Solar PV performance is susceptible to a variety of external factors. Among them are insects, wildlife, and plants – from pest infestations within critical components to overgrown vegetation encroaching on solar modules or facilities, these biological issues frequently result in measurable drops in power generation. Identifying the cause for each event to restore operations, as well as conducting periodic maintenance in advance to prevent them, is indispensable for the operation of solar power plants.
In this article, we will introduce in detail the power generation damage caused by insects, wildlife, and plants at solar power facilities including the causes and countermeasures based on cases Shizen Operations has handled so far.
Do Wildlife and Vegetation Cause Damage to Solar Power Facilities?
In Japan, high voltage and extra high voltage solar power plants are often constructed in rural flatlands or mountains. Because they are surrounded by nature, damages caused by wildlife and vegetation are surprisingly common.
For example, the following damages occur:
- Crows using transmission towers or substations as roofs to build nests
- Ants or wasps entering equipment and building nests
- Insects or small animals such as lizards touching wiring, causing short circuits
- Vines encroaching and causing breakdowns, or fences collapsing due to wind pressure or weight
- Trees, vines, or grass growing from gaps between solar modules, covering the surface
- Bamboo pushing up solar modules, causing damage
- Dragonflies laying eggs, soiling modules near retention ponds
These issues not only affect the amount of power generation or lead to breakdowns but can also lead to the collapse of fences or injuries. Neglecting these “minor” natural factors can escalate into structural failure or significant financial loss. Early intervention is not just a preference but an operational necessity.
Case Studies of Damage Caused by Insects, Wildlife, and Vegetation at Solar Power Facilities
Shizen Operations conducts Operation and Maintenance (O&M) and Asset Management businesses for renewable energy power plants, including solar power plants. We provide services aimed at improving the performance of our extensive solar portfolio across Japan.
We have encountered various biological challenges across the sites we manage. Here are some real-world examples, causes, and their solutions we applied:
Case Study 1: Issues Caused by Insects
The initial case study is on damages caused by insects. Here are the outlines:
- Soiling from Mayfly Swarms
- Equipment Burnout Due to Slugs and Ants
1-1. Soiling from Mayfly Swarms
The first case is the soiling of solar modules due to a mass outbreak of mayflies. Mayflies originating from rivers and mountain streams swarmed , causing soiling over the modules that led to a drop in power output.
The Solution: In this instance, we performed a thorough cleaning of the solar modules. By cleaning them at an early stage, we restored the original output and minimized the loss of revenue.
1-2. Equipment Burnout Due to Slugs and Ants
The second case is the burnout of a communication board due to slugs and ants entering the combiner box. They entered through tiny gaps in the cable entries leading to failure.
The Solution: We reinforced enclosure seals at cable entry points. By using sealants, we ensured all gaps are completely closed and ensured they are weather resistant, preventing any future recurrence.
Case Study 2: Issues Caused by Vegetation
The following section presents case studies of damage to solar power generation facilities previously managed by Shizen Operations, specifically focusing on issues caused by vegetation. The cases are as follows:
- Soiling of solar modules due to resin (sap)
- Collapse of fences caused by vines and ivy
- Damage to solar modules resulting from the collapse of dead trees
2-1. Soiling of Solar Modules by Resin (Tree Sap)
One common issue is the accumulation of resin on solar modules. Tree sap dripping from nearby trees can harden into resin, soiling the solar modules, causing power loss. Besides sap, organic dirt from pollen or livestock barns also causes soiling of solar modules. These sticky dirt cannot be removed by natural washing from wind and rain.
The Solution: Similar to the case of the mass outbreak of mayflies, we washed the solar modules to restore the original power performance.
2-2. Fence Collapse Due to Vines
When vines such as Kudzu wrap around the perimeter fencing, it makes it difficult for wind to pass through causing the fence to act as a sail, catching the wind. As the wind load increases, it will reach a point where the fence could not withstand the strong wind pressure during strong winds and collapse.
The Solution: To mitigate this risk, we implemented a more frequent weeding schedule. By proactively removing invasive vines before they reach full maturity, we prevent both collapse of fences and the revenue loss associated with module shading.
2-3. Damage from Falling Deadwood
The third case is damage to solar modules due to the collapse of dead trees. As a result of leaving standing dead trees around the solar power facility unattended, they fell and hit the solar modules, causing damage. This could lead to a double loss due to repair costs in addition to the decrease in power generation.
The Solution: We fell the standing dead trees before they fall. By doing this, we prevent collapses caused by natural decay as well as those triggered by extreme weathers such as typhoons.
Case 3: Issues Caused by Wildlife and Animals
Finally, we will examine cases involving wildlife based on Shizen Operations’ extensive field experience:
- Severed PV Connectors caused by Wild Boar and Deer
- Structural Damage to Fencing from Deer
- Module Damage due to Crows Dropping Stones
3-1. Severed PV Connectors by Wild Boars and Deer
The first case involves the disconnection of PV connectors by wild boar and deer. PV connectors serving as relay connectors linking cables between solar modules were torn apart by animals.
