Note: The information contained in this periodical weblog may be outdated. This was my personal weblog published before January 1, 2015. Since then I have been the co-owner and Principal Solar Designer at Florida Solar Design Group.

Solar Energy Production in the Winter

Snow on Solar Panels
At least we don't have to deal with snow on our solar panels in Southwest Florida!

Today, the winter solstice, is the shortest day of the year. That means your solar electric, solar pool heating, and solar water heating panels will have the least time in the sun today. It also means that your solar panels are probably not at an optimal tilt angle to capture the most radiation possible. Most solar power or water heating installations are geared to collecting the most energy over the whole year, so naturally there will be a best day and a worst day for solar.

The good news is that this time of the year is generally cloud-free in Southwest Florida. Although days are shorter, sometimes the solar production can exceed a cloudy day other times of the year. Nonetheless, this is the time of the year that people just can’t get their pool warm enough or don’t produce as much solar electricity as in the heydays of summer.

Most roofs in Southwest Florida are pitched at around 25 degrees. This happens to be the area’s approximate latitude, and it is the optimal tilt angle for annual solar production on a south facing roof. While your roof tilt may vary, it is usually close enough to optimal where any difference is negligible. However, the combination of short days and a tilt angle optimized for the annual average makes solar production this time of year less than average.

So today is a bad day for solar, but rest assured that the shortest day of the year is now behind us, and longer days ahead will assure increased solar energy performance for your system.

1 Comment

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