As solar generation and battery storage continue to expand across the UK and internationally, the buried metallic infrastructure surrounding these developments faces increasing corrosion and interference risks. Solar farms occupy large areas of land, rely on extensive steel foundations, and are increasingly constructed alongside existing pipeline and utility corridors. This combination of widespread earthing, steel piles, and high-capacity electrical systems means that interactions with nearby buried assets must be understood from the outset. In parallel, the steel piles that support the solar arrays face their own long-term corrosion challenges, which require separate assessment and management.
Corrpro Europe is already active in the solar market, delivering both electrical impact assessments for nearby pipelines and the implementation of cathodic protection on solar developments. This article sets out the corrosion and interference challenges specific to solar farms and battery storage plants, and how cathodic protection and interference control address them.
The corrosion challenge on a solar site
A utility-scale solar farm is, from a corrosion perspective, a large array of buried steel foundations connected to an extensive earthing and cabling network. The principal concerns are:
- Pile foundations: thousands of driven or screwed steel piles support the module tables. Buried in soil of varying resistivity and chemistry, these steel piles are susceptible to long-term corrosion and require appropriate assessment and, where needed, cathodic protection.
- Buried cabling and earthing: Solar farms include extensive buried DC and AC cabling and large earthing networks. These components do not corrode like steel piles or pipelines; however, their presence and electrical behaviour are important to understand when assessing safety and corrosion risks to nearby buried metallic assets.
Soil resistivity and chemistry vary significantly across a solar or BESS site, meaning corrosivity and stray-current behaviour are rarely uniform. A soil resistivity survey identifies where the ground is most aggressive and helps determine whether steel piles or other buried steel require cathodic protection. In addition to resistivity testing, we can deploy specialised monitoring equipment capable of measuring the actual corrosion rate on steel within the site. This allows us to quantify how internal DC stray currents, copper earthing coupling, and soil conditions are affecting corrosion in real time. By understanding the true corrosion rate before deterioration occurs, we can accurately assess risk and, where necessary, implement targeted cathodic protection to ensure long-term structural integrity.
Solar farms and electrical interference
The more distinctive challenge on solar developments is electrical interference, and it works in two directions.
Interference affecting nearby pipelines and utilities
Solar farms and battery energy storage systems (BESS) introduce extensive earthing networks and large DC and AC electrical systems into an area. Modern sites include high-capacity DC arrays, MV/HV internal distribution cables, and an AC export connection to the grid. These electrical systems do not corrode themselves, but they create electrical environments that can influence the corrosion behaviour of nearby buried metallic assets.
Where a solar or BESS development is constructed close to a buried pipeline or other cathodically protected structure, the presence of these electrical systems — including the AC export cable, MV/HV circuits, DC cabling, and the site earthing network — can interact with the external asset. This interaction can affect cathodic protection performance and, in some cases, introduce a corrosion or safety risk that must be assessed.
Interference and stray current within the solar site
Within solar farms and BESS facilities, internal DC systems can create conditions that accelerate corrosion on the site’s own buried steel, particularly the steel piles. Any DC leakage or imbalance from the arrays, inverters or battery systems can enter the surrounding soil and seek a return path. When high-conductivity copper earthing conductors are installed close to steel piles — especially in low-resistivity soils — a coupling effect can occur. The copper provides a preferential current pathway, and the resulting redistribution of current in the soil can increase the current density on adjacent steel surfaces, accelerating corrosion at those locations.
If the earthing network is not continuous, DC current may be forced to return through isolated steel piles instead of through the intended copper conductors. This concentrates current discharge at specific points on the pile, creating localised corrosion where the current leaves the steel. These internal stray-current effects are distinct from external pipeline interference and require dedicated assessment to ensure long-term structural integrity of the solar farm’s foundations.
Corrpro Europe assesses both directions of interference using field investigation, data logging and, for complex scenarios, computer modelling to predict induced voltages and current before mitigation is designed. This is the same interference capability applied across pipeline and energy corridor projects, brought to solar developments.
How cathodic protection and interference control are applied
The approach on a solar project follows the same engineering discipline as any other CP scheme, tailored to the site:
- Survey and assessment: soil resistivity surveys across the site, corrosion assessment of buried steel, and interference screening where pipelines or utilities are nearby.
- Interference study and modelling: quantifying AC and DC interference between the solar infrastructure and adjacent structures, using computer modelling for complex layouts.
- Cathodic protection design: where buried steel request protection, a CP system is designed to the relevant standards, using galvanic or impressed current methods according to the current demand and soil conditions.
- Mitigation design and implementation: adding Depending on the assessed interference risk, mitigation may include optimising the solar asset earthing arrangements, installing zinc ribbon anodes and decoupling devices along the pipeline, selective bonding of metallic components, and applying targeted cathodic protection to affected buried steel. These measures are designed to control stray-current and interference effects and to protect both the solar/BESS infrastructure and neighbouring buried assets.
- Materials supply and monitoring: UK-manufactured anodes, transformer rectifiers and reference cells, with remote monitoring where continuous oversight is valuable across a large site.
Supporting the energy transition
Extending the service life of renewable energy infrastructure is part of what makes it sustainable. Protecting solar farm foundations and buried infrastructure from corrosion reduces the need for early replacement, minimises waste and helps ensure that the asset delivers over its full intended life. Corrpro Europe supports the renewable energy sector across solar, offshore wind, hydrogen and carbon capture, applying decades of corrosion protection experience to the assets of the energy transition.
Frequently asked questions
Do solar farms need cathodic protection?
It depends on the site. Solar farms are founded on buried galvanised steel piles and carry extensive buried cabling and earthing, all exposed to soil corrosion. Where soil conditions are aggressive, or where buried steel is critical to the structure’s life, cathodic protection can be considered. A soil resistivity survey and corrosion speed assessment establish where it is needed.
How do solar farms affect nearby pipelines?
A solar farm and BESS systems introduce large earthing systems and DC and AC electrical infrastructure. Where it is built near a buried pipeline or other cathodically protected structure, these systems can interact with the structure and affect its CP performance, and in some cases introduce a corrosion or safety risk. An interference study quantifies the effect so that mitigation can be designed where needed.
Can interference between a solar site and a pipeline be mitigated?
Yes. Once an interference study has quantified the interaction, mitigation is designed using earthing, bonding and decoupling measures appropriate to the situation. Corrpro Europe assesses, designs and implements this mitigation, drawing on the same interference expertise applied to pipelines in shared power corridors.
Does Corrpro Europe work on solar projects?
Yes. Corrpro Europe is active in the solar market, delivering electrical impact assessments. interference mitigation projects and implementing cathodic protection on solar developments, as part of its wider work across the renewable energy sector.
Corrpro Europe delivers cathodic protection and interference mitigation across the renewables sector, including solar, offshore wind, hydrogen and carbon capture projects, backed by UK manufacturing and over 50 years of corrosion protection experience.
To discuss cathodic protection or an interference study for a solar development, contact our engineering team or explore our Renewables sector page.
