This document provides an overview of solar photovoltaics. It discusses various methods of harvesting solar energy, focusing on photovoltaics which directly convert sunlight to electricity. The process by which photons liberate electrons in silicon to produce current is described. Factors limiting the efficiency of silicon photovoltaic cells to around 23% are also covered. The document discusses the costs and economics of residential and larger-scale photovoltaic installations. It profiles the author's personal solar power system and a larger solar array at UCSD.
Solar cells convert sunlight into electricity through the photovoltaic effect. The document discusses various types of solar cells like crystalline silicon, cadmium telluride, and gallium arsenide. It also covers the basic components and workings of solar photovoltaic systems including solar panels, batteries, inverters, and their connections to either the electric grid or for off-grid use. Calculations for sizing solar arrays and estimating power outputs are also presented.
S.V. Power Solutions presents an initiative to go green with solar energy. Thermal power plants that use coal contribute significantly to global warming, air pollution, water pollution, and waste heat. Solar energy is a more sustainable alternative that converts sunlight into electricity using solar panels. The key advantages of solar energy are lowered utility costs over time, a long system lifetime of 35+ years, producing zero emissions, and environmental benefits such as reduced carbon dioxide and water usage. Common components of residential solar power systems include solar panels, an inverter to convert DC to AC current, and batteries for energy storage in off-grid systems.
A photovoltaic cell, or solar cell, converts sunlight directly into electricity through the photovoltaic effect. Solar cells are made of semiconducting materials like silicon that produce electricity when struck by photons. In a solar cell, photons excite electrons in the material, allowing them to flow through an external circuit and produce a current. Solar cells are combined into solar panels or modules that provide higher voltages suitable for consumer applications. Proper sizing of solar PV systems involves determining power demands, sizing PV modules to meet those demands, selecting an appropriately sized inverter, and choosing battery capacity based on energy needs and days of autonomy required.
The document summarizes information about a solar power plant, including:
1) It describes the basic components of a solar power plant including solar modules, controllers, batteries, inverters, and lighting loads.
2) It explains how solar energy is converted into electricity through both photovoltaic and concentrated solar power systems. Photovoltaic cells convert sunlight directly into electricity while concentrated solar power uses mirrors to focus sunlight and generate heat to power turbines.
3) It provides an overview of the advantages of solar power plants in being renewable, clean, and requiring little maintenance over time.
In this PPT we are add all ditels and latest data.And in this PPT we are make char to when the sun light is reflact in soalr penal and we produced high power.
This document discusses a solar power plant, including its components and how it works. It notes that solar power plants convert sunlight into electricity directly using photovoltaic cells or indirectly using concentrated solar power. The key components of a solar power plant are solar modules, controllers, batteries, inverters, and lighting loads. Solar modules contain solar cells that generate electricity when struck by photons. Controllers ensure maximum power generation by tracking optimal operating conditions. Batteries store excess power for nighttime use. Inverters convert the solar module DC output to AC used in homes.
Desgin and development of solar powered air conditioning sysytemAkshay Saraf
Using solar powered air conditioning is useful both inside and outside.
In this PPT we will discuss about the calculation of solar powered air conditioning system
Solar cells convert sunlight into electricity through the photovoltaic effect. The document discusses various types of solar cells like crystalline silicon, cadmium telluride, and gallium arsenide. It also covers the basic components and workings of solar photovoltaic systems including solar panels, batteries, inverters, and their connections to either the electric grid or for off-grid use. Calculations for sizing solar arrays and estimating power outputs are also presented.
S.V. Power Solutions presents an initiative to go green with solar energy. Thermal power plants that use coal contribute significantly to global warming, air pollution, water pollution, and waste heat. Solar energy is a more sustainable alternative that converts sunlight into electricity using solar panels. The key advantages of solar energy are lowered utility costs over time, a long system lifetime of 35+ years, producing zero emissions, and environmental benefits such as reduced carbon dioxide and water usage. Common components of residential solar power systems include solar panels, an inverter to convert DC to AC current, and batteries for energy storage in off-grid systems.
A photovoltaic cell, or solar cell, converts sunlight directly into electricity through the photovoltaic effect. Solar cells are made of semiconducting materials like silicon that produce electricity when struck by photons. In a solar cell, photons excite electrons in the material, allowing them to flow through an external circuit and produce a current. Solar cells are combined into solar panels or modules that provide higher voltages suitable for consumer applications. Proper sizing of solar PV systems involves determining power demands, sizing PV modules to meet those demands, selecting an appropriately sized inverter, and choosing battery capacity based on energy needs and days of autonomy required.
The document summarizes information about a solar power plant, including:
1) It describes the basic components of a solar power plant including solar modules, controllers, batteries, inverters, and lighting loads.
