How do solar panels work? Everything you need to know
From fossil fuels to hydro, most energy begins with the sun. Solar panels harvest power directly from this incredible resource by converting photons into electricity.
Solar panels can power an incredible range of energy applications. Solar generation can provide power for a remote cabin and keep the lights on in the International Space Station, but we all know solar isn’t just for providing remote power needs.
As solar panels have gone down in price, they’ve become a competitive energy option for homes and businesses. Aside from saving some green, going solar is one of the best ways a consumer can green their energy consumption. Solar panels provide extensive environmental benefits, potentially eliminating dependence on carbon-emitting fossil fuels and improving air quality.
For these reasons, millions of homes and businesses have “gone solar.” Here are just a few interesting examples:
- A Rhode Island home installed a 9.5 kWh system in 2016. The array saves the homeowners 3,845 a year, and will pay for itself by 2022.
- California’s Lake County Sanitation District installed nearly 9,500 solar panels in 2008 to power three sanitation facilities. The project is on track to save taxpayers 5 million over the system’s 20-year lifespan, and provides enough power to decrease grid electricity loads from the plant by 90 percent.
- Vintage Wine Estates in California’s Napa Valley installed a 945 kWh solar system that will provide 10 million in energy savings over 30 years.
How Do Solar Panels Work?
Here’s a rundown of what happens from sun-to-plug in a photovoltaic system :
- Photovoltaic cells absorb photons from the sun and converts them to direct current (DC) electricity
- An inverter transforms direct current to alternate current (AC) to power appliances
- AC current travels via wire to a breaker box for distribution throughout the building
- Any unused electricity flows back into the utility grid or into solar energy storage
Understanding Solar Energy
Solar energy is radiant light and heat emitted from the sun. It’s harvested in myriad ways, such as photosynthesis in plants and solar heating.
Solar energy for electrical production relies on subatomic particles called photons. These particles start their journey in the center of the sun, traveling through the various layers before careening into space. A journey from the center of the sun to the surface can take anywhere between 100,000 to 50 million years to complete.
Once photons escape the sun, they take a little over 8 minutes to reach earth, where they collide with solar panels and initiate the photovoltaic effect.
The Photovoltaic Effect (How solar panels generate electricity)
A solar panel’s secret sauce lies in its ability to convert photons into electrons. In a nutshell, a solar panel converts photons into direct current, which is then converted to alternate current for use in home and business applications.
Solar cells are typically constructed of silicon, a semiconductor capable of producing electricity. When sunlight strikes the panel, photons interact with silicon atoms, releasing electrons in a phenomenon called the photovoltaic effect.
A solar cell is manufactured with a positive and negative silicon sheet sandwiched together. An upper silicon layer is infused with phosphorus for a negative charge, and a boron-infused bottom layer maintains a positive charge. The resulting field funnels electrons towards conductive metal and out of the panel.
Once the photovoltaic process produces a current, the electricity has to flow somewhere. Since the current produced by a solar panel is DC, it needs to be converted into AC before it can be used in most situations. Once converted to AC, energy from solar can be used in multiple ways.
The most common method is entry into a grid-tied system. A grid-tied system draws a significant portion of its energy needs from solar panels during the day. Depending on the size of the system, more energy may be produced than the site needs, so surplus electricity is sent back to the grid. When the sun goes down, the consumer draws supplemental energy from the utility.
While grid-tied systems aren’t completely self-sufficient, they’re an effective way to lower energy bills and do good for the environment.
A major advantage of a grid-tied system is the ability to sell surplus solar energy back to the utility through a process called net metering. On cloudy days and during the night, a solar system may not produce enough energy to meet demand. The opposite is true for very sunny days: When energy use is low but production is high, panels will collect surplus energy, usually more than enough for a customer’s energy needs.
Net metering measures electrical flow in both directions: How much energy a system draws from the utility, and how much is put in. When a solar system is overproducing, the meter actually runs backward, resulting in the utility company rewarding credits for the surplus power.
These credits can be used to purchase energy from the utility when a solar system isn’t able to meet demand.
What Components Make up a Solar System?
Solar panels are the most obvious components of a photovoltaic system, but only represent about 30% of the total system’s cost. The high-tech shimmer of a solar panel is just the tip of the iceberg that a photovoltaic system uses to harness renewable energy from the sun.
Let’s take a closer look at the important components that make up a solar system.
Solar Photovoltaic Panels
A typical solar panel consists of silicon cells, a metal frame, wiring elements. and glass. An insulative layer and a protective back sheet protect the panel from excessive heat and humidity.
