The Power of Solar Energy
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The Power of Solar Energy Carroll Electric Cooperative Corp. Page 2 INTRODUCTION: The power of solar energy is fascinating. How can something transform sunlight into electricity? The purpose of this informational bulletin is not to answer that question. Rather, this bulletin is intended to address many of the questions members of the Cooperative have about solar energy. As you can see from each region of the map, the distance, angle, and duration of the sunlight all aﬀect solar energy production. Given the sunlight available in the areas served by the Cooperative, one could reasonably expect 4.5 to 5.0 hours (see below) of solar production. Obviously, the duration of the sunlight during most days is much longer. This map translates available sunlight to a continuous duration of energy production at a solar panel’s full capacity. A number of hours (including mornings, evenings, and cloudy periods) will have less than ideal solar production capabilities. Only a few hours will approach maximum production capacity. Averaged out, solar energy (rated at maximum capacity) is available in the Cooperative’s service area about 4.5 to 5.0 hours during an average 24-hour day.
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 3 BACKGROUND: At the outset, it is important to recognize some of the common advantages and disadvantages associated with solar energy. The Cooperative recognizes not all members agree on the balance of advantages and disadvantages of solar power. Some are opposed to any generation source that produces carbon emissions. Some are opposed to any form of tax subsidies. This bulletin cannot resolve, nor is it intended to inﬂame positions held by individual members. The information provided is intended to simply present facts. Advantage Disadvantage Solar energy consumes more land footprint per kilowatt of power Solar energy does not produce any generation. Environmental pollutants or other emissions. Some panels have questionable manufacturing processes. Solar energy indicates a high degree of If NOT properly interconnected, solar Safety safety when properly connected. energy can be lethal. Does not produce energy at night. Reduced output during cloudy periods, Reliability Functional with sunlight. mornings, and evenings. (See previous page) Overall production diminishes as solar panels age. Like all generators, solar panels and their power inverters can fail. Solar panels are not prone to mechanical maintenance and wear For optimum performance some Durability associated with conventional turbine maintenance is required. power generation. Panels are not immune from physical damage. Sunlight is free. Solar bears no fuel cost to generate each kWh. Lifetime costs per kWh produced are still Aﬀordability Federal tax credits can mitigate some of higher than most traditional sources of the upfront (ﬁxed) costs. energy. Fixed costs per kWh are on the decline.
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 4 PRODUCTION MODELS: Electric energy (no matter the means of production) can, to a limited extent, be stored in batteries. However, energy is lost during the storage and subsequent release of energy into and out of a battery. While it is practical to store energy in a battery that might power something like a calculator, it quickly becomes impractical to have suﬃcient battery storage to power electrical needs of a conventional home. Batteries for Community Solar and Utility Scale do not exist. Utility In light of the inherent storage Scale Community limitations and the intermittent Solar reliability (see page 2) of solar Home or Rooftop energy, conventional sources of (Net Utility Scale power generation Battery Metering) must continue to exist in order Charging to meet electrical demands at all hours of the day. However, that is not to say solar energy does not have an important role in energy production: • Battery Charging: Solar panels are successful at charging batteries. This can be a valuable method for low energy appliances or providing power to things like electric fences that are not in close proximity to conventional power sources. • Home or Rooftop (Net Metering): At the time this bulletin was issued, 68 of the Cooperative’s 92,100 member-accounts utilize on-site solar panels through the Cooperative’s Net Metering agreement. (This bulletin will go into greater detail about the opportunity for members to participate in Net Metering.) • Community Solar: A number of for-proﬁt and not-for-proﬁt enterprises (some who are utilities and some who are not) are embarking upon projects that divide a cluster of panels among interested individuals. There is a wide variety of economic structures to fund the panels’ up-front costs and/or generate proﬁts. Often, subscriptions to a pro-rata share of the panels are sold to individuals. Without regard to any proﬁt motive, the success in generating individual subscriptions is fundamentally connected to a utility’s electric rates. Carroll Electric’s rates are among the lowest in the nation. While low rates are good for the Cooperative’s members, they are a disadvantage in generating individual subscriptions in a Community Solar project. The Cooperative will be monitoring closely the developments in Community Solar.
