Skip to content
How Much Roof Space Is Needed For Home Solar Panels. Solar rooftop system installation

How Much Roof Space Is Needed For Home Solar Panels. Solar rooftop system installation

    How Much Roof Space Is Needed For Home Solar Panels?

    When it comes to residential solar panels, your home’s roof is the most obvious place to put them. But it’s easy to get confused about how much roof space is needed for solar panels in order to install a home solar power system. Not all roofs are constructed to the same size or specifications, and some homes have roofs with steeper pitches, while others have roofs with more faces or odd shapes.

    We’d love to tell you a simple formula for the exact amount of square footage that is required for a certain number of panels, but it’s not quite that simple. Each residential solar panel array is custom designed to match the homeowner’s needs and the unique size, shape, and dimensions of their roof, so the square footage that’s needed is going to depend on a number of factors.

    If you’re wondering, “How many solar panels will fit on my roof?” then here are a few things to consider.

    How To Calculate The Solar Potential Of Your Roof

    There are a few rules of thumb you can follow that can offer a general idea of how much roof space is needed for solar panel installation. These guidelines can also help determine how much roof space you have available to put solar panels on.

    Generally, every square foot of roof space has the potential to generate about 15 watts of solar energy. Thus, a solar panel installation on a small home might only need around 200 square feet of roof space, while a larger home can require more than 1,000 square feet of roof space to properly offset electricity usage.

    To offset an average amount of energy usage by the average American home, you’ll typically need around 18 to 24 panels to be effective. That is, of course, if everything about those panels is ideal, where the positioning is optimal, the panels are of a standard rating, and the location gets adequate sunlight year-round. If you change any of those variables, the number of panels you need is going to change as well.

    If you want to get a sense of how many panels a roof can support, you don’t need a fancy solar panel square footage calculator. Here’s an easy calculation you can do: Multiply the square footage of your roof by.75 to account for the required solar setback. ( on that below.) Take that number, and divide it by 17.5, which is the average square footage of the standard solar panel size. The resulting number is the maximum number of solar panels you can fit on your home’s roof.

    If you’re not sure of the square footage of your roof, there’s another relatively easy calculation you can do: First you need to know the dimensions of your roof from ground level. You can measure two sides of your roof from the ground, and then multiply those numbers together to get the square footage. If your roof isn’t flat, you need to account for the angle of your roof as well, so measure the angle from the ground (most smartphones have angle measurement apps that you can use) or just use 35 degrees to get a rough estimate if you don’t have an unusually steep or shallow roof. Then take the square footage that you measured from the ground and divide it by the cosine of your roof’s angle to get the total square footage. If you need a solar panel square footage calculator, you can click this link to get a sample calculation for a roof that measures 400 square feet from the ground, and has a 35 degree angle, and then just change those values to match the measurements that you take.

    How Close Can Solar Panels Be To The Edge Of The Roof?

    Most roof-mounted solar installations will need a “solar panel setback” for safety. This is one of the most common roof requirements for solar panels in local and state building codes. This setback is the open space between the edge of the solar array and the edge of the roof, and it provides an unobstructed pathway around your rooftop for emergency responders like firefighters to get better access to your home in case of an emergency.

    The minimum solar panel setback varies from state to state, but generally, the setback will take up about 25 percent of your roof’s usable space. This accounts for two roughly 36-inch wide pathways that run along the edge of your roof, on a roof with just two basic faces. If your roof is more complicated than that, with multiple faces, or different shapes that come together at odd angles, your setback requirements may be different, which is why it’s important to work with solar professionals when designing your home solar power system. Palmetto’s team of solar designers not only make sure your roof space is optimized for power production but that it also meets the requirements of all jurisdictions as well.

    Factors to Consider When Determining How Many Solar Panels You Need

    When determining how many solar panels you need, it’s important to start by thinking about what your goals are and why you want to go solar in the first place. Do you want to maximize your return on investment? Do you want to save as much money as possible? Do you want to reduce your upfront costs? Do you want to have the biggest environmental impact and reduce your carbon footprint as much as possible? Most people want a balance of these goals, and may have other priorities as well, so it’s helpful to get a clear idea of what your specific end goals are before you start designing a solar power system.