While the general construction of solar panels is pretty standard, the silicon cells are manufactured in two distinct formats:
- Monocrystalline cells are one solid silicon crystal. Mono cells provide more space for electrons to flow, resulting in a smaller, more efficient panel. The downside is they tend to be more expensive.
- Polycrystalline cells are constructed of many individual shards of silicon melted together. While not as efficient as mono cells, poly cells have a lower price point.
Mono and poly cells serve the same purpose. Aesthetics and budget will help you determine which is right for your next project. Mono panels tend to have a darker, more uniform color, while poly panels are lighter (usually blue). If the site is space-limited, mono panels may be the way to go thanks to their higher efficiency. But if space isn’t an issue or you’re up against a tight budget, poly panels are still an excellent choice.
Solar energy comes right off the panel as direct current. But the energy needs to be converted to alternate current before it can be used in a commercial electrical grid. Thankfully, DC is easily converted to AC, a job left to an inverter.
Inverters are classified into 4 broad categories:
- Stand-alone inverters draw DC energy from batteries charged by solar panels and don’t interact with the grid.
- Grid-tie inverters match electrical current from solar panels to those of the utility. Grid-tie inverters shutdown during power outages, so they can’t be relied on for backup power.
- Battery backup inverters draw energy from a battery and export surplus energy to the grid. Battery backup inverters are capable of delivering AC energy during a power outage.
- Intelligent hybrid inverters are all-in-one solutions that can be used for grid-tie, stand-alone, or backup applications. Intelligent hybrid inverters are often attached directly to solar arrays and manage solar load, battery storage, and grid interaction.
Racking and Mounting System
Racking and mounting hardware do far more than secure panels to a roof or the ground — they provide the correct positioning for maximum exposure to the sun. Selecting the right mounting configuration and position is essential for ensuring maximum output from any system.
Solar racking and mounting systems fall into 3 categories:
- Ground mount systems. Traditional ground mount systems anchor stacked panels to the ground, often two to four panels high. Two rails generally support each panel, which can be oriented in a portrait or landscape position. These systems are anchored to the ground with steel rods, screws, or ballasts such as concrete blocks.
- Tracking systems. Motorized tracking systems follow the sun throughout the day, maximizing sunlight exposure. Tracking systems are classified as single axis or dual axis. Single axis systems follow the sun from east to west in a straight line. Dual axis systems track the sun in a circular pattern for improved sunlight exposure.
- Roof mounting systems. The most common roof mounting systems utilize rails anchored securely to a roof. Other roof-mounted systems attach panels directly to bolts or screws anchored into the roof, eliminating the use of rails and providing a more sleek aesthetic and lighter load. Ballasted and non-penetrating systems are usually used on flat roofs or roofs that can’t support mounting hardware.
Performance Monitoring Systems
A performance monitoring system is a dashboard that provides a complete picture of your system’s performance. Aside from the fuzzy feelings of seeing your meter spin in reverse, a solar performance monitoring system offers valuable insights into a photovoltaic system.
A performance monitoring system offers information about energy output and consumption, optimizes energy usage, and can inform you about problems in your solar system. Solar monitoring systems work through inverters, usually through monitoring software that runs liaison between the inverter and other devices.
Performance monitoring systems gather information as the inverter converts direct current to alternate current, and make that information accessible to the homeowner through companion apps and Smart home devices. The best performance monitoring systems collect data through a central inverter or from individual microinverters affixed to each solar panel. The later option provides greater insight into individual solar panel performance, and allows faster diagnosis of potential problems.
How Are Solar Panels Made?
Basic solar panel constriction hasn’t changed much in recent decades. Like the arrays that first started showing up on houses decades ago, most modern solar panels are still constructed of a silicon matrix between a front glass plate and rear polymer sheet.
Solar panels have to stand up to severe weather conditions over the course of their 25-plus year lifespan. The best solar panels are engineered to stand the test of time, which requires a few basic materials and meticulous manufacturing standards.
Solar panels are best pictured as a silicon and glass sandwich. The materials that go into solar panels are relatively straightforward:
Silicon, the element that gives solar panels their electricity-generating magic, is the active ingredient in the solar-panel-sandwich recipe, and also the most energy intensive to produce. Silicon is one of the most abundant elements on earth, and is the main component of beach sand. But converting sand into pure silicon suitable for solar panels is an energy-intensive process requiring refinement in high temperature arc furnaces.
Once silicon is refined, the raw product is ready to be manufactured into a solar panel.
