Photovoltaic Array
If photovoltaic solar panels are made up of individual photovoltaic cells connected together, then the Solar Photovoltaic Array, also known simply as a Solar Array is a system made up of a group of solar panels connected together.
A photovoltaic array is therefore multiple solar panels electrically wired together to form a much larger PV installation (PV system) called an array, and in general the larger the total surface area of the array, the more solar electricity it will produce.
A complete photovoltaic system uses a photovoltaic array as the main source for the generation of the electrical power supply. The amount of solar power produced by a single photovoltaic panel or module is not enough for general use.
Most manufactures produce a standard photovoltaic panel with an output voltage of 12V or 24V. By connecting many single PV panels in series (for a higher voltage requirement) and in parallel (for a higher current requirement) the PV array will produce the desired power output.
A Photovoltaic Solar Array
Photovoltaic cells and panels convert the solar energy into direct-current (DC) electricity. The connection of the solar panels in a single photovoltaic array is same as that of the PV cells in a single panel.
The panels in an array can be electrically connected together in either a series, a parallel, or a mixture of the two, but generally a series connection is chosen to give an increased output voltage. For example, when two solar panels are wired together in series, their voltage is doubled while the current remains the same.
The size of a photovoltaic array can consist of a few individual PV modules or panels connected together in an urban environment and mounted on a rooftop, or may consist of many hundreds of PV panels interconnected together in a field to supply power for a whole town or neighbourhood. The flexibility of the modular photovoltaic array (PV system) allows designers to create solar power systems that can meet a wide variety of electrical needs, no matter how large or small.
It is important to note that photovoltaic panels or modules from different manufacturers should not be mixed together in a single array, even if their power, voltage or current outputs are nominally similar. This is because differences in the solar cell I-V characteristic curves as well as their spectral response are likely to cause additional mismatch losses within the array, thereby reducing its overall efficiency.
The Electrical Characteristics of a Photovoltaic Array
The electrical characteristics of a photovoltaic array are summarised in the relationship between the output current and voltage. The amount and intensity of solar insolation (solar irradiance) controls the amount of output current ( I ), and the operating temperature of the solar cells affects the output voltage ( V ) of the PV array. Photovoltaic panel ( I-V ) curves that summarise the relationship between the current and voltage are given by the manufacturers and are given as:
Solar Array Parameters
- VOC = open-circuit voltage: – This is the maximum voltage that the array provides when the terminals are not connected to any load (an open circuit condition). This value is much higher than Vmax which relates to the operation of the PV array which is fixed by the load. This value depends upon the number of PV panels connected together in series.
- ISC = short-circuit current – The maximum current provided by the PV array when the output connectors are shorted together (a short circuit condition). This value is much higher than Imax which relates to the normal operating circuit current.
- Pmax = maximum power point – This relates to the point where the power supplied by the array that is connected to the load (batteries, inverters) is at its maximum value, where Pmax = Imax x Vmax. The maximum power point of a photovoltaic array is measured in Watts (W) or peak Watts (Wp).
- FF = fill factor – The fill factor is the relationship between the maximum power that the array can actually provide under normal operating conditions and the product of the open-circuit voltage times the short-circuit current, ( Voc x Isc ) This fill factor value gives an idea of the quality of the array and the closer the fill factor is to 1 (unity), the more power the array can provide. Typical values are between 0.7 and 0.8.
- % eff = percent efficiency – The efficiency of a photovoltaic array is the ratio between the maximum electrical power that the array can produce compared to the amount of solar irradiance hitting the array. The efficiency of a typical solar array is normally low at around 10-12%, depending on the type of cells (monocrystalline, polycrystalline, amorphous or thin film) being used.
Photovoltaic I-V characteristics curves provide the information designers need to configure systems that can operate as close as possible to the maximum peak power point. The peak power point is measured as the PV module produces its maximum amount of power when exposed to solar radiation equivalent to 1000 watts per square metre, 1000 W/m 2 or 1kW/m 2. Consider the circuit below.
Photovoltaic Array Connections
This simple photovoltaic array above consists of four photovoltaic modules as shown, producing two parallel branches in which there are two PV panels that are electrically connected together to produce a series circuit. The output voltage from the array will therefore be equal to the series connection of the PV panels, and in our example above, this is calculated as: Vout = 12V 12V = 24 Volts.
The output current will be equal to the sum of the parallel branch currents. If we assume that each PV panel produces 3.75 amperes at full sun, the total current ( IT ) will be equal to: IT = 3.75A 3.75A = 7.5 Amperes. Then the maximum power of the photovoltaic array at full sun can be calculated as: Pout = V x I = 24 x 7.5 = 180W.
The PV array reaches its maximum of 180 watts in full sun because the maximum power output of each PV panel or module is equal to 45 watts (12V x 3.75A). However, due to different levels of solar radiation, temperature effect, electrical losses etc, the real maximum output power is usually a lot less than the calculated 180 watts. Then we can present our photovoltaic array characteristics as being.
Bypass Diodes in Photovoltaic Arrays
Photovoltaic cells and diodes are both semiconductor devices made from a P-type silicon material and a N-type silicon material fused together. Unlike a photovoltaic cell which generates a voltage when exposed to light, PN-junction diodes act like solid state one way electrical valve that only allows electrical current to flow through themselves in one direction only.
The advantage of this is that diodes can be used to block the flow of electric current from other parts of an electrical solar circuit. When used in a photovoltaic solar array, these types of silicon diodes are generally called Blocking Diodes.