    Once you have your goals in mind, then you can determine how many solar panels you need to get there. This calculation is going to depend on how much energy your family uses, how much roof area you have available for solar panels, the location of your home and the angle of your roof, how much sunlight shines in your part of the country, the efficiency of the solar panels you’re using, and if your local utility offers net metering. Plus, you also need to consider your budget, because a large solar power system might produce more energy, but it’s going to cost more for the initial installation as well.

    Here are a few things you should think about when determining how many solar panels you need for your roof.

    Energy Usage

    How many solar panels you’ll need, and thus how much roof area for solar panels you’ll need, starts with an estimate of how much power you use in a given year. There are plenty of ways to determine your annual energy usage, but the easiest is to simply take a look at your current monthly energy bill. It should tell you how many kilowatt-hours of energy you use in a given month, then just multiply that number by 12 to get an annual estimate. If you don’t know your own estimated energy usage, a good starting number is that the average American home uses about 11,000 kWh of energy every year.

    much, roof, space, needed, home

    You should also consider any potential changes to your family’s energy usage in the future that you might want to account for. For example, if you buy a new electric vehicle that you plan to charge at home, or if you start working from home more often, or if you expand your family with a new child, your energy needs might change pretty significantly from the previous year.

    Location (How Much Sunlight You Get)

    Different parts of the country get different amounts of sunlight. For instance, Arizona is famous for intensely sunny days. On average, Arizona gets 300 days of sunshine every year. Conversely, Juneau, Alaska, spends more than two-thirds of the year in darkness.

    This impacts how much roof space is needed for solar panels, because depending on where you live, you’ll need more or fewer solar panels. So if you live somewhere with lots of sun, you might only need enough roof space for a few solar panels. But if you live in Juneau, you’ll need lots of solar panels on your roof to harness the available energy.

    The direction of your roof also determines how many solar panels you need, as southern-facing roofs in the northern hemisphere are ideal, as they receive more direct sunlight and can use that sunlight to create more energy. If your roof does not face south, you may either need a more complicated installation to get your panels facing the right direction, or you may need more panels to make up for the difference in energy-creating potential.

    Size and Rating of Your Solar Panels

    Solar panels can vary in size and rating, leading to different sized systems for the same amount of energy output. Some panels might be smaller but have a higher watt rating, which means they’re more efficient than a larger panel with a lower rating. That’s why you must consider the efficiency of the panels when determining the total solar panel system size for your roof.

    While the efficiency of solar panels might vary, solar panel sizes typically don’t, as most companies have a standard solar panel square footage to make installation easier. The standard solar panel size dimensions are about 65 inches by 39 inches, which is roughly 17.5 square feet.

    Your Solar Budget

    Generally, larger systems are a great way to quickly offset your current electrical and fossil fuel energy usage. However, larger systems are naturally more expensive. While you may have the roof real estate for a large array, you might not have the financial budget for it, and vice versa.

    Another thing to consider when figuring out your budget is whether your local utility offers net metering, and what rate they offer for that net metering. If you’re not familiar, net metering is when your utility company offers you credits for the extra energy that your system produces and feeds back into the grid. These credits can then be used to offset the cost of power that you might need to draw back from the grid, such as at night or during storms if you don’t have a battery storage system. If your local utility offers a generous net metering policy, it may allow you to expand your initial budget and then make up that difference over time.

    Is It Possible To Install Too Many Solar Panels?

    Believe it or not, it’s not always beneficial to install as many solar panels as you can possibly fit on your roof. Adding extra panels that aren’t needed just increases the cost of your initial investment, and if you don’t have a way of capturing or getting credit for the extra energy that you’re generating but not using, then you’re not getting a good return on that investment.

    A good solar installation should offset as close to the exact amount of energy that you use as possible. That’s why we typically ask for samples of previous power bills when designing a system. These power bills help us estimate your power requirements, and design a system that matches your specific needs. Some months you might use more energy than your system produces, and some months you might use less energy than you produce, but at the end of the year, the goal is to generate about the same amount of energy as you use.

    That said, there are some instances where it makes sense to install more solar panels to generate more energy than you plan on using. The first is if you plan on installing an energy storage system to capture that excess energy. Solar battery storage lets you use the energy you generated during the day to power your home at night, and also gives you a backup source of power in case you have a blackout or other issue.

    Another time that you might want to generate more power than you plan to use is if your utility offers a strong net metering benefit. Net metering is when the utility gives you credit for the extra electricity that your solar power system produces and then feeds back into the grid, and this can help offset the cost of any electricity that you pull from the utility when your system isn’t generating electricity, like nighttime or during large storms.

