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134-690: The Xsabo Lira Power Station (Xsabo Lira Solarline) is a US$ 45 million 50 MW/AC solar power plant in Uganda that will be implemented as a ‘’Public-Private-Partnership (PPP)’’ with Lira District Local Government. The corresponding Memorandum of Understanding (MoU) has been approved by the Attorney General of the Republic of Uganda . Xsabo Lira Solarline is part of the US$ 200 million planned investment of The Xsabo Group, whose owner and brain child

268-413: A photovoltaic system , or PV system, produces direct current (DC) power which fluctuates with the sunlight's intensity. For practical use this usually requires conversion to alternating current (AC), through the use of inverters . Multiple solar cells are connected inside panels. Panels are wired together to form arrays, then tied to an inverter, which produces power at the desired voltage, and for AC,

402-414: A "sea" of unpowered lines, as the solar array continues to deliver DC power during the power outage. Islanding is a hazard to utility workers, who may not realize that an AC circuit is still powered, and it may prevent automatic re-connection of devices. Anti-Islanding feature is not required for complete Off-Grid Systems. Although still expensive, PV systems increasingly use rechargeable batteries to store

536-477: A PV cell is defined as the fraction of incident solar irradiance that is absorbed by the cell. When the sun is at the zenith on a cloudless day, the power of the sun is about 1 kW /m , on the Earth's surface, to a plane that is perpendicular to the sun's rays. As such, PV arrays can track the sun through each day to greatly enhance energy collection. However, tracking devices add cost, and require maintenance, so it

670-403: A PV solar installation varies greatly and is typically less useful than a calculation of return on investment . While it is typically calculated to be between 10 and 20 years, the financial payback period can be far shorter with incentives . The temperature effect on photovoltaic modules is usually quantified by means of some coefficients relating the variations of the open‐circuit voltage, of

804-443: A balance of system may include any or all of the following: renewable energy credit revenue-grade meter, maximum power point tracker (MPPT), battery system and charger , GNSS solar tracker , energy management software , solar irradiance sensors, anemometer , or task-specific accessories designed to meet specialized requirements for a system owner. In addition, a CPV system requires optical lenses or mirrors and sometimes

938-476: A budgeted cost of US$ 200 million. The five solar power stations are going to be developed in tandem, one after the other. Construction is planned to be launched in December 2023, 9 months after commissioning of Xsabo Nkonge Solarline ( Nkonge Solar Power Station ) on 31 March 2023 and to be concluded with commissioning on 31 December 2024. Solar power Solar power , also known as solar electricity ,

1072-427: A cell that can reach 44.7% efficiency using the equivalent of "297 suns". Photovoltaic cell electrical output is extremely sensitive to shading (the so-called "Christmas light effect"). When even a small portion of a cell or of a module or array of cells in parallel is shaded, with the remainder in sunlight, the output falls dramatically due to internal 'short-circuiting' (the electrons reversing course through

1206-407: A cooling system. The terms "solar array" and "PV system" are often incorrectly used interchangeably, despite the fact that the solar array does not encompass the entire system. Moreover, "solar panel" is often used as a synonym for "solar module", although a panel consists of a string of several modules. The term "solar system" is also an often used misnomer for a PV system. The building blocks of

1340-496: A growing number of countries and regions all over the world. The largest manufacturers of solar equipment were based in China. Although concentrated solar power capacity grew more than tenfold, it remained a tiny proportion of the total, because the cost of utility-scale solar PV fell by 85% between 2010 and 2020, while CSP costs only fell 68% in the same timeframe. Despite the rising cost of materials, such as polysilicon , during

1474-587: A high specific heat capacity, and can deliver heat at temperatures compatible with conventional power systems. This method of energy storage is used, for example, by the Solar Two power station, allowing it to store 1.44  TJ in its 68 m storage tank, enough to provide full output for close to 39 hours, with an efficiency of about 99%. In stand alone PV systems , batteries are traditionally used to store excess electricity. With grid-connected photovoltaic power systems , excess electricity can be sent to

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1608-405: A large portion of sunlight directly. In diffuse light (i.e. under cloud or fog), tracking has little or no value. Because most concentrated photovoltaics systems are very sensitive to the sunlight's angle, tracking systems allow them to produce useful power for more than a brief period each day. Tracking systems improve performance for two main reasons. First, when a solar panel is perpendicular to

1742-420: A large rack is mounted on the ground, and the modules mounted on the rack. For buildings, many different racks have been devised for pitched roofs. For flat roofs, racks, bins and building integrated solutions are used. Solar panel racks mounted on top of poles can be stationary or moving, see Trackers below. Side-of-pole mounts are suitable for situations where a pole has something else mounted at its top, such as

1876-607: A large temperature range. Specific performance requirements for material used for wiring a solar panel installation are given in national and local electrical codes which regulate electrical installations in an area. General features required for solar cables are resistance to ultraviolet light, weather, temperature extremes of the area and insulation suitable for the voltage class of the equipment. Different jurisdictions will have specific rules regarding grounding (earthing) of solar power installations for electric shock protection and lightning protection. A solar tracking system tilts

2010-445: A light fixture or an antenna. Pole mounting raises what would otherwise be a ground mounted array above weed shadows and livestock, and may satisfy electrical code requirements regarding inaccessibility of exposed wiring. Pole mounted panels are open to more cooling air on their underside, which increases performance. A multiplicity of pole top racks can be formed into a parking carport or other shade structure. A rack which does not follow

2144-691: A limited effect on the users, but their effect on self-consumption of solar power may be limited. The original political purpose of incentive policies for PV was to facilitate an initial small-scale deployment to begin to grow the industry, even where the cost of PV was significantly above grid parity, to allow the industry to achieve the economies of scale necessary to reach grid parity. Since reaching grid parity, some policies are implemented to promote national energy independence, high tech job creation and reduction of CO 2 emissions. Financial incentives for photovoltaics differ across countries, including Australia , China , Germany , India , Japan , and

2278-570: A local scale - such as those from snow or the effects of surface coatings (e.g. hydrophobic or hydrophilic ) on soiling or snow losses. (Although in heavy snow environments with severe ground interference can result in annual losses from snow of 30%. ) Access to the Internet has allowed a further improvement in energy monitoring and communication. Dedicated systems are available from a number of vendors. For solar PV systems that use microinverters (panel-level DC to AC conversion), module power data

