Conditions (STC) are standardized test conditions to ensure the comparability of solar cells and solar modules
.The STC test conditions are used to test solar modules uniformly and independently of each other and to enable comparability of peak power and efficiency. In the standard tests, the solar modules are irradiated with daylight and a radiation intensity of 1,000 watts per square meter at an angle of incidence of 48 degrees. Since the efficiency is temperature-dependent, the solar modules have a temperature of 25 °C. The solar power generated is converted into peak power.