Isolated silicon chunks are shaped into cylindrical ingots, with special attention given to proper atomic orientation. At this stage, boron is added to give the silicon a positive charge. Ingots are then cut into thin wafers the thickness of paper, then treated with an anti-reflective coating to help better absorb sunlight.
Next, conductive metals are added to the surface of each wafer. Phosphorus is diffused across the surface, providing a negative charge to balance the positive charge of the boron and allow controlled flow of electrons.
At this stage, an individual solar cell is complete. Next, cells are soldered with metal connectors into a matrix. This assembly is sandwiched between a protective back sheet and glass covering and finished off with a junction box and frame.
How Are Solar Systems Designed?
Two important factors are considered when designing solar systems: available space and energy demand. All the nuts and bolts of solar system design hinge on these two factors, so a thorough understanding of them is essential to a well-planned solar installation.
To get started, a solar designer will calculate daily energy needs, usually by taking a look at the location’s utility bill. Next, the designer will determine the ideal number of solar panels for the project and available space to accommodate them. With energy needs and available space determined, a designer can start shopping for components.
Designing a solar system can be complicated. A designer must determine space requirements, potential shade, optimal panel pitch/angle, necessary permits, and more. Software solutions can help estimate solar energy needs and plan the best solar system.
For example, with just an energy bill, Aurora Solar’s design software automatically renders high-quality designs and materials recommendations for any location. Aurora also provides multiple planning and design tools into one intuitive package, including site design, load profiles, shade analysis, automatic system design, sales proposals, permit templates, and more.
Of course, the ins and outs of how solar panels work are just the first step. If you’re looking to learn more about solar and the solar industry, here are some additional resources:
- Now that you know how solar panels work, check out the different types of panels on the market
- See how solar panels are connected together — called “stringing” — to deliver power where it’s needed
- Interested in battery storage? Here’s a primer on everything you need to know about storing solar energy
The Solar 101 section of our blog has a number of other resources, as well, to help answer all your solar-related questions.
Schedule a demo today and fast-track your next solar installation project.
Learning Electrical Engineering
A solar cell can convert the energy contained in the solar radiation of the sun into electrical energy. Due to the limited size of the solar cell it only delivers a limited amount of power under fixed current-voltage conditions that are not practical for most applications.
In order to use solar electricity for practical devices, which requires a particular voltage and/or current for their operation, a number of solar cells have to be connected together to form a solar panel, also called a PV module. For large-scale generation of solar electricity solar panels are connected together into a solar array. A typical solar panel installation for a residential apartment is shown below:
For a residential apartment, a hybrid/grid connected system is the most appropriate. The system will be supplied electricity during the day through the solar panels as well as store energy in the batteries while the batteries will supply electricity during bad weather or night hours or grid outage. The system can also be supplied electricity through the electricity grid or a portable generator. With the portable generator or the grid, electricity is supplied to the loads and energy is also stored in the batteries. It is a stand-alone system that is self-sufficient. Note that the portable generator is only required in the worst-case scenario where the weather is bad/during night hours when the stored energy in the batteries is used up and there is no electricity from the grid.
In the process of generating the electricity from Solar panel installations, several important components are connected to produce electricity. Which components are required depends on whether the system is connected to the electricity grid or whether it is designed as a stand-alone system.
The objective here is to describe the common components used for stand-alone systems commonly used in residential buildings.
Components of a Solar Panels Power System Installations
The following components typically make up a solar electricity power system for a residential system. These components can also be found installed in large commercial power applications:
A mounting structure is used to fix the Solar panels and to direct them towards the sun. Proper positioning of the solar panels will ensure that the maximum solar radiation is captured in a given location and ensures the Solar power system performs as required. There are fixed mounting structures as well as those designed to track and follow the maximum radiation from the sun. Most residential Solar power systems are mounted on a fixed structure on the ground or most commonly on building roofs.
The main building blocks of a Solar energy power system are solar panels. They are the units that trap the sun’s solar radiation and converts it to electricity. This electricity is then used to supply electrical loads as well as stored in batteries for stand-alone systems. Solar panels are typically mounted on structures or on building roofs for most residential solar PV installations.
Energy Storage Systems
Energy storage is a vital part of stand-alone systems because it assures that the system can deliver electricity during the night and in periods of bad weather. Usually, batteries are used as energy storage units. During the day when the sun’s radiation is very high, the solar PV system supplies electricity as well as charge the batteries during bad weather or night hours. Deep cycle batteries are usually applied for this purpose – batteries that can withstand repeated charge and discharge cycles.