2412-490: A local user or users. Utility-scale solar is sometimes used to describe this type of project. This approach differs from concentrated solar power , the other major large-scale solar generation technology, which uses heat to drive a variety of conventional generator systems. Both approaches have their own advantages and disadvantages, but to date, for a variety of reasons, photovoltaic technology has seen much wider use. As of 2019 , about 97% of utility-scale solar power capacity

2546-540: A mature technology used for mainstream electricity generation. Due to the growth of photovoltaics , prices for PV systems have rapidly declined since their introduction; however, they vary by market and the size of the system. Nowadays, solar PV modules account for less than half of the system's overall cost, leaving the rest to the remaining BOS components and to soft costs, which include customer acquisition, permitting, inspection and interconnection, installation labor, and financing costs. A photovoltaic system converts

2680-504: A measure more directly comparable to other forms of power generation. Most solar parks are developed at a scale of at least 1 MW p . As of 2018, the world's largest operating photovoltaic power stations surpassed 1 gigawatt . At the end of 2019, about 9,000 solar farms were larger than 4 MW AC (utility scale), with a combined capacity of over 220 GW AC . Commercial concentrating solar power (CSP) plants, also called "solar thermal power stations", were first developed in

2814-593: A modified version of the conventional lead–acid battery  – nickel–cadmium and lithium-ion batteries. Compared to the other types, lead-acid batteries have a shorter lifetime and lower energy density. However, due to their high reliability, low self discharge as well as low investment and maintenance costs, they are currently (as of 2014) the predominant technology used in small-scale, residential PV systems, as lithium-ion batteries are still being developed and about 3.5 times as expensive as lead-acid batteries. Furthermore, as storage devices for PV systems are stationary,

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2948-552: A photovoltaic system are solar cells. A solar cell is the electrical device that can directly convert photons energy into electricity. There are three technological generations of solar cells: the first generation (1G) of crystalline silicon cells (c-Si), the second generation (2G) of thin-film cells (such as CdTe , CIGS , Amorphous Silicon , and GaAs ), and the third generation (3G) of organic , dye-sensitized , Perovskite and multijunction cells . Conventional c-Si solar cells , normally wired in series, are encapsulated in

3082-579: A rate ranging from wholesale to retail rate or above, as can be excess annual credits. A community solar project is a solar power installation that accepts capital from and provides output credit and tax benefits to multiple customers, including individuals, businesses, nonprofits, and other investors. Participants typically invest in or subscribe to a certain kW capacity or kWh generation of remote electrical production. In some countries tariffs (import taxes) are imposed on imported solar panels. The overwhelming majority of electricity produced worldwide

3216-450: A rechargeable lithium-ion battery with the aim to revolutionize energy consumption. PV systems with an integrated battery solution also need a charge controller , as the varying voltage and current from the solar array requires constant adjustment to prevent damage from overcharging. Basic charge controllers may simply turn the PV panels on and off, or may meter out pulses of energy as needed,

3350-477: A result of grid constraints preventing feedback of unused electricity into the grid as well as increased electricity costs resulting in improved economics. A typical residential solar array is rack-mounted on the roof, rather than integrated into the roof or facade of the building, which is significantly more expensive. Utility-scale solar power stations are ground-mounted, with fixed tilted solar panels rather than using expensive tracking devices. Crystalline silicon

3484-616: A shaded cell may drop 8 volts, instead of adding 0.5 volts, at a high current level, thereby absorbing the power produced by 16 other cells. It is thus important that a PV installation not be shaded by trees or other obstructions. There are techniques to mitigate the losses with diodes, but these techniques also entail losses. Several methods have been developed to determine shading losses from trees to PV systems over both large regions using LiDAR , but also at an individual system level using 3D modeling software . Most modules have bypass diodes between each cell or string of cells that minimize

3618-590: A significant role in output depending on the surface around the photovoltaic system and the type of solar cell material. A photovoltaic installation in the northern latitudes of Europe or the United States may expect to produce 1 kWh/m /day. A typical 1 kW photovoltaic installation in Australia or the southern latitudes of Europe or United States, may produce 3.5–5 kWh per day, dependent on location, orientation, tilt, insolation and other factors. In

3752-496: A single home, or an isolated device in the form of AC or DC electric. Military and civilian Earth observation satellites , street lights , construction and traffic signs, electric cars , solar-powered tents, and electric aircraft may contain integrated photovoltaic systems to provide a primary or auxiliary power source in the form of AC or DC power, depending on the design and power demands. In 2013, rooftop systems accounted for 60 percent of worldwide installations. However, there

3886-468: A solar module to protect them from the weather. The module consists of a tempered glass as cover, a soft and flexible encapsulant , a rear backsheet made of a weathering and fire-resistant material and an aluminium frame around the outer edge. Electrically connected and mounted on a supporting structure, solar modules build a string of modules, often called solar panel. A solar array consists of one or many such panels. A photovoltaic array, or solar array,

4020-507: A solar panel throughout the day. Depending on the type of tracking system, the panel is either aimed directly at the Sun or the brightest area of a partly clouded sky. Trackers greatly enhance early morning and late afternoon performance, increasing the total amount of power produced by a system by about 20–25% for a single axis tracker and about 30% or more for a dual axis tracker, depending on latitude. Trackers are effective in regions that receive

4154-447: A source of electricity for small and medium-sized applications, from the calculator powered by a single solar cell to remote homes powered by an off-grid rooftop PV system. Commercial concentrated solar power plants were first developed in the 1980s. Since then, as the cost of solar panels has fallen, grid-connected solar PV systems ' capacity and production has doubled about every three years . Three-quarters of new generation capacity

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4288-546: A strategy called PWM or pulse-width modulation . More advanced charge controllers will incorporate MPPT logic into their battery charging algorithms. Charge controllers may also divert energy to some purpose other than battery charging. Rather than simply shut off the free PV energy when not needed, a user may choose to heat air or water once the battery is full. The metering must be able to accumulate energy units in both directions, or two meters must be used. Many meters accumulate bidirectionally, some systems use two meters, but