2) It explains how solar energy is converted into electricity through both photovoltaic and concentrated solar power systems. Photovoltaic cells convert sunlight directly into electricity while concentrated solar power uses mirrors to focus sunlight and generate heat to power turbines.
3) It provides an overview of the advantages of solar power plants in being renewable, clean, and requiring little maintenance over time.
In this PPT we are add all ditels and latest data.And in this PPT we are make char to when the sun light is reflact in soalr penal and we produced high power.
This document discusses a solar power plant, including its components and how it works. It notes that solar power plants convert sunlight into electricity directly using photovoltaic cells or indirectly using concentrated solar power. The key components of a solar power plant are solar modules, controllers, batteries, inverters, and lighting loads. Solar modules contain solar cells that generate electricity when struck by photons. Controllers ensure maximum power generation by tracking optimal operating conditions. Batteries store excess power for nighttime use. Inverters convert the solar module DC output to AC used in homes.
Desgin and development of solar powered air conditioning sysytemAkshay Saraf
Using solar powered air conditioning is useful both inside and outside.
In this PPT we will discuss about the calculation of solar powered air conditioning system
Solar panels basic types, Mono, poly, Battery, MPPT Charger, Efficiency, Monocrystalline solar panels, Polycrystalline solar panels ,Amorphous solar panels,Cost and expected LifeSpan of solar panels, Charge Controller ,MPPT Maximum Power Point Tracking
This document describes how to build a solar charger using a solar panel, voltage regulator, capacitors, and USB port to charge devices. Solar energy is converted to electrical energy by the solar panel and regulated to 5V by the voltage regulator. The capacitors help regulate voltage. Connecting the USB port allows charging phones and other devices using clean, renewable solar power. Building a small, portable solar charger allows mobile energy access and helps conserve other resources by harnessing the sun's abundant energy.
The document discusses solar power generation, distribution, and storage from small-scale solar power systems. It describes how solar power works by converting sunlight to electricity through photovoltaic cells or concentrating solar power systems. The document outlines the components of a solar power generation system and discusses photovoltaic effect. It also addresses performance factors, applications, advantages and disadvantages of solar power.
This presentation provides an overview of solar power. It introduces solar power, discussing its history from 1839 to modern solar cells. It explains how solar panels work by converting sunlight into electricity through photovoltaic cells. The presentation outlines the benefits of solar power, such as being renewable, requiring little maintenance, and saving households $20,000 over 20 years. It also discusses solar inverters, which convert the variable energy from solar panels into a constant output and allow grid-connected systems to supply backup power during outages.
Solar photovoltaic (PV) technology converts sunlight directly into electricity using solar panels made of semiconductor materials. A solar PV panel generates voltage and current when exposed to sunlight, with higher intensity sunlight producing more electricity. The electricity produced is direct current (DC), which requires an inverter to convert it to alternating current (AC) for common uses. Solar PV systems have no moving parts and require little maintenance, but cannot generate power at night or when the sun is obscured by clouds. Proper system sizing requires determining energy needs and available sunlight based on location, direction panels face, shading, and other factors. Larger panels, tracking systems, and concentrating optics can increase energy capture.
How to Improve Efficiency of Solar Panel.docxAkashNaheliya
This document provides information on improving the efficiency of solar panels. It discusses how solar cells work and how efficiency is calculated. Some key methods discussed to increase efficiency include using radiators and fans to cool panels, anti-reflective coatings, choosing optimum transparent conductors, and promoting light scattering. Factors that limit efficiency gains are also examined, such as high temperatures, shading, panel orientation, and the need for regular maintenance to maximize energy production.
Solar technologies you can use in your Indian homeThe_Alternative
Greenprint Your Home: U Solar CEO Harinarayan presents the various solar technologies available in the market today for homes. More at www.thealternative.in/greenprint-your-home
This document provides information about a photovoltaic system project at IIT Roorkee. It discusses the components of a photovoltaic system including solar arrays, mounting systems, inverters, and batteries. It also describes different types of solar cell technologies like thin film and crystalline silicon, and provides background on the growth of photovoltaics over time in India and worldwide. The document highlights India's solar potential and the Indian government's support for solar energy development.
This document provides an overview of solar energy, including its history, development, technologies, applications, advantages and disadvantages. It discusses how solar cells work by converting sunlight into electricity through the photovoltaic effect. Different types of solar cells and panels are described, as well as the process of installing a solar energy system. Opportunities and challenges of solar power in Pakistan are highlighted, along with various uses of solar energy from heating to transportation.
