DOWNLOAD PDF GRID TIED SOLAR SYSTEM DESIGN

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1 Chapter 1 : Residential Solar Panel System Projects & Reviews This new large section covers the planning, design and installation of our new grid-tie PV system. The system is a watt grid-tie PV system using 10 PV panels at watts each. Add the most current 12 month kwh then divide by to get to a daily average. This number is critical to begin the process for a grid-tie system. Then average what you do have or if you are moving into a different house use the bills from your current home to get an idea of your energy usage. You can usually find the kwh near the top of the first page of you utility bills. An alternative method would be to go on line and down load the information or call your local utility company to find out your most recent 12 months total. One thing to note is that at some locations around the country you are charged extra for using electricity during a specific time of the day, usually in the afternoon hours of the summertime. It may be important to understand that peak period of higher charges because that information may help you down the road when you decide on your budget for your project and how best to maximize your return on investment. A smaller solar kit positioned to harvest and create the most energy during these peak tier rate times may be where you want to start. The fact is that when sizing a kit, it is not how much sun you have, it is how much sun strikes the earth in your zip code which can sometimes surprise customers. Little considered factors such an high humidity and elevation can play a key role. Example; most of Texas and Florida have latitudes that are farther south than Arizona but have less "sun-hours per day" because Texas and Florida have higher humidity levels and more cloud cover. The 2nd step in the design process is to look and see what the average amount of solar irradiance is available near your area from our resource map. Find the nearest city to your home and write down the average "sun-hours per day". Divide your daily average electricity use by average sun hours per day. For example, if the daily average electricity use is 30 kwh, and the site is in Davis, CA, the solar kit size would be: Multiply kwh by to get AC watts. That total will give you the approximate size solar kit you need to offset your utility bill. The next step is to consider a watt, watt or watt panel. Once you have a pretty good idea on the number of panels you will need you can go back to the solar kit main page and consider the cost of the kit compared to the budget you have in mind for your project. Factory Name Plate Rating, wire transfer loss, panel mismatch and soiling. Means dust and dirt accumulation on the face of the solar panel. Now divide the system AC watts by the solar panels name plate watt rating. In this example, the watt solar kit may be a good choice assuming all the other factors listed below have been considered. You want to go bigger than your last 12 month kwh consumption history? Utility companies are in the business of selling power not buying power. Even if you are allowed to do it, you will eliminate the best return on investment. Hawaii is one state that in some areas is the exception to that rule. Best Place to Locate Your Array; Key Considerations Mounting your system on the roof, ground or top of a pole; budget, roof dimensions, ground space or setbacks, shading and other site-specific factors call for careful consideration in your design. Compare the sizing results from your calculations in steps 1, 2 and 3 with the location and amount of space available to mount the solar array in order to get a rough idea of the maximum of panels. If you are planning to mount your array on a roof, decide which module best fits into the available roof space, taking into consideration obstructions such as chimneys, plumbing vents and skylights. Many local building codes will not allow a solar system to extend beyond the perimeter of the outside of the house footprint. You may not be able to utilize your roof overhang or eaves. A good place to start is to check with your local building department to see what their setback rules are for either a roof or ground mount array. How many panels will fit? Check out areas available to install your PV kit. A few things to consider; array dimensions, orientation, tilt and obstructions. Panels ideally should be mounted facing true south, but that rarely is the case. It does not matter if you point your panels east, south or west as long as you have at least 6 hours of sun centered around sometime near mid day. No well-planned installation should have a shading problem around noon. Heavily or regularly shaded panels even when operated with a micro inverter are NOT worth the investment! Avoid shading as much as possible. You will want to consider potential shading from trees, buildings, power lines, telephone poles, and obstructions like chimneys and vent pipes. Keep solar panels away from objects protruding from your roof by 3X the objects height. Fixed arrays tilted to the angle Page 1

