Solar panels are components of a photovoltaic system that use sunlight and convert it into electricity to support renewable energy. Solar panels consist of photovoltaic (PV) cells made from silicon within frames that include inverters, junction boxes, and mounting structures. The photovoltaic effect excites electrons when sunlight strikes PV cells and generates direct current (DC) electricity. An inverter converts DC electricity to alternating current (AC), which powers household or commercial uses.

Solar panels come in various types, including crystalline silicon (monocrystalline and polycrystalline) and thin-film technologies, with different efficiencies and applications for each. Solar installation involves site evaluation, system design approval, permitting, mounting the panels, electrical connection and final inspection for compliance and safety.

Solar panels power residential and commercial electricity generation, remote locations, water heating, agricultural drying, lighting, water pumping and space missions. Benefits of going solar include reduced electricity bills, lower greenhouse gas emissions, environmental benefits and energy independence. 

Solar panels require upfront investment and sunlight availability, but technological advances and incentives reduce costs and increase adoption of solar energy.

What is a solar panel?

Solar panel, also known as a photovoltaic (PV) panel or module, is a device that converts sunlight directly into electricity using semiconductor materials like silicon. Solar panels contain solar cells that generate an electric current through the photovoltaic effect when exposed to sunlight.

Solar panels produce clean, renewable energy for homes, businesses, and applications, reduce reliance on fossil fuels and decrease greenhouse gas emissions.

What are the components of a solar panel?

The components of a solar panel include solar cells, EVA film, glass, a back sheet, an aluminum frame, a junction box, and connectors. Each solar panel component is engineered to maximize the efficiency, durability and safety of the solar panel.

The parts of the solar panels are explained below.

• Solar cells: Solar or photovoltaic (PV) cells are the heart of a solar panel, and are made from semiconductor materials (usually silicon) that absorb sunlight and convert it into electrical energy through the photovoltaic effect. Their arrangement and quality directly affects the solar panel’s efficiency.
• Protective glass cover: Protective glass cover forms the outermost layer of a solar panel and provides structural rigidity. It uses tempered glass to shield solar cells from rain, hail and debris, and gives maximum sunlight transmission.
• Encapsulant (EVA film): EVA film in solar panels uses ethylene-vinyl acetate (EVA) to surround photovoltaic (PV) cells, hold them in place, protect them against moisture, dust and mechanical stress, and secure them between glass and backsheet.
• Back sheet: The backsheet in a solar panel acts as a durable barrier against moisture, UV radiation and environmental hazards. Backsheets use weather-resistant materials like Tedlar (polyvinyl fluoride) or TPT (Tedlar-Polyester-Tedlar composite) to protect internal components and provide electrical insulation for longevity and safety.
• Aluminum frame: The aluminum frame surrounds the edges of the panel, and provides mechanical strength, maintains panel shape, enables mounting and protects the panel from impacts and forces.
• Junction box: Junction box is located on the back of the panel, and houses electrical connections and bypass diodes. It transfers electricity and interfaces external wiring to provide protection against short circuits and reverse currents.
• Interconnectors (busbars and ribbons): Interconnectors use thin strips of conductive material, usually copper or silver-coated copper, to connect individual solar cells and allow electricity to flow from cell to cell and out of the solar panel.
• Encapsulation or lamination layer: Encapsulation or lamination layer is made of EVA seals, and protects PV cells between the glass cover and backsheet to improve durability and electrical insulation.
• Anti-reflective coating: Anti-reflective coating is a thin layer applied to the surface of PV cells to reduce sunlight reflection, increase light absorption and improve panel efficiency.
• Sealant: Sealant are materials applied around the edges of the solar panel to prevent the ingress of water, dust and other contaminants, to maintain long-term reliability and performance.

How do solar panels work?

Solar panels work by using photovoltaic cells, made of silicon, to absorb sunlight and release electrons, creating direct current (DC) electricity. An inverter then converts this DC into alternating current (AC) for home or grid use.

The step-by-step mechanism of how solar panels work is given below.