Solar cell is the device that converts energy of light directly into electrical energy (electricity) by photovoltaic effect In general, a solar cell that includes both solar and non solar sources of light
(such as photons from incandescent bulbs) is termed a photovoltaic cell. Solar cell is also know as photovoltaic cell
Most familiar solar cells are based on the effect
of photovoltaic In this effect, light falling on semiconductor device of the two layer produces a potential difference or photo voltage between the layers The voltage thus produced can drive a current through an external circuit producing useful work
PV SYSTEMS, COMPONENTS DEVICES AND APPLICATIONS.pptArpoMukherjee1
The document discusses various aspects of photovoltaic technology. It describes two main methods of harnessing solar energy - photovoltaic and thermal. It then provides details on photovoltaic technology, including the different generations of solar cell materials, characteristics of solar cells and modules, and components of solar PV systems including panels, batteries, charge controllers, inverters, and other accessories. Examples of solar PV applications are also mentioned.
The document provides information about a 5MW solar photovoltaic power plant project. It discusses key details of the project such as the annual estimated generation of 7263 MWh, cost of 48.59 crores, use of 20856 polycrystalline silicon solar modules, 10 inverters each with a capacity of 500KVA, and connection to the grid via a 33KV transmission line that is 4.2km in length. It also summarizes the site layout including 3476 foundations, protection systems, monitoring via a SCADA system, and backup power solutions in case of auxiliary power failure.
L1 Solar Energy--The Ultimate Renewable Resource.pptnehasolanki83
Solar energy originates from the sun and represents the entire electromagnetic spectrum that reaches Earth. It has the advantages of being pollution-free and sustainable, with the energy from 30 days of sunshine having the equivalent energy of all fossil fuels used and unused on Earth. Challenges include its diffuse and intermittent nature. Various technologies have been developed to collect, convert, and store solar energy for heating water and living spaces as well as generating electricity through photovoltaics and concentrating solar power towers and dishes. While solar technologies are improving, their higher initial costs compared to fossil fuels have limited widespread adoption.
The document summarizes how photovoltaic (PV) solar cells work to convert sunlight into electricity. It discusses the materials and manufacturing process used to make PV cells from silicon wafers. Finally, it covers common applications of solar PV systems and some advantages and disadvantages of the technology.
The document summarizes how photovoltaic (PV) solar cells work to convert sunlight into electricity. It discusses the materials and manufacturing process used to make PV cells from silicon wafers. Finally, it covers common applications of solar PV systems and some advantages and disadvantages of the technology.
The document discusses solar photovoltaic (PV) systems, including their advantages and disadvantages. It describes the I-V characteristics of solar cells and equivalent circuit. Variations in isolation and temperature affect the PV characteristics. Losses limit conversion efficiency. Maximizing open circuit voltage, short circuit current, and fill factor leads to high performance. Solar cells are classified based on material thickness, junction structure, and active material. PV modules, panels, and arrays are also discussed. Maximum power point tracking using a buck-boost converter can optimize solar PV output. Systems can be centralized, distributed, or hybrid to serve various applications including power generation, water pumping, and lighting.
Solar panels basic types, Mono, poly, Battery, MPPT Charger, Efficiency, Monocrystalline solar panels, Polycrystalline solar panels ,Amorphous solar panels,Cost and expected LifeSpan of solar panels, Charge Controller ,MPPT Maximum Power Point Tracking
This document describes how to build a solar charger using a solar panel, voltage regulator, capacitors, and USB port to charge devices. Solar energy is converted to electrical energy by the solar panel and regulated to 5V by the voltage regulator. The capacitors help regulate voltage. Connecting the USB port allows charging phones and other devices using clean, renewable solar power. Building a small, portable solar charger allows mobile energy access and helps conserve other resources by harnessing the sun's abundant energy.
The document discusses solar power generation, distribution, and storage from small-scale solar power systems. It describes how solar power works by converting sunlight to electricity through photovoltaic cells or concentrating solar power systems. The document outlines the components of a solar power generation system and discusses photovoltaic effect. It also addresses performance factors, applications, advantages and disadvantages of solar power.
This presentation provides an overview of solar power. It introduces solar power, discussing its history from 1839 to modern solar cells. It explains how solar panels work by converting sunlight into electricity through photovoltaic cells. The presentation outlines the benefits of solar power, such as being renewable, requiring little maintenance, and saving households $20,000 over 20 years. It also discusses solar inverters, which convert the variable energy from solar panels into a constant output and allow grid-connected systems to supply backup power during outages.
Solar photovoltaic (PV) technology converts sunlight directly into electricity using solar panels made of semiconductor materials. A solar PV panel generates voltage and current when exposed to sunlight, with higher intensity sunlight producing more electricity. The electricity produced is direct current (DC), which requires an inverter to convert it to alternating current (AC) for common uses. Solar PV systems have no moving parts and require little maintenance, but cannot generate power at night or when the sun is obscured by clouds. Proper system sizing requires determining energy needs and available sunlight based on location, direction panels face, shading, and other factors. Larger panels, tracking systems, and concentrating optics can increase energy capture.
