Curious Nature: Do solar panels continue to shine in the winter?
Walking Mountains Science Center
Solar panels are becoming more common in our community as a source of electricity. Colorado is known for 300 days of sunshine, which is ideal for solar panels to work. But as our days grow shorter in winter, do solar panels continue to be beneficial?
To answer this question, we first need to understand how solar panels work.
Every solar panel is made up of 60 cells called photovoltaic cells. These cells are 6-inch squares made of two layers of silicon. When the sun shines on the photovoltaic cells, particles of light called photons knock electrons in the silicon loose. The panels then direct the electrons through a circuit that generates electricity while the electrons travel back into place in the silicon.
To achieve this, the silicon is treated with phosphorous and boron as well as surrounded by metal plates to direct as many electrons in the right direction as possible. After traveling through the circuit, the electrons pop back into place in the silicon, and the process can start again. Since the electrons return to the photovoltaic cells after making power, solar panels can last decades.
How good are solar panels at making power, and how does winter affect them?
On average, one solar panel produces 320 watts of electricity, which is enough to power 35 LED bulbs. A U.S. home typically needs 30 solar panels to cover all of its power, but the amount of power generated by solar panels changes based on the weather conditions.
Winter brings us shorter days, more shadowing from our nearby mountains, and snow cover. All of these factors decrease the energy production of solar panels. Solar panels work best when they get direct sunlight, and they produce more power with more hours of sunlight. This means that the amount of power they produce decreases in the winter as the days get shorter and more homes are shadowed by the mountains. However, solar panels will continue to produce power despite these factors. Snow cover is the only thing that will nearly stop energy production.
Are solar panels still beneficial in the winter?
Snow, the only thing that will nearly stop energy production, doesn’t last long on solar panels. Solar panels are built at an angle to collect more sunlight, which also helps snow slide off the panels in winter. Plus, regardless of shorter days or tall mountains, solar panels will continue to produce energy in winter. The reflectivity of nearby snow and colder weather has even been found to boost energy production, so solar panels will actually produce more energy per hour of sunlight in winter.
Since solar panels continue to work in winter, the homeowner and the community continue to reap the benefits of solar all year. With our 300 days of sunshine per year, solar energy is actually more cost-effective here than in other places in the country. Unlike oil, natural gas, and other non-renewable fuels, solar panels last decades. This means that after the upfront cost of solar panels, homeowners save money every year compared to other fuel sources. In Colorado, these annual savings make up for the cost of the solar panels in just 10 years.
Solar energy also helps our community achieve our climate action goals. Solar panels do not emit any greenhouse gases, so they make our community’s air cleaner and reduce the impacts of climate change.
Between solar panel’s continued energy production in winter, annual dollar savings, and positive impact on our beautiful environment, solar energy remains a beneficial energy source for us despite our long winters.
Lauren Deriaz is the Energy Program Coordinator at Walking Mountains Science Center. Contact her for a list of local solar contractors and to discuss available solar rebates.