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Many homeowners know that investing in solar power can lower their electricity bills and reduce their environmental impact. However, most people don’t know exactly how solar panels work. Learning about the science behind solar technology will help you make more informed decisions when shopping for a system from the top solar companies. This article breaks down essential information about solar panels, how they work, and the components that support a solar energy system.
What Are Solar Panels?
Solar panels are devices that power your home by converting the sun’s energy into usable electricity. Also known as solar photovoltaic (PV) panels, they provide renewable energy to your home without the need for costly, toxic fossil fuels. PV panels are commonly mounted on your rooftop, but ground-mounted installations are also available. The number of panels you need depends on your energy usage, selected solar panel type and available space.
Cloudless, sunny days are ideal for solar panels and yield the maximum power output. Panels will function during cloudy days, but the power output will drop. Shadows from surrounding buildings or trees can also impact your solar system’s performance.
What Is the Photovoltaic Effect?
The science behind solar panels is known as the photovoltaic effect. Particles of sunlight, or photons, knock electrons from atoms. Once these electrons are set into motion, solar panels capture the electrical flows and create electricity.
Panels contain components known as photovoltaic (PV) cells that capture sunlight. PV cells are typically six inches long and six inches wide. A typical panel contains between 32 and 48 photovoltaic cells but may vary based on the panel size and power output. Within each cell is a nonmetal semiconductor material that aids in energy absorption. In traditional solar panels, this material is silicon, one of the Earth’s most abundant elements.
Silicon is not a good conductor on its own. Solar manufacturers use a process called “doping” to enhance silicon’s conductivity and cause impurities to bond with it. Two elements are added to create an electrical charge: boron and phosphorus. Boron adds a positive charge while phosphorus adds a negative one.
These elements are applied to two silicon layers and brought together to create an electrical field. The sides of the silicon solar cells are lined with metal plates which help push the electrons through the wiring as electric current. This current flows through the rest of the solar panel system and into your home.
Types of Solar Panel Materials
The most popular solar panels use crystalline silicon. These panels come in two forms: monocrystalline (mono) and polycrystalline (poly).
Mono panels use single-crystalline technology. They cost more than other types of panels but offer the most power and efficiency. Poly panels use fractured crystalline, which is a more cost-effective process because fragmented silicon can be used to produce more panels. Poly panels have a lower price point, but also a lower power output.
Thin-film solar panels are a less expensive alternative to crystalline panels. They use thin layers of PV material instead of silicon. Although thin-film panels are more affordable, they offer the lowest power production of the three options.
Solar Panel Efficiency
These different manufacturing processes affect your solar panels’ efficiency rate. Efficiency measures the amount of sunlight a panel can absorb and effectively convert into solar energy. The higher the efficiency rate, the higher the panel’s solar conversion. For example, a solar panel with an efficiency rate of 20% can absorb 20% of the sunlight that hits it. The National Renewable Energy Laboratory (NREL) reported that solar panels currently offer efficiency rates between 16% and 22% but average around 19.2%.
Monocrystalline panels, which use pure silicon, offer the highest efficiency ratings, typically between 17% and 23%. Polycrystalline panels fall slightly lower, with ratings around 13% to 16%. Thin-film panels have the lowest efficiency rates, between 7% and 11%.
Understanding How Solar Panels Work
Each component of your solar energy system plays an essential role in energy conversion. Below is a step-by-step guide to how your solar panels work.
- The sun’s energy activates the PV cells: This is when the photovoltaic effect begins. When sunlight hits the solar panels, the PV cells activate and absorb the rays. This energy is converted to electric current by the panels. Initially, the energy converts to direct current, or DC electricity.
- DC electricity becomes AC electricity: The solar inverter converts DC energy into AC electricity, the type of electricity used in every home. Inverter installation varies between two types: string and microinverters. String inverters, the most common type, are mounted on your home and convert the electricity from all of your solar panels in one central location. Microinverters are mounted to each panel and convert energy at the source of creation.
- AC electricity flows to your home: After the AC energy converts, it flows into your home through the electrical panel and to your outlets. This process is similar to receiving electricity from a utility company via the electrical grid. Some homeowners keep their solar systems tied to the grid to ensure their homes receive power when panels aren’t in use. However, you could sustain your home on solar energy alone. To go “off-grid,” you’ll need to build an energy system with backup power to support your home’s needs at night or during low sunlight days.
- Net meter regulates and monitors energy: As your system generates solar energy, a net meter keeps track of all grid-tied system usage. This device tracks the amount of energy your system generates and the amount of electricity pulled from the grid. Net meters also track any excess electricity generated by your system. If your state or local government offers a net-metering program, you can sell this excess energy back to the grid system for utility credits or annual payouts. These credits help to offset energy costs when you need power-tied electricity. To find net-metering programs in your area, check the Database of State Incentives for Renewables & Efficiency (DSIRE) for more information.
- Solar battery systems store excess electricity: If your area doesn’t offer a net-metering program or you want to keep the excess energy for yourself, you can add a solar battery to your system. Solar batteries store the extra energy until you’re ready to use it. This is useful during unexpected power outages and other times when solar panels can’t function. In some areas, stored electricity may be available during high electricity rates, which could lower your utility bills even further. You can add solar storage options with a new or current energy system.
The success of any solar system begins with the panels. We recommend investing in high-quality solar panels to maximize your savings and return on investment. Consider solar incentives such as the federal tax credit to lower your installation costs. When shopping for a solar system, compare quotes from at least three installers to find the best options. We’ve provided a tool below to help you start your search.
Solar Panel FAQ
What is solar panel efficiency?
Solar panel efficiency measures how effectively your panels absorb and convert sunlight into energy. The higher the efficiency rate, the better the panels convert energy, ultimately increasing your energy savings potential. The average solar panels have efficiency rates between 15% and 18% but may run as high as 23%.
What is the first step in how solar panels work?
The first step in how a solar panel works is absorbing the sun’s energy. When sunlight hits solar panels, they activate and absorb the sun’s energy. The solar cells that make up the panel’s surface come to life and convert the absorbed energy into direct current (DC) energy.
What are any disadvantages of solar energy?
Two disadvantages of solar energy are the roof space required for solar panels and no power production overnight. Solar panel systems require a large amount of space for rooftop installation, which may be difficult with certain home styles. And polycrystalline panels have a bluish hue that may clash with your home’s aesthetics. Also, solar panels do not work overnight, so you’ll need to invest in a solar battery or pull from the grid system to power your home during that time.
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