How to protect animals from lightning in agriculture – SPE

February 24, 2026
Emiliano Bellini

Researchers from Ilmenau University of Technology have assessed lightning-related hazards in livestock-integrated agrivoltaic systems and proposed a range of mitigation strategies and protection measures to reduce risks to animals.

“Project developers are generally aware that lightning can pose risks to livestock, especially as protective measures against lightning have already been implemented in agricultural facilities such as stables,” said the study’s corresponding author, Kamila Costa, pv magazine. “In agrivoltaic systems, however, the situation is more specific. Although PV installations are not expected to increase the likelihood of lightning strikes compared to open fields, their conductive mounting structures can alter the distribution of the ground potential during a strike. As a result, dangerous step and touch voltages can occur at locations that would otherwise remain unaffected in an open field scenario.”

Costa explained Assessing lightning safety for livestock remains complex because there is limited scientific data on animals’ tolerance to impulse currents and lightning-related step and touch voltages, and no standardized values ​​are currently available. “In our work we propose benchmark values ​​for livestock under lightning conditions; however, these limits are not standardized, making systematic design approaches more challenging” she added.

She also said that no lightning-related incidents involving livestock in agricultural voltaic facilities have been reported to date. “Agrivoltaic energy is still an emerging concept in many countries, and large-scale livestock-integrated projects are relatively recent,” she continued. “Our intent is preventative: to identify and quantify potential risks before accidents occur. A serious lightning strike affecting grouped livestock could result in significant economic losses for farmers and potentially undermine public acceptance of agrivoltaic concepts. Early consideration of lightning safety helps strengthen long-term reliability and viability.”

The cost impact of the additional measures intended to reduce lightning risks to animals would depend on the project-specific risk assessment and initial design. “Tailored lightning protection measures, such as optimized grounding systems or the selective use of insulating or local surface layer measures in critical areas, can increase the cost of the lightning protection system itself,” said Costa. “However, with an optimized and site-specific design, the impact on overall levelized energy costs (LCOE) is expected to be limited. One objective of our research is precisely to support technically effective and economically proportionate solutions, ensuring safety without imposing unnecessary costs.”

In the study “Lightning protection in agrivoltaic systems: assessment of step and touch voltages tailored to livestock”, published in Research into electrical energy systems, Costa and her colleagues identified key lightning injury mechanisms affecting livestock, established safe step and touch voltage limits under representative lightning conditions, and evaluated grounding system (ETS) designs to reduce hazardous voltages in agricultural voltaic installations.

The researchers noted that during thunderstorms, human access to PV installations is limited, but livestock remains in agrivoltaic systems and requires special safety measures. Although PV arrays do not increase the likelihood of lightning strikes, their conductive structures can redistribute ground potentials, creating dangerous step and touch voltages, even at locations far from the point of strike. Livestock are particularly vulnerable because of their body size, posture and tendency to congregate near metal supports. The main injury mechanisms include step stress, touch stress, side flashes, direct blows, upward streamers, and close strike effects.

Assessing lightning safety for livestock is challenging because data on animal tolerance to impulse step and touch voltages is limited. To address this, the team derived benchmark values ​​from the IEC and IEEE standards. They evaluated three representative lightning waveforms, estimated allowable currents based on experimental data for calves, and applied conservative body impedance values. Based on these calculations, they determined the allowable effective step and touch voltages for different current paths. Potential voltage limits were then derived by considering the ground resistance of the hooves, showing that higher soil resistance significantly increases the allowable source voltages.

The group also tested whether a conventional PV ETS can protect livestock in an agrivoltaic installation with grazing livestock. A real location was modeled to assess step and touch voltages and explore potential safety improvements. Simulations used XGSLab with frequency and time domain modules based on the PEEC method to calculate the ground potential rise and transient responses. PV mounting structures, the ETS grid and fences were modeled with defined geometries, connection configurations and LPL III lightning waveforms. Two homogeneous soil conditions (wet and dry), including frequency-dependent behavior, were taken into account to evaluate their impact on the stress distribution.

Combining XGSLab results with a Python-based algorithm, the team also calculated future step and touch stresses, taking into account the animal’s length, step distance and contactable structures. Frequency and time domain analyzes have shown that lightning strikes near the edges of agricultural voltaic systems cause the highest ground potential rise and the largest hazard areas. Touch voltages posed greater risks than step voltages, especially under dry ground and near conductive elements such as mounting structures and fences.

The study also highlighted that soil resistance and fencing grounding significantly influence voltage distribution. Low resistance soils reduce tension, while connecting fences can increase the risk of contact. The time domain results closely matched the frequency domain patterns, but frequency domain simulations proved conservative, faster, and effective for identifying hazardous zones and guiding mitigation strategies.

“Overall, conventional ETS designs optimized for human safety may not adequately protect livestock in agrivoltaic environments,” the scientists concluded. “Our findings underscore the need for animal-specific lightning safety standards and integrated grounding design practices tailored to agricultural voltaic systems.”