Solar farms embrace new tool to fight soil erosion
Solar farm operators are deploying a new solution in their quest to prevent soil erosion. Site maintenance is key to ensuring peak solar farm performance because a soil base that erodes can cause panel hardware to shift and negatively impact panel efficacy.
At two solar farms near Roanoke Rapids, N.C., totalling 2,200 acres and expected to produce 155 megawatts to support local Facebook operations, operators tested a new simulated turf erosion control mat called ShearForce10 at the drip line. Held down by pins or sod staples, this hybrid-turf instant armoring mat immediately holds the soil and seed in place, and permanently reinforces the natural vegetation that grows up through its synthetic turf structure.
The solution is proving itself a strong, highly cost-effective alternative to concrete block mats, rock riprap and conventional turf reinforcement mats. Concrete blocks or rocks can be put under the panels at the drip line, but the materials are cumbersome, as is the machinery needed to transport them. That presents a risk of hitting and damaging the solar panels during installation. Concrete and rock are also quite expensive when material, transportation and placement costs are considered. In most situations, the use of the ShearForce10 hybrid-turf instant armor mat in place of these “hard armor” materials can save projects more than 50% on total installed costs.
Concrete and rocks also don’t allow for as much vegetation. Vegetation helps enhance solar farm performance because during drier months, when erosion might be less of a concern, dirt that gathers on rocks and concrete can generate dust that harms panel performance.
Channels and other drainage systems incorporated into solar farms to prevent flooding are helpful, but such areas with concentrated water flow are prone to severe soil erosion.
Following the initial ShearForce10 test, managers were pleased with the results and later installed the material on the bottoms and side slopes of channels that run between every half dozen rows of panels. The project was completed in January.
The 485-megawatt Pleinmont Solar I plant taking shape in Spotsylvania, Va., features a 2,500-square-foot sediment basin that, while especially useful during construction of the initial 75-megawatt site, could erode due to its steep 20-foot side slopes. Site managers lined a critical portion of the basin with ShearForce10, and used a double net straw erosion control blanket in a surrounding area. In the first rainstorm, the straw mat washed away, so they opted to use ShearForce10 throughout.
At an 86-megawatt farm in Denton, Ga., intended to power local Facebook facilities just like at the North Carolina solar farm, ShearForce10 will line the site’s channels, though it may be used in other areas, as well. Installation began this month.
These solar farms chose ShearForce10 instead of rock and concrete blocks, but also as an alternative to other types of vegetative products such as conventional turf reinforcement mats. Traditional TRMs don’t provide highly effective immediate soil protection and can wash away if grasses haven’t had time to grow through the mat to hold it in place. And unlike TRMs, the ShearForce10’s simulated turf structure looks like natural grass upon installation, so even those shaded areas directly beneath panels where grass growth may be sparse will look nice and vegetated.
ShearForce10 also requires less maintenance as once it is installed, it can last forever without upgrade or replacement. Once natural vegetation establishes through the mat’s simulated turf structure, it can simply be mowed like a traditional lawn.
It’s a product that lends itself well to sustainable fields such as solar and wind energy farms. Vegetation provides further soil erosion mitigation and can make the site more visually appealing and environmentally friendly. At wind farms, ShearForce10 is ideal for lining channels that run alongside access roads, as well as along any sloping areas, such as at the base of the windmill. ShearForce10 is a product of St. Louis-based Grassworx.