Charge controllers are DC-DC converters that are used in stand-alone solar power systems to convert the solar panels variable electrical output voltage to a fixed voltage output that can be used to charge a battery or used as input for an inverter in a grid-connected system. Typically, the voltage output from a solar panel varies depending on the time of the day and the weather conditions which also makes the output current variable. Both a variable current and voltage are not good for good battery performance hence the need for the charge controller. The charge controller also helps to disconnect the Solar panels from the batteries when they are fully charged. This helps to prevent overcharging which affects battery performance and life.
All charge controllers use Maximum Power Point Tracking (MPPT). Owing to variations in the current and voltage output from a solar panel or array installation due to changes in solar radiation (technically called irradiance) and temperature, there exist a Maximum Power Point (MPP) on the I – V characteristic of the installation where the highest power is generated for a given irradiance and temperature. The voltage and current corresponding to MPP is Vmpp and Impp.
Given that MPP is dependent on ambient conditions, any changes in irradiance and temperature will shift the position of MPP on the I-V (current/voltage characteristics) of the solar panel/array installation. Therefore, changes in the I-V characteristics have to be tracked continuously with adjustment in the operating point to correspond to MPP after changes in ambient conditions. This process is called Maximum Power Point Tracking or MPPT. The devices that perform this process are called MPP trackers and they are built-in to modern charge controllers used in solar panel/array power installations.
Inverters are DC-AC converters that are used to convert DC voltage produced by the Solar panels to AC voltage to supply alternating current loads. Appliances and loads used in residential apartment usually utilize alternating current hence the need for an inverter. Furthermore, for grid connected solar power systems, there is need to convert the DC voltage from the solar panels before transmission into the power grid. For low power application as are common in small residential PV systems, single-phase inverters are used. They are connected to one phase of the grid. For higher powers, three-phase inverters are used that are connected to all phases of the grid.
The overall performance of Solar electricity supply systems also is strongly dependent on the correct choice of the cables. Selecting the wrong cable size can significantly affect the performance of the Solar PV power supply system.
The cables must be chosen such that resistive power losses are minimal. The power dissipated across a cable is proportional to the square of the current flowing through the cable. Hence, as the current doubles, four times as much heat will be dissipated at the cables. Therefore, modern solar panels have connected all cells in series.
Color Conventions for Cables
Solar Panels PV systems usually contain DC and AC parts. For correctly installing a solar panel system, it is important to know the color conventions for wiring.
Red is used for connecting the positive contacts of the different system components with each other.
Therefore it is very important to check the standards of the country in where the Solar PV system is going to be installed.
Solar Panel Buying Guide: Everything You Need to Know
Considering solar panels for your home? Start here for information on solar installations, tax credits, batteries, solar panel lifespans and more.
Stephen J. Bronner is a New York-based freelance writer, editor and reporter. Over his more than a decade in journalism, he has written about energy, local politics and schools, startup success tips, the packaged food industry, the science of work, personal finance and blockchain. His bylined work has appeared in Inverse, Kotaku, Entrepreneur, NextAdvisor and CNET, and op-eds written on behalf of his clients were published in Forbes, HR Dive, Fast Company, NASDAQ and MarketWatch. Stephen previously served as contributors editor and news editor for Entrepreneur.com, and was the VP, Content and Strategy, at Ditto PR. He enjoys video games and punk rock. See some of his work at stephenjbronner.com.
The case for getting some or all of your home’s energy from solar panels has never been stronger.
Jump-started by the Inflation Reduction Act, which provides a 30% tax credit for the cost of solar system installations, along with falling panel and rising energy costs, homeowners can see a return on investment on solar within seven to 12 years.
With that said, there are homeowners for whom residential solar won’t make financial sense, like those whose roofs get limited sunlight or live in states without net metering. For everyone else, here is everything you need to know about buying solar panels.
Can solar panels save you money?
Interested in understanding the impact solar can have on your home? Enter some basic information below, and we’ll instantly provide a free estimate of your energy savings.
How solar panels work
Solar panels are made of photovoltaic cells, which convert sunlight into electricity. The sun emits solar radiation, which is absorbed by the photovoltaic cells. Electrons within the solar cell are energized, escape their bonds and form an electric current. That current, which starts as direct current, is switched to alternating by the solar system’s inverter. From there it’s used up in the electronics in your home or sent back to the grid.
It’s not a magical technology, but it seems like it because you just stick something in sunlight and it makes electricity for you, said Joshua Pearce, a professor at Western University in Ontario and co-author of To Catch the Sun, a free e-book on DIY solar systems. Even being a scientist who works on this stuff all the time, it’s amazing that these things actually work.
