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100-935: Solyndra was a manufacturer of cylindrical panels of copper indium gallium selenide (CIGS) thin film solar cells . It was based in Fremont, California . In 2009, the Obama administration co-signed $ 535 million in loans to Solyndra. Heavily promoted as a leader in the sustainable energy sector for its unusual technology, Solyndra was not able to compete with conventional solar panel manufacturers of crystalline silicon . The company filed for bankruptcy on September 1, 2011. Chris Gronet founded what would become Solyndra in May 2005. In 2006, Solyndra began deploying demonstration systems globally. The company reported deploying 14 systems that were each instrumented with sensitive radiation , wind speed, temperature, and humidity measurement devices to aid in

200-417: A battery pack for energy storage, a charge controller, interconnection wiring, circuit breakers, fuses, disconnect switches, voltage meters, and optionally a solar tracking mechanism. Equipment is carefully selected to optimize energy output and storage, reduce power transmission losses, and convert from direct current to alternating current. Smart modules are different from traditional solar panels because

300-476: A microinverter . Each module is rated by its DC output power under standard test conditions (STC) and hence the on field output power might vary. Power typically ranges from 100 to 365 Watts (W). The efficiency of a module determines the area of a module given the same rated output – an 8% efficient 230 W module will have twice the area of a 16% efficient 230 W module. Some commercially available solar modules exceed 24% efficiency. Currently,

400-480: A white roof , the company claimed that systems that employ the panels on a given rooftop could produce significantly more electricity in a given year. It was thought that on a white roof, the panels can capture up to 20% more light than a black roof. The other advantage claimed by the company was that the panels did not have to move to track the Sun. The panels are always presenting some of their face directly perpendicular to

500-422: A $ 535 million loan guarantee to Solyndra, will receive nearly nothing." In 2011 and 2012, during Obama's re-election campaign, the political advocacy group Americans for Prosperity spent $ 8.4 million in swing states on television advertisements denouncing the loan guarantee. The Wall Street Journal described the advertising campaign as "perhaps the biggest attack on Mr. Obama so far." Ultimately, none of

600-574: A US Department of the Treasury official confirmed that the criminal probe of Solyndra was focused on whether the company and its officers misrepresented the firm's finances to the government in seeking the loan or engaged in accounting fraud. Emails showed that the Obama administration had concerns about the legality of the Department of Energy's loan restructuring plan and warned OMB director Jeffrey D. Zients that

700-653: A claim filed by Solyndra for $ 7.5 million, and in April 2016 Trina Solar Ltd. settled a claim filed by Solyndra for $ 45 million. In June 2016 a Stipulation Of Dismissal was filed jointly between Solyndra and Suntech Power Holdings Co Ltd. and later signed by Hon. Saundra B. Armstrong on November 30, 2017. The company manufactured its products in its second fabrication plant, Fab 2, a new $ 733 million state-of-the-art robotic facility in Fremont, California, which opened in September 2010. Fab 2

800-462: A consequence, in 2013 it imposed import tariffs of as much as 57 percent on polysilicon shipped from these two countries in order to stop the product from being sold below cost. Due to the rapid growth in manufacturing in China and the lack of regulatory controls, there have been reports of the dumping of waste silicon tetrachloride . Normally the waste silicon tetrachloride is recycled but this adds to

900-525: A cost-effective and faster alternative for producing solar-grade poly-Si thin films. Modules produced by such method are shown to have a photovoltaic efficiency of ~6%. Polysilicon doping, if needed, is also done during the deposition process, usually by adding phosphine, arsine, or diborane. Adding phosphine or arsine results in slower deposition, while adding diborane increases the deposition rate. The deposition thickness uniformity usually degrades when dopants are added during deposition. The Siemens process

1000-502: A crystal grain size smaller than the device feature size is needed for homogeneity of the devices. Another method to produce poly-Si at low temperatures is metal-induced crystallization where an amorphous-Si thin film can be crystallized at temperatures as low as 150 °C if annealed while in contact of another metal film such as aluminium , gold , or silver . Polysilicon has many applications in VLSI manufacturing. One of its primary uses

1100-460: A cylindrical shape and placed 40 of them in each 1-by-2-metre (3 ft 3 in by 6 ft 7 in) panel. Solyndra designers thought the cylindrical solar panels absorbed energy from any direction (direct, indirect, and reflected light). Each Solyndra cylinder, one inch in diameter, is made up of two tubes. The company used equipment it had developed to deposit CIGS on the outside of the inner tube, which includes up to 200 CIGS cells. On top of

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1200-435: A given amount of sunlight, but can be more expensive. Module electrical connections are made with conducting wires that take the current off the modules and are sized according to the current rating and fault conditions, and sometimes include in-line fuses. Panels are typically connected in series of one or more panels to form strings to achieve a desired output voltage, and strings can be connected in parallel to provide

1300-543: A large number of solar cells and use light energy ( photons ) from the Sun to generate electricity through the photovoltaic effect . Most modules use wafer -based crystalline silicon cells or thin-film cells . The structural ( load carrying ) member of a module can be either the top layer or the back layer. Cells must be protected from mechanical damage and moisture. Most modules are rigid, but semi-flexible ones based on thin-film cells are also available. The cells are usually connected electrically in series , one to another to