In the previous tutorial about photovoltaic panels, we saw that a bypass diode can be used in parallel with either a single or a number of photovoltaic solar cells. The addition of a diode prevents current(s) flowing from a good and well-exposed PV cells, overheating and burning out weak or partially shaded PV cells by providing a current path around the bad cell. Blocking diodes are used differently than bypass diodes.
Bypass diodes are usually connected in “parallel” with a PV cell or panel to shunt the current around it, whereas blocking diodes are connected in “series” with the PV panels to prevent current flowing back into them. Blocking diodes are therefore different then bypass diodes although in most cases the diode is physically the same, but they are installed differently and serve a different purpose. Consider our photovoltaic solar array below.
Diodes in Photovoltaic Arrays
As we said earlier, diodes are devices that allow current to flow in one direction only. The diodes coloured green are the familiar bypass diodes, one in parallel with each PV panel to provide a low resistance path around the panel. However, the two diodes coloured red are referred to as the “blocking diodes”, one in series with each series branch. These blocking diodes ensure that the electrical current only flows OUT of the series array to the external load, controller or batteries.
The reason for this is to prevent the current generated by the other parallel connected PV panels in the same array flowing back through a weaker (shaded) network and also to prevent the fully charged batteries from discharging or draining back through the PV array at night. So when multiple PV panels are connected in parallel, blocking diodes should be used in each parallel connected branch.
Generally speaking, blocking diodes are used in PV arrays when there are two or more parallel branches or there is a possibility that some of the array will become partially shaded during the day as the sun moves across the sky. The size and type of blocking diode used depends upon the type of photovoltaic array. Two types of diodes are available for solar power arrays: the PN-junction silicon diode and the Schottky barrier diode. Both are available with a wide range of current ratings.
The Schottky barrier diode has a much lower forward voltage drop of about 0.4 volts as opposed to the PN diodes 0.7 volt drop for a silicon device. This lower voltage drop allows a savings of one full PV cell in each series branch of the solar array therefore, the array is more efficient since less power is dissipated in the blocking diode. Most manufacturers include blocking diodes within their PV modules simplifying the design.
Build your own Photovoltaic Array
The amount of solar radiation received and the daily energy demand are the two controlling factors in the design of the photovoltaic array and solar power systems. The photovoltaic array must be sized to meet the load demand and account for any system losses while the shading of any part of the solar array will significantly reduce the output of the entire system.
If the solar panels are electrically connected together in series, the current will be the same in each panel and if panels are partially shaded, they cannot produce the same amount of current. Also shaded PV panels will dissipate power and waste as heat rather than generate it and the use of bypass diodes will help prevent such problems by providing an alternative current path.
Blocking diodes are not required in a fully series connected system but should be used to prevent a reverse current flow from the batteries back to the array during the night or when the solar irradiance is low. Other climatic conditions apart from sunlight must be considered in any design.
Since the output voltage of silicon solar cell is a temperature related parameter, the designer must be aware of the prevailing daily temperatures, both extremes (high and low) and seasonal variations. In addition, rain and snowfall must be considered in the design of the mounting structure. Wind loading is especially important in mountain top installations.
In our next tutorial about “Solar Power”, we will look at how we can use semiconductor photovoltaic arrays and solar panels as part of a Stand Alone PV System to generate power for off-grid applications.
Find Us On
- Standard Test Conditions
- Temperature Coefficient of a PV Cell
- Bypass Diode
- Solar Cell I-V Characteristic
- Photovoltaics Turning Photons into Electrons
- How Many Solar Cells Do I Need
- Photovoltaic Panel
- Photovoltaic Types
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Hi there my name is Matt D’Agati. Solar technology has grown to become probably the most promising and sought-after sourced elements of clean, renewable energy in the past few years. This is due to its numerous benefits, including financial savings, energy efficiency, and also the positive impact this has from the environment. In this specific article, we are going to talk about the advantages of choosing solar energy in homes and businesses, the technology behind it, and just how it could be implemented to increase its benefits. One of many benefits of using solar power in homes may be the financial savings it gives. Solar energy panels can handle generating electricity for your house, reducing or eliminating the need for traditional sourced elements of energy. This will probably bring about significant savings on the monthly energy bill, particularly in areas with a high energy costs. In addition, the expense of solar energy panels and associated equipment has decreased significantly over time, which makes it more affordable for homeowners to invest in this technology. Another good thing about using solar power in homes is the increased value it may provide into the property. Homes that have solar power panels installed are often valued greater than homes that don’t, while they offer an energy-efficient and environmentally friendly replacement for traditional energy sources. This increased value may be a significant benefit for homeowners that are trying to sell their house as time goes by. For businesses, the advantages of using solar power are wide ranging. One of several primary benefits is financial savings, as businesses can significantly reduce their energy costs by adopting solar power. In addition, there are many government incentives and tax credits accessible to companies that adopt solar technology, which makes it much more affordable and cost-effective. Furthermore, companies that adopt solar power can benefit from increased profitability and competitiveness, since they are seen as environmentally conscious and energy-efficient. The technology behind solar technology is not at all hard, yet highly effective. Solar energy panels are made up of photovoltaic (PV) cells, which convert sunlight into electricity. This electricity are able to be kept in batteries or fed straight into the electrical grid, with respect to the specific system design. So that you can maximize the many benefits of solar power, it is critical to design a custom system this is certainly tailored to your unique energy needs and requirements. This may make sure that you have just the right components in position, including the appropriate amount of solar energy panels plus the right types of batteries, to increase your power efficiency and value savings. One of several important aspects in