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 5 • Utility Scale: Conventional power plants in Arkansas typically range from 500 to 1,800 megawatts. A 12-megawatt solar array is planned for construction in Arkansas in 2015. This will by far, be the largest installation in the mid-south region of the United States. This installation will utilize 100 acres of land near Camden, Ark., and will primarily serve one industrial consumer. However, Arkansas Electric Cooperative Corp. (Carroll Electric’s wholesale power supplier) has agreed to purchase any excess generation not needed by the industrial consumer. Based on this project, it is important to note more than 4,100 acres of land would be required for a solar installation that could match (only during certain hours of the day/year) the capacity of a conventional 500 megawatt power plant. For illustration purposes, consider the actual “time of use” curves for the Cooperative: Even though maximum solar production occurs Winter Summer during the middle of the 600mW day, it remains a 8:00 AM 488mW common misconception 500mW 5:00 PM that solar energy 408mW substantially reduces the need for 400mW conventional power plants. While solar 300mW energy is chipping away at the run time of 200mW conventional plants, these plants, as 100mW illustrated to the right, must remain in service 0mW to meet demands 24 12:00 PM 1:00 PM 2:00 PM 3:00 PM 4:00 PM 5:00 PM 6:00 PM 7:00 PM 8:00 PM 9:00 PM 10:00 PM 11:00 PM 1:00 AM 2:00 AM 3:00 AM 4:00 AM 5:00 AM 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 AM hours a day.
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 6 Thanks to https://enlighten.enphaseenergy.com/pv/public_systems/ it is easy to see how much solar power is available when it is needed most. As you can see from the illustration above, the intensity of the sun is greatest during the middle of the day as indicated by the light blue areas. The dark areas indicate night, clouds, or in the case of February 16-19, 2015, snow-covered panels. It is also important to As you consider solar beneﬁts, this conversion understand this particular system has a total of 90 between “watt-hours” to “kilowatt-hours” panels installed with micro to help you understand how inverters (see appendix A). much energy you can save. It is further important to understand, the 4 “watt- hours” illustrated above are equal to four one-thousandths (4/1,000) or a total of 0.004 “kilowatt-hours.” You are billed by the Cooperative in “kilowatt-hours.” Consistent with the general indications of manufacturer’s warranties (Appendix A), these panels have produced a declining amount of energy over the past three years. For 2014, the panels produced 9% less than they did during 2012 (the ﬁrst full year of operation).
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 7 Based on the conditions from the previous page, the harsh reality of solar energy production would require about 2,600 square miles of solar panels to match the Cooperative’s expected peak demand for power. This would take a land mass that would cover four times all of the land and water in Carroll County…and this would still not produce energy at night. Land: 630 sq. miles Water: 8.7 sq. miles The big picture point is, solar energy is not a dependable or desirable resource to deal with the peak demand for electricity. Obviously, this scale of facilities would produce too much energy during other hours of the year. It would waste the power of solar energy to build more capacity than is needed. Again, until energy can be stored eﬃciently, conventional plants must remain. A balanced strategy is required. However, those who believe the utility industry, or even the Cooperative is against solar power, are mistaken. If the current price trends and tax credits continue into the future, the Cooperative expects that Utility Scale solar generation could become a solid business decision. Even if trends do not continue, it is a predictable possibility Utility Scale solar generation will be required to meet increasingly stringent government regulations. As these trends progress, an important part of the public policy debate likely will shift to the acquisition and siting of thousands of acres of land for solar generation projects. THE COOPERATIVE’S STRATEGY: The Cooperative is very sensitive to Utility Scale land use requirements and realizes the more land required for a solar project, the more valuable land resources will become. In contrast, solar energy will become less valuable as it is deployed and as it consumes more land resources.
The Power of Solar Energy Carroll Electric Cooperative Corp. Page 8 For now, the Cooperative is embarking upon a solar demonstration project. This demonstration will harvest real life, side-by-side production data about various solar energy technologies. The project is expected to be up and running in 2015. This information will be shared with members of the Cooperative to use for considering Net Metering and for future planning of Community Solar/Utility Scale projects by the Cooperative. When a Community or Utility Scale deployment of solar energy is in the best interest of the Cooperative’s members, Carroll Electric will attempt to maximize its eﬃciency…in production, cost, and land use. NET METERING: If you are interested in Net Metering, the Cooperative CECC Solar Net Metering invites you to join approximately 70 other Carroll Electric members. Accounts by County While some would