1400-500: A low-pressure reactor either by changing the pumping speed or changing the inlet gas flow into the reactor. If the inlet gas is composed of both silane and nitrogen, the inlet gas flow, and hence the reactor pressure, may be varied either by changing the nitrogen flow at constant silane flow, or changing both the nitrogen and silane flow to change the total gas flow while keeping the gas ratio constant. Recent investigations have shown that e-beam evaporation, followed by SPC (if needed) can be

1500-453: A minimum temperature, however, wherein the rate of deposition becomes faster than the rate at which unreacted silane arrives at the surface. Beyond this temperature, the deposition rate can no longer increase with temperature, since it is now being hampered by lack of silane from which the polysilicon will be generated. Such a reaction is then said to be "mass-transport-limited". When a polysilicon deposition process becomes mass-transport-limited,

1600-512: A more efficient semiconductor than polycrystalline as it has undergone additional recrystallization via the Czochralski method. Polysilicon deposition, or the process of depositing a layer of polycrystalline silicon on a semiconductor wafer, is achieved by the chemical decomposition of silane (SiH 4 ) at high temperatures of 580 to 650 °C. This pyrolysis process releases hydrogen. Polysilicon layers can be deposited using 100% silane at

1700-629: A power station. The issue of efficiency versus cost is a value decision of whether one requires an "energy dense" solar cell or sufficient area is available for the installation of less expensive alternatives. For instance, a solar cell used for power generation in a remote location might require a more highly efficient solar cell than one used for low-power applications, such as solar accent lighting or pocket calculators, or near established power grids. Polysilicon production by country in 2013 (company head-quarter, not location of facility). World total of 227,000 tonnes. The polysilicon manufacturing market

1800-477: A powerbank f.e. Special features of the panels include high flexibility, high durability & waterproof characteristics. They are good for travel or camping. Solar trackers increase the energy produced per module at the cost of mechanical complexity and increased need for maintenance. They sense the direction of the Sun and tilt or rotate the modules as needed for maximum exposure to the light. Alternatively, fixed racks can hold modules stationary throughout

1900-474: A pressure of 25–130 Pa (0.19–0.98 Torr) or with 20–30% silane (diluted in nitrogen) at the same total pressure. Both of these processes can deposit polysilicon on 10–200 wafers per run, at a rate of 10–20 nm/min and with thickness uniformities of ±5%. Critical process variables for polysilicon deposition include temperature, pressure, silane concentration, and dopant concentration. Wafer spacing and load size have been shown to have only minor effects on

2000-481: A result of a consolidation of its production facilities. The company said that it was mothballing its older plant, Fab 1, and postponing expansion of recently opened Fab 2, giving it an annual production capacity of about 300 megawatts . Market conditions were cited, with conventional solar modules manufactured in China by low-cost producers such as Suntech and Yingli offering stiff competition. Between 2009 and mid-2011

2100-543: A substrate, such as glass, plastic or metal. Thin-film solar cells are typically a few nanometers ( nm ) to a few microns ( μm ) thick–much thinner than the wafers used in conventional crystalline silicon (c-Si) based solar cells, which can be up to 200 μm thick. 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). Solar cells are often classified into so-called generations based on

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2200-452: A traditional canopy . These canopies could be a parking lot canopy, carport , gazebo , Pergola , or patio cover . There are many benefits, which include maximizing the space available in urban areas while also providing shade for cars. The energy produced can be used to create electric vehicle (EV) charging stations. Portable solar panels can ensure electric current, enough to charge devices (mobile, radio, ...) via USB-port or to charge

2300-434: A visible grain, a "metal flake effect". Semiconductor grade (also solar grade) polycrystalline silicon is converted to single-crystal silicon – meaning that the randomly associated crystallites of silicon in polycrystalline silicon are converted to a large single crystal. Single-crystal silicon is used to manufacture most Si-based microelectronic devices. Polycrystalline silicon can be as much as 99.9999% pure. Ultra-pure poly

2400-671: Is a type of chemical vapor deposition process. Upgraded metallurgical-grade (UMG) silicon (also known as UMG-Si) for solar cells is being produced as a low cost alternative to polysilicon created by the Siemens process . UMG-Si greatly reduces impurities in a variety of ways that require less equipment and energy than the Siemens process. It is about 99% pure which is three or more orders of magnitude less pure and about 10 times less expensive than polysilicon ($ 1.70 to $ 3.20 per kg from 2005 to 2008 compared to $ 40 to $ 400 per kg for polysilicon). It has

2500-457: Is as gate electrode material for MOS devices. A polysilicon gate's electrical conductivity may be increased by depositing a metal (such as tungsten) or a metal silicide (such as tungsten silicide) over the gate. Polysilicon may also be employed as a resistor, a conductor, or as an ohmic contact for shallow junctions, with the desired electrical conductivity attained by doping the polysilicon material. One major difference between polysilicon and a-Si