    In general it’s not possible to install too many solar panels (as long as your roof has space for them) but there just might not be a significant advantage to doing so.

    How To Put Solar Panels On Your Roof

    Your home’s roof space is just one of the factors that determines the optimum solar power system for your family’s needs. The arrangement of panels and the difficulty of the installation is determined by your roof, but you also need to consider your family’s energy needs, any future changes that your family might expect, your local incentives and net-metering programs, and a variety of other factors. Fortunately, Palmetto can help figure out the precise number and type of panels that will work best for your roof, and make it easy to get a system that’s perfectly matched to your family’s needs.

    To find out how many panels you can put on your roof, get started with a free solar estimate, and a Palmetto solar expert will help design a system that’s just the right size to meet your energy goals.

    How To Install Solar Panels

    We earn a commission from partner links on Forbes Home. Commissions do not affect our editors’ opinions or evaluations.

    • Working time: 20 hours
    • Total time: Up to 2 months for paperwork and inspections
    • Skill level: Advanced
    • Project cost: 18,000 for materials and labor

    Installing the best solar panels can save you money while also protecting the environment. Some systems allow independence from the electrical grid, or the ability to earn profits by selling power back to suppliers. Many people find relief in simply lowering their energy bills.

    THIS IS AN ADVERTISEMENT AND NOT EDITORIAL CONTENT. Please note that we do receive compensation for any products you buy or sign up to via this advertisement, and that compensation impacts the ranking and placement of any offers listed herein. We do not present information about every offer available. The information and savings numbers depicted above are for demonstration purposes only, and your results may vary.

    Power Your Home With Solar

    Find a network of trusted installers for your solar system, solar panels and electricity needs. Find a solar panel installer today!

    Usually, specialists or general contractors are hired to install solar panels. Once you know how to install a solar panel, you’ll better understand how the process is done, and you may even decide you can do it yourself.

    When to Install Solar Panels

    Solar panels can be installed during any time of year. If you live in an area that receives regular snowfall, it may be best to wait until the snow has melted for ease and safety, depending on the types of solar panels you choose.

    Safety Considerations

    The components of a solar panel are bulky and often installed on a roof. Use extreme caution and fall protection when working on a roof. Be particularly cautious while bringing materials to the roof and while working near the edge.

    Installation of a solar system involves working with electricity. Follow all safety procedures regarding the installation of electrical components.

    Tools

    • Tape measure
    • Pencil or marker
    • Drill with bits
    • Chalk line
    • Wrench set
    • Screwdrivers
    • Metal cutting saw
    • Electrical wiring tools

    Materials

    • Photovoltaic panels
    • Racking system
    • Roof sealant (roofing tar or silicone)
    • Power inverter
    • Batteries
    • Charge controller
    • Energy meter (optional)
    • Heat sink (if needed)
    • Electrical wiring components

    Instructions

    A solar panel is really a collection of solar photovoltaic panels (PV panels). Those panels are connected to several components that are used to control sun-generated energy.

    There are many things to consider regarding solar power for your home. If you’re thinking about installing your own solar panel, you may want to start by hiring a solar energy consultant. They’ll have all the information you’ll need to help make decisions about your project. A hired contractor, on the other hand, will have their own experts to help you make decisions.

    A consultant can also direct you to specific manufacturers that best meet your needs.

    Check for Compatibility

    To get started, make sure your home is ready to accept a solar energy system. Find out if your roof is large enough, or if you have room to place the panels at ground level. You may need to remove trees or trim branches. Your electrical panel might need upgrading. Be sure your roof is in good shape and won’t need to be replaced soon.

    Select the Size

    Once you know that your home is compatible, decide what you would like your system to provide. You can use the energy to simply run lighting or a few appliances, you can create enough energy to sell some back to the power company or anything in between.

    Get Permits

    Apply for a building permit for your locality. Some areas may also require a separate electrical permit. Oftentimes, waiting for the permits to be approved, and scheduling the subsequent inspections, are the most time-consuming parts of the project.

    Apply for Incentives

    Make the most of your solar investment. Incentive programs vary at the state and local levels. Federal incentives change from time to time, too. You may be able to receive tax credits, rebates or grants from multiple sources to offset costs. Apply for these incentives prior to starting physical work. You may consider applying for a special solar loan to finance the project.