designing a custom solar technology system is knowing the various kinds of solar energy panels and their performance characteristics. There are 2 main kinds of solar power panels – monocrystalline and polycrystalline – each featuring its own benefits and drawbacks. Monocrystalline solar power panels are made of an individual, high-quality crystal, helping to make them more cost-effective and sturdy. However, they are more costly than polycrystalline panels, that are produced from multiple, lower-quality crystals. Along with solar energy panels, a custom solar power system will also include a battery system to keep excess energy, in addition to an inverter to convert the stored energy into usable electricity. It is essential to choose a battery system that is capable of storing the actual quantity of energy you want for the specific energy needs and requirements. This can make certain you have a trusted way to obtain power in the case of power outages or any other disruptions to your time supply. Another advantage of using solar power may be the positive impact this has from the environment. Solar power is on a clean and renewable power source, producing no emissions or pollutants. This makes it an ideal replacement for traditional resources of energy, such as for example fossil fuels, that are a major contributor to polluting of the environment and greenhouse gas emissions. By adopting solar power, homeowners and businesses can really help reduce their carbon footprint and play a role in a cleaner, more sustainable future. In closing, the advantages of using solar energy both in homes and companies are numerous and should not be overstated. From cost benefits, energy savings, and increased property value to environmental impact and technological advancements, solar technology provides a variety of advantages. By knowing the technology behind solar technology and designing a custom system tailored to specific energy needs, you’ll be able to maximize these benefits and then make a positive effect on both personal finances while the environment. Overall, the adoption of solar energy is an intelligent investment for a sustainable and bright future. Should you want to learn about more info on this fact matter take a look at a blog:
Before some time I didn’t have much more knowledge about solar panel but before 2 or 3 yrs I have installed solar panel system in my home’s top roof and that time I examined many companies and much researched on this. So I can say all about the solar PV system. A PV module is an assembly of photo-voltaic cells mounted in a frame work for installation. Photo-voltaic cells use sunlight as source of energy and generate direct current electricity. A collection of PV modules is called a PV Panel, and a system of Panels is an Array. Arrays of a photovoltaic system supply solar electricity to electrical equipment.
can i connect two strings in parallel with different voltage (20 Panels x30V =600V 10 Panels x30V =300V) to a string monitoring Unit ( SMU) ?? if it connected what will be the voltage at common output terminal.
Would you please send a formal quotation for the following item: The Solar Photovoltaic Array system Your quotation should include shipping till Cairo, delivery time and all your terms and conditions.
HI there. Interesting read. I think I understand the logic. I live on a boat that has 4x Shell SM110-24 (rated output 110w; rated current 3.15A; rated voltage 35V). Becuase of the mast and boom these is often a shadow that passes over one or more of the panels – often leaving the other panels fully exposed to direct light. From what I read the shadow on one panel is likely to be affecting the performance of the whole array. It’s almost that I need each individual panel going back to the batteries individually – but thats a lot of wiring. What would be the best set up – series or parallel – and use of blockign diodes to minimise the impact of the shadow on one part of the array? Cheers.
A series or parallel connection for your panels depends on your system requirements. These panels already have Bypass diodes built-in to prevent high currents from partial shading, but yes shading affects the performance and efficiency of the array. Blocking diodes prevent reverse currents from the battery to the panel when the panel is not generating electricity, for example night time. If you are using a charging regulator then blocking diodes are not normally require as it has protection built-in, only if you are charging batteries directly.
In a series connected system, current is common to ALL panels. Therefore the current will be equal to the lowest wattage panel in the series chain as: I = P/V
Dear Sir/Madam, Highly informative and concise artical on the subject. Great service to the electrical engineering community. Keep it up, God bless you with lot of wisdom and knowledge. Best regards.
How much do solar panels cost?
Solar panels generate “free” electricity, but there are still costs associated with installing them. On average, solar panels cost 17,430 to 23,870 after federal tax credits.
Supply chain constraints led to solar photovoltaics (PV) price increases in 2021, but we saw costs go back down in 2022.
Key insights
- In 2023, the average cost for a residential system is currently 3 to 5 per watt.
- It typically takes five to 15 years to break even on installation costs.
- Solar leases and PPAs can reduce the cost but aren’t eligible for the federal tax credit.
Average solar panel cost by state
You can get a better sense of how much you can expect to pay for a solar installation in your area with a state-by-state comparison. The data in this table is based on average installation costs for a 6-kW solar panel system, a common size for a residential installation.
How much does it cost to install solar panels?
The average cost to install solar panels in the U.S. is 20,650 after federal tax incentives, according to EnergySage. Depending on the size of your home and your energy needs, however, your costs could range from 10,000 to 30,000 or more.
Most installers set the price according to the system’s wattage, with the average around 3 to 5 per watt. The cost per watt is the price you pay for each “unit” of energy the solar panel system can produce.
For example, if a solar panel system has a cost of 3 per watt, it costs 3 for every watt of energy it can produce. If the solar panel system can produce 5,000 watts of power, then the system’s total cost would be 15,000 (5,000 watts x 3 per watt).
If you just need a few panels for a small do-it-yourself project, start at around 200 to 350 per panel (between 80 cents to 1.40 per watt).
Regardless of the size of your system, it’s worth it to get a few quotes — even the difference between 3 and 4 per watt can add up to thousands of dollars.
For example, a ConsumerAffairs reviewer in California was quoted almost 26,000 for a 5-kW system (14 355-watt panels and an inverter), which works out to 5.20 per watt.
“For a 4.97-kW system … it should be priced between 13,071 and 17,047. I personally would have expected a price of 13,668 for a 4.97-kW system (2.75 per watt),” the reviewer told us.
Solar panel installation cost breakdown
Local climate and the availability of sunlight in your area all play a role in how much you end up paying.
Your energy needs Your energy needs determine how many panels you need, which affects the overall price of your solar system installation.
