Cost control and multi-scenario adaptation design practice of photovoltaic brackets

In the context of grid parity for photovoltaic power generation, cost reduction, efficiency improvement, and scenario-specific adaptation of photovoltaic brackets are key to project profitability. While ensuring structural safety, they must reduce overall lifecycle costs (materials, construction, and operation and maintenance) while also adapting to the specific needs of diverse scenarios such as "photovoltaic + agriculture," "photovoltaic + sand control," and "rooftop photovoltaics." This article examines bracket design optimization strategies based on the core dimensions of cost control, combining six typical application scenarios to provide practical technical solutions for photovoltaic projects.

I. Three Core Dimensions of Photovoltaic Bracket Cost Control

Photovoltaic bracket costs account for 8%-12% of the total investment in a photovoltaic system. Cost optimization must be integrated throughout the entire cycle of design, construction, and operation and maintenance. The key is to achieve cost reduction without sacrificing quality, balancing performance and cost through technological innovation. (I) Material Cost Optimization: Precise Matching of Strength and Usage
Steel Lightweighting: High-Strength Steel Thinning and Efficiency Enhancement
Replacing traditional Q355 steel with Q460 high-strength steel can reduce the thickness of support beams from 4mm to 3mm, while maintaining a 30% increase in tensile strength. This reduces material usage by 25%, and reduces steel costs per megawatt support by approximately 80,000 yuan. For example, a ground-mounted power station in Shandong Province used Q460 steel supports, reducing steel usage per megawatt from 55 tons to 42 tons, a 12% cost savings. Furthermore, finite element analysis confirmed that the wind load resistance still met the 1.8kN/m² requirement. The aluminum alloy bracket utilizes a "hollow profile + rib" structure, replacing solid profiles. Taking a 6063-T5 aluminum alloy column as an example, the hollow structure (2.5mm wall thickness, 50mm inner diameter) reduces weight by 40% and material cost by 35% compared to a solid column (60mm diameter). Furthermore, through the rib design (a circular rib is provided every 30cm), the bending stiffness is comparable to that of a solid column.

Auxiliary Material Replacement: A Low-Cost, Highly Adaptable Solution

Connectors utilize "hot-dip galvanized steel + plastic composite" instead of pure stainless steel. The clamping blocks between the bracket and the module utilize a combination of "galvanized steel plate + nylon liner." The nylon liner (weather-resistant PA66) prevents wear on the module frame. The cost is only one-third of that of a stainless steel clamping block, and the service life exceeds 20 years. Optimizing foundation materials: Ground supports are replaced with "cement-soil mixed piles" instead of cast-in-place concrete piles. Cement-soil (15% cement content) is 40% less expensive than concrete and requires no formwork. Construction time for a single pile has been reduced from 2 hours to 40 minutes, reducing foundation costs per megawatt by approximately 150,000 yuan.

(II) Optimizing Construction Costs: Modularization and Rapid Installation

Modular Design: Reducing On-Site Work

Pre-assembled support units: Columns, beams, and braces are factory-assembled into standard "12m x 3m" units. On-site work only requires connecting the foundation to the unit connectors. This reduces installation time for a single unit from 40 minutes to 15 minutes, shortening the construction period per megawatt from 15 days to 8 days, and reducing labor costs by 50%. For example, a distributed power station in Henan Province used modular support, allowing a 20-person team to complete a 5-megawatt installation in 10 days, saving 200,000 yuan in labor costs compared to traditional methods. Innovative quick-install connectors: Snap-on beam joints replace bolts, allowing tool-free beam splicing, increasing splicing efficiency by three times. Roof supports use self-tapping anchor bolts instead of expansion bolts, allowing direct screw insertion after drilling. This reduces installation time for a single anchor from 2 minutes to 30 seconds, and boasts a pullout resistance of 8kN, meeting roof load requirements.

Terrain-Adaptive Construction: Reduced Earthwork

Adjustable-Height Columns are used for gently sloping terrain (slope ≤ 15°). Telescopic columns (adjustable from 0.5 to 1.2 meters) adapt to terrain elevation differences without requiring land leveling. This reduces excavation by 80%, reducing earthwork costs per megawatt from 30,000 yuan to 6,000 yuan. Anchor Foundation for Mountain PV: In rocky terrain, 20mm Φ threaded steel anchor bolts (buried 1.5 meters deep) replace concrete foundations. The cost of a single anchor bolt is only 50 yuan, an 83% reduction compared to a concrete foundation (300 yuan per bolt). Drilling does not require large equipment, making it suitable for mountainous locations with inconvenient transportation.

