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A bird’s-eye view of the development and problems of recent photovoltaic cells and systems and prospects for Si feedstock is presented. High-efficient low-cost PV modules, making use of novel efficient solar cells (based on c-Si or III-V materials), and low cost solar concentrators are in the focus of this book. Recent developments of organic photovoltaics, which is expected to overcome its difficulties and to enter the market soon, are also included…. More >>

High-Efficient Low-Cost Photovoltaics: Recent Developments

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Photovoltaics, the direct conversion of sunlight to electricity, is now the fastest growing technology for electricity generation. Present “first generation” products use the same silicon wafers as in microelectronics. “Second generation” thin-films, now entering the market, have the potential to greatly improve the economics by eliminating material costs. Martin Green, one of the world’s foremost photovoltaic researchers, argues in this book that “second generati… More >>

Third Generation Photovoltaics: Advanced Solar Energy Conversion

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Current concerns regarding greenhouse gas-related environmental effects, energy security, and the rising costs of fossil fuel-based energy has renewed interest in solar energy in general and photovotaics in particular. Exploring state-of-the-art developments from a practical point of view, Nanotechnology for Photovoltaics examines issues in increasing efficiency, decreasing costs, and how these two goals can be achieved in a single photovoltaic devi… More >>

Nanotechnology for Photovoltaics

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Handbook of Photovoltaic Science and Engineering incorporates the most recent technological advances and research developments in photovoltaics. All topics relating to the photovoltaic (PV) industry are discussed and each chapter has been written by an internationally-known expert in the field. Detailed treatment covers: scientific basis of the photovoltaic effect and solar cell operation the production of solar silicon and of silicon-based so… More >>

Handbook of Photovoltaic Science and Engineering

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A lively and authoritative account of today’s photovoltaic (PV) technology and its practical applications This book covers areas including: a brief history of PV, and the current international scene; the scientific principles of solar cells including silicon and new thin-film varieties; PV modules and arrays; grid-connected PV, from home systems up to large power plants; the wide diversity of stand-alone PV systems,… More >>

Electricity from Sunlight: An Introduction to Photovoltaics

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Martin Green, a co-author of Earthscan’s Applied Photovoltaics was one of the winners of the first Zayed Future Energy Prize announced at the World Future Energy Summit in Abu Dhabi on 19th January 2009. He received the award for his groundbreaking research on the efficiency of photovoltaics over many years.

Commenting on the award, Martin Green said “I firmly believe that many of our future energy needs can be addressed by photovoltaic technology. I… More >>

Applied Photovoltaics

Photovoltaic (PV) systems convert sunlight into electricity. The photovoltaic effect is the basic physical process through which this happens. Sunlight is composed of photons, or particles of solar energy. These photons contain various amounts of energy corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell, they may be reflected or absorbed, or they may pass right through. Only the absorbed photons generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the cell (which is actually a semiconductor). With its newfound energy, the electron is able to escape from its normal position associated with that atom to become part of the current in an electrical circuit. By leaving this position, the electron causes a “hole” to form. Special electrical properties of the PV cell provide the voltage needed to drive the current through an external load (such as a light bulb).

A PV system comprises several components. The basic building block of a PV panel is the PV cell, which is a solid state, or non-mechanical, device. A solar system uses a number of PV panels, each made of silicon, plus boron and phosphorous. The output of a single cell under direct sunlight is about one watt. To increase their effectiveness, dozens of individual cells are interconnected together in a sealed, weatherproof glass package called a module. Modules come in a range of wattages, and their nature allows for great flexibility in designing systems that meet a variety of electrical needs.

Since PV modules are only capable of producing direct current (DC) electricity, an inverter is required to convert the direct current (DC) output produced by the PV array into alternating current (AC) power. AC electricity is needed to run computers, refrigerators and other appliances, and lighting.

A utility PV system, such as those installed under the Sun4Schools project, generate electricity which is supplemented by the energy provided by the existing utility grid. A PV system requires neither battery storage nor an emergency back-up system since it is connected directly to the utility grid, which is used as the storage medium. Systems that are not connected to the utility grid use batteries to store energy for use when the sun is not shining.

A well-designed and properly installed PV system with a consistent maintenance schedule will operate for more than 20 years. The PV module, which has no moving parts, has an expected lifetime of more than 30 years.

In the past 30 years, the photovoltaic industry maintained a growth rate of 20 percent on the average, while in the last five years, with an average annual growth rate of as high as 35 percent. As of 2007, the global PV power installed capacity is 9.1 million kilowatts, the growth rate go up to 33 percent. in 2007, capacity of 2.2 million kilowatts is installed, and the growth rate is 40%.

on the optimistic view , in the next 30 years ,the photovoltaic industry will maintain a growth rate of more than 25 percent, while the pessimistic view is that this opinion is not based on reality.

Optimistic faction believes that as the technological progress and industrial expansion, photovoltaic power generation costs will be quickly reduced, thereby it bring a fundamental demand for the expansion, the process will run through the entire century. The latter part of the growth rate will decline because the base PV will be huge.

