Each panel's output depends on the cosine of the angle between its face and the incoming sunlight — the closer a panel points straight at the Sun, the more of the available irradiance it captures.
P_panel = G · max(0, cosθ) · (1 − cloud) · η
G = 1000 W/m² · max(0, sin(elevation)) (clear-sky irradiance)
θ = angle between panel normal and Sun direction
- Time of day — moves the Sun across the sky; elevation sets the raw irradiance available.
- Cloud cover — scatters and blocks sunlight, cutting irradiance directly.
- Fleet size — number of panels in the array, scaling total plant capacity.
- Tracking mode — fixed tilt never moves; single-axis tracks the Sun's azimuth only; dual-axis keeps every panel pointed straight at the Sun (θ≈0) all day.
Real-world relevance: this is exactly the trade-off utility-scale solar operators weigh — dual-axis trackers can raise annual yield 25-35% over fixed tilt, but cost more to build and maintain.