Swedish researchers developed two new single-axis solar tracking strategies that dynamically adjust the panel’s tilt based on the crop’s light needs, balancing photosynthesis and energy production. One strategy prioritizes integral daily light targets before moving to energy capture, while the other uses the light response curve to optimize photosynthesis, delivering improved dual-use efficiency compared to conventional tracking methods.
Researchers from Sweden’s Mälardalen University have proposed two new single-axis solar energy tracking strategies aimed at improving crop yield in agricultural voltaic projects.
“We have embedded crop light demand directly into the tracker control, enabling dynamic prioritization of food production when crops need light and energy conversion when they do not”, the corresponding author of the study, Sultan Tekie, narrated pv magazine. “Unlike most existing agrivoltaic tracking strategies that rely on static shade thresholds or empirical rules, our new strategies utilize the crop light response curve to regulate panel orientation based on the onset of photosynthetic saturation, thereby linking photovoltaic operation to plant physiology.”
The proposed two strategies, called Daily Light Integral Tracking (DLIT) and Knee-Point Tracking (KPT), aim to ensure that crops receive sufficient, but not too much, light. “We use both strategies to respond to cumulative light demands and to adapt tracker operation to real-time environmental variability, providing a systematic path to balance energy yield and crop performance under changing climatic conditions,” Tekie continued.
Come to the on March 5 Double harvest, double problems: addressing EPC barriers in agrivoltaic system design pv magazine session in English at KEY – The Energy Transition Expo in Rimini.
Experts will share insights on current agricultural voltaic technologies, key design choices and key barriers to standardized, scalable dual-use projects in Europe and Italy, including region-specific EPC issues.
The DLIT strategy adapts solar tracker operation to meet crop-specific daily light integral (DLI) requirements, using active tracking (AT) until the target is reached, and then tilt tracking (TT) for the remainder of the day. With AT, the tracker continuously monitors the sun to maximize light on crops, prioritizing plant growth until the daily DLI target is met. After meeting the crop’s light needs, the tracker switches to maximize solar energy capture using TT for electricity, rather than accurately tracking the sun for the crop.
The KPT strategy identifies the optimal photosynthetically active radiation (PAR) on the light response curve (LRC) to select the solar panel tilt angle that maximizes photosynthesis. LRCs, modeled using a temperature-dependent non-rectangular hyperbola, generate 35 curves for 0–35 °C, with the knee point representing the PAR where photosynthesis begins to stagnate. Optimal PAR values are interpolated hourly and compared to ground irradiance to dynamically select the tilt angle, delivering an adaptive, temperature-driven tracking strategy. To reduce mechanical stress and abrupt movements during tilt adjustments, a Gaussian filter smoothes tilt angles hourly, balancing crop growth and energy efficiency.
The scientists evaluated the performance of the two strategies using three conventional tracking methods, namely time-based tracking (TT), active tracking (AT) and static tilt (ST). The analysis was based on the operation of a 26 kW agrivoltaic system in Västerås, Sweden.
The system consists of three rows of PV modules, each 20 meters long and 10 meters apart, mounted at a hub height of 1.8 meters. It uses 45 monocrystalline silicon bifacial PV modules, each rated at 580 W with a bifacial factor of 0.85. To maximize light transmission for optimal crop growth, the rotation of the sun tracker is limited to 90°.
The measurements showed that TT maximizes energy yield but has the lowest biomass, while AT maximizes biomass at the expense of energy. In contrast, ST was found to provide a balanced trade-off, while KPT maintains high biomass with moderate energy, and DLIT prioritizes energy after DLI targets are achieved.
Overall, all strategies show a trade-off between energy and crop productivity, with KPT and ST providing balanced performance, and DLIT favoring energy once crop light needs are met.
“DLIT maintained energy conversion within approximately 1% of TT while reducing biomass by approximately 10%, indicating that daily crop light limitations can maintain energy production with limited agronomic impacts,” the academics said. “KPT has further improved this balance by limiting biomass loss to approximately 2% compared to AT, while retaining more than 85% of the energy yield achieved by TT.”
“The analysis also showed that flattening the tilt angle trajectories reduced biomass yields by more than 20% across all strategies, underscoring the importance of dynamic and responsive tracker operation for crop performance,” they concluded. “Overall, the key advantage of the proposed DLIT and KPT frameworks lies in their physiological basis and operational flexibility. By directly linking tracker control to cumulative and instantaneous crop light requirements, these strategies go beyond fixed schedules and empirical thresholds, providing a robust path to improved dual-use land efficiency in agricultural voltaic systems.”
Their findings are available in the study “New operational strategies to maximize crop and electricity production in single-axis agricultural voltaic systems based on the light response curve and daily light integration”, published in Results in technology.
This content is copyrighted and may not be reused. If you would like to collaborate with us and reuse some of our content, please contact: editors@pv-magazine.com.
Popular content