2 of your locations latitude will generate the highest year round efficiency. However, largely because of aesthetics, most people would choose flush mount arrays slightly raised off of pitched roofs for the majority of home installations. Raising the panels off the roof about 4-6" will allow for ventilation behind the panels. Solar cells produce less electricity as they heat up. Top-of-pole mount kits are sometimes great option when you have the ground space and additional budget because you can usually orient the panels facing true south and adjust the tilt several times a year to achieve a maximum solar energy harvest. Roof type and age. If you plan on re-roofing within 5 years but are not ready yet, some homeowners will replace only the shingles located under the solar array when the panels are installed and leave the rest for later. Solar cells are activated by visible light not ultra-violet or infra-red. Solar panels produce electricity when exposed to sun light, but plan to keep your inverter s in the shade. Inverters work better when located in shaded well ventilated areas. For grid-tie inverters we sell, they can be mounted outdoors or indoors. But either location your choose, shaded well ventilated areas are best. When the water dries, the dirt or mud builds up across the bottom which can shade the entire row of lower solar cells on each solar panel. In most areas of the country you will be required to enter into a "interconnect agreement" with your local utility company. This is a simple form that lets them know you will be producing some of your electricity at your location and the equpment you are proposing is UL listed and approved. Just go to your local utility website to download the document or call your local utility customer service line and have them send one to you. Electrical Distribution; Making the Grid Connection How Electricity Flows Wire carries electricity in much the same way as a garden hose carries water. When you turn on a breaker, a electron flows in one direction and knocks another electron which knocks another one until eventually an electron comes out the other end. Voltage is the electrical pressure behind the flow of current or electrons. Current, which is measured in amps, is the measure of quantity of electrons flowing through a wire. The higher the voltage the more current the source can produce. Watts are the measure of power. Current can be increased by increasing the voltage or by lowering the resistance IE: Size of Wire or Conductor. Resistance is the inherent physical opposite to current flow. A good analogy would be to think of it as a dam holding back water. Resistance is created by electrons refusing to be stripped of their atoms and bumped or sent down the wire. The higher the resistance in the wire, the less current will flow. The only way to overcome that resistance, is to increase the pressure volts or decrease the resistance Larger Wire. An AC disconnect is more likely to be required if the inverter is not close to the main service panel. If an AC disconnect is required, is should not need to be fused unless it is the primary disconnect for the line side connection. Main Service Panel Arrh This is where it all comes together. Your homes main service panel is the heart of your electrical system and how we connect the solar system to this panel using what option is the key to everything we have done so far in the design planning. Here is why that is important to understand the difference. Before we can go any further in the final connection or exactly where we are going to connect we need to know one rule that we call a biggie in the solar industry. If the size of your system requires a 60A OCPD, this exceeds the maximum allowable backfed current for a load side connection for the given MSE specifications max. To go above that 40 amp back feed solar breaker there are several alternative One alternative to consider without having to replace your main breaker panel would be to decrease the size of the main buss bar. By lowering a amp main breaker to amps may bring your in compliance if you have to go to a 60 amp backfeed breaker for your solar system. However, before you do that a careful study by a licensed electrician should be conducted to make sure you will not stress the breaker with your existing loads. On a grid-tie solar system when the utility goes down, the solar system will also go down. What many homeowners fail to realize when they purchase a standard grid tied system is when the grid goes down, so does the power being produced by the solar panels. If that were not the case, there could be a utility worker in front of your home who thinks the electricity is off and become injured. Line Side Connection Another alternative is to consider a line side connection. A line side connection or supply-side connections means the connection between the utility company meter and your main breaker box. If you have no room in your existing service panel to add your solar system, see if the number of breakers in your main breaker box can be reduced or consider upgrading the service panel. A line side connection requires a fused blade AC disconnect. If that is required and the solar kit you select states that we will supply the AC disconnect, we will provide the upgrade Page 2

3 to a fused AC 60 amp disconnect at no additional cost to you. Our System Integrators provide polished technical advice on the design and execution of all types of installations. This single point of contact, who is already familiar with your project, is your free life line to answer your questions and help walk you through any obstacles you might incur during the process. When you buy a grid-tie kit from Blue Pacific Solar, we supply a custom electrical line drawing that shows you exactly how to connect everything. We will specify on our drawing what size and type of wire and breaker you will need to be NEC code compliant. The line drawing can be used for your interconnect agreement application with your local utility company and for your permit with the local authority having jurisdiction commonly referred to as AHJ Building Department. If you need help with your full permit documents for your local AHJ anywhere in the country, our permit document service is available to help take the hassle out of your solar purchase. While the industry has rightly focused on The Metal clad cable needs to comply with Page 3