argue this doesn’t sound like very many, Barry, MO 3 northwest Arkansas has the highest concentration of Net Metered Benton, AR 23 accounts in the state. Boone, AR 1 Carroll, AR 22 Madison, AR 6 Carroll Electric is happy to visit with you about any facet of Net Newton, AR 12 Metering. If we don’t have the answer, we will do our best to get it Stone, MO 1 for you. Feel free to make inquiries at 1-800-432-9720. Total 68 Arkansas Law (Code § 23-18-601) enables you to participate in Net Metering within certain requirements prescribed by the Arkansas Public Service Commission (APSC). As presently implemented, you can receive a full retail kWh credit for each kWh generated on a monthly net basis, even if at the time that kWh is generated it ﬂows back onto the Cooperative’s system. In essence, the other members of the Cooperative are purchasing these kWh at retail prices instead of wholesale. This subsidy to incentivize Net Metering is insigniﬁcant today. However, if distributed generation gains market share, those who cannot aﬀord the up-front costs associated with Net Metering will bear an increasing share of the costs for those who can make these investments. Regardless of how you feel about this, the bottom line is to understand there is no assurance this level of incentive will continue into the future. To assist members in navigating the process of Net Metering, the Cooperative has developed a checklist for members to use:
Net Metering Checklist: 1-800-432-9720 | www.carrollecc.com Ask for one of our Contact the Cooperative P.O. Box 4000 Member Services Berryville, AR 72616 Representatives Certain safety requirements are your legal responsibility. Review The Cooperative is also required to ensure the connection to your Net Information Metering facility meets certain code requirements. Packet The goal is to ensure you, the public, and our employees operate in a safe environment. Solar panels come in a wide range of selections. This is a good area for you to do your homework Consider prior to signing any contracts. Product Often overlooked, is the type of power inverter Appendix A Options needed to make your system function its best. Understand what the product warranty covers. Consider How a panel is installed dramatically affects its Installation performance. Appendix B Methods The economics can vary greatly based on your Do the Math decisions above. Appendix C The Cooperative cannot install the system for you. Even though Carroll Electric will inspect the Select a system to ensure it meets safety specifications, Qualiﬁed your electrical components must be installed by Appendix D Installer a licensed electrician. All hardware and components must be UL listed. It is up to you to select someone you trust. Complete all requested information, including a Within 30 days, one of the Return Cooperative’s technicians diagram of the system. Required will schedule a safety inspection of your Documents A completed Net Metering Agreement must be facilities. Pending approval, a unique meter to the signed by the member holding service at this required to properly bill Cooperative location. your account will be installed. After the field visit has been satisfactorily completed, the Cooperative will execute the Keep your agreement and return a signed copy to you. Agreement The billing for your account will continue based on rates, terms, on Hand and and tariffs approved by the APSC and the calculations of the meter. Appendix E your System You must notify the Cooperative of any modifications to your Net Metering installation 30 days in advance of making any changes. Functioning Net Metering installations require annual inspections at the rates and tariffs approved by the APSC.
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.1 Product Options: PANELS Power Typical High Space Low Upfront High Cost Technology Output Residential Efficiency Cost Efficiency Efficiency Installation Amorphous Not practical for residential applications. Thin Film Cadmium Telluride ** Panels Copper Indium Gallium Selenide * * Organic Photovoltaic Crystalline Monocrystalline Silicon Panels Polycrystalline * High power output and space efficiency have only been achieved in laboratories. ** If space efficiency is not an issue, this type should be given consideration in residential applications. Thin Film Solar Panels There are four common thin film solar panels: • Amorphous Silicon (a-Si) Panels: Because the output of electrical power is so low, a-Si solar cells have traditionally only been used in small scale applications such as in pocket calculators. However, recent innovations have made them more attractive for large scale installations. A manufacturing technique called “stacking” is being utilized bringing their efficiency up to 6-8%. The stacking process involves stacking several layers of a-Si solar cells on top of one another. Stacking is expensive. Therefore, the Cooperative does not recommend a-Si panels for residential installations. • Cadmium Telluride (CdTe) Panels: CdTe panels have surpassed the cost-efficiency of crystalline silicon panels in large scale applications. The efficiency of CdTe panels varies from 9-11%. In residential applications, space efficiency is often an issue and other types of panels are available that have higher space efficiency values. Therefore, CdTe panels are not typically a homeowner’s best choice. However, if space efficiency is not an issue, CdTe panels should be given consideration.
