Optimizing agrivoltaic systems for crops and clean energy

Agrivoltaic systems, which combine solar power generation with agricultural practices, offer a promising solution to the growing demand for both renewable energy and food production. By integrating solar panels with crops, these systems not only address the land use conflict between agriculture and energy production, but they also provide important benefits such as reducing crop water stress and offering protection against extreme weather events.

In addition, agrivoltaics can contribute to biodiversity by providing pollinator habitats and forage production. For ecosystems in water-scarce regions, these systems have been shown to increase flower production and delay blooming, which supports late-season pollinators. Research also shows that solar panels can perform better in agrivoltaic systems, thanks to the microclimate created underneath them.

As agrivoltaic systems become an increasingly important part of the global energy transition, the need for tailored tracking strategies to optimize their performance is growing. Horizontal single-axis tracker (HSAT) systems, which adjust the angle of solar panels throughout the day to track the sun, offer significant potential in this regard.

Effective control of panel positioning helps balance the dual objectives of maximizing energy generation and preserving agricultural yields. Such optimization is particularly relevant as agrivoltaic systems need to meet yield loss thresholds in order to qualify for subsidies, thus improving their economic viability.

A recent study published in the Journal of Photonics for Energy provides valuable insights into how solar panel positioning can be optimized to achieve this balance. The research focuses on a case study of apple orchards in southwestern Germany, but the findings are broadly applicable to various agricultural settings.

The study proposes a new methodology for dynamically optimizing solar panel positioning based on the light needs of crops. Unlike traditional shading strategies, which are based on general guidelines or structures like hail nets, this new approach uses specific irradiation targets to meet the precise light requirements of different crop varieties. The research team ran simulations using a custom tool called APyV to assess how varying solar panel positions would impact light availability for the crops.

APyV uses advanced ray tracing techniques to evaluate the distribution of solar radiation and its impact on both the photovoltaic panels and the underlying crops. The tool automates design optimization of agrivoltaic systems based on key performance indicators, the interface with different crop models, and the integrated simulation of specialty crops. It allows direct calculation of the light received by the crop and a more accurate simulation of its impact on the overall agrivoltaic system.

The results of the case study revealed that with tailored solar panel control, 91% of the light needed for the apple trees was delivered over the course of the year, with only a moderate 20% reduction in solar energy production. However, the study also identified periods when the light requirements of the apple trees were not fully met, indicating the challenges of achieving optimal crop and energy performance simultaneously. Despite these limitations, the study lays a strong foundation for future research, which is already underway.

According to corresponding author Maddelena Bruno, who is leading the study as a doctoral candidate at Fraunhofer ISE, “Our study shows that the combination of solar energy and farming can be enhanced by smart PV-trackers that adjust the position of solar panels based on weather conditions, crop types, and their growth stages. This approach ensures an optimal balance between light available for photosynthesis and light available for electricity production.”

Bruno notes that the proposed irradiation targets and tracking strategy are to be field-tested during the current growing season in Nussbach, providing an opportunity to validate or challenge the reported results. These field tests will contribute significantly to a deeper understanding of the impact of agrivoltaic systems on apple orchards and the surrounding environment.

Ultimately, this research will provide critical insights that can guide the optimization of agrivoltaic systems, making them more effective in balancing agricultural productivity and renewable energy generation while supporting the ongoing energy transition.