To eliminate your electric bill entirely, you must generate 100% of the electricity your home needs. Most American homes end up needing 15 to 30 panels to meet their electrical demands. The standard size for solar panels is about 5½ feet long by 3 feet wide, so consider the size of your roof.
Larger systems require more materials and labor to install, so they generally cost more than smaller systems. If you have limited roof space, you might need to get more efficient (and more expensive) panels.
- Durability: Solar panels are designed to last decades, so they should withstand harsh weather conditions and extreme temperatures. Look for panels with a strong frame and tempered glass.
- Efficiency: Higher-efficiency panels convert more sunlight into electricity, meaning you can generate more power with fewer panels. Look for panels with a high efficiency rating — typically above 18%.
- Warranty: Panels typically come with a warranty ranging from 10 to 25 years. A longer warranty indicates that the panel manufacturer is confident in the quality of its product.
Of the three types of panels available, monocrystalline and polycrystalline are most commonly used to power homes. In general, monocrystalline panels are more efficient, but they’re also more expensive compared with polycrystalline panels.
Hard and soft costs Installing a solar panel system has two main expenses: hard and soft costs. Hard costs are the materials needed for the design, such as the panels, wiring and inverter. Soft costs are associated with labor, permits, deposits and administrative expenses.
Solar panels — the main component of a system — usually make up the largest portion of the cost, but other hardware (for example, you might also want to buy a solar battery for energy storage), plus labor and permits, factor into the overall price.
- Inverter: This device converts the generated DC electricity into AC electricity that can be used to power your home. The cost of an inverter depends on its size and efficiency, but on average, it can cost between 1,000 and 3,000.
- Mounting system: This is what holds the panels in place on your roof. Costs vary depending on the type of installation, but it generally costs between 7 cents and 20 cents per watt.
- Electrical wiring and hardware: This includes the wiring, switches and circuit breakers required to connect the solar panel system to your home’s electrical system. Electrical wiring and hardware costs typically range from 10 cents to 20 cents per watt.
- Labor: The cost to install also includes an electrician, who handles wiring, hooking it up to your house and setting up various electronics to convert the power from the panels to the same AC voltage as you have in your home. Labor costs usually range from 50 cents to 1 per watt but can vary greatly depending on where you live and the complexity of the installation.
- Permits: Permits ensure the solar panel installation is safe, follows regulations and can qualify for incentives and rebates. Fees vary based on location, but residential solar permits typically cost a few hundred dollars. Some state regulations cap permitting fees (Colorado caps them at 500 for residential projects and 1,000 for commercial projects; California caps residential fees at 450).
The condition of your roof Get a thorough inspection of your roof now, and make sure you get pictures. If your roof needs repairs, it’s better to take care of that before installing solar panels — it’s more cost-effective than removing the panels and reinstalling them later.
A reviewer in California told us they discovered leaks in their roof a year after installing panels. They said the solar company charged 5,000 “to take the panels down and reinstall them after the roof was replaced” and said “if I had known the roof was in such bad shape, I would’ve replaced the roof before installing the panels.”
Federal and state incentives The federal solar tax credit, also known as the Investment Tax Credit (ITC), is a tax credit for 30% of the total cost of a new solar PV system. Homeowners, businesses and nonprofits can qualify, but there are some limitations. For example, you must own the panels — solar leases and PPAs do not qualify for the tax credit.
State incentives also help reduce the initial cost, but not everyone can take full advantage of them. Look for policies and incentives by state through the Database of State Incentives for Renewables Efficiency (DSIRE). Some states, like Massachusetts, offer additional discounts or even free systems for low- and moderate-income households.
It’s usually in your best interest to take advantage of state clean energy programs when you can — it lowers your upfront costs and shortens your payback period.
How much do solar panels save?
Switching to a solar energy system could cut your energy bill by 75% or more. The savings you see will depend on where you live, what the climate is like and your particular energy needs.
Like a lot of solar energy customers we talk to, a reviewer in Pennsylvania said they went solar to “help [the] environment while saving money. During the summer when the central air is going full blast, my electric bills are either 0 or less than 10.”
The average U.S. electric bill is 80 to 178 per month, according to the U.S. Energy Information Administration.
The average American electric bill is currently between 80 and 178 per month, totaling around 1,500 each year, according to the U.S. Energy Information Administration. Depending on how much you pay out of for a solar energy system, it could take seven years or longer to break even, according to Wayne Turett, the founder of The Turett Collaborative, an architectural firm that specializes in sustainable designs.
Another reviewer in Texas was able to take their “electricity bill down significantly, so even with the price we’re paying for the solar panels and the amount of electricity we’re using … it’s still much cheaper than what we were paying before we had them.”
But some people see their electricity bills go back up if they run into a problem with their system — a reviewer in Nevada didn’t realize their inverter needed to be replaced, leading to an unexpected increase in their utility costs.
“Everything had been going well and my energy bill had averaged 13 to 15 a month,” said one reviewer in Nevada. “Until I received a bill at the end of September 2022 in the amount of 429 from NV Energy.”
So, keep in mind there’s some maintenance after installation, like panel cleaning and occasional repairs, which adds to the overall cost. Most solar energy companies offer monitoring apps that help you see how much energy your system is producing and when maintenance may be required.
How can I pay for solar panels?
Like buying a new car, you can pay for solar panels outright — but most people don’t.
Homeowners and business owners often use loans, solar leases or power purchase agreements (PPAs) to pay for the upfront costs. You might also consider a cash-out refinance or HELOC.