    THIS IS AN ADVERTISEMENT AND NOT EDITORIAL CONTENT. Please note that we do receive compensation for any products you buy or sign up to via this advertisement, and that compensation impacts the ranking and placement of any offers listed herein. We do not present information about every offer available. The information and savings numbers depicted above are for demonstration purposes only, and your results may vary.

    Compare Quotes From Top-rated Solar Panel Installers

    Select a State To Get Started With Your No Commitment, Free Estimate

    Preparation

    Because solar panel requirements vary greatly depending on needs and locations, solar panel components that are unique to your project often need to be ordered from a retailer. Order everything you’ll need at one time, if possible, to ensure all of the materials are compatible with each other.

    Install Racking System

    Measure and mark a layout for the system on your roof or on the ground. Install the metal racking system, following manufacturer instructions. Seal any holes through roof shingles with roofing tar or silicone caulk.

    much, roof, space, needed, home

    Install Panels

    Connect the PV panels to the racking using the supplied clamps to secure them in place. Then, wire each panel to the adjacent panels.

    Install Heat Sink

    A heat sink is a device used to reduce heat generated by the panels. They also increase the efficiency of the array. Heat sinks are often integrated into PV panels. If not, an external heat sink will need to be added.

    Install Charge Controller

    The charge controller sends electricity to where it is needed. It automatically allows electrical current to flow through the system or into the batteries for storage. Install it between the panels and battery bank.

    Install Battery Bank

    Generated energy that is not immediately used in your home will be stored in a battery bank for use when the sun is not shining. Wire the batteries together in series to essentially create one big battery.

    Best Solar Companies By States And Cities

    Install Power Inverter

    The power coming directly from your solar panel and batteries will be direct current (DC) electricity. It must be converted to alternating current (AC) for use in household wiring. For this purpose, install a power inverter after the batteries and power controller, and before the connection to the house.

    Install Energy Meter

    Most solar systems include the use of an energy meter. This device allows you to know how much electricity you are generating and using. It can also keep track of the amount of energy needed from, or sent back to, the electrical grid.

    Check Electrical

    Before wiring your new solar panel system to the house, be sure to double-check all wiring. Be certain to ground the system at the PV panels. There will need to be an electrical inspection performed by your municipal inspector at this point.

    Connect to Electrical Panel

    Wire the power inverter directly to the electrical panel following device instructions depending on how the system will be used.

    THIS IS AN ADVERTISEMENT AND NOT EDITORIAL CONTENT. Please note that we do receive compensation for any products you buy or sign up to via this advertisement, and that compensation impacts the ranking and placement of any offers listed herein. We do not present information about every offer available. The information and savings numbers depicted above are for demonstration purposes only, and your results may vary.

    Compare Quotes From Top-rated Solar Panel Installers

    Free, No-commitment Estimates

    When to Call a Pro

    Installing a solar panel is a complex, time-consuming task. Most homeowners opt to have their system installed by specialized solar companies from start to finish. A solar contractor will also know how to help you receive any incentives you’re entitled to.

    For DIY installations, hiring a contractor for certain parts of the job is common. Many people install the entire system and leave the wiring to a licensed electrician. Call in a professional to complete any portion of the job that you’re not comfortable doing yourself.

    Looking For Hassle-Free Solar Installation

    Find a network of trusted installers for solar system, solar panels and electricity needs. Find a solar panel installer today!

    THIS IS AN ADVERTISEMENT AND NOT EDITORIAL CONTENT. Please note that we do receive compensation for any products you buy or sign up to via this advertisement, and that compensation impacts the ranking and placement of any offers listed herein. We do not present information about every offer available. The information and savings numbers depicted above are for demonstration purposes only, and your results may vary.

    Get expert advice on your home, design tips, how much to pay for pros and hiring experts, delivered to you daily.

    I agree to receive the Forbes Home newsletter via e-mail. Please see our Privacy Policy for more information and details on how to opt out.

    How to Install Solar Panels

    Installing a home solar system is one of the best gifts for your family. You will save on utility bills, conserve the environment, and even create jobs. However, if you want to go solar, you must first understand how to install solar panels. There are some solar projects that you can install with little knowledge, even if you aren’t a professional.

    But when dealing with larger projects, the installation process might get tricky, and you’ll end up hiring an expert to do the job.