Can solar panels save you money?
Interested in understanding the impact solar can have on your home? Enter some basic information below, and we’ll instantly provide a free estimate of your energy savings.
The benefits of solar panels
Why would you want home solar panels?
- Savings on energy: The most direct benefit is that you can gain the opportunity to power your own home outside of the electrical grid. That saves you money, and if you generate extra power, you might even be able to get credit on your bill from the electric utility via net metering. The average payback period for solar panels is six to 12 years, according to some sources.
- Solar is an abundant power source: According to the US Department of Energy, just one hour of noontime summer sun meets the annual US electricity demand. Depending on your situation, turning it into electricity can save on your electricity bill.
- Help with your home value: If you plan to sell your home down the line, having home solar panels can be a major perk to buyers and can help increase your home’s value.
- Going green: Since solar is a renewable resource, you can shrink your carbon footprint.
- Independence from electrical grid failures: Some areas have electrical grids that are less than reliable. If you experience frequent power outages in your area, your own solar power can keep the lights on.
- Power your campsite: Some small solar panel arrays fit right onto RVs, or you can take them camping so you have electricity, no matter how remote the location.
Where to buy solar panels
Many businesses specialize in selling and installing solar panels for homes. Search online to locate solar panel suppliers and installers in your area. You can start with CNET’s best list of solar panel companies.
You can even shop for solar panels at major home goods stores like Home Depot. Stores like this can even set you up with professional installation to help you get a residential solar panel setup.
Major installers often offer solar financing options, too, though you might be best served by shopping around for a loan. Many solar installers also offer solar panel leases or power purchase agreements, which you can enter with no money down (though savings over the lifetime of your panels are typically lower).
You can also apply for the federal solar tax credit, that will give you 30% of the cost of your solar back to you on your taxes, assuming you have that much tax liability.
Solar panel installation
Most residential solar arrays are installed by a professional. Installing solar panels yourself is technically possible, but you run the risk of voiding warranties. You should only attempt it if you have the necessary expertise. If you opt for a professional installation, be sure to shop around for the best deal. Compare the warranties installers offer along with price, customer service and how well their proposed plans meet your needs.
A reputable solar installer will advise you on the age of your roof before installation. Replacing your roof before installation may ultimately be the cheaper option, since removing the panels to replace the roof will be an additional expense.
Care and lifespan of solar panels
Many solar panels are warrantied to last 25 years, though their useful life is likely longer. On top of that, they’re fairly maintenance free, just requiring that you keep them free of obstructions like dirt, leaves and snow. extensive repairs may be covered by warranty.
Solar panels get less efficient over time, though that downward trend isn’t necessarily a problem for you. A typical manufacturer’s warranty will guarantee that your solar panels won’t lose more than 2% efficiency in the first year and not more than 0.5% per year in the next 24 years. That means your panels are guaranteed to produce at 84% their original capacity after year 25. Some panels will set a higher benchmark.- like 92%.- after 25 years, but you’ll still be getting plenty of electricity out of them two decades on.
Do you need a solar battery?
Installing a solar battery in your home will allow you to store excess energy produced by your panels. However, they are currently almost as expensive as a solar panel system (from 12,000 to 22,000), so while a battery is nice to have, it’s not a necessity.
There are instances where a solar battery is worth the investment. Those who live off the grid will need a battery to use solar power. And if your area is prone to frequent blackouts or you have medical needs that require refrigerated medicine or machinery, a battery may be worth the cost.
How to pay for solar panels
There are a breadth of options for paying for the installation of residential solar panels, aided in part by the 30% federal tax credit. Homeowners can pay out of for the entire project, then receive money back from the government. There are also relatively cheap solar financing options, with plans that offer 1.99% APR over 25 years, that also result in the tax credit. Interest rates have shifted higher over the last year or so and you should shop around for the terms that best fit your needs. Other financing options include bank loans or a home equity loan, but given their higher interest rates, consider these financial tools carefully.
For those without the financial means to buy or finance a system, there are solar leases and power purchase agreements. A solar lease is similar to that of a vehicle.- you pay a set amount each month for a system that will be owned by the installer. Under a power purchase agreement, you pay a set rate for the energy generated by the solar panels (the rate may increase after a certain amount of time), rather than the system itself. The drawback of these mechanisms is that you won’t own the solar panels yourself, and hence won’t get any of the tax credits or have the ability to sell renewable energy certificates.
How the solar tax credit works
The federal residential solar energy credit, which grants a 30% credit to homeowners who install panels on their home through 2032. (If your entire project costs 30,000, you’ll be granted a credit of 9,000). The credit applies to homeowners who purchase a system with cash or through financing.
