How a ground-mounted PV structure affects the efficiency and durability of a photovoltaic farm

INVESTING IN A PHOTOVOLTAIC FARM – WHY THE GROUND-MOUNTED STRUCTURE MATTERS

Investing in a photovoltaic farm is a decision for a minimum of 25 years. Most investors focus on choosing photovoltaic modules and inverters, while the structure supporting the PV panels is treated as a secondary cost item. This is a mistake that can cost thousands of zlotys annually in lost energy production and premature repairs. The ground-mounted structure is the foundation of the entire PV installation and directly impacts how much solar energy is converted into revenue over the farm’s operational life.

Why cheap PV mounting structures reduce your farm’s profitability

Many investors are tempted to save on the mounting structure, thinking: if it only holds the panels, why overpay? This calculation overlooks a critical fact: a ground-mounted structure must maintain panels at the optimal tilt angle for 25 years, withstand extreme weather conditions, and remain stable despite thousands of thermal cycles.

Corrosion and steel profile degradation

Problems typically appear after two to three years of operation. Cheap PV mounts begin showing signs of degradation. Steel profiles develop rust in areas where the anti-corrosion coating is too thin or improperly applied. Bolted connections loosen due to wind-induced vibrations, affecting the stability of the PV structure. Over time, the frame loses rigidity, and the panel tilt angle deviates from the design value.

Loss of PV system efficiency

For a single panel, a three-degree deviation from the optimal tilt angle results in a 2–4% drop in energy production. On a farm with thousands of modules, these losses add up to tens of thousands of zlotys annually. Over 25 years, the investor loses many times the initial savings on the structure, not to mention repair costs, replacement of corroded elements, and downtime in energy production.

Types of ground-mounted structures and their impact on energy production

The choice of PV ground structure should be based on location conditions, budget, and expected ROI. There are three main categories, each offering a different cost-to-energy-benefit ratio:

Fixed ground-mounted structures

The most common solution for PV farms in Poland. Panels are mounted at a fixed angle optimized for the latitude, increasing solar efficiency. In central Poland, the optimal tilt angle is 30–35°. Fixed structures have lower initial costs, simpler installation, and lower maintenance requirements. This solution is especially suitable for large ground-mounted PV installations where predictable operational costs are a priority.

Freestanding adjustable PV structures

Allow seasonal adjustment of panel angles – steeper in winter, shallower in summer. Manual adjustment twice a year can increase annual energy production by 3–5% compared to fixed structures. However, it requires extra work and carries the risk of errors in adjusting the panels.

Trackers and solar tracking systems

Freestanding ground structures with drives automatically follow the sun’s position. Single-axis trackers increase energy production by 15–25%. Trackers require regular maintenance, increasing farm operating costs and extending ROI.

How tilt angle affects PV panel efficiency

Energy production depends on the sunlight hitting the panel surface. Maximum efficiency occurs when sunlight is perpendicular to the cells. Because the sun’s position changes daily and seasonally, fixed installations are always a compromise.

In Poland, the optimal tilt is 30–35° south-facing. A 5° deviation reduces annual output by 1–2%; a 10° deviation increases losses to 3–5%. Over 25 years, even small deviations can translate into significant lost revenue.

Support profiles and driven posts requirements

The structure must maintain the design tilt angle over the entire lifespan. Support profiles must be stiff enough not to bend under panel weight and snow loads. Driven posts must remain vertical despite seasonal soil movements caused by freezing. Professional ground-mounted PV structures are designed with installation tolerances that minimize errors during setup.

Durability and stability of steel ground structures

The longevity of ground-mounted PV structures depends on material quality and corrosion protection. PV farms operate in variable environments, requiring robust structures. UV exposure, moisture, and temperature changes accelerate degradation. Summer temperatures can exceed 60°C, while winter brings freezing and moisture.

Steel profiles and anti-corrosion protection

Steel is standard for PV farms, offering durability and stability at a favorable cost-to-strength ratio. Hot-dip galvanizing provides the most effective corrosion protection. A zinc layer of at least 80 µm protects steel for 25+ years under typical weather conditions. Corrosion-resistant elements require no additional maintenance and maintain load-bearing capacity throughout the farm’s lifespan. Cheaper protection methods, such as powder coating, have shorter lifespans and require periodic maintenance.

Stability under wind and snow loads

Steel profiles must be correctly dimensioned for static and dynamic loads. Wind speeds of 120 km/h can exert hundreds of kilograms per square meter of panel surface. Snow loads in mountainous areas further stress the structure. Stability depends on proper sizing and quality of connections. Savings on materials can lead to excessive bending and reduced energy production.

Foundations and PV panel mounting on the ground

The foundation method determines the farm’s stability. Selection depends on geology, terrain, and design requirements. Geotechnical studies must be conducted to determine soil bearing capacity and groundwater levels.

Driven posts

The most common solution in stable soils. Steel C- or sigma-profile posts are driven 1–2 meters into the ground using specialized machinery. This allows fast installation, low cost, and minimal soil impact, with easy disassembly after decommissioning. Suitable for cohesive and sandy soils; not suitable for rocky or heavily stony ground.

Concrete foundations

Used where soil conditions prevent driving posts. Concrete foundations can be pad footings or continuous strips. They provide maximum stability but increase material, labor costs, and construction time. Concrete foundations require curing time, extending the project schedule by several weeks.

Stenerg’s comprehensive solutions for PV farms

Stenerg specializes in designing and manufacturing ground-mounted PV structures that meet the highest energy industry standards. Support structures are made of hot-dip galvanized steel, ensuring corrosion resistance throughout the farm’s life. Prefabricated elements allow rapid panel installation without on-site welding.

This approach lowers costs and shortens project timelines. Stenerg’s comprehensive solutions give investors confidence that the foundation maximizes ROI.

Ground-mounted structures – the foundation of a profitable PV farm

The ground-mounted structure affects long-term efficiency and revenue. Savings on PV frames during construction almost always lead to much higher losses during operation due to reduced energy production, early corrosion, or repair costs.

Selecting the right structure requires considering location conditions, optimal tilt, climate loads, and expected lifespan. Investing in high-quality ground-mounted PV structures from a trusted manufacturer pays off throughout the farm’s life, ensuring stable panel performance and predictable ROI.

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