4422-407: A surplus to be later used at night. Batteries used for grid-storage also stabilize the electrical grid by leveling out peak loads , and play an important role in a smart grid , as they can charge during periods of low demand and feed their stored energy into the grid when demand is high. Common battery technologies used in today's PV systems include the valve regulated lead-acid battery  –

4556-463: A tenth of their electricity from solar, with China making up more than half of solar growth. Almost half the solar power installed in 2022 was mounted on rooftops . Much more low-carbon power is needed for electrification and to limit climate change . The International Energy Agency said in 2022 that more effort was needed for grid integration and the mitigation of policy, regulation and financing challenges. Nevertheless solar may greatly cut

4690-440: A thin coating of boron. The “Bell Solar Battery” was described as 6% efficient, with a square yard of the panels generating 50 watts. The first satellite with solar panels was launched in 1957 . By the 1970s, solar panels were still too expensive for much other than satellites . In 1974 it was estimated that only six private homes in all of North America were entirely heated or cooled by functional solar power systems. However,

4824-533: A unidirectional meter (with detent) will not accumulate energy from any resultant feed into the grid. In some countries, for installations over 30  kW p a frequency and a voltage monitor with disconnection of all phases is required. This is done where more solar power is being generated than can be accommodated by the utility, and the excess can not either be exported or stored . Grid operators historically have needed to provide transmission lines and generation capacity. Now they need to also provide storage. This

4958-455: A voltage range that can charge 12-volt batteries directly, so addition of a PV system requires only panels, a charge controller, and wiring. Solar systems on recreation vehicles are usually constrained in wattage by the physical size of the RV's roof space. In urban and suburban areas, photovoltaic arrays are often used on rooftops to supplement power use; often the building will have a connection to

5092-481: Is cost-effective . In 2018, the estimated soiling-induced revenue loss was estimated to between 5 and 7 billion euros. The long‐term reliability of photovoltaic modules is crucial to ensure the technical and economic viability of PV as a successful energy source. The analysis of degradation mechanisms of PV modules is key to ensure current lifetimes exceeding 25 years. Solar insolation is made up of direct, diffuse, and reflected radiation . The absorption factor of

5226-467: Is (or is predicted to become) the cheapest source of energy in all of Central America, Africa, the Middle East, India, South-east Asia, Australia, and several other regions. Different measurements of solar irradiance (direct normal irradiance, global horizontal irradiance) are mapped below: In cases of self-consumption of solar energy, the payback time is calculated based on how much electricity

5360-476: Is a linked collection of solar modules. The power that one module can produce is seldom enough to meet requirements of a home or a business, so the modules are linked together to form an array. Most PV arrays use an inverter to convert the DC power produced by the modules into alternating current that can power lights , motors, and other loads. The modules in a PV array are usually first connected in series to obtain

5494-536: Is a notable trend towards utility-scale systems, as the focus on new installations is shifting away from Europe to sunnier regions, such as the Sunbelt in the U.S., which are less opposed to ground-mounted solar farms and cost-effectiveness is more emphasized by investors. Driven by advances in technology and increases in manufacturing scale and sophistication, the cost of photovoltaics is declining continuously. There are several million PV systems distributed all over

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5628-707: Is a trend away from rooftop and towards utility-scale PV systems, as the focus of new PV installations is also shifting from Europe to countries in the sunbelt region of the planet where opposition to ground-mounted solar farms is less accentuated. Portable and mobile PV systems provide electrical power independent of utility connections, for "off the grid" operation. Such systems are so commonly used on recreational vehicles and boats that there are retailers specializing in these applications and products specifically targeted to them. Since recreational vehicles (RV) normally carry batteries and operate lighting and other systems on nominally 12-volt DC power, RV systems normally operate in

5762-497: Is a type of solar cell that includes a perovskite-structured compound, most commonly a hybrid organic–inorganic lead or tin halide-based material as the light-harvesting active layer. Perovskite materials, such as methylammonium lead halides and all-inorganic cesium lead halide, are cheap to produce and simple to manufacture. Concentrated solar power (CSP), also called "concentrated solar thermal", uses lenses or mirrors and tracking systems to concentrate sunlight, then uses

5896-451: Is about a square meter in size. Such a module may be expected to produce 0.75 kilowatt-hour (kWh) every day, on average, after taking into account the weather and the latitude, for an insolation of 5 sun hours/day. Module output degrades faster at increased temperature. Allowing ambient air to flow over, and if possible behind, PV modules reduces this problem, as the airflow tend to reduce the operating temperature and, as consequence, increase

6030-424: Is around 10 kilowatts and mounted on a sloped roof, while commercial systems may reach a megawatt-scale and are generally installed on low-slope or even flat roofs. Although rooftop mounted systems are small and have a higher cost per watt than large utility-scale installations, they account for the largest share in the market. There is, however, a growing trend towards bigger utility-scale power plants, especially in

6164-466: Is assembled into a protective weatherproof enclosure, thus making a photovoltaic module or solar panel . Modules may then be strung together into a photovoltaic array. In 2012, solar panels available for consumers had an efficiency of up to about 17%, while commercially available panels can go as far as 27%. By concentrating the sunlight it is possible to achieve higher efficiencies. A group from The Fraunhofer Institute for Solar Energy Systems has created

6298-426: Is automatically provided. Some systems allow setting performance alerts that trigger phone/email/text warnings when limits are reached. These solutions provide data for the system owner and the installer. Installers are able to remotely monitor multiple installations, and see at-a-glance the status of their entire installed base. A photovoltaic system for residential, commercial, or industrial energy supply consists of

6432-576: Is critical for revenue and O&M efficiency. Monitoring of array performance may be part of contractual agreements between the array owner, the builder, and the utility purchasing the energy produced. A method to create "synthetic days" using readily available weather data and verification using the Open Solar Outdoors Test Field make it possible to predict photovoltaic systems performance with high degrees of accuracy. This method can be used to then determine loss mechanisms on

6566-601: Is expected to be commissioned on 31 December 2024. The Lira solar power project site is in Ngeta, a suburb of Lira Municipality located just off Lira-Kitgum Road in Lira District , in Northern Uganda . Lira is approximately 257.9 kilometres (160.3 mi) by road north of Kampala , the country's capital and largest city. The power station will have a 50 megawatt capacity. Its output will be sold directly to

