If you’re looking for a simpler way to install a solar project on a large scale, a ground installation is possibly the most advantageous way to maximize your panel density and provide the flexibility needed for the panels to track the sun across the sky.
Most ground systems utilize frames, usually constructed of aluminum, stainless or galvanized steel pipe and built into a framework of grid-like supports for the solar cells. At times the framework used can end up seeming very bulky, but despite the inherent bulk they provide important rigidity, in an installation area that could have high winds for example, and the mounts in turn need to be sturdily anchored to the ground. Once the cells have been mounted to the frame and ensuring they have the proper tilt and angle (typically 30 degrees), they can be mounted facing the correct way (South) and anchored to the ground via concrete foundation.
At Solora Solar, we’ve recognized that there is not a single installation type that will work for all sites, simply because through our experience we’ve come to know every site is unique. Factors of geography and topography have to be considered, as well as the sites requirements for structural loading. Taking all elements of the installation into consideration, such as the type of mounting used for the solar modules, overall size of the project, and even conditions of the soil, Solora Solar provides custom-designed racking and ground mount solar installation solutions specific for every type of project. At Solora Solar, we use the information from certified geotechnical reports, coupled with engineering analysis, and work with the customer to design the most economical solution.
By using one of the two common ground-mount systems for your solar panels, pole or ground, advantages over other types of installs become clear – the ease of use and installation, and the flexibility your panels can be afforded as they track the sun across the sky. Other reasons to consider a ground mount system:
- Overall lowering of cost for installation of a sun tracking system
- Introduces the option to operate a manually adjusting tilt system for seasonal changes
- Generally, there is more space on the ground than the roof in rural areas, so a larger system can be considered
- Having the solar cells at ground level allows for easier cleaning and maintenance, though keeping the installation area free from growth or items that could introduce panel shading is important. An option would be to raise the mount using poles or concrete blocks, for example.
A ground installation is also becoming more common in rural settings, or in areas where a structural addition to a roof might not be suitable for a solar install at all. Other factors:
- Available roof area is simply not enough to support an install
- Orientation of the roof is poor (the optimal roof orientation in Central Washington is facing South at a tilt of 30 degrees)
- Too many shadows leading to overall poor exposure to the sun
- A desire for a larger wattage system than a standard roof mount system could support
- A sun-tracking system is desired to maximize sun exposure
- You have good availability of sun-exposed land
There are a few drawbacks and disadvantages to ground installations:
- Not typically considered an option in cities or neighborhoods due to a lack of necessary ground space
- Visually, a ground install could be more aesthetically undesirable
- To account for storms or high winds, stability needs to be provided by site-built solid foundations plus concrete footing, which can lead to a greater installation expense
One size fits all?
No matter what style of installation is ultimately chosen, all of them need a secure, stable support system as well as foundation. The overall longevity and strength of the solar investment is dictated by the weakest component in the system. As such, it’s crucial to provide a high-quality and engineered foundation that will meet the needs of the specific application or project. Key points used to determine the proper foundation:
- Aspects of the solar energy system such as sun tracking or tilt angle
- Environmental or elemental factors like wind speeds in the area, or yearly snow load
- Configuration and type (aluminum pipe, galvanized or stainless steel) of racking and support
- Total size and weight of the solar modules in use
- Any local design and building codes, or project specific requirements
- Soil analysis results showing items of concern, such as stability of slope, sliding, friction, salinity, frost level, etc.
- Instability due to landfill or brownfield
Determining the correct type of support for the solar system involves understanding and analyzing various soil composition and environmental factors, such as those listed above, as well as considering engineering calculations and applicable building codes. Engineers and developers working on the project will take those factors into consideration while selecting the foundation that will then meet the project needs of engineering, overall design, and best economical choice while meeting the other criteria. This is a critical point where the experience of the engineers and developers, and their knowledge of foundation types becomes one of many key elements of the design of the solar mount system.
Options to consider for foundation type:
- Screw Piles
- Driven Post
- Precast or Cast-in-Place Concrete Ballast
- Concrete Pier
- Helical Piles
When considering a large-scale ground mount PV installation, it is important to understand the dynamics of the methods and means of construction, especially for foundations. The foundation is the key to supporting the ground mount solar racking system. Without a solid foundation, owners risk having solar racking structures and solar modules flying through the air or toppled over due to the loading and soil conditions at the project site.
In these instances, a geo-technical engineer would analyze the data from the soil reports and other factors and make a likely recommendation of a driven pile foundation over a standard concrete foundation for the installation. Driven piles tend to take up less ground space, reduce the down-time of waiting for concrete to set, and reduces the many challenges coordinating the required, multiple deliveries of concrete used for concrete foundations. Some of the more common reasons for this decision would be large design loads, evidence of poorer soil at shallower depths, possible environmental impacts, economics and any site constraints. Ideal soil conditions permitting, driven pile foundations can be the favorable option for large-scale ground mount PV installs, as there could be advantages recognized on material (cost), installation time (reduction), and even on the projects’ environmental impact overall.
Pole mounts are a long popular solar panel mounting system. There are two types: top-of-pole and side-of-pole. Top-of-pole mounts essentially consist of a steel or aluminum rack that is bolted to a large sleeve which fits over a pole. Side mounts are usually used when mounting to a telephone pole, communications tower, or the like and typically involve smaller panels.
Top mounts are simple but difficult to install. They are simple in design but often difficult to physically install. Larger mounts can be very heavy and may even require a small crane or several people in order to set the mount on the pole. Pole mounts require a steel pole around 12 feet in length set in concrete. In softer soil you may have to dig quite deep because of wind resistance.
Pole mount systems may also include an automatic solar tracker which will track the sun across the sky over the course of the year. Although homeowners can usually adjust the panels they on a three-month schedule.
Despite the simplicity of both ground mount systems, they are usually installed by a professional solar installer. It may be advantageous to hire a pro with experience to anchor and lift mounts and panels, not to mention wiring.