2600-404: Is commonly used for the conducting gate materials in semiconductor devices such as MOSFETs ; however, it has potential for large-scale photovoltaic devices. The abundance, stability, and low toxicity of silicon, combined with the low cost of polysilicon relative to single crystals makes this variety of material attractive for photovoltaic production. Grain size has been shown to have an effect on

2700-742: Is deposited using low-pressure chemical-vapour deposition ( LPCVD ) reactors at high temperatures and is usually heavily doped n-type or p-type . More recently, intrinsic and doped polysilicon is being used in large-area electronics as the active and/or doped layers in thin-film transistors . Although it can be deposited by LPCVD , plasma-enhanced chemical vapour deposition (PECVD), or solid-phase crystallization of amorphous silicon in certain processing regimes, these processes still require relatively high temperatures of at least 300 °C. These temperatures make deposition of polysilicon possible for glass substrates but not for plastic substrates. The deposition of polycrystalline silicon on plastic substrates

2800-434: Is distinct from monocrystalline silicon and amorphous silicon . In single-crystal silicon, also known as monocrystalline silicon , the crystalline framework is homogeneous, which can be recognized by an even external colouring. The entire sample is one single, continuous and unbroken crystal as its structure contains no grain boundaries . Large single crystals are rare in nature and can also be difficult to produce in

2900-534: Is growing rapidly. According to Digitimes , in July 2011, the total polysilicon production in 2010 was 209,000 tons. First-tier suppliers account for 64% of the market while China-based polysilicon firms have 30% of market share. The total production is likely to increase 37.4% to 281,000 tons by end of 2011. For 2012, EETimes Asia predicts 328,000 tons production with only 196,000 tons of demand, with spot prices expected to fall 56%. While good for renewable energy prospects,

3000-503: Is limited primarily by geographic latitude and varies significantly depending on cloud cover, dust, day length and other factors. In the United Kingdom , seasonal capacity factor ranges from 2% (December) to 20% (July), with average annual capacity factor of 10–11%, while in Spain the value reaches 18%. Globally, capacity factor for utility-scale PV farms was 16.1% in 2019. Overheating

3100-404: Is motivated by the desire to be able to manufacture digital displays on flexible screens. Therefore, a relatively new technique called laser crystallization has been devised to crystallize a precursor amorphous silicon (a-Si) material on a plastic substrate without melting or damaging the plastic. Short, high-intensity ultraviolet laser pulses are used to heat the deposited a-Si material to above

Solyndra - Misplaced Pages Continue

3200-617: Is reflected. To maximize total energy output, modules are often oriented to face south (in the Northern Hemisphere) or north (in the Southern Hemisphere) and tilted to allow for the latitude. Solar tracking can be used to keep the angle of incidence small. Solar panels are often coated with an anti-reflective coating , which is one or more thin layers of substances with refractive indices intermediate between that of silicon and that of air. This causes destructive interference in

3300-416: Is that the mobility of the charge carriers of the polysilicon can be orders of magnitude larger and the material also shows greater stability under electric field and light-induced stress. This allows more complex, high-speed circuitry to be created on the glass substrate along with the a-Si devices, which are still needed for their low- leakage characteristics. When polysilicon and a-Si devices are used in

3400-401: Is the most commonly used method of polysilicon production, especially for electronics, with close to 75% of the world's production using this process as of 2005. The process converts metallurgical-grade Si , of approximately 98% purity, to SiHCl 3 and then to silicon in a reactor, thus removing transition metal and dopant impurities. The process is relatively expensive and slow. It

3500-595: Is the most important factor for the efficiency of the solar panel. Polysilicon Polysilicon is produced from metallurgical grade silicon by a chemical purification process, called the Siemens process . This process involves distillation of volatile silicon compounds, and their decomposition into silicon at high temperatures. An emerging, alternative process of refinement uses a fluidized bed reactor . The photovoltaic industry also produces upgraded metallurgical-grade silicon (UMG-Si), using metallurgical instead of chemical purification processes. When produced for

3600-578: Is used in the semiconductor industry, starting from poly rods that are two to three meters in length. In the microelectronics industry (semiconductor industry), poly is used at both the macro and micro scales. Single crystals are grown using the Czochralski , zone melting and Bridgman–Stockbarger methods. At the component level, polysilicon has long been used as the conducting gate material in MOSFET and CMOS processing technologies. For these technologies it

3700-693: Is yet unclear which companies will be able to produce at costs low enough to be profitable after the steep drop in spot-prices of the last months. Wacker's projected its total hyperpure-polysilicon production capacity to increase to 67,000 metric tons by 2014, due to its new polysilicon-production facility in Cleveland, Tennessee (US) with an annual capacity of 15,000 metric tons. Prices of polysilicon are often divided into two categories, contract and spot prices, and higher purity commands higher prices. While in booming installation times, price rally occurs in polysilicon. Not only spot prices surpass contract prices in

