How Do Solar Panels Work?

Understanding how a solar panel works is a simple idea with a complex execution. The use of a solar panel in an array is pretty straight forward. The sun hits the solar panels, and the ultraviolet (UV) light wavelengths converts into usable electricity.

However, how the light from the sun converts into electricity is a bit more complicated. Knowledge is king when looking into solar, which is why Go Solar Group wants to make sure interested parties understand how solar panels work.

How Do Solar Panels Work? Residential Solar Power for Beginners

Just like other industries, solar experts have solar-related jargon that few outside the industry understand. Solar terms, like inverter, kilowatt, power grid, and monocrystalline, aren’t typically used outside of solar and other energy-related industries.

As a newbie to solar, it is helpful to know the basics. Understanding the basic idea behind how solar works helps customers feel comfortable considering solar for their homes and comparing solar companies.

The Epicenter of Solar Power – the Sun

Just like everything else in our galaxy, solar panels begin with the sun. This gigantic mass of energy fuses hydrogen into helium. As a result, it emits different wavelengths of light on the earth.

Of these light wavelengths, 99 percent are in the form of visible light, which are composed of ultraviolet rays and infrared rays. UV rays have shorter wavelengths and therefore are more energetic than the other rays emitted from the sun.

Solar panels capture these active rays and convert them into electricity. The sun lights up our planet, and with solar panels, it can also light up our lives.

How Solar Panels Generate Electricity

Each residential solar panel has roughly 60 cells. Each cell has electrons that create an interplay of electrical motility when the photons in UV rays hit them, which produces an electric current. 

While this is the basics of how solar panels generate electricity, remember, there are many determinants of a solar panel's ability to produce energy for homes, including, but not limited to, roof space. Solar panel function isn't the only aspect of solar worth assessing when considering rooftop solar.

Types of Solar Panels

Solar panel comparisons aren’t as straightforward as some products, like cars, when it comes to prospects’ understanding. Because most need a car at some point, the differentiating components in a car are often well known. For instance, families who are looking, know they need space, while a commuter is looking for good gas mileage.

However, when it comes to solar panels and the manufactured materials, these items rarely mean anything to homeowners considering rooftop solar. While each solar panel type has several differences, efficiency is what sets them apart for the customer. Determining the efficiency of solar panel types is mostly about the electrons’ ability to potentiate energy within the solar cell.

Monocrystalline Solar Panels

If we hyphenate the word monocrystalline, it’s easier to deduce the meaning of this term. Mono-crystalline means one crystal.

The solid crystals in monocrystalline solar panels give the electrons more movement within the panel, making them more efficient. Most crystalline solar panels use silicon as this crystal. These solar panels are manufactured by melting the silicon and dipping a crystal of silicon into the liquid, forming an ingot. The ingots slice into silicon wafers, which form the square-like shapes in the solar panel.

Polycrystalline Solar Panels (Also Referred to as Multicrystalline Solar Panels)

In the same steps as we underwent with monocrystalline solar panels above, hyphenating the word polycrystalline and multi-crystalline (poly-crystalline and multi-crystalline) reveals these kinds of solar panels are made by multiple crystals or crystalline processes.

Although the manufacturing for polycrystalline panels is similar to monocrystalline in that they each rely on melted silica, The difference is that the silicon is allowed to cool, and the panels are melted together.

These panels are slightly less efficient and cheaper to make than monocrystalline panels and are therefore the main product that most solar companies use. Melting many fragments of silica together as solar panel manufacturers do when making polycrystalline panels, makes for less room for the electrons to move fully throughout the cell of the panel, creating a less efficient form of solar energy production for homeowners, even in sunnier cities, like Reno, Nevada.

Amorphous Thin-film Solar Panels

Thin-film panel creation involves putting a semiconductor, like silicon, onto glass or another like material, also known as a substrate. These solar panels have the lowest efficiency.

If a homeowner has a lot of space, these might be a good option. However, typically thin-film solar panels are not an ideal solution for home solar installations.

Residential Solar Installation can take longer with thin-film solar panels

Using these kinds of solar panels can sometimes increase the cost of installation. Most solar installers only handle more relevant and modern solar products, which brings us to our next point regarding innovation and thin-film solar panels.

