Fotowoltaika na gruncie – jak dobrać konstrukcje gruntowe?

GROUND STRUCTURES FOR PHOTOVOLTAICS

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Ground-Mounted Photovoltaics on Challenging Terrain – Slopes, Waterlogged Areas, Weak Soils

Do you have a plot of land where you want to install ground-mounted photovoltaics, but the site is far from ideal? Slopes, waterlogged areas, weak soils? Have you heard from many contractors that “it can’t be done” or that “it will be very expensive”?

From our many years of experience, we know that most sites which at first glance appear problematic can be used for a photovoltaic installation with the use of ground structures. It requires the right design approach, flexible ground structures, and sometimes a slightly greater workload, but in most cases it is possible. In this article, we will show you how to handle even the most challenging conditions.

Is every site suitable for ground-mounted photovoltaics?

The ideal plot for a photovoltaic installation is flat or slightly sloped terrain, stable soil, no waterlogging, and easy access. In reality, however, most available plots differ from this ideal. Especially if you are looking for a larger area for a solar farm, you need to expect certain imperfections.

At Stenerg, we have designed ground structures on a wide variety of terrains — from flat meadows to hilly post-industrial sites, from dry sandy soils to clayey, moist ground. Every project has taught us something new and helped us develop solutions tailored to challenging conditions. What initially seems like a problem that disqualifies the investment can often be solved with the right design and proper site preparation.

Of course, there are limits — not every site is suitable for photovoltaics. However, those limits are much further than most investors think. Experience shows that most areas considered “difficult” can be used with the right approach.

In single sentences, do not use them.

Sloped terrain is one of the most common concerns when planning ground-mounted photovoltaics. A plot with a visible incline raises questions — is it even possible to build anything here? Will it require massive investment to level the ground?

When a Slope Helps Rather Than Hinders

A gentle slope does not have to be a disadvantage at all. On the contrary, it can sometimes be an advantage. A site sloping դեպի south provides natural optimization of the angle for photovoltaic panels. You do not have to artificially raise one side of the structure — the terrain does it for you.

In our practice, areas with a natural slope of up to ten percent usually do not require any special measures. We design Stenerg ground structures to adapt to such terrain. Driven foundation piles are made in different lengths, which allows the structure to be leveled on uneven ground without significant interference with the site.

What About Larger Elevation Differences?

When the slope exceeds ten to fifteen percent, the situation needs to be carefully analyzed. It is important to consider the direction of the slope. A site descending from north to south can be advantageous, as the lower part has excellent sun exposure. On the other hand, an east–west slope means that one part of the installation will receive better sunlight in the morning and the other in the afternoon.

On very steep terrain, we sometimes divide the plot into segments at different levels. This requires partial leveling, but there is no need to level the entire area. It is enough to create several flat platforms on which the ground structures will be installed. Our driven system works better here than concrete foundations, because each pile can be driven to an individual depth, providing greater flexibility in adapting to the terrain.

Does Ground-Mounted Photovoltaics on Waterlogged Land Make Sense?

Water is one of the greatest enemies of steel structures. Constant moisture accelerates corrosion, undermines foundations, and complicates installation. That is why waterlogged areas raise justified concerns when planning ground-mounted photovoltaics.

Where Does the Water Come From and What Can Be Done About It?

Before you dismiss a waterlogged site as unprofitable, it is worth understanding the source of the problem. A high groundwater level is a different situation than periodic flooding after heavy rainfall or standing water caused by poor drainage. A geotechnical survey shows the groundwater level and its seasonal variability. Observing the site after intense rainfall reveals where water accumulates and how quickly it drains.

In many cases, waterlogging can be resolved through proper surface drainage. Simple drainage ditches, appropriate grading, and drainage systems are proven methods that address the issue effectively. If water remains because it has nowhere to flow, creating a system of ditches can completely change the situation. This requires some investment during site preparation, but it solves the problem at its source.

Ground Structures Resistant to Moisture

When moisture cannot be completely eliminated, the quality of materials becomes decisive. This is where the value of the Magnelis coating used on our ground structures becomes evident. It is not ordinary galvanization, but an advanced alloy that provides exceptional corrosion protection even in very humid conditions.

We guarantee protection for twenty-five years, and Stenerg structures with a Magnelis coating will last much longer, even in environments with high moisture levels. We have seen our ground-mounted photovoltaic installations in areas with high groundwater levels — after years, they still look like new. This is the result of combining high-quality S320–S450 steel with an advanced anti-corrosion coating.

Our driven structures also have an advantage over concrete foundations on wet soils. A driven pile bypasses the moist soil layer and reaches stable ground at a greater depth. There is no concrete that could lose its properties when exposed to water. Installation is faster and does not require waiting for curing.