Cash
If you can pay cash, it’s usually cheaper in the long run. For example, consider this review from a customer in California:
“Financing it was 18,000. But if I paid cash, it was 15,000 and they gave me a 1,000 debit card. It only cost me 14,000. I’m totally satisfied. I haven’t paid any electric bills in six months now. I’d recommend it to anybody.”
Solar loan
In general, solar loans work a lot like any other kind of loan: There’s an application and approval process, and you repay the loan amount in installments over time. Whether or not it makes sense for you comes down to your terms and break-even point.
A solar customer in California “did the math,” and everything worked out:
“Instead of paying 100 or 200 for the electric bill, if I use the same amount of energy or less, I will end up paying just the financing, which is 150,” they said. “But only for six years, and then after that, the panels will be mine and I don’t have to pay anymore.”
Just remember to pay attention to the interest rate. Another reviewer in California said they’re “paying more for the loan payment than I save from the utility. Interest payments alone are over 1,000 per year and this will continue for a long, long time.”
Lease
With a solar lease, you don’t own the equipment; instead, you make monthly payments to use them for the duration of the lease term. Your leasing company is responsible for maintaining and repairing the solar panel system during this time.
Another customer in California said they “opted for the lease approach instead of a purchase. So, we did not have to put any money upfront at all. Zero. I work in finance/accounting and generally feel that if it sounds too good to be true, it usually is. But in this case, it truly has turned out even better than we could have hoped for.”
At the end of the term, you typically have the option to renew the lease, purchase the system at “fair market value” or have the leasing company remove the system from your property.
Power purchase agreement
A power purchase agreement (PPA) is another way to get solar panels installed on your property without paying for them upfront.
An energy service company (ESCO) installs the panels for you but owns and maintains them. You then purchase the electricity generated by the solar panels from the ESCO at a fixed price.
You can still save money on your electricity bills with a PPA, but some reviewers describe feeling “stuck” with a company.
» WHAT’S THE DIFFERENCE? Solar lease vs. solar PPA
FAQ
In general, installing solar panels is a good investment. Studies show that homes with solar panels sell for more than homes without them, and that increase in value can be significant.
- A study by the Department of Energy’s Lawrence Berkeley Laboratory found homes with solar panels sold for about 15,000 more, on average, than comparable homes without solar panels.
- A National Bureau of Economic Research study found that solar panels added an average of 20,194 to the sale price of homes in the San Diego and Sacramento areas.
- Zillow found that, on average, homes with solar panels sold for 4.1% more than comparable homes without solar panels.
How much value the solar panels add depends on your system’s quality, location and other factors.
The number of solar panels you need varies based on your energy usage, the efficiency of the panels and other factors.
The average household uses 886 kWh per month in electrical power, according to the Energy Information Administration.
A solar panel typically produces about 1.5 kilowatt-hours (kWh) per day, so if your daily kWh usage is 30, you would need 20 solar panels to generate all of your energy needs.
- Energy usage: To estimate the amount of energy you’ll need, you need to know your average kilowatt-hours (kWh). This number should be on your utility bill as “kWh used.” To get your monthly average, look at bills for the past year, add up the stated kWh used and divide by 12.
- Panel efficiency: Next, you need to find the solar panel efficiency, which is the amount of energy the panel can produce per hour of sunlight it receives.
Sometimes, you might make more electricity than you need, especially on sunny or windy days.
Net metering is a system that lets you send any extra power your panels produce back into the power grid (the big network of wires that carries electricity to everyone’s houses). In exchange, you get a credit on your electricity bill.
This means that when your solar panels aren’t generating enough electricity, such as at night or on cloudy days, you can still use electricity from the grid without paying for it because you’ve already earned credits through net metering.
A reviewer in Texas explains how it worked for them: “When I first signed up, my contract was a net metering, so I paid a certain cost of kilowatt-hours used, and the utility company purchased back from me at that same price. If I generated 200 and consumed 200, my net usage was zero, and my bill was essentially zero. My contract ended and I had to renew it.
They continued: “Now, I’m paying 21 cents a kilowatt-hour for usage, and I’m only getting back 10 cents a kilowatt-hour for anything I push back to the grid. There’s another 40 a month service fee from the utility company as well. So the incentive isn’t quite what it was a year ago. Still, it’s a good value.”
It’s a win-win situation: You save money on your bill, and the power grid gets more electricity to distribute to people who need it.
Actually installing solar panels takes only a few days at most. Wiring is installed to connect the panels to an inverter, which converts the DC power generated by the panels into AC power for use in your home.
“One of the most common misconceptions is that going solar is a complicated process that involves a lot of work and expensive equipment,” said Alan Duncan, founder of Solar Panels Network USA. “In reality, the process of buying and installing solar panels is relatively straightforward, and many companies offer turnkey solutions that take care of everything from the design to the installation of the system.”
Once the installation is complete, an inspector checks the system to ensure it meets local safety and building codes. The system is then connected to your utility’s power grid.
Once that’s done, your solar panel system is activated and ready to generate electricity. You can monitor the system’s performance and energy production using a monitoring system provided by the installer.
Bottom line
Buying solar panels can get expensive. vary based on efficiency, capacity and location, but a residential solar panel system generally costs anywhere from 10,000 to 30,000. This includes the cost of the panels themselves, installation and any additional equipment needed.
The good news is we expect to see solar hardware continue to get cheaper, thanks to advancements in technology and increased competition in the market.
If you aren’t financially ready to install solar panels yet, you still have options to incorporate solar technology into your life with solar phone chargers, solar panel cars and passive solar home design.
- EnergySage, “How much do solar panels cost in 2023?” Accessed April 13, 2023.
- Center for Sustainable Energy, “How much does a typical residential solar electric system cost?” Accessed April 11, 2023.