3800-722: The world's largest photovoltaic power stations . Additionally, the materials used in thin-film solar cells are typically produced using simple and scalable methods more cost-effective than first-generation cells, leading to lower environmental impacts like greenhouse gas (GHG) emissions in many cases. Thin-film cells also typically outperform renewable and non-renewable sources for electricity generation in terms of human toxicity and heavy-metal emissions . Despite initial challenges with efficient light conversion , especially among third-generation PV materials, as of 2023 some thin-film solar cells have reached efficiencies of up to 29.1% for single-junction thin-film GaAs cells, exceeding

3900-451: The CIGS material, it added an "optical coupling agent", which concentrates the sunlight that shines through the outer tube. After inserting the inner tube into the outer tube, each cylinder is filled with a silicone oil , then sealed with glass and metal to exclude moisture, which erodes CIGS's performance. The hermetic sealing technology is commonly used in fluorescent lamps . When combined with

4000-494: The FIT policies of Italy. The solar PV price survey and market research firm, PVinsights, reported that the prices of polysilicon might be dragged down by lack of installation in the second half of 2011. As recently as 2008 prices were over $ 400/kg spiking from levels around $ 200/kg, while seen falling to $ 15/kg in 2013. The Chinese government accused United States and South Korean manufacturers of predatory pricing or "dumping" . As

4100-473: The Siemens process. GT Solar claims a new Siemens process can produce at $ 27/kg and may reach $ 20/kg in 5 years. GCL-Poly expects production costs to be $ 20/kg by end of 2011. Elkem Solar estimates their UMG costs to be $ 25/kg, with a capacity of 6,000 tonnes by the end of 2010. Calisolar expects UMG technology to produce at $ 12/kg in 5 years with boron at 0.3 ppm and phosphorus at 0.6 ppm. At $ 50/kg and 7.5 g/W, module manufacturers spend $ 0.37/W for

Solyndra - Misplaced Pages Continue

4200-525: The Sun. The daily production of flat solar panels has an output curve that has a clear peak while Solyndra claimed their system produced more power throughout the day. The Solyndra panels allow wind to blow through them. According to the company, these factors enable the installation of PV on a broader range of rooftops without anchoring or ballast , which are inherently problematic. Solyndra claimed that wind and snow loads are negligible and that its panels are lighter in weight per area. The company claimed

4300-462: The U.S. Bankruptcy Court for the District of Delaware ruled "that the evidence does not support a finding that the principal purpose of the plan was tax avoidance." "Solyndra's owners, Argonaut Ventures I LLC and Madrone Partners LP" will "realize the tax benefits of between $ 875 million and $ 975 million of net operating losses, while more senior creditors, including the Department of Energy, which provided

4400-503: The U.S. Department of Energy. Following the company's 2011 bankruptcy, the government had expected to recoup $ 27 million under the Solyndra restructuring plan, or up to 100% of loaned funds from a $ 1.5 billion lawsuit filed against Chinese polysilicon solar-panel makers for alleged price fixing. The outcomes of the lawsuits were that, in November 2015, Yingli Green Energy Holding Co Ltd. settled

4500-523: The ability of some materials to create an electrical charge from light exposure was first observed by the French physicist Edmond Becquerel . Though these initial solar panels were too inefficient for even simple electric devices, they were used as an instrument to measure light. The observation by Becquerel was not replicated again until 1873, when the English electrical engineer Willoughby Smith discovered that

4600-1218: The active (sunlight-absorbing) layers used to produce them, with the most well-established or first-generation solar cells being made of single - or multi - crystalline silicon . This is the dominant technology currently used in most solar PV systems . Most thin-film solar cells are classified as second generation , made using thin layers of well-studied materials like amorphous silicon (a-Si), cadmium telluride (CdTe), copper indium gallium selenide (CIGS), or gallium arsenide (GaAs). Solar cells made with newer, less established materials are classified as third-generation or emerging solar cells. This includes some innovative thin-film technologies, such as perovskite , dye-sensitized , quantum dot , organic , and CZTS thin-film solar cells. Thin-film cells have several advantages over first-generation silicon solar cells, including being lighter and more flexible due to their thin construction. This makes them suitable for use in building-integrated photovoltaics and as semi- transparent , photovoltaic glazing material that can be laminated onto windows. Other commercial applications use rigid thin film solar panels (interleaved between two panes of glass) in some of

4700-447: The best achieved sunlight conversion rate (solar module efficiency) is around 21.5% in new commercial products typically lower than the efficiencies of their cells in isolation. The most efficient mass-produced solar modules have power density values of up to 175 W/m (16.22 W/ft ). The current versus voltage curve of a module provides useful information about its electrical performance. Manufacturing processes often cause differences in

4800-406: The cells themselves convert 12 to 14 percent of sunlight into electricity , an efficiency better than competing CIGS thin-film technologies. However, these efficiencies are for the cells laid flat. The company did not post any numbers about performance when the cells are rolled up. The Solyndra 100/200 spec sheet doesn't mention the cells or the panel efficiencies directly. However, calculating from

4900-671: The charge could be caused by light hitting selenium . After this discovery, William Grylls Adams and Richard Evans Day published "The action of light on selenium" in 1876, describing the experiment they used to replicate Smith's results. In 1881, the American inventor Charles Fritts created the first commercial solar panel, which was reported by Fritts as "continuous, constant and of considerable force not only by exposure to sunlight but also to dim, diffused daylight". However, these solar panels were very inefficient, especially compared to coal-fired power plants . In 1939, Russell Ohl created

