The sun is the most powerful source of energy in our world. Averaged over one year, it produces a quantity of energy so large it would take 44 million large power plants to match it. In 90 minutes, the sun sends enough energy earthward to supply the entire planet with electricity for a year.
Until fairly recently, the problem was how to harness that energy for human use. During the past 70 years, give or take, a solution has emerged: the solar panel.
In this article, we’ll break down how solar panels work to corral the sun’s immense power. We’ll discuss the difference between solar power and solar panels, and explain what solar panels are made of and how solar panels work at night. We’ll also dig into how private home solar panels work, how they work on a cloudy day, and answer the question how do I know if my solar panels are working? We’ll also tackle any remaining frequently asked questions about solar panels and solar power.
Break out the SPF and get ready to bask in some rays of knowledge.
How Does Solar Power Work?
The key to solar power is a process called the photovoltaic effect. That’s a fancy name for what happens when sunlight hits panels made of silicon and generates electric current. Photons from the sun’s rays dislodge electrons from the silicon. These electrons flow through the solar panel, down wires and into an enclosure called a junction box. At this stage, the electrons form a direct current (DC). They then travel to an inverter to be transformed into alternating current, which can provide electricity for homes and buildings.
The solar power comes from the sun’s rays, and the solar panel is the tool that catches and directs that power.
What Are Solar Panels Made Out Of?
Solar panels are composed of multiple solar cells. The cells produce electricity through the photovoltaic effect, and the panel is the framework that protects the cells while magnifying and directing the energy they produce. The vast majority (about 84%) of solar cells are made of crystalline silicon (c-Si), and break down into two categories: monocrystalline and polycrystalline.
Monocrystalline cells are the more expensive of the two, and tend to overcome shady or unusually hot conditions better than polycrystalline cells. If you see panels that are black or dark gray, they’re most likely composed of monocrystalline cells.
Panels with polycrystalline cells show a dark blue hue when exposed to bright light, and they tend to be less efficient than their monocrystalline counterparts in high temperatures. They’re also less expensive.
If your setup provides plenty of roof space and sun exposure, the less expensive polycrystalline model could work for you. But if roof space is limited and you have to contend with shady conditions, you’ll want to go with the higher efficiency monocrystalline option.
How Do Solar Panels Work on a House?
When it comes to energizing homes, solar power falls into two categories, “grid-tied” systems and battery-storage systems. The vast majority of residences use the grid-tied mode, which means the house’s solar gear and electrical system are both connected to the community utility grid.
During the day, these homes run on solar power. At night, they use electricity from the local grid. If their solar panels generate excess electricity during the day, the surplus can be pushed onto the utility grid. These homes typically use a net meter to track solar production, and when there’s an excess, the homeowner earns credits they can exchange for an equal amount of energy down the line. They are effectively storing their excess solar power on the local grid.
How do house solar panels work with the other, less prevalent, form of home solar power? The answer is the battery-storage method. The difference in this setup is that the excess power generated during the day goes to batteries in the home or garage, where it can be stored for later use. If you live in an area that doesn’t have net metering, or if you want to go off-grid and run your home entirely on renewable energy, this may be the best option for you.
How Do Solar Panels Work at Night?
You’ve no doubt heard the proverb make hay while the sun shines. Well, it’s not just for farming, or for making the most of a good situation while it lasts. It also applies to solar power, which, true to its name, derives all of its energy from the sun. No home (or commercial) solar system accumulates power after the sun goes down.
How solar panels can work at night is to store excess energy they’ve harvested from the sun during daylight hours. This happens in one of two ways: for most home solar systems, excess power gets pushed onto the local electrical grid. Homeowners can use net metering to get credit for this energy that they can use at a later time, including at night, when their solar systems are not producing.
For home solar panel systems that use battery storage, the excess power gets sent to a battery lodged in or outside of the residence, depending on the local climate and weather (and fire-safety precautions). The solar battery will store the excess energy and allow the homeowner to access that power at nighttime.
So home solar panels don’t technically work after sunset, but they typically do accumulate enough surplus power during their operating hours to get homeowners through the night.
How Do Solar Panels Work on Cloudy Days?
Unlike at night, when solar panels are entirely cut off from the source of their power, they can still produce energy on a cloudy day. That’s because solar panels can capture both direct sunlight and indirect sunlight (light that’s filtered through cloud cover). Your solar panels won’t function at maximum efficiency in cloudy or rainy conditions, but they can produce approximately 10% to 25% of the energy they would capture on a completely sunny day.