- Solar Energy Industries Association, “Low-Moderate Income Solar Principles.” Accessed April 10, 2023.
- U.S. Energy Information Administration, “2021 Average Monthly Bill- Residential.” Accessed April 10, 2023.
- Lawrence Berkeley National Laboratory, “Berkeley Lab Illuminates Price Premiums for U.S. Solar Home Sales.” Accessed April 10, 2023.
- National Bureau of Economic Research, “UNDERSTANDING THE SOLAR HOME PRICE PREMIUM: ELECTRICITY GENERATION AND “GREEN” SOCIAL STATUS.” Accessed April 10, 2023.
- Zillow, “Homes With Solar Panels Sell for 4.1% ” Accessed April 3, 2023.
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Learn about solar energy
Solar energy is all around us. Learn how solar panels harness the power of the sun to produce electricity.
Solar energy: what you need to know
Solar power is simply usable energy generated from the sun in the form of either electric or thermal energy. Solar energy is captured in a variety of ways, with the most common being a solar photovoltaic system, or PV system, that converts the sun’s rays into usable electricity. Aside from using photovoltaics to generate electricity, solar thermal energy, or concentrating solar power (CSP), is commonly used to heat indoor spaces or fluids. Residential and commercial property owners can install solar hot water systems and design their buildings with passive solar heating in mind to fully take advantage of the sun’s energy with solar technology.
Types of solar energy systems
Interested in benefiting from solar power? Solar panels are installed at three main scales: residential, commercial, and utility. Homeowners can take advantage of residential-scale solar, typically in the form of rooftop solar or in ground-mounted solar installed in open land. Generally, residential solar systems are between 5 and 20 kilowatts (kW), depending on the size of the home.
Commercial solar energy projects are typically installed at a greater scale than residential solar. While individual installations can vary greatly in size and cost, commercial-scale solar arrays serve a consistent purpose: to provide on-site solar power to businesses and nonprofits. Finally, utility-scale solar projects are typically large-scale solar power plants that are several megawatts (MW) in size — utility-scale solar installations provide solar energy to a large number of utility customers.
For some solar shoppers who may not be able to install solar on their property due to cost or other factors, community solar is a viable solar option that more directly connects utility-scale solar energy projects to residential consumers. As such, community solar farms are typically built in central locations as opposed to on any single property. Subscribers (homeowners, renters, businesses, or non-profits) can join a community solar project to receive many of the benefits of solar power without installing solar panels on their property.
How do solar panels work?
A solar panel (also known as a solar module) consists of a layer of silicon cells, a metal frame, a glass casing unit, and wiring to transfer electric current from the silicon. Silicon (atomic #14 on the periodic table) is a nonmetal with conductive properties that allow it to absorb and convert sunlight into usable electricity. When light hits a silicon cell, the light causes electrons in the silicon to be set in motion, initiating a flow of electric current. This is known as the “photovoltaic effect,” and it describes the general functionality of solar panel technology.
The science of generating electricity with solar panels boils down to this photovoltaic effect. It was first discovered in 1839 by Edmond Becquerel and can be thought of as a property of specific materials (known as semiconductors) that allows them to create an electric current when they are exposed to sunlight.
The photovoltaic process works through the following broad steps:
- The silicon photovoltaic solar cell absorbs solar radiation
- When the sun’s rays interact with the silicon cell, electrons begin to move, creating a flow of electric current
- Wires capture and feed this direct current (DC) electricity to a solar inverter to be converted to alternating current (AC) electricity
A brief history of solar power
In 1954, Bell Labs developed the first silicon photovoltaic cell. Although solar energy had previously been captured and converted into usable energy through various methods, only after 1954 did solar power begin to become a viable source of electricity to power devices over extended periods of time. The first solar cells converted solar radiation to electricity at an efficiency of 4 percent — for reference, many widely available solar panels today can convert sunlight to solar power at above 20 percent efficiency, a number constantly on the rise. Although solar energy adoption was slow at first, a number of state and federal incentives and policies contributed to driving down the cost of solar far enough to become more widely adopted.
The cost of solar energy
Concurrent with an increase in solar efficiency, the cost of solar panels has fallen substantially. In the last decade alone, the cost of a solar panel installation fell over 70 percent, and many industry experts predict that will continue to fall in the years to come.
Additionally, depending upon where you live, several rebates or incentives for solar power may contribute towards lowering the cost of solar energy even further. Nationwide, the federal Investment Tax Credit (ITC) is one of the primary incentives available to anyone interested in solar energy, as it allows you to deduct 30 percent of the cost of installing a solar array system from your federal taxes. This incentive won’t last forever: in 2033, the federal ITC steps down to 26% and it will go away completely for residential solar installations in 2035. Many states and utilities offer further incentives (such as net metering) in addition to the federal ITC, dropping the cost of solar power even further.
Interested in seeing what solar will cost you? Try our solar calculator for a quick estimate.
Solar energy is a renewable power source
Solar energy is a clean, inexpensive, renewable power source that is harnessable nearly everywhere in the world — any point where sunlight hits the surface of the earth is a potential location to generate solar power. And since solar energy comes from the sun, it represents a limitless source of power. Renewable energy technologies generate electricity from resources that are infinite.
Compare producing electricity with renewable resources to fossil fuels: it took hundreds of thousands of years for oil, gas and coal to form. So, every time one of those resources is burned to create electricity (and emissions!), that finite resource is moved marginally closer to depletion. Using a renewable resource — such as wind, solar and hydropower — to generate electricity does not deplete that resource. There will always be consistent sunlight shining on Earth’s surface, and after turning sunlight into electricity, there is still an infinite amount of sunlight to turn into electricity in the future. That is what makes solar power, by nature, renewable energy.