    How to Install Solar Panels on the Roof

    The following are things to consider before the installation process:

    The Size of Your Home

    your home’s physical design will determine the number of solar panels to install and where you can mount them. For instance, big houses with large roofs can accommodate more panels compared to small roofs.

    Additionally, the roof design determines if it’s possible to fix the solar facing the sun’s direction.

    Accessories Materials Necessary

    The next thing to do is making a quick checklist of materials necessary for the installation. They include a battery, power inverter, charge controller, and solar panels.

    Energy Consumption

    The power requirement in your residential place depends on the appliances and the lighting systems that use electricity. When using power from the grid, you’ll get the energy needed from solar energy through analyzing your monthly energy bills. After that, you can offset most of your electricity expenses with solar energy.

    Number of Sun Hours

    According to TurbineGenerator, Texas has approximately 5 sun hours in a day. The energy produced by a solar panel depends on the number of sun hours in that area. The more the sun hours, the more power you receive with a few solar panels. But if the sun hours are less, you’ll have to fix more panels to deliver the same amount of power.

    That’s why it’s vital to understand the number of sun hours in your locality before you start installing the solar panels.

    Step-by-step Guide to Install Solar Panels on your Roof

    Step 1: Choose the Right Location

    Start by surveying your house to find the best location to fix the solar panels.

    Don’t forget that just because the sun targets a specific area within the rooftop doesn’t mean it’s the right place to place the panels. The direction and the pitch of your roof affect the efficiency of the solar modules.

    Therefore, be sure to use a location that will offer the panels proper exposure to the sun.

    Step 2: Mount Installation

    The next thing to do is fixing the roof mounts that will hold the solar panels. It can be flush mounts or roof-ground mounts, but this depends on the installation requirement. Additionally, the base structure offers maximum sturdiness and support, and more care is given on the direction under which the PV panels will be fixed.

    Additionally, the mounting structure should be tilted slightly at an angle of between 18-36 degrees Celsius. Most solar panel installation organizations use a solar tracker to boost conversion efficiency.

    When designing the mounting system, ensure you have in mind the width and length. Please make mounting strong to sustain extreme weather conditions.

    Step 3: Now Install the Panels

    Now it’s time to fix the panels on the mounting structure. You can do this by tightening the bolts and nuts. The role of the bolts is to make sure that the modules are firmly held on the platform.

    You must be careful while installing the solar panels to get rid of damages and accidents.

    Step 4: Do The Wiring

    While doing the wiring, you have to wire together the solar modules using a fused combiner or junction connector. Ensure that the cables are properly insulated to prevent power accidents from leakages. Once you complete, fix the interior control panels with the exterior wiring.

    The connection allows energy to move from the disconnect to the charge controller system, then to the battery bank for power storage. Power can also flow directly from the disconnect to the inverter.

    The wiring process is very crucial, and that’s why you shouldn’t do the installation personally when you aren’t an expert. Instead, look for professionals with good experience in wiring to prevent damage or injury to the system.

    Step 5: Ground the Mounting System and The Panels

    Earthing the mounting system plus the solar panels is vital during the panel installation since:

    • Offer safety against chances of fire that may arise from the system
    • Protects you and your family from the electric shock that may be catastrophic
    • Protects the solar panels against lightning as it creates a power surge

    That’s why you must install the grounding rods about six inches above the ground. Furthermore, the mounting system is made of metal; that’s why you must earth it. You must also ground the control panel inside the house if you lack an earthing network in place.

    Step 6: Connect Your Electrical Components

    Since the connection determined by the kind of solar system is in place, connecting the remaining parts should never be a a big deal. In case the system has a battery backup, you can place as many components as possible.

    But in this case, you must use the right connections between the charge controller, battery, and solar panels. From there, direct the power from the inverter to the control panel of your house.

    Step 7: Perform A Test Run

    It would be best if you looked over everything once again before you initialize a test run. The primary purpose of carrying out a test run is to ensure that every connection is properly working. Immediately after you finish, you can now close the book then begin reaping the benefits of solar energy.