How to Improve Efficiency of Solar Panel.docxAkashNaheliya
This document provides information on improving the efficiency of solar panels. It discusses how solar cells work and how efficiency is calculated. Some key methods discussed to increase efficiency include using radiators and fans to cool panels, anti-reflective coatings, choosing optimum transparent conductors, and promoting light scattering. Factors that limit efficiency gains are also examined, such as high temperatures, shading, panel orientation, and the need for regular maintenance to maximize energy production.
Solar technologies you can use in your Indian homeThe_Alternative
Greenprint Your Home: U Solar CEO Harinarayan presents the various solar technologies available in the market today for homes. More at www.thealternative.in/greenprint-your-home
This document provides information about a photovoltaic system project at IIT Roorkee. It discusses the components of a photovoltaic system including solar arrays, mounting systems, inverters, and batteries. It also describes different types of solar cell technologies like thin film and crystalline silicon, and provides background on the growth of photovoltaics over time in India and worldwide. The document highlights India's solar potential and the Indian government's support for solar energy development.
This document provides an overview of solar energy, including its history, development, technologies, applications, advantages and disadvantages. It discusses how solar cells work by converting sunlight into electricity through the photovoltaic effect. Different types of solar cells and panels are described, as well as the process of installing a solar energy system. Opportunities and challenges of solar power in Pakistan are highlighted, along with various uses of solar energy from heating to transportation.
Solar cell is the device that converts energy of light directly into electrical energy (electricity) by photovoltaic effect In general, a solar cell that includes both solar and non solar sources of light
(such as photons from incandescent bulbs) is termed a photovoltaic cell. Solar cell is also know as photovoltaic cell
Most familiar solar cells are based on the effect
of photovoltaic In this effect, light falling on semiconductor device of the two layer produces a potential difference or photo voltage between the layers The voltage thus produced can drive a current through an external circuit producing useful work
PV SYSTEMS, COMPONENTS DEVICES AND APPLICATIONS.pptArpoMukherjee1
The document discusses various aspects of photovoltaic technology. It describes two main methods of harnessing solar energy - photovoltaic and thermal. It then provides details on photovoltaic technology, including the different generations of solar cell materials, characteristics of solar cells and modules, and components of solar PV systems including panels, batteries, charge controllers, inverters, and other accessories. Examples of solar PV applications are also mentioned.
The document provides information about a 5MW solar photovoltaic power plant project. It discusses key details of the project such as the annual estimated generation of 7263 MWh, cost of 48.59 crores, use of 20856 polycrystalline silicon solar modules, 10 inverters each with a capacity of 500KVA, and connection to the grid via a 33KV transmission line that is 4.2km in length. It also summarizes the site layout including 3476 foundations, protection systems, monitoring via a SCADA system, and backup power solutions in case of auxiliary power failure.
L1 Solar Energy--The Ultimate Renewable Resource.pptnehasolanki83
Solar energy originates from the sun and represents the entire electromagnetic spectrum that reaches Earth. It has the advantages of being pollution-free and sustainable, with the energy from 30 days of sunshine having the equivalent energy of all fossil fuels used and unused on Earth. Challenges include its diffuse and intermittent nature. Various technologies have been developed to collect, convert, and store solar energy for heating water and living spaces as well as generating electricity through photovoltaics and concentrating solar power towers and dishes. While solar technologies are improving, their higher initial costs compared to fossil fuels have limited widespread adoption.
The document summarizes how photovoltaic (PV) solar cells work to convert sunlight into electricity. It discusses the materials and manufacturing process used to make PV cells from silicon wafers. Finally, it covers common applications of solar PV systems and some advantages and disadvantages of the technology.
The document summarizes how photovoltaic (PV) solar cells work to convert sunlight into electricity. It discusses the materials and manufacturing process used to make PV cells from silicon wafers. Finally, it covers common applications of solar PV systems and some advantages and disadvantages of the technology.
The document discusses solar photovoltaic (PV) systems, including their advantages and disadvantages. It describes the I-V characteristics of solar cells and equivalent circuit. Variations in isolation and temperature affect the PV characteristics. Losses limit conversion efficiency. Maximizing open circuit voltage, short circuit current, and fill factor leads to high performance. Solar cells are classified based on material thickness, junction structure, and active material. PV modules, panels, and arrays are also discussed. Maximum power point tracking using a buck-boost converter can optimize solar PV output. Systems can be centralized, distributed, or hybrid to serve various applications including power generation, water pumping, and lighting.