5000-433: The company claimed, covering significantly more of the typically available roof area and producing more electricity per rooftop on an annual basis than a conventional panel installation. The company's panels were claimed to be unlike any other product ever tried in the industry: they were made of racks of cylindrical tubes (also called tubular solar panels), not traditional flat panels. Solyndra rolled its CIGS thin films into

5100-427: The company posted $ 100 million in revenue. It was estimated that its production and sales growth could lead to a market cap between $ 1.76 and 2 billion. In 2010, revenues were approximately $ 140 million. Brian Harrison, a veteran of Intel Corporation, briefly led Solyndra. He took the reins on July 27, 2010, less than a year before the company went bankrupt. Harrison replaced founder Gronet, who had served as CEO since

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5200-570: The company's inception in 2005. Solyndra received a $ 535 million U.S. Department of Energy loan guarantee, the first recipient of a loan guarantee under President Barack Obama 's economic stimulus program, the American Recovery and Reinvestment Act of 2009 . The loan program took a $ 528 million loss from Solyndra. Additionally, Solyndra received a $ 25.1 million tax break from California's Alternative Energy and Advanced Transportation Financing Authority. SoloPower also received similar funding from

5300-477: The company. Federal agents visited the homes of Brian Harrison, the company's CEO, and Chris Gronet, the company's founder, to examine computer files and documents. Also, in September 2011, the US Department of the Treasury launched an investigation. Bloomberg reported in 2011 that Solyndra's $ 733 million plant had whistling robots and spa showers, along with many other signs of extravagant spending. Also in 2011,

5400-410: The cost. Not requiring a silicon wafer alleviates the silicon shortages occasionally faced by the microelectronics industry. An example of not using a silicon wafer is crystalline silicon on glass (CSG) materials A primary concern in the photovoltaics industry is cell efficiency. However, sufficient cost savings from cell manufacturing can be suitable to offset reduced efficiency in the field, such as

5500-699: The current limits. Blocking and bypass diodes may be incorporated within the module or used externally to deal with partial array shading, in order to maximize output. For series connections, bypass diodes are placed in parallel with modules to allow current to bypass shaded modules which would otherwise severely limit the current. For paralleled connections, a blocking diode may be placed in series with each module's string to prevent current flowing backwards through shaded strings thus short-circuiting other strings. Outdoor solar panels usually include MC4 connectors , automotive solar panels may include an auxiliary power outlet and/or USB adapter and indoor panels may have

5600-929: The data provided shows the high-end 210 panel has a field efficiency of about 8.5%. Solar panel A solar panel is a device that converts sunlight into electricity by using photovoltaic (PV) cells. PV cells are made of materials that produce excited electrons when exposed to light. The electrons flow through a circuit and produce direct current (DC) electricity, which can be used to power various devices or be stored in batteries . Solar panels are also known as solar cell panels , solar electric panels , or PV modules . Solar panels are usually arranged in groups called arrays or systems . A photovoltaic system consists of one or more solar panels, an inverter that converts DC electricity to alternating current (AC) electricity, and sometimes other components such as controllers , meters , and trackers . Most panels are in solar farms or rooftop solar panels which supply

5700-435: The day at a given tilt ( zenith angle ) and facing a given direction ( azimuth angle ). Tilt angles equivalent to an installation's latitude are common. Some systems may also adjust the tilt angle based on the time of year. On the other hand, east- and west-facing arrays (covering an east–west facing roof, for example) are commonly deployed. Even though such installations will not produce the maximum possible average power from

5800-495: The deposition process. The rate of polysilicon deposition increases rapidly with temperature, since it follows Arrhenius behavior, that is deposition rate = A·exp(–qE a /kT) where q is electron charge and k is the Boltzmann constant . The activation energy (E a ) for polysilicon deposition is about 1.7 eV. Based on this equation, the rate of polysilicon deposition increases as the deposition temperature increases. There will be

5900-446: The desired current capability (amperes) of the PV system. In string connections the voltages of the modules add, but the current is determined by the lowest performing panel. This is known as the "Christmas light effect". In parallel connections the voltages will be the same, but the currents add. Arrays are connected up to meet the voltage requirements of the inverters and to not greatly exceed

6000-410: The desired voltage, and then in parallel to increase current. The power (in watts ) of the module is the voltage (in volts ) multiplied by the current (in amperes ), and depends both on the amount of light and on the electrical load connected to the module. The manufacturing specifications on solar panels are obtained under standard conditions, which are usually not the true operating conditions

6100-494: The development of energy yield forecasting software tools. According to the company, over 1,000 systems were installed worldwide, representing 100 megawatts of power. Major investors included George Kaiser Family Foundation, U.S. Venture Partners , CMEA Ventures , Redpoint Ventures , Virgin Green Fund , Madrone Capital Partners, RockPort Capital Partners, Argonaut Private Equity, Masdar and Artis Capital Management. In 2009,