Amorphous Panels are Past Their Prime and Abandoned by Innovators in the Solar Energy Field

Thin-film solar panels received recognition and where applied to solar projects in the 1990s. However, as solar technology has continued to advance, this solar panel type hasn't been able to compete. While thin-film solar panels are still popular for smaller technologies, such as calculators, they are not ideal for the high electricity needs of the 21st-century residential solar energy landscape.

Current Solar Cell Technology Underway: Perovskite and Organic

Perovskite technology has received a lot of hype lately. In lab conditions, this technology has reached a cell performance of 22 percent. NREL has many scientists working on improving perovskite and organic-cell technologies, but they are still in the testing stages.

How do Solar Panels Convert Solar Energy into Electrical Energy? The PV/Solar Inverter

Without the inverter, solar panels would be useless. The inverter turns direct current (DC) from the solar panels into alternating current (AC), so it is usable in the home. It connects the solar panels to the home (and battery backup where applicable) and, ultimately, the power grid. 

On a more technical level, solar panels sometimes have electronics inserted into their photovoltaic (PV) structure to facilitate a maximum power point tracking (MPPT) mechanism. This mechanism ensures electrical output every five to ten minutes, guiding the panels’ production. 

Solar panels are a small component of a complex process. The various types of inverters play nuanced and distinct roles in turning direct current absorbed by solar panels into alternating current.

String Inverters

A string inverter takes the DC from an array of solar panels and transforms it into AC. The drawback of a string inverter is how shade impacts its production. 

The Best Conditions for String Inverters 

Homes that have full sun exposure are best for string inverters. Cutting down or trimming the trees around the home may be enough for a solar service team to justify installing a string inverter. 

String inverters work well with solar panels installed in blocks, such as four rows with four solar panels per row, in one location on the roof. It is best if the roof is unobstructed with a large surface area.

To learn more about monitoring an existing SMA string inverter, see this video with one of our solar technicians explaining the SMA set up.

Central Inverter

Central PV inverters are a larger version of a string inverter. Their design allows them to support more strings of solar panels. 

Uses for Central Inverters 

These inverters are best for commercial-grade solar installs. They require less wiring and conduit connectivity. However, they also need a combiner box. 

Micro-Inverters

Microinverters are mini inverters installed on the back of each solar panel. They convert the DC from the solar panel to AC at the solar panel, which is different from a string inverter, which converts the current further along in the process.

How Microinverters Handle Shade

Microinverters manage each solar panel individually, which decreases the impact that shade has one production. It also makes adding solar panels later easier.

Microinverter Monitoring

Microinverters, monitor each solar panel. Allowing solar installation technicians to monitor the system’s production remotely and resolve any inverter issues that arise.

Power Optimizers and String Inverters: A Newfound Trend

Some string inverters have DC power optimizers. While a typical string inverter, like an SMA Sunny Boy, will be more efficient at the peak sunlight hours of any given day, an optimized string inverter, like the SolarEdge, will provide solar homeowners consistent power throughout the day.

Optimized string inverters have a power optimizer under each solar module. These devices increase the DC before sending it to the inverter, which improves the power efficiency of the residential solar array.

Optimized String Inverters and Shade

The SolarEdge inverter, which Go Solar Group uses, is an Israeli-engineered string inverter with optimizers. The biggest pro of using the SolarEdge inverter is the solar panels in the shade have less impact on the efficiency of the array than a solar panel connected to a typical string inverter.

Using Optimized String Inverters on Homes with Limited Space 

Because the strings on an optimized string inverter can be smaller, this option works well for rooftops with limited space. Short panel strings allow the installer to take advantage of multiple smaller areas.  

Maintenance of Optimized String Inverters

Optimized string inverters have an inverter installed at the ground level, which means most inverter problems don't require installers to go on the roof. Power optimizers on the back of the solar panels also allow solar installers to monitor each solar panel, so they can determine the cause of an issue without having to test every solar panel.

Battery Backup: How to Get the Most out of Declining Net Metering Returns

Most solar homeowners don't purchase battery backup because they have great net metering rates that cover the cost of the power pulled off the grid when the sun isn't out. However, those that want power when the grid is down or don't have a great net metering rate should consider battery backup.