    How to Install Ground-Mounted Solar Panels

    If you choose to ground mount the solar panels, here’s the process

    Step 1: Build a Strong Foundation

    Even though Ground mounting is different from roof mounting, most principles still apply. Therefore, start by building a sturdy foundation under which you’ll fix the racking rails by pouring concrete and setting piers. Make sure you use protective gear while doing this to prevent injuries. Here are some important guidelines for setting up a foundation:

    • Make sure the ground is level.
    • Use a string line or chalk to mark the exterior measurements and the location of the piers.
    • Construct a temporary lumber substructure to place the piping in a superior position as the concrete solidifies.
    • Get everything else in a good position before mixing the concrete once it’s wet, and you won’t get time to make changes and adjust forms.
    • Relax for one week between constructing the piers and constructing the rest of the array. The concrete takes about three weeks to dry fully. Don’t touch the wooden brace until the concrete is cured fully.

    Step 2: Install the Racking Rails

    The racking report specifies the spacing for the system plus the rail size. You must keep it handy during this process.

    Start by spacing the rails to match the mounting holes’ measurement at the back of the panel. The exact sizes are on the racking report.

    When you start a new row, create some space to accommodate the panel overhang on both sides. Additionally, make a ½ to 1-inch gap between the panels.

    Step 3: Mount the Panels

    With the racking rails housed and installed in a strong concrete foundation, the solar panels are now ready for mounting.

    • Position the panel in a proper place to allow the mounting holes to line up with the rails. Use Universal Fastening Object clamps to hold the panel in place. Begin with the far end on the array’s exterior side and then drop the T-bolt in the slot within the rail.
    • Next, torque the clamps using stopper sleeves to make them snug against the exterior sides of the first panel then lock it in place.
    • After that, slot the second pair of clamps on the first panel’s inner edge then position the next panel on the rails to ensure that the clamps are wedged between all the panels.
    • Properly tighten the clamps on the panels then do the same for each panel within your array.

    Step 3: Battery Installation

    When installing an off-grid system, the last phase of the installation process is establishing a battery bank. Once done with the installation process, your city or country inspector should sign off on it. Accomplish this by planning an inspection meeting with them.

    If you still don’t have solar panels fixed in your home, it’s time to invest in one. Use the steps above to install it personally. But when the project is large, be sure to hire experts.

    We can help you install solar panels and say goodbye to utility bills. Get in touch with us for a free solar quote. Enjoy free energy from solar!

    Perfect Guide For Rooftop Solar PV Systems

    Akshay VR. 21 Jan 2022

    Introduction

    The Rapid urbanization of the world has led to major changes in housing, land use and environmental effects. In these times, switching to renewable energy for our electricity demands is the best potential in terms of investment and also in terms of solving the energy crisis. However, the available land for installing large renewable energy systems seems to be depleted due to Rapid construction and architectural developments.

    So to accommodate these obstacles, a type of solar photovoltaic (solar PV) system had been developed which is known as rooftop solar PV systems. This is a type of solar PV system that involves the generation of electricity using solar panels mounted on the rooftops of residential, commercial or industrial buildings or structures.

    The rooftop systems include solar modules, inverters, electrical accessories and mounting cables and systems. These systems usually have power capacities in the megawatt range. Residential buildings usually vary between 5-20kW whereas commercial structures/buildings have power capacities reaching up to 100kW. This system mitigates the need for extra land by using the large rooftops of buildings and integrally alleviates environmental concerns.

    For more such amazing content, do follow our LinkedIn page.

    They can also be developed as hybrid systems by combining with other power components such as wind turbines, batteries, generators, etc. whether they are on-grid or off-grid systems [1]. Therefore, to shed light on this system and its potential, this article will be elaborating on solar PV rooftop systems, its components, mounts, exporting of generated electricity and some of its technical challenges.

    Factors affecting Rooftop Mounting

    Some of the factors that can affect the performance of rooftop solar systems are mentioned below:

    • Latitude
    • Weather conditions
    • Time of the year
    • Shading from adjacent structures and/or vegetation
    • Roof Slope
    • The orientation of roof mounts
    • Airflow: airflow is better because it helps to cool down the panels which aid in maintaining the voltage levels at an optimum. Higher the voltage, the higher the power and the output energy because

    Components of a Rooftop Solar PV System

    A rooftop solar PV system consists of several components all of which have to be accommodated on the roofs of different building structures. The components which make up a rooftop solar PV system are:

    1] Solar Panels: These devices are commonly made from silicon and are comprised of multiple solar cells which absorb sunlight and use the energy from the sun, photon energy, to generate electricity. Solar panels are often laminated and protected by tempered glass and frames to protect them from any damage which can affect the performance of electricity generation.