6700-455: Is forecast to be solar, surpassing coal as the largest source of installed power capacity. Utility scale is forecast to become the largest source of electricity in all regions except sub-Saharan Africa by 2050. According to a 2021 study, global electricity generation potential of rooftop solar panels is estimated at 27 PWh per year at costs ranging from $ 40 (Asia) to $ 240 per MWh (US, Europe). Its practical realization will however depend on

6834-571: Is key for high self-consumption. The match can be improved with batteries or controllable electricity consumption. However, batteries are expensive, and profitability may require the provision of other services from them besides self-consumption increase, for example avoiding power outages . Hot water storage tanks with electric heating with heat pumps or resistance heaters can provide low-cost storage for self-consumption of solar power. Shiftable loads, such as dishwashers, tumble dryers and washing machines, can provide controllable consumption with only

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6968-420: Is more common for PV arrays to have fixed mounts that tilt the array and face due south in the northern hemisphere or due north in the southern hemisphere. The tilt angle from horizontal can be varied for season, but if fixed, should be set to give optimal array output during the peak electrical demand portion of a typical year for a stand-alone system. This optimal module tilt angle is not necessarily identical to

7102-429: Is needed. If both of those fail, installations over 30kWp can automatically shut down, although in practice all inverters maintain voltage regulation and stop supplying power if the load is inadequate. Grid operators have the option of curtailing excess generation from large systems, although this is more commonly done with wind power than solar power, and results in a substantial loss of revenue. Three-phase inverters have

7236-407: Is normally hydro-storage, but other means of storage are used. Initially storage was used so that baseload generators could operate at full output. With variable renewable energy , storage is needed to allow power generation whenever it is available, and consumption whenever needed. The two variables a grid operator has are storing electricity for when it is needed, or transmitting it to where it

7370-421: Is not purchased from the grid. However, in many cases, the patterns of generation and consumption do not coincide, and some or all of the energy is fed back into the grid. The electricity is sold, and at other times when energy is taken from the grid, electricity is bought. The relative costs and prices obtained affect the economics. In many markets, the price paid for sold PV electricity is significantly lower than

7504-695: Is potentially an important issue, particularly in off-grid applications and for future 100% renewable energy scenarios. Solar is intermittent due to the day/night cycles and variable weather conditions. However solar power can be forecast somewhat by time of day, location, and seasons. The challenge of integrating solar power in any given electric utility varies significantly. In places with hot summers and mild winters, solar tends to be well matched to daytime cooling demands. Concentrated solar power plants may use thermal storage to store solar energy, such as in high-temperature molten salts. These salts are an effective storage medium because they are low-cost, have

7638-482: Is required. A solar inverter may connect to a string of solar panels. In some installations a solar micro-inverter is connected at each solar panel. For safety reasons a circuit breaker is provided both on the AC and DC side to enable maintenance. AC output may be connected through an electricity meter into the public grid. The number of modules in the system determines the total DC watts capable of being generated by

7772-489: Is solar, with both millions of rooftop installations and gigawatt-scale photovoltaic power stations continuing to be built. In 2023, solar power generated 5.5% (1,631 TWh) of global electricity and over 1% of primary energy , adding twice as much new electricity as coal. Along with onshore wind power , utility-scale solar is the source with the cheapest levelised cost of electricity for new installations in most countries. As of 2023, 33 countries generated more than

7906-430: Is stored or used directly by island/standalone plant. PV systems are generally designed in order to ensure the highest energy yield for a given investment. Some large photovoltaic power stations such as Solar Star , Waldpolenz Solar Park and Topaz Solar Farm cover tens or hundreds of hectares and have power outputs up to hundreds of megawatts . A small PV system is capable of providing enough AC electricity to power

8040-859: Is the Germany-based Ugandan Dr. David Alobo, in Uganda for a total capacity of 150MW. When completed, Xsabo Lira Solarline is expected to be the largest grid-connected, privately funded solar power plant not only in Uganda, but also in Sub-Saharan Africa (excepting South Africa), ahead of Soroti Solar Power Station (10 MW), Tororo Solar Power Station (10 MW) and The Xsabo Group's own two large solar power plants, namely its 20MW Pilot Solar Park in Kabulasoke ( Kabulasoke Solar Power Station ) and Xsabo Nkonge Solarline ( Nkonge Solar Power Station ) (20MW). Xsabo Lira Solarline (50MW)

8174-465: Is the conversion of energy from sunlight into electricity , either directly using photovoltaics (PV) or indirectly using concentrated solar power . Solar panels use the photovoltaic effect to convert light into an electric current . Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus a large area of sunlight to a hot spot, often to drive a steam turbine . Photovoltaics (PV) were initially solely used as

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8308-761: Is the designated special purpose vehicle for The Xsabo Group’s Solar Power Project in Lira. According to official public pronouncements by the Government of the Republic of Uganda, in particular the Electricity Regulatory Authority (ERA) and the Office of Uganda's Vice President Edward Kiwanuka Ssekandi as well as the involved Local Governments of the Republic of Uganda, The Xsabo Group plans to construct five solar power stations in different parts of Uganda with total capacity of 150 megawatts, at

8442-408: Is the predominant material used in 90 percent of worldwide produced solar modules, while its rival thin-film has lost market-share. About 70 percent of all solar cells and modules are produced in China and Taiwan, only 5 percent by European and US- manufacturers . The installed capacity for both small rooftop systems and large solar power stations is growing rapidly and in equal parts, although there

8576-768: Is then used for power generation or energy storage. Thermal storage efficiently allows overnight electricity generation, thus complementing PV. CSP generates a very small share of solar power and in 2022 the IEA said that CSP should be better paid for its storage. As of 2021 the levelized cost of electricity from CSP is over twice that of PV. However, their very high temperatures may prove useful to help decarbonize industries (perhaps via hydrogen) which need to be hotter than electricity can provide. A hybrid system combines solar with energy storage and/or one or more other forms of generation. Hydro, wind and batteries are commonly combined with solar. The combined generation may enable

8710-435: Is used immediately because traditional generators can adapt to demand and storage is usually more expensive. Both solar power and wind power are sources of variable renewable power , meaning that all available output must be used locally, carried on transmission lines to be used elsewhere, or stored (e.g., in a battery). Since solar energy is not available at night, storing it so as to have continuous electricity availability