1. Sunlight activation: Solar panels are installed on rooftops or open spaces to maximize sunlight exposure. Sunlight activates photovoltaic (PV) cells embedded within the solar panels to convert solar energy into usable electricity.
2. Absorption of photons: Photovoltaic (PV) cells, integral components of solar panels, are made of silicon and absorb photons from sunlight. Light energy frees these electrons within the silicon material to initiate electricity generation.
3. Generation of electron-hole pairs: Photons strike silicon atoms within the photovoltaic (PV) cells of solar panels, exciting electrons and freeing them from atomic bonds, in order to create holes that facilitate electrical flow.
4. Creation of an electric field: Solar cells use two silicon layers, n-type doped with phosphorus (extra electrons) and p-type doped with boron (extra holes). Their interface forms a p-n junction that creates an internal electric field.
5. Separation and movement of charges: The electric field at the p-n junction drives freed electrons to the n-type layer and holes to the p-type layer. Their movement generates an electrical current that contributes to the solar panel’s energy output.
6. Collection of electric current: Metal plates on the top and bottom of the PV cell collect moving electrons and channel them into wires, forming a direct current (DC).
7. Conversion from DC to AC: DC electricity generated by solar panels is sent to an inverter that transforms it into AC electricity, suitable for use in homes, businesses, and the electrical grid. The AC electricity then flows to the building’s electrical panel, which distributes the power to lights, appliances, and other devices throughout the structure.
8. Net metering and battery storage: The excess electricity that the solar system produces is sent back to the grid through a utility meter, and net metering allows homeowners to earn credits for the extra energy supplied. Some solar installations include batteries to store excess electricity for later use, such as during nighttime or cloudy days when the panels are not producing power.

Modern solar systems include monitoring systems to track performance and efficiency. Regular maintenance, including cleaning solar panels and inspecting electrical connections, is important for maintaining optimal energy production and extending solar system longevity.

The image below illustrates how photovoltaic cells generate electricity from sunlight.

What are the types of solar panels?

There are three main types of solar panels including monocrystalline, polycrystalline and thin-film solar panels, each differing in their materials, efficiency, appearance and ideal applications. Monocrystalline solar panels offer the highest efficiency and sleek design, polycrystalline panels provide a balance between cost and performance, and thin-film panels are lightweight and flexible but less efficient.

1. Monocrystalline solar panels

Monocrystalline solar panels are a type of solar panel made from a single pure silicon crystal sliced into wafers, with a uniform dark black color and rounded edges. Monocrystalline panels are the most efficient and space-saving, as they offer the highest power output and longest lifespan, but they are also the most expensive due to complex manufacturing.

2. Polycrystalline solar panels

Polycrystalline or multicrystalline solar panels are a type of solar panel made from multiple silicon crystals melted together to form a bluish hue and a less uniform appearance. Polycrystalline panels are less efficient than monocrystalline panels but more affordable. They balance cost and performance which makes them popular among budget-conscious homeowners.

3. Thin-film solar panels

Thin-film solar panels are a type of solar panel made by depositing a thin layer of photovoltaic material onto a substrate like glass, plastic or metal. They are lightweight, flexible and the least expensive, but have the lowest efficiency and require more space to generate the same amount of electricity as crystalline panels. Thin-film panels are used in large-scale projects or where flexibility and portability are needed.

There are also some emerging and specialized solar panel types, including passivated emitter and rear cell (PERC), bifacial, concentrated photovoltaic (CPV), and perovskite solar panels that offer improved efficiency.

What are the uses of solar panels?

The uses of solar panels include generating electricity for homes and businesses, powering remote areas, heating water, charging batteries, supporting off-grid systems and reducing reliance on fossil fuels.

The applications of solar panels are given below.

