200MW Chongzuo Agrivoltaic Project — Hot Dip Galvanized Steel Coil Solution for High-Humidity Farmlands

The 200MW Chongzuo agrivoltaic station in Guangxi, China, required structural steel capable of withstanding 80%+ annual humidity, acidic fertilizer exposure, and typhoon-season wind loads over a 25-year design life. Shandong Pinjie New Materials supplied zone-specific Q355B hot dip galvanized steel (HDGI) coils with 100–120 μm zinc coatings tailored to terrain and moisture conditions across the site. After 12 months of operation - including one full typhoon season - on-site inspections recorded zero visible rust on all mounting structures, with structural deflection remaining within design limits. Sugarcane yields held steady at pre-project levels, and on-site solar power reduced the farm's grid electricity costs by approximately 70%.

With 10 years of specialized experience producing galvanized steel products for solar mounting and agricultural infrastructure, Shandong Pinjie New Materials has supplied materials for dozens of agrivoltaic projects across southern China and Southeast Asia. The 200MW Chongzuo station in Guangxi is a representative example of how site-specific material specification delivers long-term performance in humid, high-corrosion environments. Below we break down the project's constraints, our material approach, and verified results after one full year of operation.

The Chongzuo site sits on existing sugarcane farmland in southern China's Guangxi Zhuang Autonomous Region. Built as a dual-use agrivoltaic system, it generates solar power above ground while preserving full crop cultivation below. The EPC contractor required a structural steel material that could withstand the local subtropical climate, support 25 years of continuous operation, and provide adequate under-panel clearance for standard agricultural equipment.

From our experience, this type of farmland solar project is far more demanding on steel materials than standard ground-mount solar stations. Farm environments bring additional corrosion factors - such as fertilizer residues and frequent soil moisture - that many standard material specifications do not account for.

Utility-scale agrivoltaic installations in humid southern China face consistent constraints that directly impact long-term performance and return on investment.

Corrosion Pressure from High Humidity and Farm Chemicals

Guangxi records annual average relative humidity above 80%, with frequent seasonal rainfall. On top of that, regular acidic fertilizer application in sugarcane fields creates a more aggressive environment for exposed steel than ordinary open-land solar sites. Unprotected or lightly coated steel structures in this setting can develop visible rust within a few years, failing to meet the required 25-year design service life.

Structural Requirements for Complex Terrain and Typhoon Conditions

The site features hilly terrain with mixed soft soil formations. The mounting system must carry the full load of solar panels while resisting wind loads during the annual typhoon season. Material tensile strength and foundation compatibility are both critical for long-term structural stability.

Clearance Standards for Uninterrupted Farming Operations

A dual-use system only delivers real value when it does not reduce farming output. The mounting structure must be tall enough for full-size sugarcane harvesters and tillage equipment to pass underneath, without forcing compromises to panel layout and power generation efficiency.

For outdoor agricultural solar projects of this scale, hot dip galvanized steel coil (HDGI) is the industry-standard material choice, balancing structural performance, corrosion resistance, and total lifecycle cost. We supplied HDGI coil for all primary mounting beams and support posts of the Chongzuo project, with adjusted specifications for different zones of the site.

The corrosion protection of hot-dip galvanized steel works through two primary effects:

 The zinc coating forms a continuous physical barrier, separating the base steel from direct contact with moisture, soil chemicals, and atmospheric corrosion factors.

 If the coating sustains minor scratches during transportation or on-site construction, the zinc corrodes preferentially to slow rust spread on the exposed steel area. This does not repair the coating, but it delays substrate degradation compared to uncoated steel.

Structurally, the HDGI coil we supplied uses Q355B grade base steel, which meets local wind load design requirements for the region. The material can be roll-formed into various mounting profiles to fit different project layouts.

Compared to alternative materials, HDGI coil reduces upfront material cost by roughly 25–30% versus aluminum and 45–50% versus stainless steel (based on Shandong Pinjie 2024–2025 market price benchmark for structural steel profiles), while meeting the 25-year service life requirement for most inland and moderately corrosive sites. For coastal areas with heavy salt spray, additional protective coatings are recommended to extend service life.

The Chongzuo 200MW station was completed and connected to the grid in early 2025, covering nearly 300 hectares of sugarcane farmland. We collaborated with the EPC team to adjust material specifications across different sections of the site based on terrain and moisture levels.

 Material specs: Main structural components are roll-formed from Q355B HDGI coil, with a standard zinc coating thickness of 100 μm. For low-lying sections of the farm where moisture and fertilizer runoff accumulate, we specified a thicker 120 μm zinc layer for improved corrosion resistance.

 Mounting height: The system is installed with a 2.8-meter net clearance above ground, calibrated to allow unobstructed passage of standard sugarcane harvesting equipment. Farmers carry out all planting, maintenance, and harvest operations without modification to their existing workflows.

After one full year of operation, including a complete typhoon season, third-party on-site inspections show zero visible rust on all mounting structures, with structural deflection remaining 15% below design limits.

The farm maintains a sugarcane yield of approximately 120 tons per hectare, consistent with pre-project levels. Solar power generated by the station supplies on-site irrigation systems, reducing the farm's grid electricity costs by about 70%. Farmers also receive additional income from land lease fees for the project.

Drawing on 10 years of supplying HDGI steel coil for solar and agricultural projects, we recommend matching zinc coating thickness and steel grade to actual site conditions rather than using a one-size-fits-all standard.

We always advise clients to conduct site-specific corrosion assessments before finalizing material specs, as local soil and atmospheric conditions can vary significantly even within the same region.

The Chongzuo 200MW project demonstrates that properly specified galvanized steel coil can reliably support dual-use agrivoltaic systems in humid, typhoon-prone regions. After 10 years working on projects like this, we've found that the biggest risk to long-term ROI isn't upfront material cost, but mismatched specifications that lead to early corrosion.

At Shandong Pinjie New Materials, we work with each client to align zinc coating thickness and steel grade with their exact climate, crop type, and soil conditions. With 10 years of focus on galvanized steel for solar and agricultural infrastructure, we have supported 60+ agrivoltaic projects across China and Southeast Asia. We don't sell standard coils - we deliver site-matched material solutions built for 25-year service life.

If you are planning an agricultural solar project and need support with material selection, reach out to our engineering team for a custom quotation tailored to your site conditions.