    2] Inverters: Rooftop solar systems are connected to either micro-inverters or string inverters. These devices convert the DC power from the panel into AC power which can be sent to the grid.

    3] DC/AC wiring: These are wires which connect inter-connect panels and which connect panels to inverters. Such cables and wires should not be hanging from the roofs or touching roof surfaces to protect them from degradation and weathering.

    4] Mounting clamps: These are usually made from aluminium and stainless-steel brackets and bolts which secure the solar panels to the roof, to the rails and each other. These clamps often vary in design to accommodate the different types of roof materials and orientations.

    5] Rails or racking: These structures are often made in parallel orientation to the roof and are made with metals. They are levelled with the roofs so that the panels can be mounted securely and evenly.

    6] Mounts: These structures attach the rails to the roofs using bolts or flashings into the rafters or trusses of the roof. These structures also vary in design to accommodate the different roof configurations and styles.

    7] Flashings: These are materials such as metal plates which act as a water-resistant seal between the roofs and the mounts to prevent water damage

    Different Types of Rooftop Mounting Systems

    The mounting of solar panels on rooftops depend on the slope of the roof and for residential building, the roof mounts are aligned with the slope of the roof. For commercial or industrial buildings, the roofs are often flat and there are roof mounts for such systems as well. These are covered below:

    1] Steep-Sloped Roof Mounts: Sloped roof requires mounts which need to be penetrated or anchored into the roofs. They are common for residential installations and are classified as flushed mount, shared-rail, and rail-less systems. These systems usually have solar panels oriented either horizontally or vertically with clamps attached to rails. These rails are secured on the roof by using bolts and screws.

    a) Flush-Mount Systems: These systems are usually mounted with around 3-6 inches between the solar module and the roof surface. This space between them helps to keep them cool which reduce voltage losses due to temperature effects. Flush-mount systems usually are mounted on roofs which are made from asphalt shingles, tiles, wood shake shingles and metal roofs which make them versatile for residential installations. Such systems are waterproofed through a method called ‘Flashing’ which is the overlapping of materials to prevent the intrusion of water. This creates a watertight seal to prevent water damage to the system.

    b) Shared-Rail Systems: These systems involve 4 rails attached to 2 rows of solar panels. There is one rail in the middle that is shared, and such systems require a lesser number of penetrations which makes installation quicker. The panels installed in such systems can be oriented in any direction and these rails which are clamped with panels allow the accurate positioning on panels in the desired orientation.

    c) Rail-less Systems: As the name suggests, the solar panels are directly connected to the bolts and screws in the roof wherein the frames of the panels act as rails. These systems are lower in costs due to lesser manufacturing components and shipping costs but they still need the same amount of attachments as that of a shared-rail system. Panels can be oriented in any direction and are not limited by the rigidity of the rails and the installation time is faster for such systems.

    2] Low-Slope Roof Mounts: These roof structures are most common for commercial or industrial buildings where the roof can even be flat. Due to the nature of the roof, PV systems installed on such roofs do not have frames and only have PV laminates. This is because if the panels get soiled through dirty water, snow or any other matter, the flatness or low slope of the roof prevents the particulates from sliding down. If frames are used, the dust and dirt will accumulate near the frames which will increase maintenance requirements and reduce total power output. There are mainly 2 types of low-slope roof mounts and they are:

    a) Penetrating Systems: These mounts attach the racking system to a strong part of the roof using structural attachments such as posts, pedestals, standoffs or jacks. The strong parts of the roof comprise of trusses, rafters or purlins which are capable of withstanding the weight of the PV systems.

    b) Ballasted Systems: These mounts are not structurally penetrated to the roofs but are designed in such a way that something heavy is placed on the PV system to hold and keep it down. Materials like rectangular concrete blocks commonly known as paving stones are often used. Ballasted systems are useful when the roof is unable to take extra loads or if the geographical location is a windy region. These racking systems are also designed with wind deflectors to keep them stable in windy conditions.

    3] BIPV and Solar Shingles: This is the 3rd type of mount systems which involve integrating solar panels into the buildings to avoid any structural attachments. It’s designed as a built-in structure which eliminates the need for mounting systems. However, although it is aesthetic and convenient, these panels tend to operate at higher temperatures due to lower airflow which will affect the overall efficiency of the PV system. It’s also more expensive since it’s not mass-produced like other solar technologies. The concept of BIPV is covered in another article.