4 Chapter 2 : Grid Tied Solar Systems Home Grid Tie Solar alte A grid-tied with battery backup system is one of the most complicated RE systems to installâ if you plan to hire a local installer, do your homework, and ask pointed questions about their related experience. Thinking about going solar with a grid-tied solar system? The first step is to figure out how much energy you use so you can appropriately size your grid-tied home solar system. One way to determine your aggregate energy use is to look at past energy bills from your utility provider. The more data on your energy use you have, the better. The more information you have on your energy usage, the more accurate you will be when sizing your grid-tied solar system. No worries at allâ we here at alte have you covered! Check out our grid-tie solar electric system calculator to begin creating a load list for your home. And for more, watch our video above for some tips and tricks on how to use the calculator. Get started on your solar journey today! In this video we discuss all of the components and their role in a grid-tied system. Components of a grid-tied solar system Solar Panels Over Current Protection Inverter or microinverters Grid-tied solar systems are generally the most common types of solar systems in areas where there is access to the electrical grid. One common misconception about grid-tied solar systems is that they will produce power when the grid is down. This is not the case. Grid-tie solar systems are most often designed to first satisfy the energy needs of the home and then feed any additional electricity produced back to the grid when allowed by the utility. Utilities require grid-tie systems to stop sending electricity to the grid during outages to protect line workers from electrocution. Grid-tie system with battery backup Already have electric utility service and a grid-tied solar system, but want the security of uninterrupted power in outage-prone locations? Check out our full offering of grid-tie systems with battery backup. Watch our video above where we discuss two options for adding battery backup to a grid-tied solar system via either AC coupling or DC coupling. Depending on your needs these are both great ways to augment an existing grid-tie solar system. Click over to our main grid-tie with battery backup page or watch to learn moreâ and see if these options are right for you. Page 4

5 Chapter 3 : Solar Power Systems - Grid-Tie & Off-Grid Solar Kits alte A grid-tied solar system generates energy from the sun and stores it in the utility grid, so you can use it anytime you need it. If you have access to the utility grid, and your main concern is getting the most value from your investment, grid-tied solar is the way to go. Sometimes, squeezing the maximum number of modules on the roof takes thinking outside the box. At some sites, ground-mounted arrays can take advantage of larger areas and better solar access than roof-mounted arrays. Pole-mounted arrays and trackers get the modules up off the ground, away from shading obstructions like bushes and snow. Beginner Interested in clean power? Already on the grid? Are utility blackouts infrequent? Have a sunny location to mount PV modules? If this describes your situation, then a batteryless grid-tied PV system could be the perfect fit. Compared to their off-grid counterparts, batteryless grid-tied systems are simple to understand and design, with only two primary components: PV modules and an inverter that feeds AC electricity back into the electrical system to offset some or all of the energy otherwise purchased from the utility. These systems are cheaper, easier to install and maintain, and operate more efficiently than battery-based systems of comparable size. Their main drawback is that when the grid goes down, they cannot provide any energy for you to use. If the grid is mostly reliable, and outages are infrequent, these systems can offer the best payback for the least price. Sizing for kwh The primary goal of a grid-tied PV system is to offset all or some of your electricity usage. Yet the first step in going solar is not sizing the PV system, but reducing electricity usage through conservation and efficiency measures. Plus, the resulting smaller system means fewer modules, which consume raw materials and energy in their manufacture and shipping. Annual energy use figures can be requested from your utility, and these values can be used to determine the PV array size. But you can guesstimate the new annual energy use if you know your consumption patterns and the approximate energy savings for your new energy-efficient appliances. For example, say you upgrade to a more energy-efficient washing machineâ you can calculate the kwh savings per load and multiply that by how many loads of laundry are washed per year to figure out its annual consumption reduction, and then repeat this calculation for all of your upgraded appliances. Once we have these two values, along with an overall system efficiency factor, a simple calculation can be used to figure the PV array size needed to offset your utility usage. After implementing energy-efficiency strategies, this home consumes 4, kwh per year. To calculate the array size needed to offset annual energy consumption, divide the annual kwh consumption by This gives an average daily consumption in kwh. Divide this amount by average daily peak sun-hours to get the approximate array size in kw. While our example system is located in New Mexico, if our house was in a less sunny climate, such as Eugene, Oregon, which has an average peak sun-hour value of 4. By plugging in various PV array size values and a few other system specifics, you can find what size array matches your annual energy production goal. You can also use PVWatts to double-check your manual calculations. You will also see that they