8844-512: Is used, the so-called energy payback time decreases to one year or less. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity, have also greatly supported installations of PV systems in many countries. The levelised cost of electricity from large-scale PV systems has become competitive with conventional electricity sources in an expanding list of geographic regions, and grid parity has been achieved in about 30 countries. As of 2015,

8978-818: The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies. Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the United States (SERI, now NREL ), Japan ( NEDO ), and Germany ( Fraunhofer ISE ). Between 1970 and 1983 installations of photovoltaic systems grew rapidly. In

9112-463: The 2021–2022 global energy crisis , utility scale solar was still the least expensive energy source in many countries due to the rising costs of other energy sources, such as natural gas. In 2022, global solar generation capacity exceeded 1 TW for the first time. However, fossil-fuel subsidies have slowed the growth of solar generation capacity. About half of installed capacity is utility scale. Most new renewable capacity between 2022 and 2027

9246-614: The Sahara desert, with less cloud cover and a better solar angle, one could ideally obtain closer to 8.3 kWh/m /day provided the nearly ever present wind would not blow sand onto the units. The area of the Sahara desert is over 9 million km . 90,600 km , or about 1%, could generate as much electricity as all of the world's power plants combined. Modules are assembled into arrays on some kind of mounting system, which may be classified as ground mount, roof mount or pole mount. For solar parks

9380-528: The Uganda Electricity Transmission Company Limited (UETCL) for integration into the national grid. The power will be evacuated via a substation adjacent to the solar power park. The power station is being developed by The Xsabo Group, also owners of the 20 megawatt Kabulasoke Solar Power Station and Xsabo Nkonge Solarline ( Nkonge Solar Power Station ), also with a capacity of 20MW. Xsabo Lira Solarline Limited

9514-467: The United States and even across states within the US. In net metering the price of the electricity produced is the same as the price supplied to the consumer, and the consumer is billed on the difference between production and consumption. Net metering can usually be done with no changes to standard electricity meters , which accurately measure power in both directions and automatically report

9648-459: The balance of system (BOS). PV systems range from small, rooftop-mounted or building-integrated systems with capacities ranging from a few to several tens of kilowatts to large, utility-scale power stations of hundreds of megawatts. Nowadays, off-grid or stand-alone systems account for a small portion of the market. Operating silently and without any moving parts or air pollution , PV systems have evolved from niche market applications into

9782-442: The direct current (DC) from the solar modules to AC. Grid connected inverters must supply AC electricity in sinusoidal form, synchronized to the grid frequency, limit feed in voltage to no higher than the grid voltage and disconnect from the grid if the grid voltage is turned off. Islanding inverters need only produce regulated voltages and frequencies in a sinusoidal waveshape as no synchronisation or co-ordination with grid supplies

9916-466: The electrical grid , while off-grid systems are somewhat more common in Australia and South Korea. PV systems rarely use battery storage. This may change, as government incentives for distributed energy storage are implemented and investments in storage solutions gradually become economically viable for small systems. In the UK, the number of commercial systems using battery storage is gradually increasing as

10050-486: The electrical grid . Net metering and feed-in tariff programs give these systems a credit for the electricity they produce. This credit offsets electricity provided from the grid when the system cannot meet demand, effectively trading with the grid instead of storing excess electricity. When wind and solar are a small fraction of the grid power, other generation techniques can adjust their output appropriately, but as these forms of variable power grow, additional balance on

10184-606: The fast-growing global PV market is rapidly approaching the 200 GW mark – about 40 times the installed capacity in 2006. These systems currently contribute about 1 percent to worldwide electricity generation. Top installers of PV systems in terms of capacity are currently China, Japan and the United States, while half of the world's capacity is installed in Europe, with Germany and Italy supplying 7% to 8% of their respective domestic electricity consumption with solar PV. The International Energy Agency expects solar power to become

10318-445: The power grid , in which case the energy produced by the PV array can be sold back to the utility in some sort of net metering agreement. Some utilities use the rooftops of commercial customers and telephone poles to support their use of PV panels. Solar trees are arrays that, as the name implies, mimic the look of trees, provide shade, and at night can function as street lights . Uncertainties in revenue over time relate mostly to

10452-399: The silicon solar cell in 1954. These early solar cells cost US$ 286/watt and reached efficiencies of 4.5–6%. In 1957, Mohamed M. Atalla developed the process of silicon surface passivation by thermal oxidation at Bell Labs . The surface passivation process has since been critical to solar cell efficiency . As of 2022 over 90% of the market is crystalline silicon . The array of

10586-463: The "sunbelt" region of the planet. Large utility-scale solar parks or farms are power stations and capable of providing an energy supply to large numbers of consumers. Generated electricity is fed into the transmission grid powered by central generation plants (grid-connected or grid-tied plant), or combined with one, or many, domestic electricity generators to feed into a small electrical grid (hybrid plant). In rare cases generated electricity

10720-567: The 1860s was driven by an expectation that coal would soon become scarce, such as experiments by Augustin Mouchot . Charles Fritts installed the world's first rooftop photovoltaic solar array, using 1%-efficient selenium cells, on a New York City roof in 1884. However, development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum . Bell Telephone Laboratories’ 1950s research used silicon wafers with

10854-684: The 1980s. The 377 MW Ivanpah Solar Power Facility , located in California's Mojave Desert, is the world's largest solar thermal power plant project. Other large CSP plants include the Solnova Solar Power Station (150 MW), the Andasol solar power station (150 MW), and Extresol Solar Power Station (150 MW), all in Spain. The principal advantage of CSP is the ability to efficiently add thermal storage, allowing

10988-590: The British Standard BS 7671 , incorporating regulations relating to microgeneration and photovoltaic systems, and the US UL4703 standard, in subject 4703 "Photovoltaic Wire". A solar cable is the interconnection cable used in photovoltaic power generation. Solar cables interconnect solar panels and other electrical components of a photovoltaic system. Solar cables are designed to be UV resistant and weather resistant. They can be used within

