A Beginner’s Guide to Solar Panels
September 10, 2021
If you’re new to solar panels, both the technology and the installation process can seem complex. That’s why we’ve put together this beginner’s guide to solar panels.
We’ll cover the basics, as well as delve deeper into what you need to know about going solar and understanding solar panels.
What Are Solar Panels?
A solar panel is a collection of solar photovoltaic (PV) cells that absorb sunlight and convert it into electricity.
For most installations, technicians connect multiple solar panels to create a solar array. The components of a solar panel include the solar cells, glass casing, backsheet, metal frame and cabling to transmit electricity.
A Brief History of Solar Electric Power Technology
Thomas Edison developed direct current (DC) electricity, a circuit in which electrons flow in a single direction. DC electricity works similar to a battery powering a lightbulb: the standard in the U.S. until the 1880s.
Nikola Tesla believed alternating current (AC) electricity was a better solution because scientists could easily convert it to different voltages. This made AC electricity easier to transport over long distances.
The tide began to turn when George Westinghouse chose Tesla’s technology for the Chicago World’s Fair in 1893. AC electricity became the standard for the electric power grid in the U.S.
In fact, Tesla, Inc. is now the name of a company Elon Musk founded. The company uses AC electricity for its energy-efficient vehicles and solar technologies.
The sun’s energy is critical to all life on Earth, and humans have always found ways to harness its energy. As we know it today, solar PV technology has been around since Bell Labs created the first silicon cell in 1954. By 1960, solar cell efficiency had improved from 4% to 14%.
The solar energy industry continued to expand through the following decades. Solar technology improved because of research and development investments and solar interconnection regulatory frameworks that federal and state governments established. Both included policies such as tax credits, rebates and renewable energy standards.
[Related: Guide to Federal Solar Panel Incentives]
By 1999, cumulative installed solar capacity had reached 1,000 megawatts (MW). In 2000, while astronauts installed solar panels on the International Space Station, Sandia Laboratories invented the modern inverter. This inverter significantly improved system safety during power outages.
In the decades since, solar panel costs have fallen dramatically for two main reasons:
- Solar panel design innovations
- Racking system improvements that make installations easier and faster to complete
According to Statista, worldwide net solar PV power generation increased from 1,288 MW to 633,700 MW from 2000 to 2019.
Solar technology innovation will continue to advance. In turn, these advancements will make it easier for average people to acquire highly efficient panels. New systems also will likely focus on materials beyond or in addition to silicon.
For example, recent breakthroughs with perovskites may lead to higher-efficiency panels and the ability to coat surfaces with solar as easily as painting.
Given that the amount of sunlight reaching Earth hourly is enough to power the globe’s entire electricity needs for a year, solar power has practically unlimited potential.
Types of Solar Panels
Solar panel manufacturers use various solar cells and solar technologies, but the most common solar cell material is silicon (Si). Silicon is a key component of different solar panel types, each with unique advantages and disadvantages. But depending on how you use solar energy, knowing the benefits of emerging solar cell technologies using additional techniques or materials is important.
Manufacturers make solar cells from silicon and build them with a positive and negative layer that creates an electric field, similar to a battery. Most solar panels are made from either monocrystalline or polycrystalline silicon.
- Average efficiency range: Its average efficiency is 15% to 24%.
- How it’s made: Wafers are cut from a single crystal block of highly pure silicon with cells that form a distinctive shape.
- Appearance: Monocrystalline cells have a uniform appearance of small black squares with notched corners. Solar panels made with these solar cells typically have a white or black backsheet.
- Features: These panels conduct electricity more efficiently and perform better in high temperatures and shade, which helps them generate more solar power than other panels of the same size. Because this technology is the most established, it also has a proven track record of durability. However, they’re the most expensive panels and generate more waste during the manufacturing process.
Polycrystalline (or Multicrystalline) Silicon
- Average efficiency range: Its average efficiency is 12% to 16%.
- How it’s made: Fragments from multiple silicon crystals are heated, melted and compressed to form a large solar cell.
- Appearance: These solar cells have a multifaceted, nonuniform, gemlike surface and are usually blue in color.
- Features: Polycrystalline solar panels are less efficient but less expensive, and they’re less wasteful during the silicon manufacturing process. These are the most prevalent solar panels globally, primarily due to a production boom in China over the past few years. Additionally, a glass casing typically made from antireflective glass (to increase sunlight absorption and improve solar panel efficiency) covers these solar cells, and a backsheet protects them.
Thin-Film Solar Panels
- Average efficiency range: Their average efficiency is 7% to 13%.
- How they’re made: A thin layer of PV material or combination of materials, such as noncrystalline amorphous silicon (a-Si), cadmium telluride (CdTe) or copper indium gallium selenide (CIGS), is deposited onto a surface such as glass, plastic or metal.
- Appearance: Thin-film silicon panels are generally larger and have a uniform, solid black appearance.
- Features: These panels use newer commercially available technology, and they’re suitable for homes or businesses where space isn’t an issue. Thin-film solar panels are low cost, easy to produce, flexible, portable and lightweight. However, they’re less durable and have a shorter life span.