have more conservative default values, such as inverter efficiency. Another handy feature of the PVWatts program is the ability to test the effects of various PV array tilt angles and orientations on energy output. Conversely, PVWatts can be used to find the optimal array tilt angle by entering various angles and noting which one gives the most kwh per year. Sizing within Space Constraints In residential areas especially, a primary constraint to PV array sizing can be the size of the available shade-free mounting area. PV modules can be mounted on a roof, the ground, or a pole which includes trackers. Roof-mounting generally takes advantage of underutilized space, but the installation may require penetrations through the roof, and can cause wear and tear on the roofing material while the work is being done. Ground-mounted systems take up yard space that might be preferred for other purposes garden, etc. Plus, ground-mounted systems allow more airflow around the modules for less power loss from module heating. Pole mounting has the same basic pros and cons as the ground-mounted approach, but offers the advantage of raising the array off the ground, mitigating shade issues from snow buildup or nearby bushes. Site specifics will dictate which mounting method makes the most sense for each installation. Regardless of which mounting method is used, the shade-free area, minus clearance needed for maintenance or roof setbacks required by local fire department Page 5

6 guidelines, will limit how large the array can be see Access. Crystalline PV module output averages about 12 W per ft. Where feed-in tariff FIT programs are availableâ which pay a premium rate for solar-generated electricityâ some homeowners will opt to maximize use of their roof space, which in some cases will oversize the array and produce a surplus. Even without access to a FIT program, life changes such as a new baby and increasing loads of laundry per week often provide opportunities for using those extra solar-produced kwh. Sizing by Budget Often the most confining consideration is budget. Without any federal, state, or local incentives, the array size will be limited to between 1. Each situation and site, and available incentive programs, will dictate the final PV system size and cost. But once you figure out a few specifics, you can be well on your way to meeting your renewable energy goals. Page 6

7 Chapter 4 : Sizing Batteryless Grid-Tied PV Arrays Home Power Magazine Compared to their off-grid counterparts, batteryless grid-tied systems are simple to understand and design, with only two primary components: PV modules and an inverter that feeds AC electricity back into the electrical system to offset some or all of the energy otherwise purchased from the utility. The Trojan L16 is a classic flooded lead-acid battery used in renewable energy systemsâ Ah at 6 V. This sealed gel-cell by FullRiver Battery requires less maintenance, but more delicate treatment than flooded batteries. This 2 V flooded lead-acid battery by Surrette provides 1, Ah, giving high capacity with a single series string. System sizing starts with the loads, which determine system components and cost. Sizing the PV array or other RE source of a battery-based grid-tied system is done similarly, but sizing the inverter and battery bank requires more information and calculation. Nameplate ratingsâ volts, amps, and possibly wattsâ are printed on most appliances. Watts is an instantaneous measurement of how much power is needed or produced at a given moment. Multiplying watts by the number of hours the load runs gives you its energy use in watt-hours Wh per dayâ then dividing by 1, will translate it to kwh. These tools measure volts, amps, watts, and cumulative kwh for each load. Inverter Sizing The inverter in a grid-tied battery-based system must be sized to do two things: To calculate the inverter power rating, sum the total backup loads. If surge loads pumps, compressors, induction motors are anticipated, the inverter should be sized to also handle the maximum combined surge loads. Most inverters can handle a surge twice their rated output for a few seconds. If more power is needed than a single inverter can supply, you can stack the outputs of multiple inverters to increase the total connected power and surge capabilities, or multiple inverters can separately feed separate loads. The voltage and frequency of the inverter must also match the loads. If you only need to back up V loads, then a V inverter will be your most economical choice. The second inverter selection factor is the ability to send renewable-made energy to the grid. If you have a PV array rated at 4, W, the inverter needs to be able to process the full amount. Select an inverter that will handle the larger of the two factors: Array output and maximum combined backup loads. Begin battery bank sizing by determining how many days you want to power your backed-up loads without a charging source days of autonomy. Using historical information, you can estimate the average length of time your site experiences utility outages. You can also add in a safety factor to account for extreme situations. Finally, if the days of autonomy exceed three, consider adding an engine generator as a third energy source. This will help keep overall system costs down, and result in a more reasonably sized and better utilized battery. Batteries can only supply a limited amount of energy before they are depleted. A battery-based backup power system may undergo 10 cycles per yearâ often less. For an off-grid home that cycles batteries often daily, a more conservative approach may be necessary. Once you know the desired days of autonomy, possible battery discharge level, and the energy requirements of your loads, you can size the battery. Start