11122-746: The Sun's radiation , in the form of light, into usable electricity . It comprises the solar array and the balance of system components. PV systems can be categorized by various aspects, such as, grid-connected vs. stand alone systems, building-integrated vs. rack-mounted systems, residential vs. utility systems, distributed vs. centralized systems, rooftop vs. ground-mounted systems, tracking vs. fixed-tilt systems, and new constructed vs. retrofitted systems. Other distinctions may include, systems with microinverters vs. central inverter, systems using crystalline silicon vs. thin-film technology , and systems with modules. About 99 percent of all European and 90 percent of all U.S. solar power systems are connected to

11256-476: The US, residential solar cost from 2 to 4 dollars/watt (but solar shingles cost much more) and utility solar costs were around $ 1/watt. The productivity of solar power in a region depends on solar irradiance , which varies through the day and year and is influenced by latitude and climate . PV system output power also depends on ambient temperature, wind speed, solar spectrum, the local soiling conditions, and other factors. Onshore wind power tends to be

11390-543: The United States, President Jimmy Carter set a target of producing 20% of U.S. energy from solar by the year 2000, but his successor, Ronald Reagan , removed the funding for research into renewables. Falling oil prices in the early 1980s moderated the growth of photovoltaics from 1984 to 1996. In the mid-1990s development of both, residential and commercial rooftop solar as well as utility-scale photovoltaic power stations began to accelerate again due to supply issues with oil and natural gas, global warming concerns, and

11524-540: The World Wide Web, such as OSOTF . Knowing the annual energy consumption in Kwh E d {\displaystyle E_{d}} of an institution or a family, for example of 2300Kwh, legible in its electricity bill, it is possible to calculate the number of photovoltaic panels necessary to satisfy its energy needs. By connecting to the site https://re.jrc.ec.europa.eu/pvg_tools/en/ , after selecting

11658-559: The arid tropics and subtropics. Deserts lying in low latitudes usually have few clouds and can receive sunshine for more than ten hours a day. These hot deserts form the Global Sun Belt circling the world. This belt consists of extensive swathes of land in Northern Africa , Southern Africa , Southwest Asia , Middle East , and Australia , as well as the much smaller deserts of North and South America . Thus solar

11792-429: The availability and cost of scalable electricity storage solutions. A photovoltaic power station , also known as a solar park, solar farm, or solar power plant, is a large-scale grid-connected photovoltaic power system (PV system) designed for the supply of merchant power . They are different from most building-mounted and other decentralized solar power because they supply power at the utility level, rather than to

11926-605: The cheapest source of electricity in Northern Eurasia, Canada, some parts of the United States, and Patagonia in Argentina whereas in other parts of the world mostly solar power (or less often a combination of wind, solar and other low carbon energy) is thought to be best. Modelling by Exeter University suggests that by 2030, solar will be least expensive in all countries except for some in north-eastern Europe. The locations with highest annual solar irradiance lie in

12060-415: The cost of energy. Geography affects solar energy potential because different locations receive different amounts of solar radiation. In particular, with some variations, areas that are closer to the equator generally receive higher amounts of solar radiation. However, solar panels that can follow the position of the Sun can significantly increase the solar energy potential in areas that are farther from

12194-560: The cost of solar power, which is a problem for countries where contracts may not be honoured, such as some African countries. Some countries are considering price caps , whereas others prefer contracts for difference . In many countries, solar power is the lowest cost source of electricity. In Saudi Arabia, a power purchase agreement (PPA) was signed in April 2021 for a new solar power plant in Al-Faisaliah. The project has recorded

12328-506: The data from the inverter or retrieve all of the data from the communicating equipment (probes, meters, etc.). Monitoring tools can be dedicated to supervision only or offer additional functions. Individual inverters and battery charge controllers may include monitoring using manufacturer specific protocols and software. Energy metering of an inverter may be of limited accuracy and not suitable for revenue metering purposes. A third-party data acquisition system can monitor multiple inverters, using

12462-446: The desired voltage ; the individual strings are then connected in parallel to allow the system to produce more current . Solar panels are typically measured under STC (standard test conditions) or PTC (PVUSA test conditions), in watts . Typical panel ratings range from less than 100 watts to over 400 watts. The array rating consists of a summation of the panel ratings, in watts, kilowatts, or megawatts. A typical 150 watt PV module

12596-581: The desired frequency/phase. Many residential PV systems are connected to the grid when available, especially in developed countries with large markets. In these grid-connected PV systems , use of energy storage is optional. In certain applications such as satellites, lighthouses, or in developing countries, batteries or additional power generators are often added as back-ups. Such stand-alone power systems permit operations at night and at other times of limited sunlight. In "vertical agrivoltaics " system, solar cells are oriented vertically on farmland, to allow

12730-421: The difference, and because it allows homeowners and businesses to generate electricity at a different time from consumption, effectively using the grid as a giant storage battery. With net metering, deficits are billed each month while surpluses are rolled over to the following month. Best practices call for perpetual roll over of kWh credits. Excess credits upon termination of service are either lost or paid for at

12864-586: The dispatching of electricity over up to a 24-hour period. Since peak electricity demand typically occurs at about 5 pm, many CSP power plants use 3 to 5 hours of thermal storage. The typical cost factors for solar power include the costs of the modules, the frame to hold them, wiring, inverters, labour cost, any land that might be required, the grid connection, maintenance and the solar insolation that location will receive. Photovoltaic systems use no fuel, and modules typically last 25 to 40 years. Thus upfront capital and financing costs make up 80% to 90% of

12998-438: The effects of shading and only lose the power that the shaded portion of the array would have supplied, as well as the power dissipated in the diodes. The main job of the bypass diode is to eliminate hot spots that form on cells that can cause further damage to the array, and cause fires. Sunlight can be absorbed by dust, snow, or other impurities at the surface of the module (collectively referred to as soiling ). Soiling reduces

13132-532: The energy gained by using tracking systems can outweigh the added complexity. For very large systems , the added maintenance of tracking is a substantial detriment. Tracking is not required for flat panel and low-concentration photovoltaic systems . For high-concentration photovoltaic systems, dual axis tracking is a necessity. Pricing trends affect the balance between adding more stationary solar panels versus having fewer panels that track. As pricing, reliability and performance of single-axis trackers have improved,

