Size a grid-tied solar PV system for your farmhouse, barn or irrigation load. Estimate system capacity, panel count, roof/ground area, annual generation, annual bill savings and payback period.
Enter daily electricity use, peak sun hours, panel wattage, system efficiency, available area, electricity price, subsidies and installed cost per watt. The tool outputs system kW, panel count, area, annual kWh, annual savings and payback.
✓ Expert Reviewed: This calculator and its content have been reviewed by agricultural experts. Formulas are based on standard extension service recommendations and the Farm Financial Standards Council. For site-specific advice, consult your local agronomist or extension agent.
Estimate your average daily kWh use from a year of bills, look up peak sun hours for your region (typically 4-6 h/day), choose a common panel wattage (350-450 W), apply 75-85% system efficiency losses, and enter local electricity price, installed cost per watt, and any subsidy. Click Calculate.
About
System kW = Daily kWh ÷ (Peak Sun Hours × Efficiency). Panels = System kW × 1000 ÷ Panel Wattage. Area ≈ panels × 2 m². Annual generation = Daily kWh × 365. Annual savings = annual kWh × price. Payback = (gross cost − subsidy) ÷ annual savings. For 40 kWh/day, 5 h sun, 80% eff, 400 W panels, $0.15/kWh, $1.60/W, $2,000 subsidy: system = 40/(5×0.8) = 10 kW, 25 panels, 50 m², 14,600 kWh/yr, $2,190/yr savings, gross $16,000, net $14,000, payback ~6.4 yr. Common mistakes: using peak sun hours too high, ignoring shading/soiling losses, and forgetting that battery storage adds 30-50% to cost.
Most of the contiguous US averages 4.5-5.5 peak sun hours/day; the Southwest 6-7, the Pacific Northwest 3.5-4. Use a NASA PVWatts or NREL map for your specific latitude and orientation.
Roughly 2 m² per panel and 7-10 m² per installed kW. A 10 kW system needs ~50-70 m². Ensure south-facing orientation (Northern Hemisphere), minimal shading, and adequate structural load for rooftop mounts.
6-10 years is typical in the US after subsidies, with system life of 25-30 years. Shorter payback (4-6 yr) in high-insolation, high-electricity-price areas. Compare the lifetime savings (20+ years free power) against the upfront cost and financing.
If you are off-grid or need backup, yes. If you have net metering, grid-tied without batteries is usually cheaper and simpler. Batteries add 30-50% to the installed cost but capture self-consumption of midday surplus.
Agrivoltaics co-locates solar panels with crop or livestock production: elevated panels let forage, vegetables or grazing continue underneath, diversifying income from the same land. It is growing but requires careful panel spacing and crop choice.