Winter vs. Summer PV generation

It is common to hear the assertion: “In winter solar panels don't generate anything!” But is it true?

If you live in a region with marked seasons, there are several factors to consider in winter, almost all of which have a negative impact on generation:

❄️ The temperature is lower, which increases the efficiency of the system.

☁️ There is usually more cloud cover, reducing the irradiance reaching the modules.

🌞 The sun follows a lower trajectory, reducing the irradiance on the plane or requiring a very steep tilt of the modules.

🌳 The sun's path also increases the impact of shadows due to geographical features and nearby obstacles.

🕰️ There are fewer available daylight hours.

☃️ Snowfall is possible, and modules may be partially or completely covered.

As you can imagine, in general terms, an installation in winter generates less than in summer, but how much less? The amount depends on the location and characteristics of the installation.

We have calculated the DC generation for an installation with 950 modules of 530 Wp with a 15º tilt and East - West configuration located in different locations. As you can see in the image, the differences between the generation between summer and winter depend a lot on the location, with an 80 % difference in Paris compared to a 61 % difference in Malaga.