13266-456: The equator. Daytime cloud cover can reduce the light available for solar cells. Land availability also has a large effect on the available solar energy. Solar power plants use one of two technologies: A solar cell , or photovoltaic cell, is a device that converts light into electric current using the photovoltaic effect . The first solar cell was constructed by Charles Fritts in the 1880s. The German industrialist Ernst Werner von Siemens

13400-473: The evaluation of the solar resource and to the performance of the system itself. In the best of cases, uncertainties are typically 4% for year-to-year climate variability, 5% for solar resource estimation (in a horizontal plane), 3% for estimation of irradiation in the plane of the array, 3% for power rating of modules, 2% for losses due to dirt and soiling , 1.5% for losses due to snow, and 5% for other sources of error. Identifying and reacting to manageable losses

13534-414: The fact that most of the world is not on the equator, and that the sun sets in the evening, the correct measure of solar power is insolation – the average number of kilowatt-hours per square meter per day. For the weather and latitudes of the United States and Europe, typical insolation ranges from 2.26 kWh/m /day in northern climes to 5.61 kWh/m /day in the sunniest regions. For large systems,

13668-457: The grid is needed. As prices are rapidly declining, PV systems increasingly use rechargeable batteries to store a surplus to be used later at night. Batteries used for grid-storage can stabilize the electrical grid by leveling out peak loads for a few hours. In the future, less expensive batteries could play an important role on the electrical grid, as they can charge during periods when generation exceeds demand and feed their stored energy into

13802-404: The grid requires the transformation of DC into AC by a special, synchronizing grid-tie inverter . In kilowatt-sized installations the DC side system voltage is as high as permitted (typically 1000 V except US residential 600 V) to limit ohmic losses. Most modules (60 or 72 crystalline silicon cells) generate 160 W to 300 W at 36 volts. It is sometimes necessary or desirable to connect

13936-420: The grid when demand is higher than generation. Solar PV systems PV systems convert light directly into electricity and are not to be confused with other solar technologies, such as concentrated solar power or solar thermal , used for heating and cooling. A solar array only encompasses the solar panels, the visible part of the PV system, and does not include all the other hardware, often summarized as

14070-502: The improving economic position of PV relative to other energy technologies. In the early 2000s, the adoption of feed-in tariffs —a policy mechanism, that gives renewables priority on the grid and defines a fixed price for the generated electricity—led to a high level of investment security and to a soaring number of PV deployments in Europe. For several years, worldwide growth of solar PV was driven by European deployment , but it then shifted to Asia, especially China and Japan , and to

14204-399: The inverter manufacturer's protocols, and also acquire weather-related information. Independent smart meters may measure the total energy production of a PV array system. Separate measures such as satellite image analysis or a solar radiation meter (a pyranometer ) can be used to estimate total insolation for comparison. Data collected from a monitoring system can be displayed remotely over

14338-423: The junction. This breakdown voltage in common cells is between 10 and 30 volts. Instead of adding to the power produced by the panel, the shaded cell absorbs power, turning it into heat. Since the reverse voltage of a shaded cell is much greater than the forward voltage of an illuminated cell, one shaded cell can absorb the power of many other cells in the string, disproportionately affecting panel output. For example,

14472-638: The land to both grow crops and generate renewable energy. Other configurations include floating solar farms , placing solar canopies over parking lots, and installing solar panels on roofs. A thin-film solar cell is a second generation solar cell that is made by depositing one or more thin layers, or thin film (TF) of photovoltaic material on a substrate, such as glass, plastic or metal. Thin-film solar cells are commercially used in several technologies, including cadmium telluride (CdTe), copper indium gallium diselenide (CIGS), and amorphous thin-film silicon (a-Si, TF-Si). A perovskite solar cell (PSC)

14606-406: The large commercial and utility-scale market. Market-share for central and string inverters are about 44 percent and 52 percent, respectively, with less than 1 percent for micro-inverters. Maximum power point tracking (MPPT) is a technique that grid connected inverters use to get the maximum possible power from the photovoltaic array. In order to do so, the inverter's MPPT system digitally samples

14740-400: The life of the PV system. In one study performed in a snow-rich area ( Ontario ), cleaning flat mounted solar panels after 15 months increased their output by almost 100%. However, 5° tilted arrays were adequately cleaned by rainwater. In many cases, especially in arid regions, or in locations in close proximity to deserts, roads, industry, or agriculture, regular cleaning of the solar panels

14874-424: The light that strikes the cells, which in turn reduces the power output of the PV system. Soiling losses aggregate over time, and can become large without adequate cleaning. In 2018, the global annual energy loss due to soiling was estimated to at least 3–4%. However, soiling losses vary significantly from region to region, and within regions. Maintaining a clean module surface will increase output performance over

15008-457: The location in which to install the panels or clicking on the map or typing the name of the location, you must select "Grid connected" and "Visualize results" obtaining the following table for example relating to the city of Palermo: Using the wxMaxima program, the number of panels required for an annual consumption of 2300 kWh and for a crystalline silicon technology with a slope angle of 35°, an azimut angle of 0° and total losses equal to 21.88%

15142-457: The lower energy and power density and therefore higher weight of lead-acid batteries are not as critical as, for example, in electric transportation Other rechargeable batteries considered for distributed PV systems include sodium–sulfur and vanadium redox batteries, two prominent types of a molten salt and a flow battery, respectively. In 2015, Tesla Motors launched the Powerwall ,

15276-471: The module efficiency. However, it was recently demonstrated that, in the real-world operation, considering a larger scale photovoltaic generator, increase in wind speed can increase the energy losses, following the fluid mechanics theory, as the wind interaction with the PV generator induces air flux variations that modify the heat transfer from the modules to the air. Effective module lives are typically 25 years or more. The payback period for an investment in

15410-460: The modules partially in parallel rather than all in series. An individual set of modules connected in series is known as a 'string'. A set of series-connected "strings" is known as an "array." Photovoltaic systems are generally categorized into three distinct market segments: residential rooftop, commercial rooftop, and ground-mount utility-scale systems. Their capacities range from a few kilowatts to hundreds of megawatts. A typical residential system

15544-527: The price of bought electricity, which incentivizes self-consumption. Moreover, separate self-consumption incentives have been used in e.g., Germany and Italy. Grid interaction regulation has also included limitations of grid feed-in in some regions in Germany with high amounts of installed PV capacity. By increasing self-consumption, the grid feed-in can be limited without curtailment , which wastes electricity. A good match between generation and consumption