Battery backup is a battery that can be charged by the excess energy that a solar array produces. Having enough battery back up to meet all of a homeowner's energy needs is ideal, but unfortunately, this isn't an option for everyone.

These are several battery backup options on the market. They range from portable batteries to home batteries. Which one to get depends on the customer's needs and priorities. 

Off-grid Solar and Home Batteries 

Home batteries are the best option for people that need an off-grid system. It is close to the same price or slightly cheaper than having power lines brought to a remote location, and it provides people with the tools to become self-reliant.

Unfortunately, off-grid solar is not an affordable option for the average solar customer. Battery backup technology is progressing, and more options at competitive prices will continue to be available, but currently, Tesla is leading the way.

Emergency Battery Backup 

Until home batteries can catch up to consumer needs and price range, there is another option to help solar homeowners when the power goes out. Emergency battery backup allows individuals to power essential items when the grid is down. Go Solar Group offers a home battery and several emergency battery backup options.  

Battery Backup and Solar Array Compatibility 

Battery Backup provides security in an emergency. Whether or not the solar customer has decided to get battery backup, it is good to make sure that the system is compatible with battery backup.

Not all photovoltaic systems are compatible with battery backup. When battery backup prices go down, and they will go down, customers that have checked for compatibility can easily take advantage of the opportunity.

The Net Meter and Net Meter Number

A net meter is a device that measures the electricity put on and taken off of the power grid. The power company installs the net meter after the homeowner signs their net metering agreement and installs their solar array.

If off-grid solar is not a good fit, the electric company will install a net meter. Because home battery technology is still evolving into a more affordable option, most people sign up for a net metering agreement.

This agreement allows the utility's customers to use their excess solar power to offset the electricity pulled from the grid at night. The power company decides the worth of the solar-generated electricity put onto the power grid by the customer. These rates often determine how big of a system homeowners install and what forms of energy storage they choose.

The Power Grid

A typical home connects to the grid, but in a very different and less efficient way than homes that are powered by solar. The power grid is an electrical highway composed of power lines and collection towers that connect our homes to large power plants. Most of these power plants are coal-powered, though some rely on other fuel sources such as natural gas.

Solar and Battery Backup's Relationship with the Grid

Those that don't have battery backup stay connected because they don't have another power source at night or when inclement weather occurs. Those with home batteries that could provide enough power to keep a home running at night, often stay connected because it adds another layer of security.

How Do Solar Panels Work within the Broader Residential Solar Process?

While converting solar energy into solar power is a complicated process, those looking into solar, don't need to know all the gritty details of how a solar array works. They do, however, need to understand the basics of residential solar, so they know what to look for in a solar array. 

Those looking at residential solar have a couple of things they need to keep in mind. First, they need to make sure that the solar array is going to meet their energy needs. Secondly, they need to have a backup-power option picked. 

Sizing Solar Correctly for a Home 

Each home has different energy needs. One family may have large energy consumption items, such as a hot tub or an aquarium, while another family in the same size home is hardly home to turn on the lights.

It is for this reason that solar estimates use the home's energy use, also known as usage, to determine the size of solar array a home needs. A correctly sized system is vital to a quality solar experience. 

A correctly sized system prevents homeowners from being charged for energy that the array could have produced or from producing more than the home uses.  

The Reason Solar Arrays Need Battery Backup

After DC from the solar panels converts into AC, it can power a home. However, most use more electricity at night when the sun is down. Without the sun, solar panels don't have any UV radiation to absorb, which means it doesn't have anything to convert into electricity. 

Thankfully there are a couple of solutions to this problem, one of which is battery backup

Designing a Solar Panel System: Space, Production and Projections 

 

While determining the usage of the home is the first step, it isn't the only step that goes into the design of a solar array. A properly sized system has a couple of factors that go into it. 

Some of these elements include determining the available space, possible shading issues, power needs of the home, calculating solar production, system type, and projected factors. Below we have gone through the basics of what goes into configuring a system.