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.2 Copper Indium Gallium Selenide (CIGS) Panels: Compared to other thin film panels, CIGS panels currently have the most potential. In laboratories, an efficiency rating of 18.7% has been achieved, but it has yet to be proven if CIGS panels can be mass produced at that efficiency. For now, CIGS panels do not appear to be ideal for a homeowner. • Organic Photovoltaic (OPV) Panels: OPV panels consist of at least one layer of organic electronic material sandwiched between two metallic layers. One of the metallic layers is typically made of indium tin oxide while the other is made of aluminum, magnesium, or calcium. The electronic material is typically a small molecular polymer such as plastic. OPV panels are relatively inexpensive to manufacture, but their efficiency ratings are typically less than 1%. OPV panels are not recommended for residential applications. Depending on the technology, thin film prototype panels have reached efficiencies between 7-13% and production panels operate at about 9%. In the future, thin film panels are expected to reach efficiencies of 10-16%. About 5% of panels installed in the United States residential sector are thin film panels. Crystalline Silicon Panels While thin film panels will produce electricity, the Cooperative typically recommends using one of the following types of crystalline panels: • Monocrystalline Panels: These are typically the most efficient panels manufactured. Their coloring is uniform which is indicative of high purity silicon. Advantages Best efficiency rating (15% - 20%) Higher efficiency ratings = higher space efficiency (do more with less) Highest life expectancy - many companies offer a 25 year warranty (see below). Tend to perform better than similarly-rated polycrystalline panels in low-light conditions. Disadvantages Least affordable upfront cost. During the manufacturing process large amounts of silicon are wasted. (http://news.yahoo.com/solar-industry-grapples-hazardous-wastes-184714679.html)
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.3 • Polycrystalline Panels: These have lower efficiency ratings than monocrystalline panels. Their coloring is sometimes described as “sparkling blue” which indicates lower purity silicon was used to manufacture them. Advantages The manufacturing process is less expensive than that of monocrystalline panels making polycrystalline panels more affordable. The manufacturing process yields less wasted silicon. (http://news.yahoo.com/solar-industry-grapples-hazardous- wastes-184714679.html) Disadvantages Lower efficiency rating (13% - 16%) than monocrystalline panels. While polycrystalline panels typically have the same warranty as monocrystalline panels, research indicates a shorter life expectancy. Some believe the “sparkling blue” coloring to be less aesthetically pleasing than the uniform coloring of monocrystalline panels. Most (95%) residential panels installed in the United States are made from crystalline silicon. The purity level of the silicon holds a direct relationship with the efficiency of the panel. Product Options: POWER INVERTERS There are three main types of solar power inverters: stand alone, grid tie, and dual inverters. The following explanations will help one decide which inverter is best for his/her situation. Also, micro inverters are relatively new technology to the solar industry. The advantage of using micro inverters will also be discussed. 1. Stand Alone Inverters are used for off-grid solar arrays. With off-grid arrays, the solar panels generate direct current (DC) electricity. The electricity is stored in rechargeable batteries. When energy is required, direct current is sent from the battery to the stand alone inverter where it is converted to alternating current (AC). AC power is the type of power Carroll Electric provides to its members’ homes and businesses. Employing the use of DC appliances would eliminate the need of an inverter in off- grid systems.
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.4 If any large appliances or equipment are to be powered using a stand-alone solar system, it is necessary that a surge-compliant inverter be installed. These inverters are also necessary for most residential and commercial grid tie solar applications. Large appliances require a surge of energy when first being powered up, therefore it is necessary the inverter is able to supply this surge of electricity when required. Most larger off-grid inverters have this capability. However, it should be verified this feature is available before making a purchase. 2. Grid Tie Inverters are for use in any situation that a solar array is connected directly to the local power grid. By law, a Net Metering Agreement must be signed and all required safety measures must be achieved before tying to the grid. Please note when connecting to Carroll Electric’s grid, all equipment must be UL listed. With grid tie solar systems, direct current is generated by the solar panels. The DC power is sent to the grid tie inverter where it is converted to AC power. From the inverter, the AC power is sent to Carroll Electric’s meter. The meter constantly monitors the amount of electricity being used by your home or business and the amount of electricity you are producing. At the end of each billing cycle, the meter is read. If more electricity is used than the panels produced, Carroll Electric bills the member for the net amount. If the panels produce more electricity than the equipment being powered has consumed, the net difference is rolled over to the next billing cycle. All grid tie systems are required to have a solar energy inverter with anti-islanding protection which forces the solar array to shut down in case of power outages. Without anti-islanding protection, your solar array would continue to generate electricity and energize the electric grid during power outages. This energy would stay in the local power grid and is referred to as an island. These islands are extremely dangerous for utility workers who are repairing the grid during a power outage or anyone who might come near a downed power line. 3. Dual Inverters are also known as backup battery inverters and are used in a multi- function solar facility. In this system, the direct current generated by the solar panels is first sent directly to a battery array. The energy from the batteries is then sent to the
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.5 inverter and converted to alternating current whenever electricity is required. However, when the batteries are fully charged, any excess direct current electricity generated is sent directly to the inverter and is then sent into the local power grid. This system combines the other two systems into one. A dual inverter allows one to produce, store, and consume any electricity a solar facility produces. A Net Metering Agreement and satisfaction of all safety protocols are required when installing this type of system or any other system that is tied to the grid. 4. Micro Inverters, as previously mentioned, are relatively new technology in the solar power industry. If micro inverters are not used when panels in a solar array are wired together, the panels must be wired in series. A series circuit relies on all components to function properly or the entire system will not work. An example is a string of Christmas lights not working because of one bad bulb. Micro inverters allow solar panels to be wired in parallel. A parallel circuit allows electricity to continue to flow even if one or more components of the circuit fail. This innovation makes solar arrays more reliable than they were in the past. A central inverter is not needed if micro inverters are used. Micro inverters are highly recommended. Virtually all new residential installations utilize micro inverters.