Ground Structures on Weak Soils – When Foundations Are the Key

Soil bearing capacity is a fundamental issue for any photovoltaic installation. Weak, sandy, or peat soils raise concerns about the stability of the structure over the next twenty to thirty years of operation.

Why Conduct a Soil Survey Before Installing Photovoltaics?

We never skip a geotechnical soil survey, especially if there are any doubts. It is an investment that always pays off. The report shows exactly the type of soil at different depths, its bearing capacity, the groundwater level, and any anomalies. Based on this, we design foundations for ground structures suited to the specific conditions.

This is not a one-size-fits-all approach for every site. Every plot intended for ground-mounted photovoltaics has its own characteristics and requires individual analysis. That is why we offer custom designs rather than ready-made templates, because we know that the ground holds many variables.

How to Anchor Structures in Weak Soil?

When the upper soil layers are weak, the solution is to go deeper — to where the ground has adequate bearing capacity. Our driven ground structures allow for flexible adjustment of the foundation depth. In practice, this means longer piles in areas where the soil is weaker and shorter ones where it is stronger.

We design this individually based on the site’s geotechnical map. The result is a stable structure even on heterogeneous soil. In extreme cases, we use additional reinforcements — an increased number of support points, extra horizontal bracing, or special piles.

Our flexibility in designing ground structures allows us to adapt the solution even to very challenging conditions. Sometimes this means greater design input and a slight increase in costs, but ultimately it ensures a stable photovoltaic installation that will safely generate energy for decades.

Challenging Terrain with Multiple Issues at Once – What Should You Do?

In practice, we rarely deal with a single, isolated problem. More often, a site has a slope and is also waterlogged in certain areas. Or it has weak soils combined with an uneven surface. This is what most plots for ground-mounted photovoltaics actually look like.

When there are multiple issues, a comprehensive approach is required. You cannot solve each challenge separately, because addressing one may create new problems. You need to think systemically and look for ground structures that tackle all challenges at once.

At Stenerg, we have experience with such complex projects. We have seen plots that at first glance seemed impossible to use for ground structures. Yet after thorough analysis and thoughtful design, fully functional photovoltaic installations were built on them. However, let’s not distort reality — not every site can be used for photovoltaics in an economically justified way.

We always speak honestly with our clients about how we assess their land. If we see that the required investment will be disproportionately high, we do not pretend that everything is fine. It is better to have an honest conversation at the beginning than face disappointment later. Sometimes we recommend looking for a different plot or changing the concept.

Site Preparation for Ground-Mounted Photovoltaics – When Is It Necessary?

Some issues can be resolved through proper site preparation before installing ground structures. It involves additional cost and time, but sometimes it is the most reasonable solution.

Is It Necessary to Level the Entire Site?

Not always. Often, partial leveling in key areas is enough — removing the largest mounds and filling the deepest depressions. This minimizes the workload and cost while significantly facilitating the subsequent installation of ground-mounted photovoltaics. We advise which works are truly necessary and which can be skipped. Sometimes it is better to allocate those funds to a higher-quality structure that can handle uneven terrain.

Drainage as an Investment in the Future

In waterlogged areas, a drainage system installed before mounting ground structures can be crucial for the proper operation of the installation. Shallow drains that remove surface water, and sometimes deeper systems that lower the groundwater level. These are not inexpensive solutions, but they protect the entire photovoltaic installation from problems in the years to come.

When designing a drainage system, we take a comprehensive view — not only in terms of ground-mounted photovoltaics, but the entire site. Proper drainage increases the value of the land and makes its future use easier, so it is an investment that goes beyond the PV installation itself.

Monitoring Ground Structures on Challenging Terrain

Installing ground-mounted photovoltaics on challenging terrain may require slightly greater attention during operation. This does not mean it will be problematic, but it is worth being aware of certain aspects.

On weak or waterlogged soils, it is advisable to check the condition of the foundations and the stability of the structure more frequently. This is especially important after the first year, when the soil has settled and it becomes clear how the ground structures behave under load.

The drainage system requires periodic maintenance — cleaning ditches, inspecting drains, and removing overgrowth. These are simple tasks, but they require consistency. A neglected system stops functioning properly, and that is when moisture-related issues affecting the ground structures begin to appear.

Ground Structures on a Challenging Plot

Challenging terrain is a difficulty, but rarely a final obstacle when planning ground-mounted photovoltaics. Slopes, waterlogging, weak soils — each of these issues has its own solutions. The key is a reliable analysis of site conditions, a flexible approach to ground structures, and high-quality workmanship. If you would like to learn more, contact the experts at Stenerg, who will assess the potential of your plot.