the modules plays a significant role in determining which crops can thrive.
4. CONCLUSIONS
Agrivoltaic systems represent a transformative approach to land use, merging the production of solar energy with agricultural activities. This dual-use model addresses the increasing competition for land between renewable energy projects and food production, offering a sustainable solution that maximizes the benefits of both sectors. Through careful consideration of design factors such as module height, tilt, orientation, and spatial configuration, agrivoltaic systems can be optimized to enhance both solar energy yield and agricultural productivity. Different solar PV technologies, including monocrystalline, polycrystalline, and innovative solutions like CdTe and DSSCs, offer varied benefits and challenges, influencing the efficiency and economic viability of agrivoltaic projects.The successful implementation of agrivoltaic systems depends on a deep understanding of crop-specific light and temperature requirements, ensuring that shading from PV panels supports rather than hinders crop growth. Performance metrics such as the Land Equivalent Ratio (LER) provide valuable insights into the efficiency of land use, highlighting the advantages of integrated systems over traditional, separate approaches. Additionally, the height and spacing of PV modules must be tailored to accommodate different crops and farming practices, from low-height vegetables to tall orchards and vineyards.
Ongoing research and development are essential to refine these systems, addressing ecological impacts and optimizing configurations for diverse agricultural environments. By leveraging the synergy between solar energy generation and agriculture, agrivoltaics offer a promising pathway to sustainable development, aligning with global goals for clean energy and climate action while supporting food security and rural economies. As the field advances, continued innovation and adaptation will be key to realizing the full potential of agrivoltaic systems worldwide.
DATA AVAILABILITY
The data used to support the findings of this study are available from the author upon request.
ACKNOWLEDGEMENT AND FUNDING STATEMENT
The authors are grateful for the financial support provided by the Universiti Malaysia Pahang Al Sultan Abdullah (www.umpsa.edu.my) through the Doctoral Research Scheme (DRS) to Mr Rittick Maity and Post Graduate Research Scheme (PGRS 230384).
CONFLICTS OF INTEREST
The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr K Sudhakar reports financial support was provided by University of Malaysia Pahang Al-Sultan Abdullah. Dr K Sudhakar reports a relationship with University of Malaysia Pahang Al-Sultan Abdullah that includes: employment. Dr K Sudhakar reports a relationship with Elsevier Inc that includes: board membership. The corresponding author is serving on the Editorial board of Heliyon as Associate Editor If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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| Pages | 16-20 |
| Year | 2025 |
| Issue | 1 |
| Volume | 9 |