Kinetic studies on malachite green dye adsorption from aqueous solutions by A...Open Access Research Paper
Water polluted by dyestuffs compounds is a global threat to health and the environment; accordingly, we prepared a green novel sorbent chemical and Physical system from an algae, chitosan and chitosan nanoparticle and impregnated with algae with chitosan nanocomposite for the sorption of Malachite green dye from water. The algae with chitosan nanocomposite by a simple method and used as a recyclable and effective adsorbent for the removal of malachite green dye from aqueous solutions. Algae, chitosan, chitosan nanoparticle and algae with chitosan nanocomposite were characterized using different physicochemical methods. The functional groups and chemical compounds found in algae, chitosan, chitosan algae, chitosan nanoparticle, and chitosan nanoparticle with algae were identified using FTIR, SEM, and TGADTA/DTG techniques. The optimal adsorption conditions, different dosages, pH and Temperature the amount of algae with chitosan nanocomposite were determined. At optimized conditions and the batch equilibrium studies more than 99% of the dye was removed. The adsorption process data matched well kinetics showed that the reaction order for dye varied with pseudo-first order and pseudo-second order. Furthermore, the maximum adsorption capacity of the algae with chitosan nanocomposite toward malachite green dye reached as high as 15.5mg/g, respectively. Finally, multiple times reusing of algae with chitosan nanocomposite and removing dye from a real wastewater has made it a promising and attractive option for further practical applications.
Download the Latest OSHA 10 Answers PDF : oyetrade.comNarendra Jayas
Latest OSHA 10 Test Question and Answers PDF for Construction and General Industry Exam.
Download the full set of 390 MCQ type question and answers - https://www.oyetrade.com/OSHA-10-Answers-2021.php
To Help OSHA 10 trainees to pass their pre-test and post-test we have prepared set of 390 question and answers called OSHA 10 Answers in downloadable PDF format. The OSHA 10 Answers question bank is prepared by our in-house highly experienced safety professionals and trainers. The OSHA 10 Answers document consists of 390 MCQ type question and answers updated for year 2024 exams.
Optimizing Post Remediation Groundwater Performance with Enhanced Microbiolog...Joshua Orris
Results of geophysics and pneumatic injection pilot tests during 2003 – 2007 yielded significant positive results for injection delivery design and contaminant mass treatment, resulting in permanent shut-down of an existing groundwater Pump & Treat system.
Accessible source areas were subsequently removed (2011) by soil excavation and treated with the placement of Emulsified Vegetable Oil EVO and zero-valent iron ZVI to accelerate treatment of impacted groundwater in overburden and weathered fractured bedrock. Post pilot test and post remediation groundwater monitoring has included analyses of CVOCs, organic fatty acids, dissolved gases and QuantArray® -Chlor to quantify key microorganisms (e.g., Dehalococcoides, Dehalobacter, etc.) and functional genes (e.g., vinyl chloride reductase, methane monooxygenase, etc.) to assess potential for reductive dechlorination and aerobic cometabolism of CVOCs.
In 2022, the first commercial application of MetaArray™ was performed at the site. MetaArray™ utilizes statistical analysis, such as principal component analysis and multivariate analysis to provide evidence that reductive dechlorination is active or even that it is slowing. This creates actionable data allowing users to save money by making important site management decisions earlier.
The results of the MetaArray™ analysis’ support vector machine (SVM) identified groundwater monitoring wells with a 80% confidence that were characterized as either Limited for Reductive Decholorination or had a High Reductive Reduction Dechlorination potential. The results of MetaArray™ will be used to further optimize the site’s post remediation monitoring program for monitored natural attenuation.
The modification of an existing product or the formulation of a new product to fill a newly identified market niche or customer need are both examples of product development. This study generally developed and conducted the formulation of aramang baked products enriched with malunggay conducted by the researchers. Specifically, it answered the acceptability level in terms of taste, texture, flavor, odor, and color also the overall acceptability of enriched aramang baked products. The study used the frequency distribution for evaluators to determine the acceptability of enriched aramang baked products enriched with malunggay. As per sensory evaluation conducted by the researchers, it was proven that aramang baked products enriched with malunggay was acceptable in terms of Odor, Taste, Flavor, Color, and Texture. Based on the results of sensory evaluation of enriched aramang baked products proven that three (3) treatments were all highly acceptable in terms of variable Odor, Taste, Flavor, Color and Textures conducted by the researchers.
Evolving Lifecycles with High Resolution Site Characterization (HRSC) and 3-D...Joshua Orris
The incorporation of a 3DCSM and completion of HRSC provided a tool for enhanced, data-driven, decisions to support a change in remediation closure strategies. Currently, an approved pilot study has been obtained to shut-down the remediation systems (ISCO, P&T) and conduct a hydraulic study under non-pumping conditions. A separate micro-biological bench scale treatability study was competed that yielded positive results for an emerging innovative technology. As a result, a field pilot study has commenced with results expected in nine-twelve months. With the results of the hydraulic study, field pilot studies and an updated risk assessment leading site monitoring optimization cost lifecycle savings upwards of $15MM towards an alternatively evolved best available technology remediation closure strategy.
