In the simplest terms, solar panels work by converting the sun’s energy into electricity. Solar panels may seem like a complex way to power your home, but they’re actually much simpler than conventional utility power. There’s no mining, fracking, or extraction involved - just clean technology that harnesses the abundant power already produced by the sun. In this article, we’ll answer the question, “How do solar panels work?” and then look at why so many homeowners are using solar to power their homes.
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How Solar Panels Generate Electricity
Solar panels are made of silicon, which is the same element that beach sand is composed of. When sunlight interacts with the silicon cells in solar panels, electrons are set into motion, initiating the flow of electric current through a process known as the photovoltaic (PV) effect. Solar panels generate direct current (DC) energy, and an inverter converts that energy into alternating current (AC) energy that can be used in your home.
Silicon is a semiconductive material, which means it functions as an insulator under most conditions, but can function as a conductor when enough energy is introduced. This semiconductive property allows it to absorb the sun’s energy, and convert it into electricity.
To answer the question, “How do solar panels work to generate electricity?” we have to understand the difference between a solar cell, a solar panel, and a solar array.
A typical solar cell is made up of layers of silicon that are either monocrystalline (made from a single crystal of silicon) or polycrystalline (many silicon fragments melted together). These solar calls are combined into solar panels (sometimes called solar modules) by putting them on a backing sheet with a protective glass layer on top, which is then surrounded by a metal frame, with wiring running throughout for the electric current to flow through. Solar panels are then installed together in groups to form a solar array.
The silicon crystals used in solar panels contain impurities (introduced through a process called doping) that increase the conductive properties of the material. Like sunlight, silicon is an abundant resource that is actually the second most abundant element on Earth, behind only oxygen.
What is the photovoltaic effect?
It’s hard to talk about how solar panels work without taking about the photovoltaic effect, a characteristic of some materials, like silicon, that allows them to generate electricity when exposed to sunlight. The photovoltaic effect was first discovered by Edmond Becquerel in 1839, and is the basis for all solar power technology.
So how do solar pv panels work? When the silicon in solar pv panels is exposed to the sun’s radiation, the photovoltaic effect means that electrons within that silicon material will begin to move. Electricity is the movement or interaction of electrons, so when the electrons in the silicon are moved by the sun’s energy, they are creating electricity.
How much power do solar panels generate?
If you’re asking yourself, “How do solar panels work for your home?” then you’re probably also wondering about how much power solar panels generate, since the electricity that solar generates is what you need to power your home. Individual solar panels or solar modules are often grouped together to form a solar grid or solar array, allowing you to capture and harness large amounts of energy for your needs. Because solar panels typically work together as a group, there are two ways to answer this question:
How much power does one solar panel generate?
Solar panels are rated on the amount of direct current energy (DC energy, measured in Watts) they produce under standard test conditions. The amount of energy a solar panel can produce is referred to as the panel’s wattage, capacity, or power output. In addition to energy generation, solar panels are also rated on energy efficiency, which measures their power output relative to the panel size.
When thinking about the question, “How do home solar panels work?”, keep in mind that most home solar panels on the market today have a power output between 200 and 400 Watts, and an efficiency rating of around 15%. Palmetto uses premium solar panels that boast a power output of up to 400 Watts, and an efficiency rating of greater than 20%.
How much power can I generate with a solar power system?
Given enough space, there really isn’t a limit to the amount of power that you can generate with a solar power system. For example, the Tengger Desert Solar Park in China covers roughly 17 square miles, and generates 1.5 gigawatts of solar generation capacity, or enough to power more than 600,000 homes!
But when you’re thinking about, “How do rooftop solar panels work?”, you’re probably just thinking about one rooftop - yours. In that case, the amount of power you can generate is going to depend on a number of factors, including your current energy usage, the size and layout of your roof, and your preferred level of energy independence. For more information, check out How Much Roof Space Is Needed For Solar Panels?
When designing a solar power system and determining the right size for a family’s home, most designs are based on a target solar power offset, which estimates the percentage of power that a home uses that would be provided by that solar power system. A 100% solar power offset means that over the course of a year, the solar power system would generate the same amount of energy as that family uses over the same period of time.
If your goal is to produce as much energy as you currently use (meaning you achieve a 100% solar power offset) then you want to start by calculating the total kilowatt-hours you consume in a given year, and work backward to design a system that will meet your needs. Check out our Solar Savings Estimator to find out what our recommended solar size would be, based on your home’s energy usage.
According to 2019 data from the US Energy Information Administration, the average US home uses about 10,600 kWh of energy per month. It would require between 28-34 solar panels to generate that much electricity, depending on the home's size and geographic location, the placement of the panels, and the panel efficiency.
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Are there ways to boost your solar panel efficiency?
While solar panels are very efficient and don’t often require maintenance, there are a few things you can do to make sure you’re getting the most out of your solar array. We can’t talk about how solar panels work without also talking about how to make sure solar panels are working efficiently.
For peak efficiency, make sure your solar panels are free of dust and debris. Normally rain and wind will do most of that cleaning work for you, but an annual solar panel cleaning can help ensure that your solar panels are operating at peak efficiency, and catch any potential issues before they become a larger problem.
You can also monitor your energy production and consumption to better understand your typical energy usage patterns, and identify any times when those patterns change. Palmetto customers get access to this data through the Palmetto App (consumption data may require additional equipment) and active monitoring can alert you to changes in production which may indicate a need for maintenance.