with the total Wh per day for backed-up loads and divide by 0. That computes the total DC amp-hours Ah per day. Divide this by 0. Then multiply this total by your days of autonomy to get the adjusted DC Ah total. Battery capacity in Ah is rated at several different discharge rates. For general sizing, use the Ah capacity at a hour discharge rate; this is a realistic discharge rate for batteries in an RE system. Once a battery has been selected, divide your autonomy-adjusted DC Ah per day by the Ah capacity rating of your chosen battery to determine the number of parallel battery strings needed. If this number is greater than three, select a larger-capacity battery to promote a balanced charge across all strings. Each parallel string of batteries will contain as many individual cells as needed in series to reach your nominal battery voltage. For example, assume that the backup load daily requirement is 8, Wh. First, correct for inverter loss by dividing by 0. This gives you 9, DC Wh per day. Dividing this by the nominal battery voltage of 48 equals Ah per day. Multiply that by 4 days of autonomy this home tends to be among the last reconnected to the grid after an outage for a total of Ahâ the minimum size battery needed. Eight Ah, 6 V batteries in series yields 48 V at Ah. Divide the Ah total capacity by Ah series battery capacity, which equals 2. Round up to 3 since batteries cannot be dividedâ the total bank consisting of 24 batteries will provide a capacity of 1, Ah. If the number of paralleled strings needed is greater than three, then source a Page 7

8 higher-capacity battery as the basic building block. The two common styles of charge controllers used with these systems attain this goal differently. Either type can be used in battery backup grid-interactive systems. Pulse-width-modulation PWM charge controllers regulate charging by adjusting the width and frequency of the full current pulses sent to the battery. The closer a battery is to full, the farther the pulses are apart, effectively lowering the charging current. Maximum power point tracking MPPT charge controllers have several advantages. Their software algorithms can operate a PV array at its MPP over a wide range of operating conditions and at a voltage much higher than the battery voltage. A 60 A controller charging a 12 V battery can only pass watts but if configured to charge a 48 V battery, it can pass nearly 3, W. Oversizing the controller slightly can be beneficial since the controller will not have to work at the upper limits of its capabilities all the time and it can harvest any unexpected wattage that could come from extra irradiance or environmental conditions. If the PV array is capable of producing more power than one charge controller can handle, consider upgrading to a larger-amperage controller, installing multiple controllers, or increasing the battery bank voltage to get more wattage out of each controller. BOS Components Bypass breakers allow bypassing the inverter and battery-based system to power all loads directly via the grid. Most commonly, these are installed for inverter or other removal and repair. A battery meter is critical to understanding a battery bank. Most systems include a production meter to measure the amount of energy produced by your renewable energy system. Incentive programs commonly require a utility-grade kwh meter. In a batteryless system, the production meter is installed between the inverter and the grid connection to measure all energy flowing between the inverter and the grid. To get a true reading of how much energy is being produced, a special kwh meter must be used. For V systems, two of these meters are needed. All electrically live parts are kept in enclosures of some type. The backed-up AC loads have their own panel; DC inputs or loads have another; and batteries are in their own enclosure. Batteries can discharge massive amounts of current if shortedâ via a dropped wrench or other conductive materialsâ so their terminals must be protected. When charging to a high voltage batteries give off hydrogen gas, which must be vented outdoors to lower the risk of fire or explosion. The battery enclosure must be sealed but vented passively or mechanically from its high point. Incoming air should be introduced at the bottom of the enclosure, and wire conduit should also extend to the bottom. Putting It All Together A grid-tied with battery backup system is one of the most complicated RE systems to installâ if you plan to hire a local installer, do your homework, and ask pointed questions about their related experience. The recent boom in PV installations has led to many new companies that have done only batteryless grid-tied work, which is much simpler and requires comparatively little design work. A North American Board of Certified Energy Practitioners NABCEP certification is good sign that the prospective installer has been tested on the basics of battery-based systems, but not a sure sign of an extensively experienced installer in that field. Access Flint Richter flint at rockygrove. He is teaching his young daughters the difference between a solar module and a solar panel. Battery Backup Inverter Manufacturers: Page 8