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.6 Product Options: WARRANTIES When considering which vendor to select, you should carefully read the warranty in effect at the time. Like all products, solar panels are subject to failure. Most solar panel manufacturers offer a 20-25 year warranty for the panels they manufacture. It is important to understand the 20-25 year warranty is generally only for power output. Shorter warranties generally apply to batteries (if installed), inverters, tracking motors (if installed), and parts and labor. With any warranty, there are always exceptions. One of the most common warranty stipulations is proper equipment installation. With this in mind, be sure to hire a qualified and trustworthy contractor. Power Output Chart 1: Solar Panel Warranty Comparison Most solar panel production (As a Percenage of Rated Output) warranties are for less than the rated output and drop over time. 100% Defective Panels Solar panels are typically 95% warranted for defective material or workmanship (factory defects). tenKsolar 90% This portion of the warranty is Trina Solar typically around 10 years in length Sunpower from the date of installation. A 85% Standard proper warranty should cover Suntech items such as delamination or early Yingli Solar failure. (See below.) 80% Batteries Battery warranties range widely 75% 1 3 5 7 9 11 13 15 17 19 21 23 25 from 1 - 10 years, but it is said that Year CECC Feb. 2015 many batteries have a life expectancy of up to 20 years. Batteries tend to be one of the least troublesome components of a solar system. If one malfunctions, it is most likely due to a factory defect and the failure typically occurs before the warranty has expired. Inverters Inverters typically carry 5 - 10 year warranties. Top manufacturers claim life expectancies of 20
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.7 years. An inverter is usually the most expensive single piece of equipment in a solar facility. Inverters are also the most common component to fail. It is highly recommended to install a quality inverter. With most inverters, there is a direct correlation between quality and length of warranty. Higher quality inverters typically have warranties of approximately 10 years. Tracking Systems A variety of systems are available to track the sunlight (see Appendix B). Some are motorized and some utilize other technologies to initiate movement of the panels. Some warranties require routine maintenance such as greasing the moving parts and can vary as much as 2 to 10 years in length. The Cooperative recommends you carefully evaluate the warranty elements of the tracking system being considered. Parts and Labor Parts and labor warranties are sometimes offered by installers in addition to the factory warranties of the system components. It is recommended that a dealer who offers a parts and labor warranty be hired. Additional Considerations • Solar panels do not operate well in high heat locations. Always allow good airflow around panels. For example, never mount solar panels directly to a roof. A raised mounting bracket is highly recommended for roof installations. This allows for airflow across the back of the panel. Lack of airflow around a panel can be extremely harmful to the panel. In fact, it is rarely recommended to install panels on a roof. However, sometimes it is the best option. It is a good idea to consult with your installer to ensure your installation method does not invalidate your product warranty. • One of the common sources of panel failure is delamination (http://breakingenergy.com/2011/10/07/solar-panels-dont- Delamination due to humidity. work-and-no-one-knows/), which can result from loss of adhesion between encapsulants. Encapsulants are the outer layers of the panel that encompass the other layers of the panel. Within the encapsulants are more layers that gather the sun’s energy.
The Power of Solar Energy Appendix A: Product Options Carroll Electric Cooperative Corp. Page A.8 According to researchers, higher than acceptable sodium phosphorous content in the outer glass layer of a panel can cause delamination, especially in damp/hot areas. This can only be avoided during the manufacturing process. The best way to address this issue is to ensure the panels are purchased from a reputable manufacturer who will honor the warranty of the panels. • Production warranties generally do not cover accumulations of dust, leaves, snow, and ice or panel installations that receive any shade from sunlight. Generally, if any portion of a single panel is covered by shade or anything else, at minimum, that panel will stop producing power. Without a micro inverter, the entire array will stop producing power. Do your homework to understand if your panels are insured for damage by your property owner’s insurance policy. For rooftop installations, it is a good idea to ensure roof damage and/or leaks remain adequately covered. • Physical damage to a solar panel due to hail, tree limbs, fire, or other hazards is typically not covered by the warranty.