According to the Office of Energy Efficiency Renewable Energy, you should seek professional tax advice to determine your eligibility, then fill out IRS Form 5695 following the IRS’s instructions.
Improve your home’s efficiency first
Before you start the process of going solar, you should try to improve your home’s energy usage in other ways.
Solar is an exciting type of infrastructure, but if the ultimate goal is to save money on your electricity bills, I encourage homeowners to think about efficiency upgrades first, said Gilbert Michaud, assistant professor at Loyola University Chicago’s School of Environmental Sustainability. Those could include insulation, upgrading and replacing Windows or other things that are maybe less fun, but can help you realize savings immediately and lower costs. Once you’ve done those efficiency retrofits or upgrades, maybe solar is a good idea.
These upgrades will give you a clearer idea of how many solar panels you’d need to power your home, too. That means you’ll likely need less panels.- reducing the cost of the installation.- than if you didn’t do efficiency upgrades first. Here’s some suggestions.
- Check your insulation: Inside your walls is a layer of material meant to keep hot or cold air where it is. In the winter, this means the warm air from your heating system stays inside your house, and vice versa for cool air in the summer. If there are leaks in your insulation, hot or cold air is escaping or getting in, which makes your HVAC system work harder and costs you more money.
- Upgrade or replace Windows: Much like insulation, your Windows play a large role in keeping your home heated or cooled. If your Windows are out of date, air could be coming in or out, which is not great for your energy bills.
- Replace old household items with efficient ones: If you have older appliances, thermostats or light bulbs, replace them with newer, more efficient ones to realize energy savings.
Solar panel FAQs
How much money will solar panels save me?
Many experts say that homeowners will see a return on investment on a solar panel installation in a period between seven to 12 years. That’s when the money saved from paying your energy bills will exceed the initial money spent on a solar project. Those who go solar through a lease or power purchasing agreement should see savings practically immediately.
The 3 Different Types of Solar Power Systems Explained
There are three basic types of solar power systems: grid-tie, off-grid, and backup power systems. Here’s a quick summary of the differences between them:
- Off-grid solar is designed to bring power to remote locations where there is no grid access.
- Off-grid systems require a battery bank to store the energy your panels produce. They are often paired with a generator to provide backup during long stretches without sunlight.
- A backup power system connects to the grid, but also includes batteries. Backup power systems (also called “hybrid systems” or energy storage systems) provide backup power in case the grid goes down.
Each system type requires unique equipment that is compatible with the application, so understanding which one you need is the first step in the process of going solar.
Let’s take a closer look at the different types of solar power systems and make a comparison between them.
Grid-Tie Solar Power Systems
Grid-tie solar is, by far, the most cost-effective way to go solar. Because batteries are the most expensive component of any solar system, but grid-tie solar owners can skip them completely!
So how do grid-tie solar power systems work?
First, let’s define what we mean by the “grid”. The grid is the utility company’s network of equipment that brings electricity from the power plant to your home or commercial building. If a building is getting electricity from the power company, it is connected to the grid.
Grid-tie solar systems send the energy they generate into the grid, where it is stored for later use. Under a net metering agreement, the system owner receives credit for anything they generate, and they can make use of that energy at any time.
It’s kind of like a bank account: sending energy into the grid is like making a deposit, and using electricity is like withdrawing against your account balance. If you overdraft i.e. use more energy than you produce in a given month, the utility bills you for the difference. No added fees, thankfully.
Advantages of Grid-Tie Solar Power Systems
Grid-tie solar is the best option if you want to offset your electricity bill and save money over the life of your system.
Most grid-tie systems pay for themselves within 5-10 years. With solar panels warrantied for 25 years, grid-tie solar is the only option that reliably turns a profit for the system owner over the life of the panels.
Another advantage is that grid-tie systems can be smaller — you don’t need to generate 100% of your power each month. The grid can supply additional power beyond your production, which is useful when bad weather hampers the output of your panels, for example.
Some people choose to size a grid-tie system for a partial offset of their bill, with plans to expand the system later once their budget allows for it. Design requirements are less demanding than in an off-grid environment, where you are fully responsible for your energy needs.
Disadvantages of Grid-Tie Solar Power Systems
The main disadvantage of grid-tie systems is that they are still vulnerable to power outages.
But wait, you might say, if I’m generating power from sunlight, why does it matter if the grid goes down?