9 Chapter 5 : Grid Tie Solar System ebay A grid-tied solar system will reduce your current electric bill, increase your property value and mitigate future rate increases. Very nice PV array sizing tool and solar radiation tool for Europe and Africa. Includes effects of local weather, obstructions, A lot of emphasis on the conservation steps needed to get demand down. Not a lot of hands-on, but a very good introduction. Backwoods Solar Catalog The printed version of the Backwoods Solar Catalog has a lot of good educational and reference material. Available on request from their website. Concentrates primarily on obtaining government grants to reduce the cost of the system. List of good discussion forums This is a list of discussion forums I like. You can post questions on these forums and get answers. As always on the Internet, the level of expertise varies from very high to very very low, so be careful to confirm the advice you get in some way. What is the actual output from a "1 KW" PV rig? Home Energy Magazine article www. Wind Sun Solar electric library and buyers guide. Quite a few downloadable PV equipment specs, brochures, manuals. Design and Installation Manual A very good and detailed reference on designing and installing PV systems -- the best that I know of. Provides information on sizing, wiring, component selection, Also, provides a detailed check list. Some of the information is specific to California installations, but most id broadly applicable. It seems like a potentially good concept that is worth looking into. If you have had a good or bad experience with the program, please let me know They make the deal sound very attractive. So, be very very careful. On the other hand, this NREL analysis finds at least some of the lease programs to be more attractive than other forms of ownership My alternative thought would be to look at the Half Plan, and do the energy saving projects that will cost you little and save you a lot -- then, buy your PV system from the savings on other projects. Our experience with PV economics compared to other energy project economics Technol, Feb The Energy Blog article this came from Every once in a while you still find people saying that the energy and pollution involved in making PV cells exceeds the energy use or pollution they prevent during their life. This is completely and totally false -- here is the latest paper verifying this. Conclusion of the study: This is a simple and easy to build solar PV system that will provide some emergency power during power outages, and can also be used for camping or for supplying power to a few things around the house on a routine basis. It is very easy to build and a good introduction to solar projects. It can be used for camping or emergencies. The watts of PV fit on the existing roof rack, and the amp-hours of batteries in the side compartments. A pair of Morningstar charge controllers complete the system. Great system for camping, tradesmen, RVs, power outage emergencies, Page 9

10 Chapter 6 : Grid-connected photovoltaic power system - Wikipedia SolarWorld solar panels are designed and manufactured to the highest standards of quality, performance and durability.. The grid-tied solar modules from SolarWorld have an elegant modern design making them perfect for any home PV system. More Info on Solar Power Systems Introduction to Solar Power Systems Watch our introduction to solar power systems video and learn which type of solar power kit is right for you and your specific situation. We offer a variety of solutionsâ not a one-size fits all approachâ because no two homes, individuals or families are alike. Get introduced to the various types of solar power systems so you can identify the right solution for you and start generating energy with the sun today! Types of Solar Power Systems Grid-Tie Solar Systems - Best for those who already have electric utility service, but wish to significantly reduce their electric bill. Grid-Tie Solar Systems with Battery Backup - This is for those who already have electric utility service, but want the security of uninterrupted power in outage-prone locations. Off-Grid Cabin Solar Systems - Perfect for the scaled-down power needs of small homes and remote cabins, going off the grid. An off-grid system is designed for the power needs of mid-to-large size homes, going off the grid. Considering a Solar Power System? Some questions to consider: Will you be in your home for the longer term? Have you taken initial steps to become more energy efficient? Is your house south facing? Do you have a clear shot of the sun from approximately 10AM - 3PM? If not, can you remove some trees to reduce the shading effects on the solar panels? The advantages of solar energy in a home solar system include: Solar power systems harness the power of the sun to make electricity for your home, cabin, or tiny house. These renewable energy systems are available for homes that are connected to the electric grid, off-grid locations, and a hybrid of grid-tied with battery back-up. Our solar powered system packages provide you with high quality solar panels from top solar panel manufacturers, including components made in the USA. These systems include an inverter to convert the DC power from the solar panels for grid-tie systems or deep cycle batteries to AC power for your appliances for off-grid power or hybrid systems where you want both grid power and backup power. Systems that include batteries give you the ability to choose the type of battery that is right for your needs and budget. Multiple solar panel racking options are also available to safely install the solar panels, be it on the roof or on a pole. The balance of system components i. Page 10