Available Space for Residential Solar 

Determining the amount of space a home has influences the size and type of array the homeowner can install. Homes that don't have adequate unshaded space are not a good fit for solar. If the roof doesn't have enough space, it may be a good idea to consider a ground mount

The Amount of Space Needed  

On average residential solar panels are 5.4 feet by 3.3 feet, which means each solar panel needs about 18 square feet of unshaded space. The number of solar panels a home needs depends on the wattage of the modules, home usage, and the production offset of the array. 

The Impact of Shade on Solar Panel Placement 

One of the determining factors of solar panel placement is shade. Shaded solar panels don't work as well. Homeowners with large trees that shade the roof may want to consider trimming them to optimize their roof for solar.  

Current Power Use and Estimated Solar Production

To properly size a solar array, the home's typical energy use needs to be determined. That energy usage then needs to be matched by accurate solar production. 

Home Usage 

Energy usage is the amount of electricity that a home uses. It is often recorded as energy usage at the end of the monthly utility bill and measured in watts or kilowatt-hours (kWh).  

Production Metrics and Important Units of Measurement for Solar Panels

After determining a home's annual energy, PV designers match it with solar production. To match the production to the consumption, they use a slew of terms and math. Common solar terms include kWh, voltage, amperage, wattage, net metering, and peak solar production hours.

Kilowatt Hours

(kilowatts) (number of hours running) = Kilowatt Hours

Commonly expressed as KWH or kWh, kilowatt-hours are a measurement for electricity and solar production. Although the term may seem confusing, it is only a verbal expression of a simple multiplication problem.

An example of this type of equation in action would be finding the kilowatt-hours for a 7,000-watt (7 kW) rooftop solar array that is producing solar energy for 8 hours on one particular day. After doing the multiplication problem above, we find that the total number of kilowatt-hours (kWh) is 56.

Voltage 

Energy/ Charge = Voltage

Voltage is the pressure of an electrical current. Energy provides voltage, which is necessary for the flow of an electrical current. Symbols often used for voltage include V and U. 

Amperage

Wattage/ Voltage = Amperage

Amperage is the strength of an electrical current measured in amperes. Essentially, it is the amount of electrical current flowing through a conduit or system. The product of voltage and amperage is the amount of wattage. It only takes .75 amps to stop someone’s heart.

Wattage

(voltage)(amperage) = wattage.

For solar installation technicians to do their jobs correctly, they must be able to configure the system to maximize wattage, which is the total amount of electricity conducted. Each solar panel on a solar-powered home typically has 250 to 310 watts.

Peak Solar Production Hours

Unfortunately, not every hour of the day throughout the year provides that same amount of ultraviolet radiation. There are between three to five peak hours per day in the united states.

The peak production hours for an area depends on the intensity of light produced during the day. These hours are when the sun is highest in the sky. To find the peak hours for a specific area, use an isolation map.

Electronics perform best when allowed to cool off, and solar panels are no exception. Because they are allowed to cool, solar panels are more efficient on a clear-cool day than on a cloudless hot one. However, because days are longer, it is typical to have more production hours during the summer, and in areas closer to the equator.

Projected Solar Elements that Determine System Design

Other considerations that go into solar array design include the projected weather conditions and the longevity of the array.  

Weather Conditions 

matching the necessary size of a solar array with the usage of the home comes from historical weather patterns and how much sunlight the solar panels can absorb in an average year.

Will my solar panels work in the wintertime or with snow?

In the winter, snow is a concern for many. When snow covers solar panels, the solar panels won’t produce as much electricity. However, they will often produce enough to melt the snow. 

If there isn't a large build-up of snow, the solar panels heat up and melt the snow as they absorb sunlight throughout the day. However, when thick, the snow won't melt in a day. It would be hard for any UV light to get through the snow and to the solar panels. 

If the build-up of snow is too thick, it is time to invest in a roof rake. These devices allow homeowners to pull the snow off the roof without needing to get on the roof. It's important to make sure the roof rake has rollers to protect the roof and solar panels from possible damage.

The longevity of the Array 

An array is a 25-year investment because solar panel warranties are typically over this time frame. While solar panels have and do last longer, all electrical equipment becomes less efficient the older it is. 