Monitor indicators of genetic diversity from space using Earth Observation dataSpatial Genetics
Genetic diversity within and among populations is essential for species persistence. While targets and indicators for genetic diversity are captured in the Kunming-Montreal Global Biodiversity Framework, assessing genetic diversity across many species at national and regional scales remains challenging. Parties to the Convention on Biological Diversity (CBD) need accessible tools for reliable and efficient monitoring at relevant scales. Here, we describe how Earth Observation satellites (EO) make essential contributions to enable, accelerate, and improve genetic diversity monitoring and preservation. Specifically, we introduce a workflow integrating EO into existing genetic diversity monitoring strategies and present a set of examples where EO data is or can be integrated to improve assessment, monitoring, and conservation. We describe how available EO data can be integrated in innovative ways to support calculation of the genetic diversity indicators of the GBF monitoring framework and to inform management and monitoring decisions, especially in areas with limited research infrastructure or access. We also describe novel, integrative approaches to improve the indicators that can be implemented with the coming generation of EO data, and new capabilities that will provide unprecedented detail to characterize the changes to Earth’s surface and their implications for biodiversity, on a global scale.
2. UCSD Physics 12
Spring 2013 2
Methods of Harvesting Sunlight
Passive: cheap, efficient design;
block summer rays; allow winter
Solar Thermal: ~30% efficient;
cost-competitive; requires direct sun;
heats fluid in pipes that then boils
water to drive steam turbine
Solar hot water: up to 50% efficient; several $k to
install; usually keep conventional backup; freeze
protection vital (even in S.D.!!)
Photovoltaic (PV): direct electricity; 15% efficient;
$5 per Watt to install without rebates/incentives;
small fraction of roof covers demand of typ. home
Biofuels, algae, etc. also harvest solar energy, at few % eff.
3. UCSD Physics 12
Spring 2013 3
Photovoltaic (PV) Scheme
• Highly purified silicon (Si) from sand, quartz, etc. is “doped” with intentional
impurities at controlled concentrations to produce a p-n junction
– p-n junctions are common and useful: diodes, CCDs, photodiodes, transistors
• A photon incident on the p-n junction liberates an electron
– photon disappears, any excess energy goes into kinetic energy of electron (heat)
– electron wanders around drunkenly, and might stumble into “depletion region”
where electric field exists (electrons, being negative, move against field arrows)
– electric field sweeps electron across the junction, constituting a current
– more photons more electrons more current more power
n-type silicon
p-type silicon
photon of light
liberated electron
electric field
Si doped with
boron, e.g.
Si doped with
phosphorous, e.g.
4. UCSD Physics 12
Spring 2013 4
Provide a circuit for the electron flow
• Without a path for the electrons to flow out,
charge would build up and end up canceling
electric field
– must provide a way out
– direct through external load
– PV cell acts like a battery
current flow
external load
5. UCSD Physics 12
Spring 2013 5
PV types
• Single-crystal silicon
– 15–18% efficient, typically
– expensive to make (grown as big crystal)
• Poly-crystalline silicon
– 12–16% efficient, slowly improving
– cheaper to make (cast in ingots)
• Amorphous silicon (non-crystalline)
– 4–8% efficient
– cheapest per Watt
– called “thin film”, easily deposited on a wide range of
surface types
6. UCSD Physics 12
Spring 2013 6
How good can it get?
• Silicon is transparent at wavelengths longer than
1.1 microns (1100 nm)
– 23% of sunlight passes right through with no effect
• Excess photon energy is wasted as heat
– near-infrared light (1100 nm) typically delivers only
51% of its photon energy into electrical current energy
• roughly half the electrons stumble off in the wrong direction
– red light (700 nm) only delivers 33%
– blue light (400 nm) only delivers 19%
• All together, the maximum efficiency for a silicon
PV in sunlight is about 23%
– defeating “recombination loss” puts the limit in the low
30’s %
7. UCSD Physics 12
Spring 2013 7
Silicon Photovoltaic Budget
• Only 77% of solar spectrum is absorbed by silicon
• Of this, ~30% is used as electrical energy
• Net effect is 23% maximum efficiency
8. UCSD Physics 12
More Detail on Do the Math site
• Explains the physical
factors involved in
setting PV efficiency
limits
– http://physics.ucsd.edu/
do-the-
math/2011/09/dont-be-
a-pv-efficiency-snob/
Spring 2013 8
9. UCSD Physics 12
Spring 2013 9
PV Cells as “Batteries”
• A single PV cell (junction) in the sun acts like a battery
– characteristic voltage is 0.58 V
– power delivered is current times voltage
– current is determined by the rate of incoming solar photons
• Stack cells in series to get usefully high voltages
– voltage ≠ power, but higher voltage means you can deliver power
with less current, meaning smaller wiring, greater transmission
efficiency
• A typical panel has 36 cells for about 21 V open-circuit
(no current delivered)
– but actually drops to ~16 V at max power
– well suited to charging a nominal 12 V battery
3.5 volts
0.58 V +0.58 V +0.58 V +0.58 V +0.58 V +0.58 V
10. UCSD Physics 12
Spring 2013 10
Typical I-V curves
• Typical single panel (this one: 130 W at peak power)
• Power is current times voltage, so area of rectangle
– max power is 7.6 amps times 17.5 V = 133 W
• Less efficient at higher temperatures
3Q
11. UCSD Physics 12
Spring 2013 11
How much does it cost?