11 Chapter 7 : Solar Kits DIY Installation Packages SolarEdge SMA Enphase Design your own grid-tied solar PV system! By inputting a few choices in our Grid-Tied Solar PV System Designer below, you'll get the estimated price for a solar PV system sized to your needs using the components you want. Tweet Grid-Tied Photovoltaic Solar Systems With the continued increase in electric costs and improved solar panel technology, residential solar systems are becoming very popular. Grid-tied photovoltaic PV systems consist of solar panels, an inverter sometimes more than one, power conditioning equipment, and a connection to the utility system grid. The home can still draw power from the utility grid during the night, or poor solar generating days due to weather or time of year. Roof mounted systems are mounted directly to the roof in a fixed position. Depending on the orientation of your roof the efficiency of the system will vary. South facing roofs are ideal and its important that they are not shaded by trees or other nearby buildings. Ground mounted systems can be either fixed or tracking. Fixed systems are oriented for the ideal southern exposure and avoidance of shading from trees and buildings. Ground mounted tracking systems come in two different versions. Single-axis tracking and dual-axis tracking. Single-axis trackers follow the sun from east to west in a single line. Dual-axis trackers an follow the sun more precisely in a circular motion from the east to west improving efficiency even more. Which one is best for you? Well that is a loaded question and best answered with the help of your solar contractor. However, here are some of the things to consider for each: Roof Mounted PV Systems â Roof mounted PV systems are typically the least expensive to install because the roof becomes the supporting structure. While this type is often the cheapest, it comes with some compromises such as: These are cheaper than the tracking units but do require space in your yard. A nice benefit over the roof mounted systems is not having to remove them for a new roof. Not likely to be an option for home owners. The increased efficiency will certainly pay for the extra construction costs over the life of the system. These systems are often smaller in size as well due to the increased efficiency. Tracking systems can require some additional maintenance to the tracking motors. Grid-Tied Net Metering I recently had a large ground mounted, dual-axis, tracking system installed at my home. The system is Our peak usage occurs in the summer time when we have central air running, a pool heater, and electric dryer. This is an ideal situation because the summer season is also the highest solar potential especially here in New England. At the end of each month the power bill can vary depending no the time of the year and power use. Some months the bill may include credits for excess power that was generated. Those credits can be applied to future bills. Above is a snap shot from our solar monitoring software that tracks our daily power generation. On this particular day we generated We likely used about 90 kw-hours of power for the day so the net power needed from the grid was only about 24 kw-hours. This was on December 17th, which is almost the shortest day of the year, so as the days get longer, and the sun gets higher in the sky, the system will generate much more power. Lately lots of our customers have been asking about the financial feasibility of installing a solar power system at their home. In most situations a solar system does make financial sense in the long term. The system will perform for well over 25 years and likely longer than that so the math made lots of sense for us. Do your home work, check references, and look at all the numbers to see if the payback meets your financial needs and goals. Page 11

12 Chapter 8 : Grid-Tied, Off-Grid and Hybrid Solar Systems - Energy Informative Grid-Tie Calculator: Size Your System for Grid-Tie. This solar panel calculation will give you an approximate system wattage so that you can get an idea of cost and components needed for your system. Estimate your rebate amount and annual system output Superior Technical Support and Engineering Services Our staff has over 60 years experience in the design and installation of photovoltaic systems. We assist you with the design over every system, from site plan review to full electrical design. Call us before you buy elsewhere! We carry grid-tie solar systems for home and business using quality name brand solar panels. Schematics denote all wiring sizing and type, and ALL recommended breakers, disconnects and components. Our schematics are very detailed. They will more than likely be all you need to obtain your installation permit for your area if one is required. We will custom build systems to suit your needs. We pride ourselves on providing the best custom electrical engineering drawings, system design and installation technical support in the industry. We will be here to support you every step of the way throughout the design, permitting and installation process. Would you like this system installed? Please contact us for details on installation through one of our authorized installers your area. The main components you need at a great price Our Discount Line of grid-tie solar kits have all of the main components for installing a solar system. These systems are an affordable way to produce energy that will reduce an electric bill by feeding electricity back into the electrical utility grid. All systems can be customized! Different module mount, module, inverter and voltage options are available. Contact us State and Federal Incentives Many states and municipalities offer significant incentives to encourage installing a solar system. Federal tax incentives are also available. Click here more incentive information. All systems we carry follow the strict guidelines set by government agencies for incentive eligibility. These systems are specifically designed to meet all rebate incentives offered by many states. We provide all of the necessary documentation for inspection. Solar grid-tie systems 10kW and larger available - call for more information or reviews. Chapter 9 : Designing and Installing a Grid-Tie PV System This workshop will cover how to Design and Select Components for a grid-tie solar electric system, including solar panels, racking, over current protection and the inverter. Category Howto & Style. Page 12