15678-422: The resulting heat to generate electricity from conventional steam-driven turbines. A wide range of concentrating technologies exists: among the best known are the parabolic trough , the compact linear Fresnel reflector , the dish Stirling and the solar power tower . Various techniques are used to track the sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight and

15812-416: The revenue measurement point, depending on whether the credited energy production is calculated independently of the customer's energy consumption ( feed-in tariff ) or only on the difference of energy ( net metering ). These systems vary in size from residential (2–10 kW p ) to solar power stations (up to tens of MW p ). This is a form of decentralized electricity generation . Feeding electricity into

15946-428: The shaded portion). When connected in series, the current drawn from a string of cells is no greater than the normally small current that can flow through the shaded cell, so the current (and therefore power) developed by the string is limited. If the external load is of low enough impedance, there may be enough voltage available from the other cells in a string to force more current through the shaded cell by breaking down

16080-404: The short‐circuit current, and of the maximum power to temperature changes. In this paper, comprehensive experimental guidelines to estimate the temperature coefficients. Due to the low voltage of an individual solar cell (typically ca. 0.5V), several cells are wired (see Copper in renewable energy#Solar photovoltaic power generation ) in series in the manufacture of a "laminate". The laminate

16214-470: The solar array and a number of components often summarized as the balance of system (BOS). This term is synonymous with " Balance of plant " q.v. BOS-components include power-conditioning equipment and structures for mounting, typically one or more DC to AC power converters, also known as inverters , an energy storage device, a racking system that supports the solar array, electrical wiring and interconnections, and mounting for other components. Optionally,

16348-439: The solar array's ever changing power output and applies the proper impedance to find the optimal maximum power point . Anti-islanding is a protection mechanism to immediately shut down the inverter, preventing it from generating AC power when the connection to the load no longer exists. This happens, for example, in the case of a blackout. Without this protection, the supply line would become an "island" with power surrounded by

16482-521: The solar array; however, the inverter ultimately governs the amount of AC watts that can be distributed for consumption. For example, a PV system comprising 11 kilowatts DC (kW DC ) worth of PV modules, paired with one 10-kilowatt AC (kW AC ) inverter, will be limited to the inverter's output of 10 kW. As of 2019, conversion efficiency for state-of-the-art converters reached more than 98 percent. While string inverters are used in residential to medium-sized commercial PV systems, central inverters cover

16616-607: The sun from left to right may allow seasonal adjustment up or down. Due to their outdoor usage, solar cables are designed to be resistant against UV radiation and extremely high temperature fluctuations and are generally unaffected by the weather. Standards specifying the usage of electrical wiring in PV systems include the IEC 60364 by the International Electrotechnical Commission , in section 712 "Solar photovoltaic (PV) power supply systems",

16750-508: The sunlight, it receives more light on its surface than if it were angled. Second, direct light is used more efficiently than angled light. Special anti-reflective coatings can improve solar panel efficiency for direct and angled light, somewhat reducing the benefit of tracking. Trackers and sensors to optimise the performance are often seen as optional, but they can increase viable output by up to 45%. Arrays that approach or exceed one megawatt often use solar trackers. Considering clouds, and

16884-407: The system to vary power output with demand, or at least smooth the solar power fluctuation. There is much hydro worldwide, and adding solar panels on or around existing hydro reservoirs is particularly useful, because hydro is usually more flexible than wind and cheaper at scale than batteries, and existing power lines can sometimes be used. The early development of solar technologies starting in

17018-467: The systems have been installed in an increasing percentage of utility-scale projects. According to data from WoodMackenzie/GTM Research, global solar tracker shipments hit a record 14.5 gigawatts in 2017. This represents growth of 32 percent year-over-year, with similar or greater growth projected as large-scale solar deployment accelerates. Systems designed to deliver alternating current (AC), such as grid-connected applications need an inverter to convert

17152-411: The tilt angle for maximum annual array energy output. The optimization of the photovoltaic system for a specific environment can be complicated as issues of solar flux, soiling, and snow losses should be taken into effect. In addition, later work has shown that spectral effects can play a role in optimal photovoltaic material selection. For example, the spectrum of the albedo of the surroundings can play

17286-400: The unique option of supplying reactive power which can be advantageous in matching load requirements. Photovoltaic systems need to be monitored to detect breakdown and optimize operation. There are several photovoltaic monitoring strategies depending on the output of the installation and its nature. Monitoring can be performed on site or remotely. It can measure production only, retrieve all

17420-401: The world's largest source of electricity by 2050, with solar photovoltaics and concentrated solar thermal contributing 16% and 11% to the global demand, respectively. A grid connected system is connected to a larger independent grid (typically the public electricity grid) and feeds energy directly into the grid. This energy may be shared by a residential or commercial building before or after

17554-471: The world's lowest cost for solar PV electricity production of USD 1.04 cents/ kWh. Expenses of high-power band solar modules has greatly decreased over time. Beginning in 1982, the cost per kW was approximately 27,000 American dollars, and in 2006 the cost dropped to approximately 4,000 American dollars per kW. The PV system in 1992 cost approximately 16,000 American dollars per kW and it dropped to approximately 6,000 American dollars per kW in 2008. In 2021 in

17688-406: The world, mostly in Europe, with 1.4 million systems in Germany alone – as well as North America with 440,000 systems in the United States. The energy conversion efficiency of a conventional solar module increased from 15 to 20 percent since 2004 and a PV system recoups the energy needed for its manufacture in about 2 years. In exceptionally irradiated locations, or when thin-film technology

17822-454: Was PV. In some countries, the nameplate capacity of photovoltaic power stations is rated in megawatt-peak (MW p ), which refers to the solar array's theoretical maximum DC power output. In other countries, the manufacturer states the surface and the efficiency. However, Canada, Japan, Spain, and the United States often specify using the converted lower nominal power output in MW AC ,

17956-506: Was among those who recognized the importance of this discovery. In 1931, the German engineer Bruno Lange developed a photo cell using silver selenide in place of copper oxide , although the prototype selenium cells converted less than 1% of incident light into electricity. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created

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