While the current electricity mix in the United States is still made up largely of fossil fuels like oil and gas, renewable energy sources like solar are steadily becoming a larger part of the country’s energy profile as the cost becomes more competitive.
Should you go solar?
When it comes to installing solar panels and switching to a more eco-friendly energy source, there’s not a one-size-fits-all approach. There are several questions you should ask to help determine if your home or business is a good candidate for solar:
- How much electricity do you consume and how much does electricity cost in your area? The more electricity you use, and the more you pay for it, the more you’ll save by going solar.
- Do you own your home? If you live in a multi-family home or rent the property, it will be much more difficult to install solar than if you own a single-family home.
- Is your roof good for solar? The ideal roof for solar would be one that’s pretty spacious, is in good condition, isn’t too complex, is southern-facing, and receives plenty of direct sunlight. If not, you should consider if you have land space for a ground-mounted system.
- Are there local, reputable solar companies in your area that can perform the installation? If you don’t live in an area with multiple installers competing for your business, you may end up paying a premium.
- What incentives are available where you live? Local and state incentives could end up saving you thousands of dollars on your solar energy system, significantly shortening your payback period.
If some of these characteristics aren’t aligned with your situation but you’re still interested in going solar, read our article about if solar is right for you for more information on whether you’re a good fit.
What to know about the solar industry
According to the Solar Energy Industries Association (SEIA), solar capacity has grown about 33 percent, on average, over the past decade. In fact, the Department of Energy (DOE) reports that the United States has about 97.2 gigawatts (GW) of installed solar power capacity to date — enough to provide clean energy to about 18 million homes.
As solar capacity continues to grow, so too does the need for new solar jobs. From installing to manufacturing to performing operations and maintenance to educating consumers, there are a number of things you could be doing as a solar industry employee! As of December 2021, the solar industry supported 255,037 jobs based on data from the Interstate Renewable Energy Council (IREC)’s National Solar Jobs Census — a 9.2% increase from 2020.
The Rapid proliferation of solar power nationwide and globally has also led to parallel growth in several adjacent areas. Notably, solar battery systems, electric vehicles, and heat pumps are all sectors poised to explode alongside the solar industry by augmenting the benefits of solar.
Want to support the solar industry? Consider switching your electricity generation source to solar power! Whether you install solar panels on your home or business, or subscribe to a community solar farm, you’ll be adding to the total capacity of installed solar energy, while helping grow the clean energy economy.
Solar Panel Size Weight: A Comprehensive Guide
Have you ever wondered how big solar panels are? Solar panel size range in a variety of sizes, factors such as solar cell type, total wattage and the type of panel all affect the overall size.
In this article we are going to lay down the foundation and give you all the factors that dictate solar panel size weight. Additionally, we have created tables which give you examples of solar panel size based on wattage and solar cell type.
How Big Are Standard Solar Panels?
Standard residential solar panels, the ones you would have installed onto your homes roof, measure on average 65 inches by 39 inches, or 5.4 feet by 3.25 feet, covering an area of 15 square feet. There are slight measurement variations depending on the solar panel’s manufacturer. For large scale solar installations like the ones built onto warehouses you could expect solar panels to measure up to 6 feet (these are known as commercial solar panels). To understand solar panel size, you need to first understand the general makeup of the panel. Solar panels are made up of smaller individual solar photovoltaic (PV) cells. PV cells always come in the same standard size:156 mm by 156 mm, which is approximately 6 inches long and 6 inches wide. The majority of small scale solar installations, like the ones you are likely to get on your home, are made up of 60 solar cells. Commercial solar installations on the other hand, are made up of 72 cells, and can go up to 98 cells or more.
Solar panel size. residential and commercial panels
| FEATURE | RESIDENTIAL PANELS | COMMERCIAL PANELS |
| Average Length (inches) | 65 | 78 |
| # of Solar Cells | 60 | 72 |
| Average Width (inches) | 39 | 39 |
| Average Depth (inches) | 1.5. 2 | 1.5. 2 |
Essentially, the number of cells found in a solar panel is directly responsible for its length. See below a comparison of residential panels VS commercial panels: Most setups, whether residential or commercial usually do not comprise of a singular solar panel. So what sort of measurements are we looking at with a full blown solar installation, say something like a 10 kW solar system? Let’s assume you use 34 average sized solar panels each with a 300 watt power rating and stack them up vertically next to one another making two rows of 17 panels each. Your 10 kW solar system will measure 55,25 feet by 10.8 feet, covering a total of 596 square feet. Of course, these overall measurements assume that you place each said panel closely next to one another, leaving minimal space in between each panel. In reality however, you will need factor in slightly more area, as you need to take into consideration the unique shape/orientation of your roof.
What is the Average Area of a Single Solar Panel?
Therefore, the average area of a modern single solar panel measures 17,6 square feet.
What Factors Determine Solar Panel Size?
When it comes to the factors that determine solar panel size, you need to consider the following criteria:
Solar Panel Type
As you may well be aware by now, solar panels come in 3 main different types: monocrystalline, polycrystalline and thin-film.
Each one of these different types have their own unique advantages/disadvantages.
Here is a quick table to give you a basic understanding of the differences:
Solar panel type dictates size because of the different materials used inside each of them.
For example, monocrystalline and polycrystalline both use cells made of silicon wafers.
However, the composition of silicon in each type of solar panel varies.
Monocrystalline solar cells are always cut from a single, pure crystal of silicon.