In addition to making your solar panels more efficient, you can also make your home use electricity more efficiently with smart home features and devices such as thermostats, shade and lighting solutions, energy-efficient appliances, and home automation systems. These smart home devices can dramatically reduce your overall energy usage, which allows you to offset even more of your energy needs with solar power.
You can further optimize your clean energy usage by scheduling high energy chores, such as doing the laundry or running your dishwasher, for sunny hours on days when production levels are at their highest.
What happens to the electricity you don’t use?
Solar panels generate electricity any time the sun’s out, but what happens to the excess energy when your home is using less power than your solar panels are producing? How do solar panels work when you use less power?
For most homes that go solar, they remain connected to the grid, and any extra electricity that they generate with solar panels goes back into the grid to be used by other buildings. If your home is located in a net metering area, any excess energy that you produce will earn you a credit on your utility bill, which can be used to offset the cost of any electricity that you use from the grid at another time.
If you choose to integrate energy storage with your solar power system via solar battery backup, any excess energy that is produced and not immediately used by your household will charge your battery. Then, any time the amount of energy that your home needs exceeds the amount that your panels produce, you can draw from your stored energy in the solar batteries, and use your own electricity instead of drawing from the grid.
For homeowners that are not connected to the grid, energy storage is an important part of their solar power system design, so they will often increase their solar storage capacity to enable uninterrupted power, regardless of weather or time of day.
How Weather Affects Solar Power
It’s a common misconception that solar panels won’t work in cloudy, rainy, or snowy areas. In fact, solar panels can still capture and generate power from indirect light, and most solar panels actually perform best in cool temperatures. While direct light is always ideal for energy production, homeowners in cloudy and overcast areas can still count on solar to generate clean energy to power their home.
When it comes to durability, solar panels are designed to withstand outdoor elements like rain, wind, snow, sleet, and even hail. In many cases, solar panels are actually stronger and more durable than the roof below them, which means that solar panels can offer the added benefit of protecting your roof from storm and weather damage. The occasional rain storm can actually help improve your overall solar performance, as it washes away any dust or dirt that may have built up on your panels, keeping your solar power system performing at peak efficiency.
During the manufacturing process, solar panels are tested and rated on a variety of performance and durability factors including hail impact resistance and maximum wind and snow surface load. When designing a solar panel system, solar companies will match the product specifications and warranty of the panels they choose with the conditions in your area, to make sure your system is well suited for the types of weather you can expect.
How do solar panels work on cloudy days?
If you’re wondering, “How do solar panels work on cloudy days?”, just know that as long as photons from the sun are hitting your solar array, your solar panels will produce electricity. That said, on cloudy and overcast days, fewer photons are hitting your solar panels, so they will likely perform below their maximum energy capacity, and you will see a reduction in the amount of energy produced.
You also might be surprised to learn that just because an area has a cloudy climate, doesn’t mean it’s a bad place to go solar. The popularity of solar is often more closely linked to the cost of electricity from other sources, not the amount of sunlight that an area can expect. As a result, many of the top cities for solar installations in the U.S. are not in hot, sunny locations like the Southwest, but in cooler, cloudier locations like the Northeast.
If you live in an area with high electricity rates, you might be surprised by how much you can save on your electricity bill, and how quickly your solar investment can hit the break-even point by cutting out your expensive power provider.
How do solar panels work when there is no sun?
Can solar panels work when there is no sun, and how do solar panels work at night? Solar panels rely on sunlight to produce electricity, so they do not work at night, and don’t generate power when there is no sun. You can still use solar power at night if you have a way of storing the excess energy that your solar panels generate during the day, and then using that stored up electricity at night. If your goal is to maximize your use of clean energy and minimize (and/or eliminate) your reliance on the grid, solar batteries are one way to access your solar energy even after the sun goes down.
How well do solar panels work in the winter?
When you understand how solar panels work, you may still be thinking about cold weather and wondering, “How well do solar panels work in the winter?” Solar panels actually perform better in cool temperatures, and as long as your panels aren’t covered in snow, they will continue to produce electricity in the winter. If you do live in a snowy area, and are looking for an answer to the question, “How do solar panels work in snow?” the good news is you can actually benefit from the light that’s reflected off of snow on the ground and in trees, which has been shown to improve photovoltaic performance as more light hits the solar panels, even if it is indirect sunlight.
Any snow that accumulates on your solar panels should be cleared away to ensure that sunlight can still reach your solar array. In most cases, this problem will take care of itself when the snow melts and slides down the panels, but if not, you can use a broom to gently push snow away from your panels and expose them to sunlight again. So if you’re wondering, “How do solar panels work in winter?” the answer is: Pretty good actually!
How To Get Solar Panels Working On Your Home
Now that you know how solar panels work, if you’re thinking about adding solar to your home, the best place to start is with our free solar savings estimator, which uses weather and utility data specific to your area to forecast your potential solar energy savings. All you need is your address and your most recent utility bill, and you’ll be able to see estimated costs and savings, as well as the annual environmental impact of going solar. (Hint: You’ll be eliminating A LOT of greenhouse gases!)
If you like what you see, then you can request more information, and we’ll put you in touch with a Palmetto solar expert who can look at your home in more detail, and provide a solar proposal with more information about the layout of your solar system, the amount of power it would generate, your monthly savings, and more.
Click here to get started, and then get ready to live in the solar-powered future!
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Cory O'BrienSenior Director - Growth MarketingCory brings over 8 years of solar expertise to Palmetto, and enjoys sharing that knowledge with others looking to improve their carbon footprint. A dog lover residing in Asheville, NC with his wife, Cory graduated from UCSB. If you run into him, ask him about the company he founded to rate and review beer!
