How Weather is Affecting Solar Performance

By Benedette Cuffari, M.Sc.Sep 6 2017

Solar power is the energy that is harnessed from the sun by using photovoltaic cells that convert light energy into electricity. It is the cleanest and most abundant source of renewable energy, and presents as a great energy alternative that can reduce carbon pollution and continue the fight against climate change.

While the United States previously did not have any utility-scale solar power plants in 2007, there are now hundreds of such plants present today, with a majority of them found in states including California, Arizona, North Carolina, New Jersey, Nevada and several others¹. While there is a definite growth in this industry, there are a few challenges associated with it including the cost of installation, drive-down manufacturing and adverse weather conditions².

Although good quality solar panels are built to withstand and perform under common weather conditions such as rain, fog, mist and high winds, the performance of these panels will be affected by extreme conditions². Anything that blocks the sun’s rays from reaching the surface of the panels will affect the efficiency of the panels’ solar power, however, these factors will not affect the performance of the solar panels as much as we would think.

For example, a typical dark rain cloud has the potential to reduce the efficiency of solar panels by 30%,² whereas wispy cirrus clouds will not affect the power harnessing capacity of the solar panels³.

The design of the solar panels ensures that the electronic components that are enclosed within the solar panels must be safe. In fact, rain helps to clear out the dust from the solar panels, thereby allowing for more efficient energy conversion³. Good quality solar panels are built to withstand winds of 90 miles per hour (mph), as well as hail velocities of over 260 mph. For instance, in the middle of May 2017, a severe outbreak occurred in Colorado, covering the state with snow and hail stones in some locations. The NREL research facility in Golden, Colorado, where hailstones up to 2.75 inches in dimeter were dropped, experienced damage to only one solar panel out of the 3,168 solar panels installed on the facility, suggesting the resilience of this solar technology⁴.

While snow could result in accumulation of snow on the panels, it is not a major concern in most areas because the snow slides off the panels rather easily and melts off quickly when the sun returns³.

Lightning could result in voltage surges in the solar panels, but this can be protected to some extent by proper grounding as well as lightning protection systems. Solar panels installed in areas prone to dust storms may be greatly affected due to the deposition of a heavy layer of dust which prevents the solar panels from accessing the sunlight, therefore requiring for a clean-up of the dust³.

The efficiency of solar panels is best in colder and sunny weather, therefore very hot climates reduces their efficiency. For every 1 degree Fahrenheit (ºF) increase in temperature above 87 ºF, the efficiency of solar panels may decrease 1% or more³. In June 2017, some south-eastern states of the US had extremely hot weather, negatively impacting the solar resources⁴.

A recent partnership between Green tech media (GTM) with a company that monitors solar performance across US, Vaisala, revealed how the weather in the U.S affected the solar performance in 2017. While the Q2 was predicted to increase in solar performance, the continued wet and hotter weather climates in the second quarter (Q2) of this year completely changed the solar power usage predictions⁴.

The month of April 2017, the Pacific Northwest states were subjected to above-normal precipitation because of variable jet streams, resulting in a more than 5% decrease in solar resources. One of the leading states that use solar energy, North Carolina experienced the wettest April on record, forcing the owners of the newly installed solar farms to deal with groundwork issues⁴.

In May, the central U.S had periods of severe weather that wa colder than the usual climate during this period, affecting the solar industry. In June, due to the sunny weather in some southeast states, and heavy rain along the gulf coast, solar projects as well as solar performance was also negatively affected⁴.  Over all, the second quarter of 2017 did not turn out to be a good year for the U.S solar performance.

Image Credit:

foxbat/ Shutterstock.com

References:

1. “Here Are The Top 10 US Solar States” – CleanTechnica
2. “Solar Energy” – Solar Energy Industries Association”
3. “How Weather Affects Solar Panels” – Renewable Energy Corporation
4. “America Is Getting Wetter and Hotter, Impacting Solar Performance Around the Country” – Green Tech Media

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