How else can solar panels work on cloudy days? Well, every cloud does indeed have a silver lining when it comes to solar power: rainfall can wash solar panels clean and restore their maximum efficiency.
Solar Panel FAQs
How Do I Know If My Solar Panels are Working?
Check with your particular solar company, but most solar panel installations will come with a solar monitor that the homeowner can use to keep track of the new system’s performance. The monitor allows solar customers to track how well their panels are working, to optimize the efficiency of their unit, and to catch any malfunctions or damage to their panels.
Going solar is a significant investment, and a solar monitor will ensure your ability to maximize your return on that investment by keeping your unit in peak operating condition. If you’re ever asking yourself how do I know if my solar panels are working, the answer isn’t too far away.
Can Solar Panels Save Me Money?
The short answer is ‘yes,’ but it can take a long time. You will definitely see savings on the very first electricity bill you receive after your solar system is up and running, but since there are significant up-front costs to going solar, your actual savings may take years to realize.
In 2023, the cost to install a solar system at home ran from $4,500 to $36,000. The average cost was about $16,000. This fairly wide range is due to a number of factors, including the size of the system, any extra gear it may require, and the tax incentives or rebates that can be applied to your installation costs.
To calculate how long it will take to realize your savings, compare your electricity bill from before you went solar to after you made the change. Divide your installation cost (after tax incentives and/or rebates) by the savings in your post-solar bill to figure out how long you’ll have to wait to break even.
Suppose you paid the national average of $16,000 for your solar system, and the average of $1,650 annually for power before you installed it. Now that it’s operational, your annual utility bill has shrunk to $260, a savings of $1,390. Dividing $16,000 by $1,390, we get 11, the number of years required to see a return on the initial investment.
Can Solar Panels Increase Your Home’s Value?
Yes, house solar panels can increase the value of your home—and on a shorter timetable. Just how much shorter depends on several factors, from where you live and how much you paid for installation, to the system you’re using, how old it is, and how much repairs typically cost.
Recent statistics put the national average for increased home value at approximately $5,911 for each kilowatt of solar panels added to the rooftop. Using that figure, if you added a 6-kilowatt solar system to your rooftop, you could see your home’s value increase by as much as $35,466.
The wrinkle here comes when you plan to sell your house and realize that value. In the best-case scenario, you’ve lived in the home long enough to eclipse the break-even point on your up-front costs for home solar installation. If not, you could be passing that responsibility on to your buyer. In a region where residential solar power is prevalent, this may not matter. But if you live in an area where solar is scarce, or even unpopular, it could make it difficult to find a buyer who appreciates the value of the technology enough to pay more for a home equipped with solar panels.
How Do I Know If My House Is Suitable for Solar Power?
The first elements to assess are the location, angle, and health of your roof. Solar panels work best on roofs in good condition that have southern exposure and a slope between 15 and 40 degrees. You don’t want to mount solar panels on an aging roof that will need to be replaced in the near future. (On the other hand, if your roof is in need of replacement, that’s a prime time to add solar power.)
Another factor to consider is the amount of shade that hits your rooftop. Shade can reduce solar panel efficiency by up to 50%. It’s not a deal breaker, though, so, depending on the amount of shade you’re facing, you can work with your solar power company to find a solution.
If your residence proves unsuitable for solar panels, you can still access 100% clean energy for your home with Inspire. Click here to learn more.
How Many Solar Panels Will I Need?
The answer depends on the amount of electricity your household consumes, the amount of peak sunlight your panels absorb per day, and the wattage power of your solar panels.
The first step is to consult your electric bill and determine how much electricity (kWh) your household uses. Next, look up the average peak sun hours per day in your location. Divide your daily electricity consumption by your average number of peak sunlight hours.
Once you have this figure, divide it by the wattage of each solar panel you’re considering.
Using current national averages, the formula looks like this:
Daily electric consumption Avg peak sun hrs
30 kWh ➗ 5 = 6 kW
Avg solar panel wattage (400w, or 0.4 kW per panel)
6 kW ➗ .4 = 15 panels
How Clean Energy Power Plans & Solar Help the Environment
Climate change is one of the most pressing issues of our time, and it’s caused by greenhouse gas emissions.
Solar power—a renewable, clean energy source—can be an essential part of the solution. Solar energy can also improve air quality and decrease water use associated with energy production.
The collective impact of millions of homes (not to mention businesses and industries)
converting to solar power would improve the environment on a large scale while also making a real difference in the fight against climate change. Learn more about accessing clean energy for your home and do your part today.
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