Corrosion that occurs due to electrochemical interaction between soil and steel is one of the most serious and often underestimated problems in photovoltaic plants. Although its relevance is well known, this problem tends to be avoided in discussions, generating concern especially in the acquisition of existing assets.
The search for savings in structural costs during the development of plants can lead to long-term consequences. Many times, decisions about materials and structures that are made in the early phases of projects negatively affect future operations, especially in the maintenance phase of the infrastructure or even for companies that are interested in acquiring the plants at a later stage.
One of the key questions is not whether corrosion will affect the plant, but how quickly it will do so, compromising the steel coating in the subsoil. The lack of adequate protection and treatment can lead to rapid degradation, putting structural stability at risk.
Corrosion in steel structures of photovoltaic plants
Within the ever-growing photovoltaic industry, corrosion of buried steel is a considerable challenge, especially in metal structures supporting solar panels. In environments known for their aggressiveness, such as in soils with high salinity, humid areas, corrosion is closely monitored. However, in seemingly more benign soils, this vigilance can be more relaxed, leading to unpleasant surprises over time. In fact, multiple factors influence corrosion, meaning that even in less aggressive soils, the risk of corrosion is still present.
When someone thinks about corrosion, it is often associated with atmospheric exposure. However, buried steel, which often does not receive the same attention, can suffer an even more accelerated corrosion process if it is not provided with adequate protection. This deterioration can accumulate over time, even leading to structural failures earlier than expected.
It is possible to see a photovoltaic plant that appears to be in perfect condition from the surface, without realizing that underground corrosion has already begun to affect the structures. This problem could go unnoticed until excavations are carried out or until a significant failure is observed in the underground poles or structures. The reality is that, in many cases, the effects of corrosion appear much sooner than expected, even in plants that have only been in operation for a few years.
Preventing and mitigating corrosion in photovoltaic plants
As worrying as the scenario may be, there are effective methods to prevent and mitigate the effects of corrosion. These measures must be implemented from the early stages of the project, during the design of the plant, through a correct evaluation of the geotechnical model of the terrain. To do this, it is essential to make a detailed geological map that allows the identification of areas with different behaviors against corrosion, complemented by the taking of soil and groundwater samples.
Likewise, physical and chemical tests carried out in specialized laboratories allow the corrosive potential of soil and groundwater to be evaluated. Although these tests do not offer an exact measurement of the corrosion rate of steel, they provide valuable information during the design phase to make better decisions.
When the plant is already in operation, there are inspection methods to evaluate the current state of the structures and determine if corrosion is present. If there are suspicions that the steel is being affected, techniques can be used to monitor the situation and ensure that the plant will fulfill its estimated life cycle.
In recent years, technology has advanced significantly, and innovative methods are being used to monitor and assess corrosion in photovoltaic plants. The use of electrochemical techniques, together with physical and chemical testing of soil and water, allows insight into the corrosion status of the plant.
From these analyses, it is possible to create a detailed diagram showing the annual corrosion rates, which facilitates the development of plans. These plans help ensure that the plant reaches its projected lifespan, also allowing, in case problems are detected, the design of solutions to mitigate the effects of corrosion.
Conclusion
Corrosion of steel due to soil conditions is a problem that directly affects the durability and efficiency of photovoltaic plants. Although it may seem that this phenomenon occurs only in highly aggressive soils, the reality is that even in soils considered safe, serious corrosion problems have been recorded in plants with only a few years of operation.