In many parts of the northern hemisphere, the leaves are falling, temperatures are dropping, and winter is just around the corner. Many people pay attention to the turning of the seasons because it means they need a new coat — but for those who utilize solar and wind energy, it’s even more important to understand how this change affects PV and wind energy systems.

1. Renewable Energy Is Site Specific

Unlike coal or natural gas power plants, which basically function the same way no matter the location, both solar and wind systems are inherently dependent on their location and the time of year. Renewable energy system designers plan for these changes, utilizing weather data, insolation maps, anemometers, and modeling software to ensure the system is reliable and efficient all year round. Often this means designing a system based on the historically least sunny and windy day of the year. 

For example, near the equator, insolation is almost constant year-round, whereas polar regions have very little sun during the winter months. Because this is so site specific, renewable energy systems are most productive and cost effective when they are customized to their unique environment. 

2. Solar Panels Are More Efficient in Cold Temperatures, But Winter Days Are Shorter

Panels capture energy from photovoltaic light — not from the sun’s heat. In fact, heat actually reduces the efficiency of solar panels, but during colder months, their energy production can increase by up to 15 percent. Despite this benefit of cold weather, winter days have fewer daylight hours, so the net change of amount of energy produced will be lower than during other times of the year.