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6200-410: The efficiency of polycrystalline solar cells. Solar cell efficiency increases with grain size. This effect is due to reduced recombination in the solar cell. Recombination, which is a limiting factor for current in a solar cell, occurs more prevalently at grain boundaries, see figure 1. The resistivity, mobility, and free-carrier concentration in monocrystalline silicon vary with doping concentration of

6300-711: The electrical parameters of different modules photovoltaic, even in cells of the same type. Therefore, only the experimental measurement of the I–V curve allows us to accurately establish the electrical parameters of a photovoltaic device. This measurement provides highly relevant information for the design, installation and maintenance of photovoltaic systems. Generally, the electrical parameters of photovoltaic modules are measured by indoor tests. However, outdoor testing has important advantages such as no expensive artificial light source required, no sample size limitation, and more homogeneous sample illumination. Capacity factor of solar panels

6400-461: The electricity grid Some advantages of solar panels are that they use a renewable and clean source of energy, reduce greenhouse gas emissions , and lower electricity bills. Some disadvantages are that they depend on the availability and intensity of sunlight, require cleaning, and have high initial costs. Solar panels are widely used for residential, commercial, and industrial purposes, as well as in space , often together with batteries . In 1839,

6500-436: The electronics industry, polysilicon contains impurity levels of less than one part per billion (ppb), while polycrystalline solar grade silicon (SoG-Si) is generally less pure. In the 2010's, production shifted toward China, with China-based companies accounting for seven of the top ten producers and around 90% of total worldwide production capacity of approximately 1,400,000 MT. German, US and South Korea companies account for

6600-415: The highest ratio of generated power per kilogram lifted into space. MJ-cells are compound semiconductors and made of gallium arsenide (GaAs) and other semiconductor materials. Another emerging PV technology using MJ-cells is concentrator photovoltaics (CPV). Thin-film solar cells are a type of solar cell made by depositing one or more thin layers ( thin films or TFs) of photovoltaic material onto

6700-641: The hiring of the chief restructuring officer Todd Neilson. In 2012, the US Department of Justice objected to the bankruptcy plan amid allegations that "the plan's primary purpose is tax avoidance through the preservation of hundreds of millions of dollars of net operating losses (NOL) after reorganization". Also, the successor company is named 360 Degree Solar Holdings, Inc ., which would have control over "approximately US$ 350 million in tax attributes", such as NOL carryovers. The case In re Solyndra LLC et al. , No. 11-12799 (Bankr. D. Del.), Judge Mary F. Walrath of

6800-469: The individual solar panels, the cost of the panels is now usually cheaper than the tracking mechanism and they can provide more economically valuable power during morning and evening peak demands than north or south facing systems. Some special solar PV modules include concentrators in which light is focused by lenses or mirrors onto smaller cells. This enables the cost-effective use of highly efficient, but expensive cells (such as gallium arsenide ) with

6900-562: The investigations of Solyndra found any evidence of wrongdoing or undue political influence. In 2012 a very small fraction of the glass tubes, which Solyndra had produced, became part of an art installation at the University of California Botanical Garden . Solyndra designed, manufactured, and sold solar photovoltaic (PV) systems composed of panels and mounting hardware for large, low-slope commercial rooftops . The panels perform optimally when mounted horizontally and packed closely together,

7000-453: The laboratory (see also recrystallisation ). In contrast, in an amorphous structure the order in atomic positions is limited to short range. Polycrystalline and paracrystalline phases are composed of a number of smaller crystals or crystallites . Polycrystalline silicon (or semi-crystalline silicon, polysilicon, poly-Si, or simply "poly") is a material consisting of multiple small silicon crystals. Polycrystalline cells can be recognized by

7100-495: The logarithm of the deposition rate against the reciprocal of the absolute temperature in the surface-reaction-limited region results in a straight line whose slope is equal to –qE a /k. At reduced pressure levels for VLSI manufacturing, polysilicon deposition rate below 575 °C is too slow to be practical. Above 650 °C, poor deposition uniformity and excessive roughness will be encountered due to unwanted gas-phase reactions and silane depletion. Pressure can be varied inside

7200-426: The market; but it is also hard to acquire enough polysilicon. Buyers will accept down payment and long-term agreements to acquire a large enough volume of polysilicon. On the contrary, spot prices will be below contract prices once the solar PV installation is in a down trend. In late 2010, booming installation brought up the spot prices of polysilicon. In the first half of 2011, prices of polysilicon kept strong owing to

7300-460: The material its typical metal flake effect . While polysilicon and multisilicon are often used as synonyms, multicrystalline usually refers to crystals larger than one millimetre. Multicrystalline solar cells are the most common type of solar cells in the fast-growing PV market and consume most of the worldwide produced polysilicon. About 5 tons of polysilicon is required to manufacture one 1 megawatt (MW) of conventional solar modules. Polysilicon

7400-544: The maximum of 26.1% efficiency for standard single-junction first-generation solar cells. Multi-junction concentrator cells incorporating thin-film technologies have reached efficiencies of up to 47.6% as of 2023. Large utility-scale solar power plants frequently use ground-mounted photovoltaic systems. Their solar modules are held in place by racks or frames that are attached to ground-based mounting supports. Ground based mounting supports include: Vertical bifacial solar cells are oriented towards east and west to catch