    Exporting Electricity to the Grid

    Owning a grid-tied solar PV system irrespective of whether they’re ground-mounted or roof-mounted can offer opportunities to send your generated electricity to the grid which can lead to 2 types of mechanisms:

    Solar Labs makes it easy to create solar design sales proposals in minutes instead of hours. We simplify 3D modeling, financial reporting and allow you to convert more customers with compelling proposals.

    1] Net-metering mechanism: Grid-tied solar PV systems such as rooftop solar systems can avail of this type of mechanism where if the generated electricity is in excess, the consumer can export the excess electricity to the electricity grid. Depending on the amount of power exported, the consumer gets credit in return. When it’s time for the billing cycle, the consumer only gets charged for the net power which is the difference between the imported and exported power to the electricity grid. This is why it is termed as net-metering. In this mechanism, there isn’t any selling of power and this mechanism is used to adjust the electricity bill by cutting down bill costs significantly. Over time, the consumer can also generate electricity for free.

    2] FIT Mechanism: This mechanism is known as the Feed-in Tariff mechanism where a grid-connected rooftop solar system can sell the generated electricity to the electric utility. The electricity that is sold can be used by the grid elsewhere. Consumers who own such solar PV systems are slowly shifting to this type of mechanism because of the revenue yield. This mechanism also enables the investor of the installer to be paid back. Utilities such as the Public Utility Commission sets a standard rate for the electricity which the utility pays for, and this rate can either be a wholesale ate or a retail rate. In either case, this mechanism has led to the solar payback period being shortened due to higher revenue yield and the installation demand for solar PV systems has increased significantly. The solar PV industry has grown exponentially in the recent decade owing to this FIT mechanism because of the thousands of jobs and revenue that are being generated from photovoltaics alone. This industry has also allowed for reduced transmission losses because of increased localization in production

    Technical Challenges

    The previous sections have elaborated on the potential of solar PV rooftop systems. However, there are some technical drawbacks when assimilating a large number of solar PV rooftop systems to the power grids. They are:

    Ramp Rates: Since PV systems are dependent on sunlight, there’s a lot of variability in power generation. The effect is more pronounced when there are intermittent clouds that impede electricity generation due to the blockage of sunlight. This further affects the voltage levels in the distribution feeder by causing an imbalance in the voltage and frequency levels. than often, this variability leads to the voltage and frequency levels to exceed the limits set unless they are accompanied by power controls in the system. There’s a formation of frequency mismatch because the centralized generators cannot match or ‘ramp’ quick enough to match with the variability leading to blackouts. This occurs due to the instability of the grid because of the constantly fluctuating voltage levels. This drawback is partially alleviated by adding storage and by distributing solar panels over a wider area on the rooftop.

    Reverse Power Flow: The distribution feeders are designed radially to allow only one-way power flow which is transmitted from centralized generators to the customer loads. Now, distributed and localized rooftop solar PV systems have led to the reverse power flow where there are chances for power to flow back to the transformers and sub-stations. These can cause significant negative impacts on the voltage regulation, protection and coordination of devices being used for such systems.

    much, roof, space, needed, home

    Despite these drawbacks, due to the advancements of technology and the timely realization of these drawbacks, performance monitoring systems using Smart technology and AI have been developed to counteract these negative effects and resolve these issues accordingly.

    Conclusion

    These days, consumers and households are shifting more towards solar and alternate energy technologies. In the past decade, solar has been revolutionized to suit the needs of the general public because it was initially seen as the’ technology for the rich’. Nowadays, due to Rapid advancements and lowering costs, many middle-class income consumers have also started to purchase and invest in solar technology especially solar rooftop systems due to its convenience and benefits which outweigh the negatives. The local, federal and state governments and utilities have also developed many incentives to shift towards renewables due to the growing concerns in electricity demand and supply. Therefore, rooftop solar PV systems have been growing in capacity in the recent past to accommodate the changing trends in the market. This is why it is essential to consider such systems as it has been covered in the article. From factors which affect rooftop systems, types of mounted structures, the export of electricity to technical challenges, this article has covered the basics of everything you need to know about solar rooftop systems. This article also aims to bring an understanding and positively change the mindset as to why shifting to renewables is the future of our industry!

    Republic Of Solar

    Insights, Resources and Opportunities.

    Leave a Reply

    Your email address will not be published. Required fields are marked *