• Electricity generation: Solar panels convert sunlight into electricity that powers homes, businesses and industries. This reduces reliance on conventional grid electricity and lowers energy costs.
• Water heating: Solar panels are used in solar water heating systems for residential, commercial and industrial purposes to provide a renewable alternative to gas or electric heaters.
• Solar lighting: Solar-powered lights are used for outdoor applications such as street lights, garden lights and security lighting. These systems store solar energy during the day and use it to power lights at night.
• Portable power: Solar panels are used in portable solar chargers and power banks to charge electronic devices like phones and tablets, that are useful in remote areas or during outdoor activities.
• Industrial process heat: Solar panels are used in industries such as dairy, textiles, paper, chemicals and beverages to generate heat for processes like sterilization, drying, pasteurization and water preheating.
• Agriculture and irrigation: Solar panels power water pumps for irrigation and other agricultural needs to support farming operations in areas without grid access.
• Transportation: Solar panels provide power for transportation infrastructure, including traffic signals, railway signals, bus shelters and electric vehicle charging stations.
• Communication systems: Solar panels are used in remote communication equipment, such as rural telephone systems, relay stations, and GPS units for reliable and off-grid power supply.
• Water distillation and purification: Solar energy is used for distilling and purifying water to make it suitable for drinking and industrial use, in areas with limited freshwater resources.
• Greenhouses: Solar panels are integrated into greenhouses to provide electricity and heat for optimal growing conditions and extending the growing season for crops.
• Public infrastructure: Solar panels are installed on public amenities like benches, bus stops and parking lots to provide lighting, device charging and shelter illumination.
• Space and remote applications: Solar panels supply power to satellites, spacecraft and remote monitoring stations, where conventional power sources are unavailable.

How to install a solar panel?

To install a solar panel, assess your energy needs, evaluate the site for optimal placement and orientation, secure permits and mount the system. You need to fasten the panels for maximum sunlight, wire and ground the components to the inverter, then inspect and test the system before activation.

10 easy steps to install solar panels at home are outlined below.

1. Assess the site: Evaluate your property for the best solar panel location, ideally a south-facing roof with minimal shading and a tilt angle matching your latitude.
2. Obtain permits and approvals: Check local requirements for building and electrical permits, and get utility company approval if needed.
3. Choose the right equipment: Select efficient solar panels and a compatible inverter based on your system’s needs and budget.
4. Install the mounting system: Securely attach mounts to the roof rafters or install ground mounts in sunny areas, positioning them for maximum sunlight.
5. Mount the solar panels: Place and fasten panels onto the mounting system, leaving small gaps for expansion and maintenance.
6. Wire the solar panels: Connect panels in series or parallel as needed, using quality cables and following safety protocols.
7. Connect the inverter: Install the inverter near the main panel, connect DC wires from panels, and link the AC output to your home’s electrical system.
8. Check grounding and safety measures: Ground the system properly and install safety disconnects and fuses as required.
9. Do final inspection and testing: Inspect all connections, test system operation, and verify correct power output.
10. Monitor performance and maintenance: Regularly monitor performance and schedule maintenance like panel cleaning and connection checks.

Prioritize your safety when installing a solar panel by using appropriate personal protective equipment or consult a professional installer. Install the solar panel battery in a cool, ventilated space and connect it to the inverter following the manufacturer’s guidelines.

The flowchart below explains the major workflow for designing and installing solar panels.

What are the benefits of solar panels?

The benefits of solar panels include clean energy production, long-term cost savings, increased property value, minimal maintenance needs, energy independence, and a positive environmental impact by using a renewable energy resource.

The advantages of solar panels are given below.

• Solar panels harness solar energy to provide clean and renewable power, and reduce reliance on fossil fuels.
• Solar panels generate electricity to lower monthly electricity costs and protect against rising energy prices.
• Solar panels have no moving parts, require minimal maintenance, need periodic cleaning and occasional checks, and remain easy and cost-effective to maintain.
• Solar energy eliminates greenhouse gas emissions and air pollutants during operation, combats climate change, and reduces carbon footprint.
• Solar panels increase property value of homes and businesses because buyers look for lower energy bills and sustainability.
• Solar panels paired with battery storage generate independent power and reduce reliance on the grid during outages.
• Solar panels generate electricity in a wide range of climates, from hot deserts to snowy regions, making them viable worldwide.

Which industries benefit the most from solar panels?

The industries that benefit the most from solar panels are listed below.

• Manufacturing industry
• Retail industry
• Agriculture industry
• Warehousing and distribution industry
• Hospitality industry
• Healthcare industry
• Education industry
• Technology industry and data centers
• Automotive (car dealerships) industry
• Self-storage facilities

What is the cost of solar panels?