(III) Optimizing Operation and Maintenance Costs: Low Maintenance and Intelligent Early Warning

Corrosion-Resistant Design Extends Lifespan: Reducing Replacement Costs

Zinc-aluminum-magnesium coated steel is used in highly corrosive environments (such as coastal areas and industrial areas). The coating contains 60% zinc, 30% aluminum, and 10% magnesium. Its salt spray corrosion resistance is five times that of hot-dip galvanizing, extending the lifespan of the support from 20 years to 25 years and reducing replacement costs (approximately 500,000 yuan per megawatt). Surface photovoltaic brackets use "HDPE floats + stainless steel connectors": The floats are made of high-density polyethylene (UV50+ resistant) with a service life of 15 years, while the connectors are made of 316L stainless steel to prevent water corrosion. This extends the O&M cycle from one year to three years, reducing the annual O&M cost per megawatt from 20,000 yuan to 6,000 yuan.

Intelligent monitoring reduces failure costs

The brackets are equipped with "stress sensors + wireless transmission modules": They monitor stress changes in beams and columns in real time (with an accuracy of ±0.1 MPa). When stress exceeds a safety threshold (e.g., 150 MPa), an automatic warning is issued to prevent bracket breakage and module damage (replacing a single module costs approximately 200 yuan). For example, after installing intelligent monitoring brackets at a surface power station in Jiangsu, fault response time was reduced from 24 hours to one hour, reducing annual failure losses by 120,000 yuan. The tracking bracket uses a "dual-motor backup design": if the main motor fails, the backup motor automatically starts, preventing tracking failure (tracking bracket failure can result in a 15%-20% drop in power generation). This reduces annual power generation loss per megawatt from 30,000 kWh to 5,000 kWh, indirectly reducing revenue losses by approximately 15,000 yuan (calculated at 0.5 yuan/kWh).

II. Bracket Adaptation Design Solutions for Six Typical Scenarios

The functional requirements of brackets for different "PV+" scenarios vary significantly, requiring customized designs based on the specific scenarios and incorporating cost optimization strategies.

(I) PV Greenhouses: Balancing Crop Growth and Load-Bearing Capacity

Scenario Requirements: The bracket must support PV panels (weighing approximately 25 kg/m2), provide space for crop growth (height 2-3 meters), and avoid blocking sunlight (panel spacing must be adapted to the crop's light requirements). Adaptive Design:
The system utilizes removable columns with adjustable heights (2-3 meters) to accommodate crops of varying heights, such as tomatoes and cucumbers. The columns are constructed with a precast concrete block foundation (50 kg), eliminating the need for excavation and preventing damage to the greenhouse soil structure.
The panels are arranged in a north-south tilted installation configuration, with a 25° tilt angle and 1.8-meter spacing between panels, ensuring a maximum sunlight intensity of 20,000 lux at noon in the crop area during winter. The support beams utilize a "C-shaped steel + reinforcement" structure, which is 30% lighter than I-shaped steel and reduces the cost per megawatt by 60,000 yuan.

Case Study: A photovoltaic greenhouse project in Hebei Province, utilizing adjustable supports, is suitable for growing three crops, generating 1.2 million kWh of electricity annually. The per-acre yield is 10% higher than in traditional greenhouses, while the support costs are 15% lower than those of fixed supports. (II) Colored Steel Tile Roofs: Lightweight and Leakage Prevention
Scenario Requirements: Colored steel tile roofs have limited load-bearing capacity (typically ≤0.3 kN/㎡). The brackets must be lightweight and avoid damaging the roof's waterproofing layer during installation (to prevent leaks).

Adaptive Design:

The material used is "6061-T6 aluminum alloy brackets." A single bracket set (including components) weighs ≤20 kg/㎡, which is below the roof's load-bearing limit. The brackets are connected to the colored steel tiles using snap-on clamps (no drilling required). The clamps engage the corrugated panels to prevent damage to the waterproofing layer.

Structural Optimization: The crossbeams feature a curved design that conforms to the curvature of the colored steel tiles, reducing wind resistance (reducing the drag coefficient by 25%). A butyl rubber pad is installed between the brackets and the colored steel tiles to further enhance waterproofing. Case Study: A factory building in Zhejiang province used interlocking aluminum alloy brackets for a color-coated steel tile roof. After installation, the brackets remained leak-free. The single-megawatt bracket weighed only 2.8 tons, 50% lighter than steel brackets, shortened construction time by 40%, and reduced costs by 80,000 yuan.

(III) Photovoltaic Sand Control: Wind and Sand Fixation and Abrasion Resistance

Scenario Requirements: In desert areas with high winds and sandstorms (≥10 sandstorms per year), the brackets needed to be wear-resistant and wind-load-resistant, while also assisting in sand fixation (preventing sand dune movement and damage to the foundation).

Adaptive Design:

Material: "201 stainless steel + ceramic coating": The bracket surface ceramic coating (80μm thickness, 9H hardness) is wind-resistant and abrasive-resistant, with a wear rate of ≤0.02mm over three years. A "wheat straw grid sand fixation belt" (2 meters wide) was laid around the brackets, forming a sand fixation system in conjunction with the bracket foundation. This reduced the dune movement rate from 5 meters/year to 0.5 meters/year. The foundation utilizes a "screw pile + sandbag counterweight" system: The screw piles (300mm diameter, buried 1.8m deep) are quickly anchored in the sand. Sandbags (50kg per pile) are placed on top to enhance pullout resistance (≥15kN). The cost of a single pile is 60% lower than that of a concrete foundation.