Whereas polycrystalline solar cells are made up of smaller fragments of silicon crystals (which are melted together in a mould before being cut into sheets of wafers).
This difference in composition/makeup of the solar cells themself create slight inefficiencies.
In this case, monocrystalline solar panels are more efficient than polycrystalline solar panels and because of this vary in size.
Take for example two solar panels capable of producing the exact same wattage (take note of the difference in size):
Monocrystalline solar panel dimensions weight – 365 watt
Polycrystalline solar panel dimensions weight – 365 watt
- Dimensions: 2000 mm x 992 mm x 35 mm. Area = 6.56 x 3,25 = 21,32 square feet
- Weight: 49 pounds
Clearly solar panel type has an affect (albeit small in the case of mono vs poly) on the overall size of the solar panel, the more efficient the makeup, the less big the actual panel needs to be.
Solar panel wattage
Solar panels are made up of series of single solar cells, all of which are connected in parallel circuits to form the entire solar panel.
Of course, the higher the solar panel wattage, the more solar cells it needs to achieve that rating.
So ultimately, the more wattage a solar panel produces, the more solar cells it will require. Thus, the bigger the overall panel size.
Are Solar Panels Too Heavy for A Roof?
Let us assume you are installing an average residential solar system on to your roof.
The average weight of a 365 watt monocrystalline solar panel is 45 pounds.
To establish a 10 kW system you will need a total of 28 solar panels mounted on top of your roof.
We know that one 365 watt solar panel weighs 45 pounds and takes up an area of 20,7 square feet.
Therefore, 28 solar panels will take up an area of 580 square feet and will weigh a total of 1260 pounds.
1260 pounds ÷ by 580 square feet = 2.17 pounds per square foot. When you take into account mounting equipment, you can raise the weight per square foot to about 3.5 pounds.
This means a 10 kW solar system (with mounting equipment) will weigh 3.5 pound per square feet.
A modern roof with concrete or clay tiles should be able to support 27 pounds per square foot.
As you can see by these calculations, a 10 kW solar system should have little to no affect on your homes roof, that is, your roof is strong enough to support some of the biggest types of solar panels.
(Please note, our advice should not take the place of a professional solar installation company.)
Here’s another video: What would happen if all the houses were covered with solar panels?
How Much Weight Do Solar Panels Add to a Roof?
This all depends on what sort of solar system you are looking to install onto your roof.
Let us assume you want to install a 5 kW, 10 kW or 15 kW solar system onto your residential home.
First things first, you need to distinguish hoe many watts make up a kW.
The calculation is easy, 1000 watts makes 1 kW. Therefore, you simply have to times the kW by 1000 to figure out the total wattage.
To understand how much weight solar panels add to our roof, we need to decide on what wattage solar panel we want to install. The average residential solar panel produce 300. 420 watts.
For this example let us use a 365 watt solar panel, we already know that they weigh about 45 pounds per panel.
The calculation is as follows: 5000 watt ÷ by 365 watt panel means you will need 14x 365 watt solar panels to make a 5 kW system 14 solar panels x 45 pounds = 630 pounds.
- 5 kW solar system will add 630 pounds to your roof.
- 10 kW solar system will add 1,260 pounds to your roof.
- 15 kW solar system will add 1,845 pounds to your roof.
(Please note, these amounts do not include mounting equipment.)
Examples of Solar Panel Sizes
Average size of solar panels
RESIDENTIAL PANELS
COMMERCIAL PANELS
Vision Solar preyed on vulnerable and built without licenses, says Connecticut
Less than nine months after Vision Solar received a contractor’s license, complaints to the Connecticut Attorney General’s office were pouring in.
A residential solar installation.
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Connecticut Attorney General William Tong has filed a lawsuit against Vision Solar. citing numerous violations committed by the company. Vision Solar, a newcomer to Connecticut, was granted a Home Improvement Contractor license in December 2020, but starting in August 2021, the Attorney General’s office began to receive the first of 14 unique complaints against the company.
The attorney general’s office states that “Vision Solar preyed on low-income, elderly, and disabled homeowners, pressuring them into unaffordable loans for solar panels that in some cases were never activated”. The company’s in-home sales tactics included overstaying permitted hours, pressuring customers into immediate signatures, falsely claiming that signatures were for “pre-approval” only, and failing to deliver contracts to customers. The attorney general also alleged that Vision Solar made sales pitches to individuals with language or intellectual challenges who were unable to make informed purchasing decisions.
Vision Solar is also accused of misrepresenting the tax benefits of solar panel installation to those with no tax liability. The attorney general further suggested that Vision Solar applied for solar permits without proper licenses and may have used the license of an electrician no longer employed by the company to apply for some of those permits. Vision Solar is also alleged to have installed solar projects without a licensed electrician.
Vision Solar’s online reviews tell a similar story. With 176 reviews, Vision Solar received 1.79 out of 5 stars on SolarReviews.com. They earned an “F” with 1.21 out of 5 stars from the Better Business Bureau. with 203 reviews. On Yelp! the company earned only 1.5 out of 5 stars. and on Angie’s List (now just ‘Angi’) they received the site’s lowest possible score, 1 out of 5.
In 2020, Vision Solar sued Momentum Solar for trade secret violations. Momentum Solar itself was sued for racist and discriminatory actions. Online searches reveal multiple lawsuits against Vision Solar in New Jersey for violation of the Do Not Call list.
Despite the numerous complaints against the company, as of March 20, 2023, Vision Solar’s license is still listed as “active”.
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John Fitzgerald Weaver
Commercial Solar Guy is a commercial utility solar developer, general contractor for commercial and residential solar, as well a consultant. We construct projects in MA, RI, NY, and soon PA.