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US researchers propose using steel ties to fix solar modules to animal farm fences as a low-cost solution for agrovoltaic applications.
A group of American and Canadian scientists have proposed using existing fences on animal farms as a low-cost solution for installing solar modules.
"This is perhaps the least cost approach," the researchs corresponding author, Joshua M. Pearce, told pv magazine . “What we did was show that at least one photovoltaic module between two vertical posts is mechanically acceptable for any type of conventional agricultural fencing. In this case, assembly is almost free”.
The researchers identified three main fencing typologies: fencing based on multiple cleats placed between the main posts to support the fence wire; fencing using posts to which the fence wires or mesh are attached; and fences that use prefabricated meshes of various designs appropriate to the need and sometimes to aesthetics. “Typically, high tensile steel wire and mild steel wire are predominantly used for fencing,” they noted. “Their diametric dimensions are typically 4mm, 3.15mm and 2.5mm for high tensile (HT) wire and mild steel wires.”
To determine if an existing fence can be used for a solar installation, developers should first investigate whether the fence can withstand a given wind load at a specific location with the addition of photovoltaic panels, as well as the topological, geographic, and climatic challenges of the fence. region. In this regard, the group noted that special attention should be paid to the size of the line posts and the spacing clearance, adding that the main factors that need to be carefully considered are the height of the fence, the depth of the footings, the design and size of the mesh fabric, as well as the resistance of the material of the poles.
The scientists also explained that wind load measurements should be made using the Main Wind Force Resistance System (MWFRS) and Components and Cladding (C&C) procedures, as well as the Code Wind Load Calculator. Open, which is a tool used to calculate the wind load on a fence in a given region of the United States. “The program outputs wind loads in terms of base shear force in pound-forces (lbf) and base moment in foot-pounds-force (ft-lbf),” they specified, adding that they calculated for a range of wind loads from 80 mph to 150 mph (129 km/h to 241 km/h).
The academics conducted a series of field tests with three Cheetah HC 72 M monocrystalline PERC panels made by the Chinese company JinkoSolar. The assembly of a single module required seven minutes and a total of four cable ties.
They also ran a series of simulations to retrofit existing fencing on sheep, goat, pig, cow, and alpacas farms, and found that solar projects based on the proposed method would be economically viable in the United States.
“The cost to retrofit the racks is just four stainless steel clips per module, which can be purchased in packs of 120 for $11, or about 37 cents per module,” they explained. "If the power of the modules is between 250 and 500 W, the cost of installing in an existing fence is less than a penny per watt."
Pearce said the research group also established what an optimal inverter strategy would be based on how much power a farmer needed. “Small farmers can use the free e-book to configure the system layout, do the installation themselves with metal ties, and then just call an electrician to connect it to the grid,” he concluded.
The scientists presented their findings in the article " The potential for fencing to be used as low-cost solar photovoltaic racking ," published in Solar Energy . “Future work is needed to determine the full scope of benefits of this vertical PV agricultural fencing approach on a global scale,” they noted, waiting to see how the proposed methodology could be improved.
The research team is made up of academics from Western University in Canada and Michigan Technological University in the United States. |
