Agrivoltaic Solar for Farms and Factories in Thailand

Agrivoltaics (also known as Agri-PV or Agrophotovoltaics) is a dual-use land concept where solar panels are installed elevated above agricultural land, allowing the same plot to produce both food and energy simultaneously. Unlike conventional solar farms that convert agricultural land exclusively into power generation sites, agrivoltaics delivers both from one plot. The concept was first proposed in 1981 by Adolf Goetzberger from Germany's Fraunhofer ISE institute and has grown rapidly in the past decade.

For Thailand, agrivoltaics has unique advantages from the tropical climate: high solar irradiance (GHI) of 1,600-1,900 kWh/m²/year delivers excellent electricity output, while many crops simultaneously benefit from partial shading in extremely hot daytime conditions of 35-42°C. The 3-5°C temperature reduction under panels decreases crop heat stress, reduces evapotranspiration, and can boost shade-tolerant crop yields by 10-30%.

Elevated Fixed-Tilt (3-5 meters high, fixed angle): The most common basic configuration. Solar panels mounted on steel structures elevated 3-5 meters, at a fixed tilt angle of 10-15° for tropical regions. The space underneath is open enough for small-to-medium agricultural machinery to pass. Suitable for crops requiring moderate-to-low light such as mushrooms, herbs, and leafy greens. Structural cost is 20-35% more than standard ground-mount due to tall poles and stronger foundations.

Vertical Bifacial East-West: Panels installed vertically (90°) facing east-west, using bifacial modules that capture light on both sides. Sunlight passes through gaps between rows throughout the day, providing more evenly distributed light than fixed-tilt. Excellent for livestock grazing (cattle, goats, sheep) and pastureland. Electricity yield per kWp is 15-25% lower than fixed-tilt, but produces twin peaks (morning + evening) that better match demand patterns.

Tracking Systems: Single-axis tracking that adjusts angle to follow the sun throughout the day, yielding 15-25% more electricity than fixed-tilt. However, cost and complexity are higher, and the shifting shade pattern throughout the day makes crop planning more complex. Best suited for large farms > 1 MWp that want maximum electricity output and can grow crops tolerant of variable shading.

Full-Sun Crops — suitable only with low GCR ≤ 25%: Rice paddies, corn, and sugarcane need full sunlight and are not suited to heavy shading. They can coexist with agrivoltaic systems using low GCR ≤ 25% or vertical bifacial systems with light passing between rows. In the northeast, pilot projects use channel PV along paddy bunds rather than panels above rice, reducing impact on rice yield to just 5-8% while generating 15-30 kWp per rai.

Electricity revenue: A 1 MWp agrivoltaic system generates 1,300-1,500 MWh/year in Thailand, saving 4.5-6.5 million THB/year (calculated at 2026 TOU rates), or selling to the grid as VSPP at 2.2-2.8 THB/kWh. For self-consumption at nearby factories or farms, electricity savings are the primary revenue because daytime generation coincides with the most expensive on-peak tariff period.

Land lease savings: For solar farm operators leasing agricultural land, agrivoltaics reduces lease costs because landowners can continue farming. Agreed lease rates are typically 30-50% lower than ground-mount solar that occupies the entire area. In Japan, the government requires agrivoltaic land to maintain crop yield ≥ 80% of normal to preserve agricultural land status — a model Thailand is likely to adopt.

Agrivoltaic system sizing is calculated from farm area × Ground Coverage Ratio (GCR 30-50% depending on crop type) × panel efficiency. GCR of 30% delivers 70% light to crops, suitable for light-demanding crops. GCR of 50% delivers 50% light, ideal for shade-tolerant crops like mushrooms and herbs.

Note: Combined revenue includes electricity savings/sales + increased crop value. Calculated at 2026 TOU rates, GCR 30-40% for moderate shade-tolerant crops. Cost includes elevated structure + foundations. Before BOI incentives.

Panel height and spacing: Minimum height 3 meters for vegetables, fruits, and herbs; 4-5 meters for medium agricultural machinery (tractors, tillers). Row spacing depends on target GCR: GCR 30% requires 6-8 meter spacing, GCR 50% requires 4-5 meter spacing. For farms using large machinery, design must ensure equipment can operate between rows without hitting structural poles.

Wind load at elevation: Structures elevated 3-5 meters experience significantly more wind load than standard ground-mount. Design must follow EIT (Engineering Institute of Thailand) standards for design wind speed ≥ 100 km/h. Foundations must be 1.5-3 meters deep depending on soil conditions — reinforced concrete or ground screws rated for uplift forces. Open terrain (paddies, plains) requires additional safety factor due to no natural windbreaks.

Inverter placement and cabling: Inverters should be mounted on pole structures at field edges, not in the middle of farming areas, to avoid obstructing farm operations. DC cables from panels to combiner boxes use cable trays on the elevated structure, not underground through farming areas (avoids cable damage during soil tilling). Earthing/grounding system must connect every pole to ground per IEC 62548 standards.