Pessimistic view is base on the biggest obstacles for photovoltaic industry is the high cost. In the Western developed countries, they mainly go through various kinds of financial subsidies to support the development of the industry, such as United States allow advance photovoltaic project with the financial and tax incentives, and support the Internet price of photovoltaic for 21.29 cents / unit.

According to our opinion, base on the cost of photovoltaic, the next three to five years, in some time and some areas, photovoltaic will have cost advantage. U.S. Environmental Co-op non-profit organization says, the cost of solar power will be equal with the traditional fossil energy for power generation costs. With the decline of the cost for solar power, while coal, natural gas and the rising cost of nuclear power, United States will come to the intersection by 2015.From Comprehensive opinion, the photovoltaic industry will have a high growth period.

Denver did reseach on :Solar Panels

A European Photovoltaic Industry Association survey covering the 1990-1994 time period showed that approximately three-fourths of PV applications involved remote locations. Remote applications include satellites, remote telecommunications sites, remote homes and villages, water pumping, camping, and boating . Remote applications can become economically feasible because of the expense of constructing distribution lines and power losses sustained in transmission of conventional power. PV facilities may be located at the point of power consumption and do not require the purchase or delivery of fuel. If a remote site requires a dependable power source or has large loads, a hybrid system may be a better option. This may consist of photovoltaic cells and a diesel generator charging a bank of batteries. In such a hybrid system, the PV cells reduce the amount of fuel consumed. The batteries reduce the runtime required of the generator. Charging the batteries during generator runtime permits the generator to operate in a more efficient load range.

Peak Load Relief

In warm-climate areas, peak load demands occur on sunny days due to heavy use of air conditioners. This coincides with the productive period for photovoltaic power. By locating photovoltaic collectors at the end of a distribution line, a power utility may be able to defer the construction of additional conventional generating capacity as well as defer an upgrade of the distribution line.

Photovoltaic System Components

We often see the cost of photovoltaic modules reported in dollars per watt. At the retail level, the cost of photovoltaic modules is currently about $5/watt. But photovoltaic modules account for only 25% to 50% of the cost of a PV system. To achieve substantial cost reduction, the expense of system components will need to be addressed. Also, poor component efficiencies can compromise the total system efficiency. PV systems can have efficiencies as low as 50% due to losses in inverters, batteries, and system voltage drops.

Green Power

Economic feasibility is not always the determining factor in selecting a power generation system. With interest in green (ecologically friendly) power growing, both consumers and providers of electrical power are turning to the use of photovoltaics in spite of its higher cost.

Industry Forecasts

A 1996 study published by the International Energy Agency (IEA), concluded that demand for alternative energy would grow strongly, yet renewable sources would only account for about 1% of total energy produced in 2010. This does not include hydropower, which would constitute about 3% of the energy supply. The World Energy Council estimates that renewable power could provide 5-8% of the total energy demand by 2020, but only with continued support for research and development .Figure .1 shows the practical implementation of photovoltaic system

Fig.1. A view of PV system

Major Manufacturers

The five companies listed below are major producers of photovoltaic modules. All have been involved in products for aerospace as well as land-based systems including thin-film technology. Some have achieved this status by recent buyouts of established PV manufacturers.

Siemens Solar

Siemens Solar is the largest manufacturer of photovoltaic cells. The parent company, Siemens, is a diversified producer of electrical equipment, involved in all types of electrical power generation, with an established worldwide marketing and distribution system.

Applications of Photovoltaic Power

Distinct advantages to PV power, such as zero pollution and absence of the need to transport fuel to the generating site, make it attractive in many applications. As efficiency improvements and manufacturing cost reductions inch PV power toward economic parity with conventional power, these applications become more numerous. This economic trend is reflected in the recent expansions of manufacturing capacity and the acquisitions of PV manufacturers by larger corporations. The use of photovoltaic as the sole source of electrical power requires the use of batteries or other storage. The cost of electrical storage prevents PV generation from replacing conventional power generation. PV systems with electrical storage are only feasible for low-power, remote applications. For remote applications requiring more power, a hybrid system may be practical. This may consist of photovoltaic cells and a diesel generator charging a bank of batteries. In such a hybrid system, the PV cells reduce the amount of fuel to be transported to the site. The batteries also reduce the runtime required of the generator, and charging the batteries during generator runtime permits the generator to be operated in a more efficient load range .

Conclusion

Photovoltaic efficiency and manufacturing costs have not reached the point that photovoltaic power generation can replace conventional coal-, gas-, and nuclear-powered generating facilities. For peak load use (no battery storage), the cost of photovoltaic power is around two to four times as much as conventional power. (Cost comparisons between photovoltaic power and conventionally generated power are difficult due to wide variations in utility power cost, sunlight availability, and numerous other variables.)

As the world advances, new technologies arise – or, in some cases, older technologies are exhumed and improved upon.