Case Study: A photovoltaic sand control project in Inner Mongolia utilizes a ceramic-coated support frame and wheat straw grid system. The project generates 1.5 million kWh of electricity annually and stabilizes 1,000 mu of sand. The annual support frame wear rate is only 0.005mm, resulting in a 20% reduction in cost compared to desert-specific support frames.

(IV) Concrete Roof: Convenient Installation and Ventilation

Scenario Requirements: Concrete roofs have a high load-bearing capacity (≥0.5kN/m2), but installation space is limited. The support frame needs to be easily transportable (elevator transport) and require heat dissipation to prevent heat degradation. Adaptive Design:
Modular Decomposition: The rack unit can be decomposed into small modules (1.2m x 0.8m) (each weighing ≤15kg), which can be transported by elevator. On-site assembly takes ≤5 minutes per module, reducing the construction period per megawatt to 5 days.
Heat Dissipation Optimization: Height-adjustable feet (10-20cm in height) are installed at the bottom of the rack to create air convection channels, reducing module operating temperature by 4-6°C and increasing annual energy production by 3%. The feet are constructed of a composite material of plastic and galvanized steel, reducing costs by 40% compared to all-steel feet.

Case Study: On a concrete rooftop project at an office building in Shanghai, a two-person team completed a 1MW installation in 3 days using small modular racks. Compared to traditional racks, the module temperature was reduced by 5°C, resulting in an additional 15,000 yuan in annual energy production revenue, while the rack cost was 12% lower than that of larger racks. (V) Surface Photovoltaic: Floating Body Stability and Aging Resistance

Scenario Requirements: Surface water (lakes, reservoirs) is subject to wind and waves (maximum wind speed ≥ 15m/s). The support float must be stable (tilt angle ≤ 5°) and resistant to water corrosion and UV aging.

Suitable Design:

HDPE + Glass Fiber Composite Float: 10% glass fiber is added to the high-density polyethylene (HDPE) base material, increasing the float's strength by 40%, achieving UV resistance of UV50+, and extending its service life from 10 to 15 years. The float also utilizes a "hexagonal splicing design" (similar to a honeycomb), allowing for a tilt angle of ≤ 3° in wind and waves, resulting in 50% greater stability than rectangular floats.

Universal Joint Connectors for Frame Connections: This allows for slight rotation (angle ≤ 10°) in wind and waves, preventing fracture due to stress concentration. The connectors are made of 316L stainless steel, which is resistant to water corrosion. The cost per megawatt float is 10% lower than that of traditional HDPE floats. Case Study: A photovoltaic project on the surface of a reservoir in Hubei Province uses a hexagonal composite floating support structure. It has survived three typhoons (maximum wind speed 18m/s) without damage, generating 1.1 million kWh of electricity annually. The cost of the floating structure is 80,000 yuan/MW lower than traditional floating structures.

(VI) Photovoltaic Parking Lot: Dual Shading and Load-Bearing

Scenario Requirements: Parking lot supports must simultaneously support photovoltaic panels (load bearing ≥ 0.2kN/㎡) and vehicle traffic (partial load bearing ≥ 2kN/㎡), and must accommodate parking space spacing (typically 2.5-3 meters). Adaptive Design:
The structure utilizes a portal frame: columns are spaced 3 meters apart (accommodating standard parking spaces). The crossbeams utilize a "Q355ND steel + double-beam design" (with a 20cm spacing between the upper and lower beams). The crossbeam thickness is increased to 5mm in some areas (vehicle traffic areas), with a load-bearing capacity of 2.5kN/㎡, meeting the needs of cars. Components are installed on top of the crossbeams to form a sunshade (shading efficiency ≥ 90%).

The foundation utilizes a "pre-buried bolt + concrete pedestal": The pedestal measures 60cm × 60cm × 30cm. Pre-buried bolts (20mm diameter) connect to the support columns to prevent foundation shifting. This reduces pedestal costs by 25% compared to stand-alone foundations, and construction can be performed without interrupting parking lot use (construction is performed in separate areas). Case Study: A photovoltaic parking lot project at a shopping mall in Guangdong utilizes portal frame gantry systems, covering 100 parking spaces. The system generates 800,000 kWh of electricity annually, ensuring smooth vehicle traffic flow. The system cost is 120,000 yuan/MW lower than traditional parking lot systems.

III. Conclusion
The cost control and application-specific adaptation of photovoltaic systems is essentially a combination of "technological innovation and demand matching." Costs are reduced through lightweight materials, modular construction, and intelligent operations and maintenance, while adaptation to diverse scenarios is achieved through structural customization and functional expansion. In the future, with the advancement of technologies such as BIM digital design (optimizing structures and reducing material waste) and the circular economy (recycling and reuse of gantry systems), photovoltaic systems will further achieve "low cost, high adaptability, and long lifespan," becoming a core support for cost reduction and efficiency improvement in photovoltaic projects, and helping to implement the "photovoltaic +" model in more scenarios.