7500-435: The melting point of silicon, without melting the entire substrate. The molten silicon will then crystallize as it cools. By precisely controlling the temperature gradients, researchers have been able to grow very large grains, of up to hundreds of micrometers in size in the extreme case, although grain sizes of 10 nanometers to 1 micrometer are also common. In order to create devices on polysilicon over large-areas, however,

7600-579: The panel structure. Solar modular cells need to be connected together to form the module, with front electrodes blocking the solar cell front optical surface area slightly. To maximize frontal surface area available for sunlight and improve solar cell efficiency, manufacturers use varying rear electrode solar cell connection techniques: A single solar module can produce only a limited amount of power; most installations contain multiple modules adding their voltages or currents. A photovoltaic system typically includes an array of photovoltaic modules, an inverter ,

7700-496: The panel. Solar panel capacity is specified by the MPP (maximum power point) value of solar panels in full sunlight. Solar inverters convert the DC power provided by panels to AC power. MPP (Maximum power point) of the solar panel consists of MPP voltage (V mpp ) and MPP current (I mpp ). Performing maximum power point tracking (MPPT), a solar inverter samples the output (I-V curve) from

7800-454: The plan should be cleared with the Department of Justice first, which the Department of Energy had not done. The emails also revealed that, as early as August 2009, an aide to then-White House Chief of Staff Rahm Emanuel had asked a Department of Energy official if he could discuss any concerns among the investment community about Solyndra but that the official dismissed the idea that Solyndra had financial problems. The bankruptcy court approved

7900-418: The polycrystalline grains which will vary the physical properties of the material. The use of polycrystalline silicon in the production of solar cells requires less material and therefore provides higher profits and increased manufacturing throughput. Polycrystalline silicon does not need to be deposited on a silicon wafer to form a solar cell, rather it can be deposited on other-cheaper materials, thus reducing

8000-578: The polysilicon. For comparison, if a CdTe manufacturer pays spot price for tellurium ($ 420/kg in April 2010) and has a 3  μm thickness, their cost would be 10 times less, $ 0.037/Watt. At 0.1 g/W and $ 31/ozt for silver, polysilicon solar producers spend $ 0.10/W on silver. Q-Cells, Canadian Solar, and Calisolar have used Timminco UMG. Timminco is able to produce UMG-Si with 0.5 ppm boron for $ 21/kg but were sued by shareholders because they had expected $ 10/kg. RSI and Dow Corning have also been in litigation over UMG-Si technology. Currently, polysilicon

8100-451: The potential to provide nearly-as-good solar cell efficiency at 1/5 the capital expenditure, half the energy requirements, and less than $ 15/kg. In 2008 several companies were touting the potential of UMG-Si, but in 2010 the credit crisis greatly lowered the cost of polysilicon and several UMG-Si producers put plans on hold. The Siemens process will remain the dominant form of production for years to come due to more efficiently implementing

8200-663: The power electronics embedded in the module offers enhanced functionality such as panel-level maximum power point tracking , monitoring, and enhanced safety. Power electronics attached to the frame of a solar module, or connected to the photovoltaic circuit through a connector, are not properly considered smart modules. Several companies have begun incorporating into each PV module various embedded power electronics such as: Most solar modules are currently produced from crystalline silicon (c-Si) solar cells made of polycrystalline or monocrystalline silicon . In 2021, crystalline silicon accounted for 95% of worldwide PV production, while

8300-541: The price of polysilicon , the key ingredient for most competing technologies, dropped by about 89% due to Chinese advances in the Siemens process . This precipitous drop in the cost of raw materials for Solyndra's competitors rendered CIGS technology incapable of competing, and other factors, including a contemporaneous drop in the price of natural gas, together with the faltering of the corresponding financial models, also contributed to Solyndra's demise, despite quickly raising capital. On August 31, 2011, Solyndra announced it

8400-532: The reaction rate becomes dependent primarily on reactant concentration, reactor geometry, and gas flow. When the rate at which polysilicon deposition occurs is slower than the rate at which unreacted silane arrives, then it is said to be surface-reaction-limited. A deposition process that is surface-reaction-limited is primarily dependent on reactant concentration and reaction temperature. Deposition processes must be surface-reaction-limited because they result in excellent thickness uniformity and step coverage. A plot of

8500-422: The reflected light, diminishing the amount. Photovoltaic manufacturers have been working to decrease reflectance with improved anti-reflective coatings or with textured glass. In general with individual solar panels, if not enough current is taken, then power isn't maximised. If too much current is taken then the voltage collapses. The optimum current draw is roughly proportional to the amount of sunlight striking

8600-512: The remainder. The polysilicon feedstock – large rods, usually broken into chunks of specific sizes and packaged in clean rooms before shipment – is directly cast into multicrystalline ingots or submitted to a recrystallization process to grow single crystal boules . The boules are then sliced into thin silicon wafers and used for the production of solar cells , integrated circuits and other semiconductor devices . Polysilicon consists of small crystals , also known as crystallites , giving

