Ground-based solar arrays have several advantages. They can produce more energy than a roof system (because they can be oriented to an optimal position), they stay cooler in the summer (improving efficiency), are readily accessible, and will more easily shed snow in the winter. They are especially ideal for off-grid systems and winter optimization.
On the other hand, ground mounts also require excavation and concrete for the structure, and a trench for running the power line to the building, adding to installation costs. They install best on level terrain, but can accommodate some slope.
In most cases, there are two options to choose from. A multi-pole structure is assembled using steel pipes as piers as a large structural assembly. Alternatively, a mono-pole system uses one large steel post with a structure on top (up to 16 panels each). The choice may depend on the terrain and soil conditions, usable space, aesthetic preference or other factors.
Pro: lower cost of materials
Pro: smaller concrete footprint
Con: fixed tilt cannot be adjusted
Con: not as compatible on a slope
Pro: aesthetic appeal
Pro: adjustable tilt
Con: higher material cost
Con: more concrete required