The cost of solar panels ranges from $24,000 to $36,000 for residential installation after federal tax credits. The national average cost is $29,360 before federal tax credits and incentives and $20,552 after applying the 30% federal tax credit, according to EnergySage data. The average solar panel cost per watt is between $2.50 and $3.30.

Solar system cost depends on the size of the system, the type of panels, how hard it is to install, where you live, available discounts and extra equipment like batteries.

Factors that influence the cost of solar panels are outlined below.

• Solar system size
• Type and efficiency of solar panels
• Location and local market conditions
• Installation complexity
• Additional hardware
• Installer choice
• Purchasing method
• Permits, inspections and approvals
• Material costs
• Market demand and supply

These factors combine to determine the final price you will pay for a solar panel system in the US. Local incentives and rebates, in addition to the federal tax credit, can reduce your net cost.

What is the maintenance cost for solar panels?

The annual maintenance cost for solar panels ranges from $300 to $740, with a national average around $400 to $570 per year for cleaning and inspection. 

Solar panel maintenance costs depend on system size, location and accessibility, while occasional repairs or inverter replacement increase expenses. Regular maintenance helps maximize efficiency and lifespan of the solar system.

What to know before getting solar panels?

Things to know before getting solar panels are outlined below.

• Assess your roof’s condition, age and orientation, as repairs are needed before solar panel installation.
• Analyze your energy needs to size the solar system correctly and check your annual electricity usage.
• Make sure your roof or site gets minimal shade and has optimal sun exposure for solar efficiency.
• Check local solar panel regulations, permits and possible incentives or net metering eligibility.
• Consider your budget, financing options and warranties for solar panels and installation.
• Choose reputable solar panel installers and high-quality equipment for long-term performance.

How much do solar panels reduce carbon emissions?

Solar panels emit about 12 times less CO₂ than natural gas and 20 times less than coal per kilowatt-hour, over their lifetime. Solar panels reduce carbon emissions by replacing fossil fuel electricity with clean energy.

An average residential solar panel system producing 10,000 kWh per year reduces about 8,460 pounds (3.8 metric tons) of CO2 annually. A rooftop solar system can offset around 200,000 pounds (90 metric tons) of CO2 emissions over a 25-year lifespan. This represents up to 80% lower carbon emissions compared to fossil fuels.

Do solar panels reduce fossil fuel usage?

Yes, solar panels reduce fossil fuel usage by generating electricity from sunlight. Solar panels decrease the need for energy from coal, oil and natural gas, leading to lower greenhouse gas emissions and less air pollution. 

Widespread adoption of solar energy offsets fossil fuel consumption and helps combat climate change.

Is solar energy renewable?

Yes, solar energy is renewable because it comes from the sun, which provides a continuous and virtually inexhaustible source of energy.

Solar energy does not deplete over time, unlike fossil fuels, and can be harnessed as long as the sun shines, making it a sustainable and environmentally friendly energy option.

What is green energy?

Green energy or renewable energy is the power generated from natural sources that are renewable and environmentally friendly, such as sunlight, wind, water and geothermal heat. 

Renewable energy produces little or no pollution or greenhouse gases which makes it a sustainable and clean alternative for meeting energy needs while protecting the environment.

What is the 120% rule in solar panel installation?

The 120% rule in solar panel installation states that the combined amperage of the main breaker and the solar system’s breaker must not exceed 120% of the electrical panel’s busbar rating, as defined by the National Electrical Code (NEC). 

The 120% rule makes sure the panel is not overloaded to maintain safety and compliance.

Are solar panels worth it?

Yes, solar panels are worth it due to long-term savings on electricity bills, increased property value and reduced carbon footprint. 

The upfront cost of solar panels can be high, but they experience price drops and improvements in efficiency. Solar panel investments achieve payback periods ranging from 4 to 10 years, after which energy is usually free.

How long do solar panels last?

Solar panels last for 25 to 30 years, maintaining most of their efficiency during this period before gradually declining in output. 

Some high-quality solar panels can function for up to 40 years, though at reduced performance. Regular maintenance and proper installation can help extend the lifespan of solar panels further.