Environmental Considerations on How Solar Panels Work

While solar panels generate green energy, many are concerned about the environmental impact of solar panel manufacturing processes. Here are some things to consider when trying to find an environmentally conscious solar panel provider.

Which Solar Panel Manufacturers Can I trust to Keep Solar Energy Green?

Tons of solar panel manufacturers are popping up across the globe. One of the main drivers for solar panel installation is the price. However, super cheap solar panels often come at a high environmental cost. Air and land quality around solar power plants that take short cuts are often low.  

Using solar panels is clean and helps our air stay clear, but if short cuts were taken during production, it can decrease these benefits. For those that want solar because they care about the environment, we highly recommend looking at the solar panel manufacturer.

One way to do this is to look at Silicon Valley Toxics Coalition's scorecard. These scorecards help people better determine how environmentally friendly different solar panel manufacturers are. 

Is There Waste from Solar Panel Production?

Although cleaner than coal and natural gas the process for producing panels is not a clean one. Chemicals such as cadmium telluride, copper indium selenide, cadmium gallium( ii) selenide, copper indium gallium (di) selenide, hexafluoroethane lead, polyvinyl fluoride, crystalline silicon and silicon tetrachloride all take part at some point in the process.

Toxic sludge is created when these metals and toxins are removed from the water used to manufacture panels. If the manufacturer doesn’t have waste treatment equipment this waste is transported to an approved dump.

The good news is that light has been shined on this topic and as a result, more consideration is being given to waste management. Going with a manufacturer that has a high solar scorecard means you are going with a company that is being responsible with the waste produced and trying to produce as little waste as possible.

A study done by FLASH and funded by Technology Foundation STW found that in order to avoid an energy sink we need to make sure that we can recoup energy waste faster than we are creating it. In their results in this study they made this statement:

“Energy pay-back times drop from around 5 years in 1992 to around just under 1 year for poly-Si and just over 1 year for mono-Si PV systems currently.”

This means that although there is waste involved in the process of creating panels it is improving. We have to take into account that solar has only been here since the 70s and therefore is still relatively new. The fact that we can recoup waste output within a year of solar array use is extremely impressive.

Recycling Solar Panels

Because solar panels last at least 25 years most of the panels that have been produced haven’t gotten to the point where they need to be recycled, but they will. As a result, efforts have been made so that these panels can be recycled correctly.

If we don’t do our part to make sure that our panels are disposed of properly toxic substances from these panels could prove to be a huge hindrance to renewable energy’s mission. Right now Europe is taking the lead but, as time goes on recycling panels will be mainstream.

As of right now, technologies have been created to recycle 96 percent of PV waste. This is just the beginning of where solar recycling is headed.

Solar Energy Facts, FAQs & Information

What Do Solar Power Plants Do?

When it comes to how solar energy is generated from the sun, there’s more to generating solar electricity than at-home solar systems entail, and that’s where solar power plants come in. Although Go Solar Group does not specialize in any services or products tailored to solar power plants, we know a lot about them and where they fit in the solar energy landscape. Solar power plants can generally be divided into two distinct categories: photovoltaic plants and solar thermal power plants.

The latter of these two makes electricity by concentrating the photoelectric energy of the sun, and the prior of these two kinds of power plants is the kind homeowners put on their rooftops every day, and in increasingly large numbers – residential solar.

This means that every residence with rooftop solar is technically a power plant, which is a pretty cool concept to think about!

How Does Solar Power Work at Night?

Solar panels use the light waves from ultraviolet rays that the sun produces to excite the electrons in the cells of a solar panel and create a current. At night, however, these specific light wavelengths aren’t there to get the electrons moving and create a charge.

Moon Power and Lunar Panels: Fact or Fiction?

The moon reflects the light that comes from the sun to the earth. These wavelengths are longer than the ultraviolet rays that are used by the sun’s direct light. Longer wavelengths do not provide enough electron movement for the panels to power anything.

Unfortunately, panels have not as of yet been created to effectively use light reflected from the moon or produced by the stars light-years away. For now, moon/lunar powered panels are still science fiction.

Salt of The Earth: Is this the key to Unlock Solar Nightlife?