• Solar PV is usually priced in dollars per peak Watt
– or full-sun max capacity: how fast can it produce energy
– panels cost $2.50 per Watt (and falling), installed cost $5/W
– so a 3kW residential system is $15,000 to install
– State rebates and federal tax incentives can reduce cost substantially
• so 3kW system can be < $10,000 to install
• To get price per kWh, need to figure in exposure
– rule of thumb: 4–6 hours per day full sun equiv: 3kW system produces ~15
kWh per day
• Mythbusting: the energy it takes to manufacture a PV panel is
recouped in 3–4 years of sunlight
– contrary to myth that…
– they never achieve energy payback
12. UCSD Physics 12
Spring 2013 12
Solar Economics
• Current electricity cost in CA is about $0.13 per kWh
• PV model: assume 5 hours peak-sun equivalent per day
– in one year, get 1800 hours full-sun equivalent
– installed cost is $5 per peak Watt capability, no rebates
– one Watt installed delivers 1.8 kWh in a year
– panel lasts at least 25 years, so 45 kWh for each Watt of capacity
– paid $5.00 for 45 kWh, so $0.11/kWh
– rebates can pull price to < $0.08/kWh
• Assuming energy rates increase at a few % per year,
payback is < 10 years
– thereafter: “free” electricity
– but sinking $$ up front means loss of investment capability
– net effect: cost today is what matters to most people
• Solar PV is on the verge of “breakout,” but demand may
keep prices stable throughout the breakout process
5Q
13. UCSD Physics 12
Spring 2013 13
Solar’s Dirty Secret
• It may come as a surprise, but the sun is not always up
• A consumer base that expects energy availability at all
times is not fully compatible with direct solar power
• Therefore, large-scale solar implementation must confront
energy storage techniques to be useful
– at small scale, can easily feed into grid, and other power plants
take up slack by varying their output
• Methods of storage (all present challenges):
– conventional batteries (lead-acid; cheapest option)
– exotic batteries (need development)
– hydrogen fuel (could power fleet of cars, but inefficient)
– global electricity grid (always sunny somewhere)
– pumped water storage (not much capacity)
14. UCSD Physics 12
Spring 2013 14
A Modest, Stand-Alone System
• In 2007, I set up a small PV
system to power my living
room
• Used two different panel types,
explored a number of charge
controllers and configurations
• Built mounts to allow seasonal
tilt adjustments
• Larger panel is 130 W poly-
crystalline silicon at 16%
efficiency
• Smaller is 64 W thin-film triple-
junction at 8% efficiency
• Large panel handled TV,
DVD/VCR (system A), smaller
one powered lights (system B)
15. UCSD Physics 12
Spring 2013 15
Dual System Components (covers removed)
12 V lead-acid
golf-cart battery for
system A: holds
1.8 kWh
identical12 V battery
for system B
class-T fuse (110 A)
class-T fuse (110 A)
ground wire (to pipe)
charge controller,
system B
MPPT charge
controller, system A
breaker box and shunts
for current measurement
system
monitor
400 W inverters for
systems A & B
extension cords go
inside to appliances
unused MPPT charge
controller
conduit carrying
PV input wires
green: ground
red: positive
white: neutral
16. UCSD Physics 12
Spring 2013 16
Three days of PV-TV monitoring
Home PV monitor for three late-October days in 2007: first very cloudy,
second sunny; third cloudy
green: battery % full
black: battery voltage
(right hand scale)
red: solar input, Watts
cyan: load usage;
baseline for inverter,
intermittent TV use
numbers at top are
total solar yield (red)
and total system usage
(cyan) for that day,
in Watt-hours
see http://www.physics.ucsd.edu/~tmurphy/pv_for_pt.html for more examples
17. UCSD Physics 12
Spring 2013 17
System Upgrades
• Over time, system has grown
– but into single system
• Four 130 W panels shown at
left
• Beefy inverter (3.5 kW max)
• “Smart” control to switch to
grid power input when
batteries low
• Started running refrigerator
most of the time off these four
panels
• Expanded to 6 panels
• Now 8 panels after we moved
– handles 60% of electricity
extensions on mounts allow tilts to 50
portion shown here only gets 10 and 20
18. UCSD Physics 12
Spring 2013 18
Refrigerator Cycles
With three panels, I
could tackle something