The Power of Solar Energy Appendix B: Installation Carroll Electric Cooperative Corp. Page B.1 Installation: The output of your system depends heavily upon the installation method. Here are four common methods: 1. Fixed Tilt The panels should face south and be tilted at latitude. An average latitude value for northwest Arkansas and southwest Missouri is 36.5°. A GPS unit can be used to find the exact latitude of an installation site. Facing the panels south and pitching them at latitude allows for optimal power generation from a fixed tilt installation. 2. One-Axis Tracking One-axis solar trackers rotate on one axis moving back and forth in a single direction. Different types of one-axis trackers include horizontal, vertical, tilted, and polar aligned which rotate as the names imply. Because this installation has the potential to absorb more sunlight, it is better than a fixed tilt installation. There are automated and manual versions of one and two-axis tracking systems. 3. Two-Axis Tracking Two-axis trackers continually face the sun because they can move in two different directions. Types include tip-tilt and azimuth-altitude. Two-axis tracking is typically used to orient a mirror and redirect sunlight along a fixed axis toward a stationary receiver. Because these trackers follow the sun vertically and horizontally they help obtain maximum solar energy generation. 4. Roof Mount The chart below gives tilt angles for various roof pitches. If possible, it is best to mount panels on a freestanding structure instead of a roof. Roof mounted panels make it more difficult to maintain the panels and roof. Roof Pitch 4/12 5/12 6/12 7/12 8/12 9/12 10/12 11/12 12/12 Degrees of 18.4° 22.6° 26.6° 30.3° 33.7° 36.9° 39.8° 42.5° 45° Tilt Angle
The Power of Solar Energy Appendix B: Installation Carroll Electric Cooperative Corp. Page B.2 Before you install on a rooftop, you should consider the age, condition, and structural strength of the existing roof. It may pay dividends in the long term to install new shingles and/or roof decking prior to installing solar panels. Consider Shading The condition and cleanliness of a solar system can be excellent, but if any portion of the array is covered by shade, the entire system could be rendered inoperable. Consider growth patterns of trees and other vegetation so no shadows are cast on the array. Plan ahead, to ensure the array is not shaded by any future structures (storage shed, home addition, additional solar panels, etc.) If periodic shading is unavoidable, the use of micro inverters (Appendix A) is strongly recommended. Panel Orientation Careful planning should be done when initially orienting a solar array. If not done properly, you will not experience the full benefits of solar energy.
The Power of Solar Energy Appendix C: Do the Math Carroll Electric Cooperative Corp. Page C.1 The Math: For many members, solar energy is NOT about the math. A number of members feel it is the responsible thing to do and view it as their contribution to the planet. The Cost/Beneﬁt Analysis on the following page will help you understand your contribution as well as the economic beneﬁts it produces. The Cooperative recommends you maximize the energy eﬃciency of your home ﬁrst. If you want to install solar panels too…Carroll Electric is here to help facilitate that. Visit www.carrollecc.com for energy eﬃciency tips or contact one of our representatives for a free home energy audit. The Cooperative’s commitment to energy eﬃciency has earned Carroll Electric recognition as an Energy Star Partner. In 2013, Carroll Electric was awarded the EPA’s Leadership in Housing Award recognizing the important contributions made by the Cooperative toward energy eﬃciency initiatives in members’ homes. Did you know… Until December 31, 2016, the federal government is offering a 30% tax credit, with no upper limit, for installation of: (1) geothermal heat pumps; (2) solar energy systems; and (3) residential wind turbines.
The Power of Solar Energy Appendix C: Do the Math Carroll Electric Cooperative Corp. Page C.2 Cost Benefits Up-front costs: Energy Savings: 1. Solar panels $ A. Watt rating for each panel watts 2. Inverters $ B. Number of panels panels 3. Batteries $ C. Total watts (line A x line B) watts 4. Installation $ D. Conversion factor (1,000 watts = 1 kilowatt) 1,000 5. Total (lines 1-4) $ E. System rating (line A divided by line B) kW F. Expected efficiency (Appendix A: Chart 1). 6. Interest or financing charge This percentage should reflect the drop in $ % percent warrantied output and could reasonably 7. Federal Tax Credit (if applicable) $ be between 80%-97% over the life of system. Estimated maintenance/replacements over useful life: G. Expected output (line C x line D) kW 8. Solar panels $ 9. Inverters $ H. Average generation time in hours. hours 10. Batteries $ 11. Labor $ I. Expected kWh per day (line E x line F) kWh/day 12. General maintenance $ J. Expected kWh per year (line G x 365) kWh/year 13. Property insurance $ 14. Total (lines 8-13) $ K. Avoided cost of power (per kWh) $ 0._______ 15. Projected Lifetime COST L. Estimated Annual BENEFIT $ $ (line 5 + line 6 - line 7 + line 14) (line J x line K) Payback period in years (line 15 divided by line L) years See Table 1 and Table 2 on next page. According to research by https://notalotofpeopleknowthat.wordpress.com/2014/04/20/solar-panel-degradation/ failure rates of some panels range from 5.5% to 22%. See Appendix A for the types of warranty information you should understand about your specific product installation. It is impossible to accurately predict costs not covered by product/vendor warranties over the life of your system. See Appendix E to get an idea of what is necessary to keep your system operating at its best. Some community solar projects are projecting 2.5% of investment as a reasonable estimate. The National Renewable Energy Laboratory estimates 4.5 to 5.0 hrs. per day. It is important you consider if your system's installation method (See Appendix B) will maximize energy output before utilizing NREL's estimates. Data indicates some systems only capture approximately 3.0 hrs. per day. The tilt and direction of your panels matter. For the 25 years between 1989 and 2014, Carroll Electric's average residential rate per kWh rose from $0.0754 to $0.0970. This is an annual increase of 1%. However, these amounts include fixed charges which are unavoidable by Net Metering accounts. These figures also include the incentives to promote Net Metering that are embedded into existing law and regulations. It is impossible to predict future fixed charges or what the law and regulations may hold for Net Metering. Using the variable portion of 2014 residential rates and applying the 25-year historical trend to that portion, one could expect the variable component of rates to average approximately $0.0987 over the next 25 years.
