The global solar energy market is booming, with over 346 gigawatts (GW) of new solar capacity added in 2023 alone—a 15% increase from the previous year. This rapid adoption of solar power highlights the need for efficient and reliable foundation methods like ground screws to support these large projects. Solar ground screws are becoming a popular choice for utility-scale solar projects due to their versatility, ease of installation, and ability to perform well in different soil conditions.
Unlike traditional methods such as driven piles, ground screws offer several advantages that can significantly improve the success and longevity of a solar installation.
This blog will explore the key considerations for selecting ground screws and comparison between ground screws and traditional foundation methods.
What Are Solar Ground Screws?
Solar ground screws are also known as helical piles or screw anchors. They are steel rods with spiral plates that are twisted into the earth to form a solid foundation. These screws support various constructions, such as solar panels, by providing a secure and stable foundation.
Key Considerations for Selecting Ground Screws
When choosing ground screws for utility-scale solar projects, it's important to consider several factors to guarantee a successful and long-lasting installation.
- 1. Soil Conditions
Testing the soil might help you determine whether ground screws are appropriate for the site. This requires an understanding of the soil type, such as clay, sand, silt, or rock. The screws' installation and weight capacity will vary depending on the soil type. It is also necessary to examine the chemical composition of the soil in order to prevent ground screw corrosion.
- 2. Site Surveys
Site surveys help identify problems and plan the installation process. Surveys should include mapping the topography to find the ideal location for solar panels and ground screws. They should also detect any subterranean utilities or rocks to prevent delays and ensure safe drilling.
- 3. Project Requirements
Ground screws should be strong enough to withstand the weight of the solar panels, mounting structures, and other equipment. They must also survive extreme weather conditions such as high winds, severe snowfall, and seismic activity in earthquake-prone locations. Addressing these load needs contributes to the stability and performance of the solar panel over time.
- 4. Installation Expertise
Experienced professionals can finish the installation more efficiently and properly, which reduces project timeframes and costs. They excel in dealing with unforeseen hurdles, such as encountering rocks or other obstructions. Furthermore, professional installers adhere to safety regulations, reducing the chance of accidents and maintaining a secure work environment.
- 5. Ground screw foundation cost
The project's financial sustainability depends on effective budget preparation. This includes making accurate cost estimates for supplies, labor, and equipment, as well as budgeting for unanticipated expenses. Planning for unforeseen issues, such as additional soil testing, can assist in reducing financial overruns. Maintaining a healthy cash flow will result in prompt payments to suppliers and contractors, preventing delays.
Ground Screws vs. Driven Pile Foundations: Which is better?
Understanding how ground screws compare to traditional foundation methods, such as driven piles, helps highlight their benefits and potential applications.
The following table compares helical piles vs driven piles across five key points:
| Comparison Point
|
Ground Screws
|
Driven Piles
|
| Installation | It is quick, less disruptive, and suitable for soil conditions without pre-drilling. | Requires heavy machinery and can be noisy and disruptive, especially in rocky or high-refusal environments. |
| Cost | Potentially higher initial unit cost but lower overall installation and maintenance costs. | Lower initial material cost but higher installation and potential pre-drilling costs. |
| Flexibility | It is more straightforward to adjust and relocate if needed. | Difficult to adjust once installed; less flexibility in placement. |
| Environmental Impact | Minimal disruption to the soil and surrounding environment. | Greater environmental disruption due to heavy machinery and extensive excavation. |
| Stability | Provides stable support in various soil types, including rocky and compacted soils. | Excellent stability in soft soils but faces challenges in hard or rocky conditions. |
Comparing Options in a High-Refusal Environment
In a high-refusal environment, soil conditions make driving foundations into the ground challenging due to obstacles like rocks or dense layers. Selecting the proper foundation in such situations can help avoid delays and increased costs. The following table highlights the key differences between helical piles vs screw piles in high-refusal environments, showcasing the advantages and challenges of each method.
| Aspect
|
Ground Screws in High-Refusal Environments
|
Driven Pile Foundations in High-Refusal Environments
|
| Adaptability | Can navigate around obstacles, reducing the likelihood of refusal and ensuring a smoother installation process. | Significant challenges due to obstacles; pre-drilling is often required, increasing costs and timelines. |
| Machinery Requirements | They do not require heavy machinery, making them more suitable for challenging terrains. | Heavy machinery is required, which can be disruptive and difficult to maneuver in rocky or uneven terrains. |
| Flexibility | If an obstacle is encountered, it can be relocated and reinstalled without significant additional costs. | Less flexible; higher risk of refusal or damage to piles in challenging soils, potentially leading to delays. |
| Pre-Drilling Requirements | No pre-drilling is needed, which reduces costs and installation time. | Pre-drilling is often needed in tough soils, increasing project costs and timelines. |
| Risk of Refusal | Lower risk of refusal due to their ability to penetrate harsh soil conditions. | There is a higher risk of refusal or damage in challenging soils, leading to potential project delays. |
Risks and Mitigation Strategies for Solar Ground Screws
The use of solar ground screws in utility-scale solar installations carries many concerns. With good planning and strategies, these risks can be quickly mitigated. Here are some of the significant risks and their respective mitigation strategies:
- 1. Soil Conditions:
Poor or fluctuating soil conditions might compromise ground screws' load-bearing capacity and stability. This causes instability in the solar array. To reduce this possibility, thoroughly evaluate the soil before installation. Understanding soil composition, density, moisture content, and corrosivity will help you select the right ground screws.
- 2. Installation Errors:
Common installation problems, such as misalignment, insufficient depth, or inappropriate anchoring, could compromise the structural integrity of solar panels. To reduce these hazards, it is critical to choose qualified and experienced ground screw installers. You can also hold training sessions for the installation staff to reduce the possibility of mishaps.
- 3. Corrosion and Durability:
Long-term exposure to corrosive soils or environmental conditions causes solar ground screws to corrode. This degradation may jeopardise their structural integrity. To prevent this, use ground screws made of corrosion-resistant materials or apply protective coatings. Conducting frequent inspections and maintenance checks can also aid in the early discovery and resolution of corrosion concerns, extending the life of the ground screws.
Conclusion
Solar ground screws for a utility scale project impact the stability, longevity, and overall success of the installation. By considering key factors such as soil conditions, load requirements, corrosion resistance, and environmental impact, you can select the most suitable ground screws for your project's requirements. Additionally, evaluating the manufacturer's reputation and seeking professional consultation can provide further assurance of quality and reliability. Unimacts' ground screws, with their various benefits, are an ideal choice for modern solar energy projects. Our ground screws offer a versatile and eco-friendly foundation solution, that contributes to the efficiency and sustainability of utility-scale projects.