Although most people are under the impression that the field of photovoltaics is a new subject, based on recent invention, this is not actually the case. But first of all lets take a look at what “photovoltaic” means.

The word “photovoltaics” can be split up in to two parts: “photo” and “votlaic”. The term “photo” is derived from the Greek word “phos” which means “light.” A “volt” is a measurement unit for electrical force. So, literally, “photovoltaic” means “electricity through light.” And that is exactly what the word means: “capturing solar energy in the form of light and converting it into electricity.”

So how do we convert sunlight into solar energy and electricity?

In order to convert sunlight into electricity you need to use a material called a “semiconductor”.

In simple terms, a semiconductor is a material that acts as an insulator, but is also able to conduct electricity under certain conditions. We employ the characteristics of semiconductors when we convert solar energy (in the form of sunlight) into electricity. It is done as follows:

When a semiconductor (such as silicon) is exposed to sunlight, it releases small amounts of electrical energy. This is due to the process that occurs when electrons (bits of electricity) leave the surface of the semiconductor, as a result of being hit by light. We call this the “photoelectric effect.”

Sunlight is made up of “photons”, which are particles of solar energy. Not all photons are the same and not all carry the same amount of energy. A simple explanation for this is that light comes in many colors. Some forms of light are visible to the eye, while some forms are invisible (such as ultraviolet or infrared light). But, regardless of color or visibility, the fact remains that light is still light and the basic particle of light is still a photon.

When a photon hits a photovoltaic cell (also called a “PV cell” for short) one of three things occurs:

1. The photon can be reflected by the photovoltaic cell

2. The photon can be absorbed by the photovoltaic cell

3. Or (believe it or not) the photon can even pass right the photovoltaic cell. Only the photons which are absorbed by the photovoltaic cell are converted into solar energy (in the form of electricity).

When a photon is absorbed by the semiconductor (the material in the photovoltaic cell which produces electricity) the solar energy of the photon is passed to an electron in one of the atoms of the semiconductor. With this additional energy the electron is able to break away from its atom. Thus an electrical current is established.

This is the simplicity of what occurs in a photoelectric cell, when sunlight is converted into electricity. The electricity so produced can now be power an electrical device.

As you can see, the field of photovoltaics consists of the technology and the principles we use to convert solar energy into a usable form.

Photovoltaic Systems

Now that we know what a photovoltaic cell is and how it works, lets take this a step further and take a look at what a photovoltaic system is.

A photovoltaic system has consists of the following components:

A “photovoltaic module”, or “pv module”. This is a group of photovoltaic cells connected together. It is commonly referred to as a solar panel, though the terms “PV module” and “solar charger” are used to describe it as well. One or more batteries to collect and store the solar energy, which was converted into electricity by the PV modules (or solar panels, solar chargers, or whatever you choose to call them). A “charge controller”. This an electrical device which prevents the batteries from being ruined through overcharging, and which also prevents electrical current from flowing back out of the battery into the PV module or solar panel. “An inverter.” An inverter an electrical device which changes the electricity produced by the PV modules into alternating current. Alternating current is the type of electricity you get from your wall sockets at home. An inverter is only used with PV systems when you want to produce alternating current as your end result. If you run your house on solar energy, the inverter is installed between the batteries and the fuse panel.

A good quality PV system will operate for more than twenty years. The PV module, having no moving parts, has an expected lifetime exceeding thirty years. Most system problems occur due to poor or sloppy installation.

So how much electricity does a photovoltaic system generate?

The average PV system will generate about 180 kilowatt-hours per square meter, in most areas of the United States.

A photovoltaic system rated at 1 kilowatt will produce 1800 kilowatt hours per year.

In case you are not clear on what a “kilowatt-hour” is, this is a way of measuring the amount of electricity produced or consumed.

Let me put it in monetary terms, which might be easier to understand. Many photovoltaic panels are guaranteed to last a minimum of twenty years – and in fact, most claim to last thirty years. Even if we factor in the natural loss of efficiency in the PV modules over a period of twenty to thirty years, a PV system will generate close to 36,000 Kilowatt-hours in twenty years and 54,000 kilowatt hours over thirty years.

This is the equivalent of $10,000 worth of electricity at current energy prices.

Therefore, though initial installation of a PV system might seem a little costly, in the long run it is far cheaper to run on solar energy.

There are different types and sizes of solar panels (photovoltaic cells) which produce varying amounts of solar power.

• ISBN13: 9780937948118
• Condition: NEW
• Notes: Brand New from Publisher. No Remainder Mark.

Product Description
Practical Photovoltaics, the now-classic reference on solar electricity, offers a unique combination of technical discussion and practical advice. Physicist, lecturer, and solar-home dweller Richard Komp explains the “how” and the “how-to” of PV, while providing valuable information on the industry, new developments, and the future. The book is a comprehensive guide to the theory and reality of solar electricity, as well as a detailed installation and maintenance ma… More >>

Practical Photovoltaics: Electricity from Solar Cells