The Solution: We asked local hunters to install traps to prevent the intrusion and damages by animals. Operators must account for intrusion of larger animals, in addition to small wildlife and vegetation especially in power plants located in or near mountains.
3-2. Structural Fence Damage by Deer
Another challenge we encountered was damage by deer. In this instance, fencing located on a deer intrusion route was compromised, allowing the animals to enter the facility. Once a fence is breached, it significantly increases the likelihood of disconnection of PV connectors mentioned in the previous case.
The Solution: To address this, we installed motion-sensor lights. We set them on the intrusion route to trigger the natural wariness of deer and prevented intrusion.
3-3. Avian Hazards: Managing Damage from Crows
Beyond ground-based animals, we also address unique hazards posed by avian activity—specifically, crows dropping stones onto solar arrays.Crows have a habit of dropping shellfish or hard nuts to break and eat them. In a solar plant environment, this transitions into play where they drop stones onto module surfaces and break them.
The Solution: A range of measures can be taken in these cases. Here are some of what we had implemented so far:
- Deterring through periodic patrols by hunters
- Wearing the same high-visibility vests as hunters during patrol
- Strobe lighting with flashing lights
- Broadcasting calls that crows consider as threat
- Install bird-repelling windmills or fishing lines
Root Cause Analysis: Why Biological Risks Occur
To manage these risks, operators must understand why they gravitate toward solar sites.
The main conceivable causes are as follows:
- Overgrown Vegetation
- Equipment Design Perceived as a Nesting Environment
- Lack of Civil/Biological Oversight
Below, we provide a detailed analysis of each cause and the corresponding professional countermeasures.
Cause 1: Overgrown Vegetation
The first conceivable cause is the growth of weeds. When maintenance around the solar power plant is neglected, overgrown vegetation creates a thriving environment for pests and small animals, which may directly lead to damage.
Since places inhabited by insects tend to attract small animals such as snakes and mice that feed on them, secondary damage may be caused by weeds. Additionally, as seen in previous cases, the growth of weeds themselves can cover solar modules or cause the collapse of fences.
The Solution: The first thing to consider is weeding. We recommend adjusting the weeding frequency and implementing a periodic maintenance schedule suitable for the site’s environment.
Cause 2: Equipment Design Perceived as a Nesting Environment
Solar power modules create a roof-like structure underneath, making it an ideal environment for nesting.
This space provides shelter from wind and rain while remaining hidden from external predators. For example, pigeons, which prefer positions that safeguard their eggs from external enemies, build nests on the under solar modules or on utility poles.
The Solution: We recommend preventive measures through visual inspections and well-defined maintenance frequencies. Nests should be removed during each periodic inspection.
Cause 3:Lack of Civil/Biological Oversight
While we highlighted solar modules damaged by deadwood, the same risk can be found for utility pole-type private transmission lines in the site. As the surrounding environment of a power plant changes over time, large-scale facilities located in natural settings must incorporate civil engineering inspections to identify and mitigate such risks.
Although the installation of fences is mandatory under the revised FIT Act, it serves more than just a measure for accident prevention and crime prevention; it is also a critical barrier against animal damage. However, the wild animals that are likely to appear differ depending on the region. It is important to develop countermeasures tailored to the local environment, which may include consulting with local experts, such as hunting associations, for their specialized knowledge.
For solar modules that have already been soiled, periodic cleaning is effective in minimizing power generation loss. It can also deal with stubborn contaminants that are difficult to remove, such as bird droppings and resin.
The appropriate cleaning frequency for solar modules varies depending on the power plant. It is essential to determine the optimal timing through several factors, such as performance decline cycles or specific maintenance.
Conclusion: Safeguarding Solar Assets through Professional Environmental Management
Operational risks in solar facilities encompass far more than electrical faults; insects, wildlife, and vegetation pose real threats to performance. Proactive prevention starts with a comprehensive understanding of these potential hazards. We encourage asset owners to continuously evaluate the site-specific biological or environmental risks inherent in their daily operations.
Core mitigation strategies center on consistent maintenance such as weeding and visual inspections around the power plant. Should an infestation occur or module soiling be detected, immediate removal and professional cleaning become necessary. However, since the optimal frequency differs for each power plant, collaborating with an expert is paramount to establishing an effective regime.
At Shizen Operations, we provide a spectrum of O&M solutions including maintenance of solar power facilities. On the maintenance front, we provide a wide range of services such as weeding, cleaning of solar modules, and civil engineering patrols and repair works. Leveraging our deep industry know-how, we propose optimized operation and maintenance strategies designed to minimize revenue loss and protect your bottom line.