Solar Panel Power Output

P = G × η × A

Quick answer

This calculator solves P = G × η × A for Power Output. With Solar Irradiance 800 W/m², Panel Efficiency 50 %, Panel Area 100 cm², the result is 4 W. It solves in 4 directions, so you can enter the values you have and get the one you need.

Calculator

Power Output (W)
—

Formula

P = G × η × A

Description

The electrical power produced by a solar panel is the product of the incident solar irradiance, the panel conversion efficiency, and the panel area. Standard test conditions (STC) use 1000 W/m² irradiance at 25°C cell temperature with AM1.5 spectrum. Real-world output is typically 75-85% of the STC rating due to temperature derating, soiling, shading, and wiring losses. Panel efficiency ranges from 15-22% for commercial silicon panels, with premium monocrystalline cells reaching 24%.

Variables

  • P — Electrical power output (W)
  • G — Solar irradiance (W/m²)
  • η — Panel conversion efficiency (0-1 or %)
  • A — Panel area (m²)

Practical Notes

Panel output decreases about 0.3-0.5% per degree Celsius above 25°C for silicon cells. A 400W panel rated at STC might produce only 320W on a hot summer day. For system design, use location-specific irradiance data (peak sun hours) and apply a system derate factor of 0.75-0.85 to account for all real-world losses.

Symbols and units

Symbol Meaning Default unit Accepted units
P Power Output W µW, mW, W, kW
G Solar Irradiance W/m² W/m²
eta Panel Efficiency — —, %
A Panel Area m² mm², cm², m²

Step by step

  1. 1. What you know: Solar Irradiance 800 W/m², Panel Efficiency 50 %, Panel Area 100 cm²
  2. 2. The relation: P = G × η × A
  3. 3. Substitute: G = 800 W/m², eta = 50 %, A = 100 cm²
  4. 4. Result: Power Output = 4 W

Worked examples

Minimum range

Given: Solar Irradiance 10 W/m², Panel Efficiency 2.5 %, Panel Area 10 mm²

Result: Power Output = 2.5 µW

Low range

Given: Solar Irradiance 100 W/m², Panel Efficiency 25 %, Panel Area 1 cm²

Result: Power Output = 2.5 mW

Typical

Given: Solar Irradiance 800 W/m², Panel Efficiency 50 %, Panel Area 100 cm²

Result: Power Output = 4 W

High range

Given: Solar Irradiance 1000 W/m², Panel Efficiency 0.8, Panel Area 1 m²

Result: Power Output = 0.8 kW

Maximum range

Given: Solar Irradiance 10000 W/m², Panel Efficiency 8, Panel Area 10 m²

Result: Power Output = 800 kW

Solving for each variable

Solve for Power Output

Solar Irradiance 10 W/m², Panel Efficiency 2.5 %, Panel Area 10 mm² → 2.5 µW

Solve for Solar Irradiance

Power Output 10 mW, Panel Efficiency 2.5 %, Panel Area 10 mm² → 40000 W/m²

Solve for Panel Efficiency

Power Output 10 mW, Solar Irradiance 10 W/m², Panel Area 10 mm² → 100

Solve for Panel Area

Power Output 10 mW, Solar Irradiance 10 W/m², Panel Efficiency 2.5 % → 400 cm²

How Power Output changes with Solar Irradiance

Solar Irradiance (input) Power Output (result)
80 W/m² 0.4 W
200 W/m² 1 W
400 W/m² 2 W
600 W/m² 3 W
800 W/m² 4 W
1200 W/m² 6 W
1600 W/m² 8 W
3200 W/m² 16 W
5600 W/m² 28 W
8000 W/m² 40 W

The same result in other units

Unit Value
µW 4000000
mW 4000
W 4
kW 0.004

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Frequently asked questions

How do you calculate Solar Panel Power Output?

Use P = G × η × A. With Solar Irradiance 800 W/m², Panel Efficiency 50 %, Panel Area 100 cm², Power Output works out to 4 W.

What is the formula for Solar Panel Power Output?

The formula is P = G × η × A. The electrical power produced by a solar panel is the product of the incident solar irradiance, the panel conversion efficiency, and the panel area.

How do you find Solar Irradiance when you know the other values?

Rearrange for Solar Irradiance: with Power Output 10 mW, Panel Efficiency 2.5 %, Panel Area 10 mm², Solar Irradiance is 40000 W/m².

How do you find Panel Efficiency when you know the other values?

Rearrange for Panel Efficiency: with Power Output 10 mW, Solar Irradiance 10 W/m², Panel Area 10 mm², Panel Efficiency is 100.

What units does Solar Panel Power Output use?

Power Output is shown in µW, mW, W, kW. Values are held in SI base units internally, so you can mix prefixes without converting by hand.

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