8700-521: The rest of the overall market is made up of thin-film technologies using cadmium telluride (CdTe), copper indium gallium selenide (CIGS) and amorphous silicon (a-Si) . Emerging, third-generation solar technologies use advanced thin-film cells. They produce a relatively high-efficiency conversion for a lower cost compared with other solar technologies. Also, high-cost, high-efficiency, and close-packed rectangular multi-junction (MJ) cells are usually used in solar panels on spacecraft , as they offer

8800-431: The same process, this is called hybrid processing. A complete polysilicon active layer process is also used in some cases where a small pixel size is required, such as in projection displays . Polycrystalline silicon is the key feedstock in the crystalline silicon based photovoltaic industry and used for the production of conventional solar cells . For the first time, in 2006, over half of the world's supply of polysilicon

8900-406: The single crystal silicon. Whereas the doping of polycrystalline silicon does have an effect on the resistivity, mobility, and free-carrier concentration, these properties strongly depend on the polycrystalline grain size, which is a physical parameter that the material scientist can manipulate. Through the methods of crystallization to form polycrystalline silicon, an engineer can control the size of

9000-458: The solar cell and applies the proper electrical load to obtain maximum power. An AC ( alternating current ) solar panel has a small DC to AC microinverter on the back and produces AC power with no external DC connector . AC modules are defined by Underwriters Laboratories as the smallest and most complete system for harvesting solar energy. Micro-inverters work independently to enable each panel to contribute its maximum possible output for

9100-469: The solar cell design that is used in many modern solar panels. He patented his design in 1941. In 1954, this design was first used by Bell Labs to create the first commercially viable silicon solar cell. Solar panel installers saw significant growth between 2008 and 2013. Due to that growth many installers had projects that were not "ideal" solar roof tops to work with and had to find solutions to shaded roofs and orientation difficulties. This challenge

9200-475: The solar panels are exposed to on the installation site. A PV junction box is attached to the back of the solar panel and functions as its output interface. External connections for most photovoltaic modules use MC4 connectors to facilitate easy weatherproof connections to the rest of the system. A USB power interface can also be used. Solar panels also use metal frames consisting of racking components, brackets, reflector shapes, and troughs to better support

9300-407: The subsequent drop in price could be brutal for manufacturers. As of late 2012, SolarIndustryMag reports a capacity of 385,000 tons will be reached by yearend 2012. But as established producers (mentioned below) expand their capacities, additional newcomers – many from Asia – are moving into the market. Even long-time players in the field have recently had difficulties expanding plant production. It

9400-417: The sun's irradiance more efficiently in the morning and evening. Applications include agrivoltaics , solar fencing, highway and railroad noise dampeners and barricades . Roof-mounted solar power systems consist of solar modules held in place by racks or frames attached to roof-based mounting supports. Roof-based mounting supports include: Solar canopies are solar arrays which are installed on top of

9500-417: The trade-off of using a higher solar exposure area. Concentrating the sunlight can also raise the efficiency to around 45%. The amount of light absorbed by a solar cell depends on the angle of incidence of whatever direct sunlight hits it. This is partly because the amount falling on the panel is proportional to the cosine of the angle of incidence, and partly because at high angle of incidence more light

9600-417: The use of larger solar cell arrays compared with more compact/higher efficiency designs. Designs such as CSG are attractive because of a low cost of production even with reduced efficiency. Higher efficiency devices yield modules that occupy less space and are more compact; however, the 5–10% efficiency of typical CSG devices still makes them attractive for installation in large central-service stations, such as

9700-411: Was being used by PV manufacturers. The solar industry was severely hindered by a shortage in supply of polysilicon feedstock and was forced to idle about a quarter of its cell and module manufacturing capacity in 2007. Only twelve factories were known to produce solar-grade polysilicon in 2008; however, by 2013 the number increased to over 100 manufacturers. Monocrystalline silicon is higher priced and

9800-509: Was built with the support of a $ 535 million federal loan guarantee along with at least $ 198 million from private investors. Solyndra had expanded production in 2008. In March, 2009, Solyndra had estimated that: According to an initial public offering by the company, the combined annual production capacity of the plants was projected to be 610 megawatts by 2013. Solyndra announced on November 3, 2010, that it would lay off around 40 employees and not renew contracts for about 150 temporary workers as

9900-534: Was filing for Chapter 11 bankruptcy protection, laying off 1,100 employees, and shutting down all operations and manufacturing. In September 2011 the company ceased all business activity, filed for bankruptcy under Chapter 11, Title 11 of the United States Bankruptcy Code, and laid off all employees. The company was also sued by employees who were abruptly laid off. Solyndra was raided by the FBI investigating

10000-430: Was initially addressed by the re-popularization of micro-inverters and later the invention of power optimizers. Solar panel manufacturers partnered with micro-inverter companies to create AC modules and power optimizer companies partnered with module manufacturers to create smart modules. In 2013 many solar panel manufacturers announced and began shipping their smart module solutions. Photovoltaic modules consist of

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