more worthy, like the
refrigerator…
Can see cyclic behavior
as fridge turns on and off
Once battery reaches
absorb stage voltage
(~29.5 V), can relax
current to battery (falling
red envelope)
When fridge pops on,
need full juice again
Some TV later in day
In this period, got 1818 W-h from sun, used 1510 W-h
Getting 1818 W-h from 340-W capacity 5.3 hours equiv. full sun
19. UCSD Physics 12
Spring 2013 19
Smart Inverter Scheme
A smart inverter can
shut off when battery
gets low, using grid power
to supply to loads
Inverter comes back on
when battery voltage hits
a certain level
Note consistency of
energy supplied (red
numbers) and energy
used (cyan numbers)
Infer 2107/2358 = 89%
efficiency across first
four days (efficiency of
sending solar juice to
inverter, including battery)
Using solar for fridge 75% of time; otherwise grid (4 panel setup)
getting most out of system, without wasting solar potential
20. UCSD Physics 12
Spring 2013 20
The Powell Solar Array at UCSD
“Solar Quilt”
“Kyocera Skyline”
grid-tie system delivering up to 11 kW
typ. home system less than 1/4 this size
22. UCSD Physics 12
Spring 2013 22
7–10 23–26
flat: 918.4 kWh in 30 days 30.6 kWh/day; tilted: 974.5 kWh 32.5 kWh/day
15
23. UCSD Physics 12
Spring 2013 23
10.60, 10.60
13.35,13.28
30.78, 32.90
37.59, 40.75
Numbers indicate kWh produced
for flat, tilted arrays, respectively
Similar yields on cloudy days
25. UCSD Physics 12
Spring 2013 25
Powell Array Particulars
• Each array is composed of 32 panels, each containing a
69 pattern of PV cells 0.15 m (6 inches) on a side
– 95% fill-factor, given leads across front
– estimated 1.15 m2 per panel; 37 m2 total per array
• Peak rate is 5,500 W
– delivers 149 W/m2
– At 15% efficiency, this is 991 W/m2 incident power
• Flat array sees 162, 210, 230 W/m2 on average for
February, March, April
– includes night and cloudy weather
• Cloudy days deliver 25% the energy of a sunny day
– 1 kW rate translates to 180 W/m2 incident during cloudy day
26. UCSD Physics 12
Spring 2013 26
UCSD 1 MW initiative: Gilman = 200 kW
At present, UCSD has installed 1 MW of solar PV, online since Dec. 2008.
UCSD uses 30 MW, 25 MW generated on campus (gas turbines, mainly)
27. UCSD Physics 12
Spring 2013 27
The Biggest of the Big
• Biggest PV installations
– http://en.wikipedia.org/wiki/List_of_photovoltaic_power_stations
– 250 MW in AZ; 214 MW in India; 200 MW China; 166 MW Germany;
150 MW in AZ
• Global totals:
– Solar hot water: 196 GW (120 GW China; 15 GW U.S.)
– PV: 98 GW (32 GW in Germany; 7.2 GW U.S.; 7 GW China)
• 74% growth in the industry in 2011; average 65% since 2007
– Solar thermal: 1.5 GW
• 1 GW in U.S. (354 MW in CA); 0.5 GW in Spain
• Added together: 296 GW
– but this is peak capacity
– day/night/weather reduce by typically factor of 5
– so call it 60 GW continuous ~0.5% of global energy demand
28. UCSD Physics 12
Spring 2013 28
Solar Economics, revisited
• In remote locations, routing grid power is prohibitively
expensive, so stand-alone PV is a clear choice
• For my experimental system at home, the cost is not
competitive with retail electricity
– small does not scale favorably: a system monitor can cost as much for a
small system as for a large system
• But dollars and cents should not be the only considerations
– consider: CO2 contributed by burning fossil fuels, and climate change
– consider: environmental damage in mining coal
– consider: environmental damage in drilling/transporting oil
– consider: depletion of finite resources: robbing future generations
– consider: concentrated control of energy in a few wealthy hands
• Going (partially) solar has been worth every penny for me,
personally
– learning, independence, environmental benefit, etc. all contribute
29. UCSD Physics 12
Spring 2013 29
Announcements and Assignments
• Read Chapter 4
• Optional from Do the Math
– 13. Don’t be a PV Efficiency Snob
– 54. My Modest Solar Setup
• HW 4 due Friday
• Midterm Monday, May 6, York 2622 at 3PM
– need red half-page scan-tron with ID NUMBER section
– and # 2 pencil
– calculator okay (just for numbers, no stored info!)
– study guide posted on web site
• problems com from this study guide!
– review session: Thursday 6:00 – 7:50 PM, Solis 110
• Quiz still on for Fridays (this week and next)