In 2009, articles started to come out with a new plausible solution to using solar power at night. Scientists found that because salt has a high melting temperature, it was perfect for storing heat.

The Crescent Dunes Solar Energy Project in Nevada uses molten salt heated by the sun during the day. This superheated salt is then used to power a turbine at night or when the weather is not conducive to solar power.

This idea is wonderful and is proving to be a much cheaper option than the lithium-ion batteries that are being used to store solar power. The problem is that this process requires a lot of space and the technology hasn’t been converted to a usable format for homeowners. Only time will tell if there is relevant progress to be made here.

Financial Considerations: How the Way Your Solar Panels Work Impacts the Rate of Return

When it comes to making large additions to your home all financial aspects need to be considered. Getting solar to replace your current power provider for the next 25 plus years is a large addition.

People need to know what to expect so that they know when they have a good deal. Using a solar savings calculator will help you get started. Here are a couple of other things to keep in mind while considering finances.

Know that the Biggest Solar Installers Usually Aren’t the Best Options

The National Renewable Energy Laboratory did a study on the relationship between installer pricing and firm size in April of 2017. It was found that large firms are more likely to aline prices with their brand’s reputation. A smaller firm, on the other hand, is more likely to cite fair prices for the customer.

This equates to large installers being about $2,000 to $5,000 more expensive than a smaller one. This being said this doesn’t mean you should completely write them off as an option. Just make sure you are looking at all the aspects of the product you are purchasing before deciding to go with the name brand that everyone knows and uses.

Solar Production and Service Warranties: An Important Consideration for Homeowners

Warranties vary depending on the manufacture of the product. There are a couple of different types of warranties that typically come with a solar installation.

A solar installation normally has a 10-year warranty. This warranty covers certain materials that are damaged within the first 10 years of use.

Production warranties typically last for about 25 years. These warranties guarantee a certain percentage of product production. Most guarantee that your panels will still produce between 80% to 90% of their original capacity in the first 25 years of use.

Making sure that your manufacturer has good warranties will ensure that your investment will last in the long run. Go Solar Group uses Axitec panels these panels have a 15-year product warranty and a 25-year production warranty of 85%.

Advantages and Disadvantages of Solar Power for Homeowners

No matter what you are looking into there will be some pros and cons to it. For all of the major decisions, Benjamin Franklin had to make he would put together a pros and cons list. His list helped him to properly weigh what was the best decision.  We have put together some of the pros and cons that we have seen in solar power for you to analyze for yourself.

Advantages of Solar Power for Homeowners

  1. Freedom from reliance on coal power.
  2. 25+ years of no or minimal electric bills
  3. Emergency preparedness
  4. Several Emergency battery back-up options( with Go Solar Group)
  5. Providing micro-loans to motivated Africans ( with Go Solar Group)
  6. Federal and state incentive programs designed to make solar affordable.
  7. Increases financial security
  8. Increases the value of your home.
  9. Technological advancement is continuing to make manufacturing a cleaner process.
  10. Process in place to make panel recycling part of the future.
  11. Power backup options are available and continuing to advance.
  12. If you get a loan for solar there is no down payment.
  13. If you pay cash for solar you will most likely get a discount on the whole system.
  14. Referring friends that want solar can decrease how much you end up paying for your system.
  15. Your solar array will decrease your carbon footprint while in use.

Disadvantages of Solar Power for Homeowners

  1. Currently, the recycling of old photovoltaic systems is not very high.
  2. Not all of the panel manufacturers report their energy efficiency.
  3. Not all Solar panel companies install their systems. (Go Solar Group does)
  4. Getting solar will most likely require a loan of some sort.
  5. Solar arrays do not produce energy at night.
  6. If you live in an area that doesn’t have a net metering program of some sort you may find it more difficult to get solar.
  7. Buying battery backup for your home is expensive right now.
  8. Not all solar arrays are equipped to have battery backup added to them. (All of Go Solar’s are)
  9. Solar industry growth could cause an energy sink if unchecked.
  10. Having to clear heavy snow off of your panels. (if you live in a colder climate)

We strongly encourage people that are interested in solar to consider all the pros and cons of solar as an industry and individual solar companies. Getting all the facts and comparing them will help you to make the best decision possible.

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