Unfortunately, grid-tie systems are wired into the utility company’s infrastructure. In case of an outage, utility workers need to troubleshoot and fix the problem, and they can’t do that if connected solar systems are still energized and feeding power to the grid. For that reason, grid-tie solar systems are switched off during outages to allow utility workers to safely make repairs.
The solution? A hybrid system that connects to the grid, but draws on a battery bank in case of outages. We’ll cover those at the end of this article, but first.
Off-Grid Solar Power Systems
Off-grid solar is best for delivering power to remote locations where there is no access to a utility line.
Folks who live off the grid are solely responsible for generating their own electricity. This is usually accomplished by building an off-grid solar system that can cover a day’s worth of electricity usage, with a backup generator to supplement production during long stretches of bad weather.
Advantages of Off-Grid Solar Power Systems
The main draw of off-grid solar is the freedom to live wherever you want. It doesn’t matter if your property is 100 miles from civilization: if you have sunlight, you have a reliable way to generate power.
Although off-grid solar components are more expensive, there can be some hidden financial benefits to living off the grid that can offset those higher costs. Undeveloped plots of land located far off the grid will naturally cost less than a prime grid-tie location. In many cases, the lower land costs do more than enough to offset the higher cost of going solar off the grid.
Disadvantages of Off-Grid Solar Power Systems
Pretty simple, really: the need for a battery bank makes off-grid solar significantly more expensive.
However, it’s often wiser to invest in an off-grid solar system than it is to run a power line to a remote location. While an off-grid system may cost more than a grid-tie system, it is still more frugal than other remote power solutions, like running a new utility line or relying on a gas generator.
One way to keep costs down is to use propane appliances where possible to reduce your demand for electricity. Opting for a propane stove, clothes dryer, wall heater and on-demand water heater means you can get away with a smaller inverter and smaller battery bank.
It also helps to stagger electricity usage — for example, running laundry and the dishwasher at different times — to reduce your peak power consumption and relieve some of the costs of energy storage.
Backup Solar Power Systems
If you live on the grid, but you want protection from power outages, your best bet is a battery backup system.
Backup power systems connect to the grid, and function like a normal grid-tie system on a day-to-day basis. However, they also feature a backup battery bank that takes over in case of outages.
When grid power goes out, your inverter automatically disconnects from the grid and draws on energy stored in your battery bank, which will keep your appliances running when the grid goes down.
Battery backup systems have been gaining popularity recently, especially in light of news stories covering grid failures in Texas and wildfires interrupting service in California. They are also favored in climates that are vulnerable to fierce storms and natural disasters like hurricanes and tornadoes. The backup battery bank offers peace of mind to shield the owner from blackouts.
Lastly, battery backup is valuable if you have appliances which require uninterrupted power. If you are running a well pump, for example, service interruptions can be a massive headache. Adding backup power to your grid-tie system will keep these critical appliances running during a blackout.
Can I start with grid-tie solar and add battery backup later?
Yes, but it’s much easier to do if you plan for expansion in advance. Traditional grid-tie inverters like the SMA Sunny Boy aren’t equipped to handle a battery bank connection. Those can be paired with the SMA Sunny Island inverters to upgrade a hybrid battery based system, but you’ll spend more coupling a second inverter to your system.
Hence, iIf you think that you may want to add battery backup to your system down the line, we recommend a solution like the Sol Ark series, a string inverter which is engineered to handle all three applications: grid tie, off grid, and battery backup.
There’s also the Enphase Ensemble, a “grid-agnostic” micro-inverter system that is designed to seamlessly swap between grid power and backup power.
You’ll be able to start with Enphase IQ micro-inverters for grid-tie use, with the option to add the Encharge storage system later without any compatibility issues.
Watch this 5-minute video from Enphase to see how it works.
How much do solar panels cost? Use our easy solar panel calculator to get a quick estimate of how many solar panels you’ll need for your home.
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What Is A Solar Panel?
A Solar panels (also known as PV panels) is a device that converts light from the sun, which is composed of particles of energy called photons, into electricity that can be used to power electrical loads.
Solar panels can be used for a wide variety of applications including remote power systems for cabins, telecommunications equipment, remote sensing, and of course for the production of electricity by residential and commercial solar electric systems.
On this page, we will discuss the history, technology, and benefits of solar panels. We will learn how solar panels work, how they are made, how they create electricity, and where you can buy solar panels.
A Short History of Solar Panels
The development of solar energy goes back more than 100 years. In the early days, solar energy was used primarily for the production of steam which could then be used to drive machinery. But it wasn’t until the discovery of the photovoltaic effect by Edmond Becquerel that would allow the conversion of sunlight solar electric energy. Becquerel’s discovery then led to the invention in 1893 by Charles Fritts of the first genuine solar cell which was formed by coating sheets of selenium with a thin layer of gold. And from this humble beginning would arise the device we know today as the solar panel.