The Power of Solar Energy Appendix C: Do the Math Carroll Electric Cooperative Corp. Page C.3 Table 1. Time Value of Money Total Interest Expense Per $1,000 Interest Rate: 5% 6% 7% 8% 9% 10% 5 years $ 132 $ 160 $ 188 $ 217 $ 246 $ 275 10 years $ 273 $ 332 $ 393 $ 456 $ 520 $ 586 15 years $ 423 $ 519 $ 618 $ 720 $ 826 $ 934 Viewed as a 20 years $ 584 $ 719 $ 861 $ 1,007 $ 1,159 $ 1,316 Loan 25 years $ 754 $ 933 $ 1,120 $ 1,315 $ 1,518 $ 1,726 30 years $ 933 $ 1,158 $ 1,395 $ 1,642 $ 1,897 $ 2,159 Example : A ten year loan at 6% for a $20,000 system would create $6,640 ($332 x $20k) in interest expense. If paid from personal savings, what "Return on Investment (ROI)" is expected? (ROI based on $1,000 investment) Interest Rate: 1% 3% 5% 6% 8% 10% 20 years $ 220 $ 806 $ 1,653 $ 2,207 $ 3,661 $ 5,727 25 years $ 282 $ 1,094 $ 2,386 $ 3,292 $ 5,848 $ 9,835 Viewed as an 30 years $ 348 $ 1,427 $ 3,322 $ 4,743 $ 9,063 $ 16,449 Investment Example : A 1% investment return on a $20,000 system expected to last 30 years, would require cost recovery of $6,960 ($348 x $20k) to match the earnings potential of simple compound interest. Enter appropriate value from either table above: $ Total Investment (line 5 from previous page) IN THOUSANDS x Multiply the previous two lines to get…line 6. Interest or financing charge $ Table 2. Property Insurance FREE STANDING ROOF MOUNT Est. Low Actual Quote Est. High Est. Low Actual Quote Est. High Current Rates $ 4.99 $ 5.87 $ 6.75 $ 7.03 $ 8.27 $ 9.51 In 5 years* $ 5.78 $ 6.80 $ 7.82 $ 8.15 $ 9.58 $ 11.02 INSURANCE In 10 years* $ 6.70 $ 7.88 $ 9.07 $ 9.44 $ 11.11 $ 12.78 Rate per In 15 years* $ 7.77 $ 9.14 $ 10.51 $ 10.95 $ 12.88 $ 14.81 THOUSAND In 20 years* $ 9.01 $ 10.60 $ 12.19 $ 12.69 $ 14.93 $ 17.17 per YEAR In 25 years* $ 10.44 $ 12.28 $ 14.13 $ 14.71 $ 17.31 $ 19.90 In 30 years* $ 12.10 $ 14.24 $ 16.38 $ 17.06 $ 20.07 $ 23.08 * Inflation based on annual increases of 3%. Enter appropriate value one of the columns above: $ Total Investment (line 5 from previous page) IN THOUSANDS x Annual Insurance Expense $ System life expectancy (in years) x Multiply the previous two lines to get…line 13. Property Insurance $
The Power of Solar Energy Appendix D: AREA INSTALLERS Carroll Electric Cooperative Corp. Page D.1 Choosing an Installer: Choosing the right installer can make all the difference in your satisfaction with your solar system. This bulletin is just a starting point for the product and vendor options available. This section is also a good place to define relationships. The installer has responsibilities to you concerning the installation of your system. That agreement is strictly between you and the installer. You and the Cooperative both have responsibilities concerning the Net Metering agreement. That agreement is strictly between you and the Cooperative. The Cooperative does NOT recommend you execute a Net Metering agreement provided by an installer. The Cooperative will provide you the most current version of the Net Metering agreement. The Net Metering agreement is a total of five pages in the format illustrated below: The next page contains a list of area installers. The list is not intended to be all-inclusive nor is it intended as a recommendation by the Cooperative.
