Solar PV Energy Yield

This formula estimates how much electrical energy a solar PV array will produce in a year by combining the size of the panels, how efficiently they convert sunlight into electricity, how much sunlight is available, and real-world losses. The area and annual irradiation tell you how much solar energy lands on the panels, the efficiency converts that sunlight into electrical output, and the performance ratio reduces the ideal result to account for temperature, wiring, inverter, shading, dirt, and other losses. It works because it is essentially an energy balance: incoming solar energy on the panel surface, multiplied by the fraction converted to electricity, then adjusted for system performance.

Use this when estimating annual PV output for a rooftop, ground-mounted array, or solar design study. It is especially useful in early-stage sizing, comparing sites, or checking whether a proposed array can meet an energy target.

• Using the panel's rated power in watts instead of the panel area in m²
• Forgetting that H must be annual irradiation, not daily sunlight hours
• Leaving out the performance ratio, which makes the estimate unrealistically high