Russel Ohl, an American inventor on the payroll of Bell Laboratories, patented the world’s first silicon solar cell in 1941. Ohl’s invention led to the production of the first solar panel in 1954 by the same company. Solar panels found their first mainstream use in space satellites. For most people, the first solar panel in their life was probably embedded in their new calculator. circa the 1970s!
Today, solar panels and complete solar panel systems are used to power a wide variety of applications. Yes, solar panels in the form of solar cells are still being used in calculators. However, they are also being used to provide solar power to entire homes and commercial buildings, such as Google’s headquarters in California.
How Do Solar Panels Work?
Solar panels collect clean renewable energy in the form of sunlight and convert that light into electricity which can then be used to provide power for electrical loads. Solar panels are comprised of several individual solar cells which are themselves composed of layers of silicon, phosphorous (which provides the negative charge), and boron (which provides the positive charge). Solar panels absorb the photons and in doing so initiate an electric current. The resulting energy generated from photons striking the surface of the solar panel allows electrons to be knocked out of their atomic orbits and released into the electric field generated by the solar cells which then pull these free electrons into a directional current. This entire process is known as the Photovoltaic Effect. An average home has more than enough roof area for the necessary number of solar panels to produce enough solar electricrity to supply all of its power needs excess electricity generated goes onto the main power grid, paying off in electricity use at night.
In a well-balanced grid-connected configuration, a solar array generates power during the day that is then used in the home at night. Net metering programs allow solar generator owners to get paid if their system produces more power than what is needed in the home. In off-grid solar applications, a battery bank, charge controller, and in most cases, an inverter are necessary components. The solar array sends direct current (DC) electricity through the charge controller to the battery bank. The power is then drawn from the battery bank to the inverter, which converts the DC current into alternating current (AC) that can be used for non-DC appliances. Assisted by an inverter, solar panel arrays can be sized to meet the most demanding electrical load requirements. The AC current can be used to power loads in homes or commercial buildings, recreational vehicles and boats, remote cabins, cottages, or homes, remote traffic controls, telecommunications equipment, oil and gas flow monitoring, RTU, SCADA, and much more.
The Benefits of Solar Panels
Using solar panels is a very practical way to produce electricity for many applications. The obvious would have to be off-grid living. Living off-grid means living in a location that is not serviced by the main electric utility grid. Remote homes and cabins benefit nicely from solar power systems. No longer is it necessary to pay huge fees for the installation of electric utility poles and cabling from the nearest main grid access point. A solar electric system is potentially less expensive and can provide power for upwards of three decades if properly maintained.
Besides the fact that solar panels make it possible to live off-grid, perhaps the greatest benefit that you would enjoy from the use of solar power is that it is both a clean and a renewable source of energy. With the advent of global climate change, it has become more important that we do whatever we can to reduce the pressure on our atmosphere from the emission of greenhouse gases. Solar panels have no moving parts and require little maintenance. They are ruggedly built and last for decades when porperly maintained.
Last, but not least, of the benefits of solar panels and solar power is that, once a system has paid for its initial installation costs, the electricity it produces for the remainder of the system’s lifespan, which could be as much as 15-20 years depending on the quality of the system, is absolutely free! For grid-tie solar power system owners, the benefits begin from the moment the system comes online, potentially eliminating monthy electric bills or, and this is the best part, actually earning the system’s owner additional income from the electric company. How? If you use less power than your solar electric system produces, that excess power can be sold, sometimes at a premium, to your electric utility company!
There are many other applications and benefits of using solar panels to generate your electricity needs. too many to list here. But as you browse our website, you’ll gain a good general knowledge of just how versatile and convenient solar power can be.
How Much Do Solar Panels Cost?
for solar panels has decreased substantially in the last couple of years. This is great because, combined with the 30 federal solar Investment Tax Credit and other applicable incentives, NOW is the best time ever to invest in a solar power system. And, consider this: a solar power system costs about the same as a mid-sized car!
Where can I buy solar panels?
Well, right here on this website, of course!
Our solar panel brands include the most respected manufacturers in the solar panel business. These brands include such names as BP Solar, General Electric, and Sharp, among others. We feature only the highest quality solar panels from manufacturers with a proven track record in solar panel technology. With over 30 years in the solar panel business, you can be sure that at MrSolar.com, we know solar panels!