Silicon Solar Panels Summary
|Silicon Cell Type||Efficiency||Key Advantages||Key Disadvantages|
|Monocrystalline||15%-24%||Most efficient, durable, proven, aesthetically pleasing||Highest cost|
|Polycrystalline||12%-16%||Lower cost, improved efficiencies||Lower efficiency, poorer aesthetics|
|Thin-Film||7%-13%||Low cost, easy to make, best aesthetics||Low efficiency, less proven|
Other Solar Cell Technologies
Multijunction solar cells are based on the same principles as silicon-based cells. However, manufacturers design them with multiple layers of different semiconductors that can capture more of the light spectrum.
Heterojunction With Intrinsic Thin-Layer (Hit)
HIT solar cells use thin intrinsic amorphous silicon layers on the top and bottom surfaces of a crystalline silicon wafer. Interestingly, Panasonic invented them.
These solar cells are made from perovskite, part of a family of crystals named after Russian geologist Lev Perovski. Perovskites are less stable than silicon, but they can achieve solar energy efficiency similar to monocrystalline cells. They also do so at a lower cost.
This promising technology is not yet commercially available. However, manufacturers could soon apply it as a film over existing silicon-based cells to boost standard solar panel efficiency. Oxford PV is piloting production of this technology in Germany.
[Related: Who Makes the Best Solar Panels]
How Solar Panels Work
Solar panel system functions are simpler than people may think.
The sun releases tiny packets of energy called photons. These photons travel to Earth, and sunlight hits panels in varying amounts depending on their orientation and location.
Solar panels then convert the sun’s energy (photons) into electricity when it strikes a solar cell by knocking electrons loose from their atoms. These electrons then flow through a conduit to an inverter.
Inverters convert that electrical energy from DC to AC. Of course, AC electricity is what we use for lights, appliances and devices (anything you plug into a wall outlet). AC electricity then flows to your electricity meter to power your home or to your city’s grid.
When the sun isn’t shining and panels don’t have any solar energy to convert to electricity, the electric grid continues to power your home. If your solar panel system generates more electricity than you use at any given moment, that electricity flows from your home back into the grid. Many utility companies have net metering policies that credit you for the excess solar power you generate.
[Related: How Do Solar Panels Work?]
Types of Inverters
Another key part of a solar electric power system is inverter technology. There are three main types of inverters:
- String inverter: The DC electricity from your solar system is routed through a single inverter, which then connects to your electric panel. String inverters are the least expensive inverter solution, but they make assessing performance issues with individual panels difficult.
- Microinverter: Microinverters attach to the backs of each panel. They tend to be more expensive, but they enable panel-level monitoring.
- Hybrid inverter: This offers a middle-ground solution that combines a centralized inverter with power optimizers on each panel. Power optimizers are a DC-to-DC converter technology that improves performance by tuning each panel’s output to match the inverter. Hybrid inverter technology offers some of the same system performance benefits as microinverters — but at a lower cost.
Inverters provide additional features beyond converting electric currents for our use. These features include ground fault protection, as well as insights into energy production and maximum power point tracking.
[Related: Who Makes the Best Solar Panels]
What Direction Should Solar Panels Face?
Ideally, solar panels mounted on a standard pitch roof should face south, allowing for maximum production. If your panels face southeast or southwest, you can expect them to generate roughly 10% less power. Nonetheless, that still may be enough to power your home.
If you can’t install your solar panels facing south, consider these alternatives:
- Installing panels facing a different direction: Panels facing west or southwest may be able to produce enough energy to fully or partially power your home. Your installation professional can make this determination.
- Installing more panels: Solar panels that don’t face south won’t receive as much direct sunlight, but you may be able to compensate by using more panels.
- Installing your panels on the ground or wall: It’s a common misconception that you can install solar panels on your roof only. If you don’t like the appearance or if your roof doesn’t face south, you can install your system on a south-facing wall that receives direct sunlight. You can opt for a ground-mounted system as long as you have the space for it, and some people prefer this option. It’s cheaper to install and maintain than a wall-mounted system.
Check out our easy-to-use solar potential calculator to find an estimate of your home’s solar potential. An installation professional can also use technology to track how the sun hits your home. That knowledge lets them install your panels facing the right direction at the right tilt.
When Should You Go Solar?
Going solar is a smart life decision at any time. That said, installing your solar panel system right before summer reaps you the most benefits.
You can potentially keep your home up to 5 degrees Fahrenheit cooler by shading your roof. Naturally, that’s especially helpful over the warm summer months — it means a 38% reduction of your home’s annual cooling load.
Transitioning to solar power not only saves you money on your electricity bill but also can help you keep your lights on when the summer heat climbs — and outages are more likely.
Because electricity rates can be volatile over the summer, it’s smart to go solar before the hot season starts. To be clear, anytime is a good time to go solar.
Find a Trustworthy Solar Installer To Help You Go Solar
We hope our beginner’s guide to solar panels helps you feel more comfortable with solar power’s many moving parts.
Don’t let anything stand between you and installing the system of your dreams. An experienced, trustworthy solar panel installer can help you harness the sun’s power no matter where you live or which direction your roof faces.