The Power of Solar Energy Appendix D: AREA INSTALLERS Carroll Electric Cooperative Corp. Page D.2 Area Installers Name Address Areas Served Contact Information Arkansas Wind and 2 Bitworks Way All of Arkansas, Southeast Local: 479-846-9300 Solar Prairie Grove, AR Missouri, and Eastern Toll Free: 888-805-5235 72753 Oklahoma www.arkansaswindandsolar.com Eureka Power and 259 CR 301 Northwest Arkansas and 479-244-0377 Light Eureka Springs, AR Southwest Missouri email@example.com 72632 Liberty Solar 38 Pintuerero Way Will travel up to three 501-463-2432 Solutions Hot Springs, AR 71909 hours from Hot Springs 501-463-2433 www.libcosolar.com Pinkley Superior 47 Vaughn St. Northwest Arkansas and 479-253-9544 Electrical and Eureka Springs, AR Southwest Missouri Communications 72632 Power Source Solar 2201 W. Battlefield Rd. Missouri and parts of (417) 833-4274 Inc. Springfield, MO 65807 Northwest Arkansas www.solardockpower.com Preferred Energy 6502 Ming Dr. Missouri and North Office: 417-453-6362 Mountain Grove, MO Arkansas Cell: 417-818-6057 65711 www.preferredenergy.com Rocky Grove 3299 Madison 3605 Most of Arkansas, 479-665-2457 Sun Company Kingston, AR 72742 Southern Missouri, and www.rockygrove.com Eastern Oklahoma Stellar Sun 126 Bearskin Lake Loop All of Arkansas 501-225-0700 Scott, AR 72142 www.stellarsun.com Sunrise Solar 1606 CR 329 Northwest Arkansas and 479-244-5139 Eureka Springs, AR Southwest Missouri firstname.lastname@example.org 72632 Stitt Energy Systems 1301 S. 8th St. All of Arkansas and Local: 479-636-8745 Rogers, AR 72756 surrounding states Toll Free: 800-367-7374 www.stittenergy.com
The Power of Solar Energy Appendix E: Keep it Going Carroll Electric Cooperative Corp. Page E.1 Making the investment is not enough. You KEEP IT will want to keep your system functioning at GOING its best. Here are some things to keep in mind: General Maintenance • Depending on where your panels are installed, you may need to prevent vegetation from growing in a manner that would shade any portion of the panel. This includes overhead vegetation and undergrowth for free-standing systems. • The mounting frame on free-standing panels should be periodically inspected for structural stability. If the mounting frame shifts, the array may not be at its optimum orientation. • Avoid allowing riding mowers, tractors, or other forces (including debris) that could damage the array or supporting structure near free-standing panels. • Periodically inspect all system components and ensure they are securely fastened to the frame. Ensure all electrical components remain unexposed. Over time, electrical connections can loosen. It is recommended to periodically check all electrical connections including wiring of panels, inverters, batteries, and any other components that require wiring. Also, check the integrity of any visible wires. • Some panels are more susceptible than others to collecting foreign materials. Layers of dust on a solar panel will hinder its ability to produce electricity. Dust may need to be periodically rinsed off the panels using water. If thick dirt, grime, bird droppings, etc. are present and cannot be rinsed off the panels, use a Dust covered panels - before sponge and cold water to remove them. Do not use and after cleaning. detergents to clean the panels. • Once the panels are clean, conduct a visual inspection. Look for cracks, chips, delamination, fogged glazing, water leaks, and discoloration. If any defects are found, they should be addressed immediately. Contact the installer or the manufacturer of the panel. It is
The Power of Solar Energy Appendix E: Keep it Going Carroll Electric Cooperative Corp. Page E.2 possible the panel is under warranty. • Snow, ice, leaves, and other types of debris should be removed from panels for optimum performance. This is especially important if you intend to store or use energy during the event of a utility outage. Tracking Systems • With a manual tracking system, it is recommended to adjust the orientation of the panels on a weekly basis. • An automatic tracking system does not have to be adjusted, but it should be periodically inspected to ensure it is properly tracking the path of the sun. The Cooperative’s Net Metering equipment cannot detect if your system fails or is operating at a reduced efficiency. If your system does not record your panels’ kWh production, we recommend you request a meter be installed to help you monitor your system. This can be done by your installer or a licensed electrician. It is up to you to know if your panels are working properly. Investing into solar energy can be an empowering endeavor. The Cooperative wants you to have all the information you need to do it properly and keep it going.
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