May 11
21
Solar Power Articles
Articles on Solar Power are often considered as the most effective means of reducing your electric bills. If you wish to benefit through solar power energy, you need to be well aware that a home solar option is readily available through online stores. If you are tired of unreasonable power cuts and wish to benefit through a regular supply of electricity, you need to take advantage through home solar options. Listed below are a few advantages of opting for solar power energy.
Home Solar Power Articles Is Readily Available
Solar power energy is abundant in nature and it is also said to be a renewable source for power generation. Hence, when the need of the hour is to pick suitable home solar power systems, you need to research well and then apply your facts to good use. Home solar options can be had through the means of a secured site and while most may appear expensive, there are a few which are really inexpensive and long lasting as well. Home solar power systems are also considered essential to meet your energy requirements as they are promoted by the government agencies.
Solar Power Energy Can Be Harnessed Through Your Backyard
The second advantage of a home solar option is that it can be harnessed through your backyard. Home solar power systems work on the basis of assembled kits which can be obtained through the means of the World Wide Web. Solar power installations can be ordered online. They come in the form of a kit, which has an instructions manual as well. Simply follow the manual book and you can ensure that your solar power installations are in perfect order. Solar power kits have the ability to be used and built from home. Hence, they can be utilized by just about any human being-you need not be a technical viz to harness solar electricity from home.
Solar Power Articles Are Very Low
The third advantage of setting up a home solar power option is the saving in terms of electricity bills. Solar power cells, which are used in producing electricity, are affordable and long lasting. Once you have them installed in your roof, you can be rest assured that they would carry on for the rest of your life. You only cost is the initial purchase of the solar powered kits and the installation charges. Nowadays, there are solar power kits which are available for under a hundred dollars. Such options can be had through the means of a reputed online manufacturer only. Thereafter, the total cost of power generation is nil and you not only generate power for your home, you also never actually spend a dime while doing so.
Solar Thermal Power Is Pure
With the rise in air pollution and the reduction in the ozone layer, the chances are that your conventional sources of energy may prove to be a hindrance to the future generations. This is when solar thermal power comes into picture. Over here, not only are your electric bills reduced drastically, you also have a chance of keeping your environment neat and tidy. This is so as solar energy is a clean energy resource and it does not emit any harmful chemicals in the atmosphere. Hence, whenever solar energy is produced from home, it is considered a blessing in disguise for the environment.
Solar Power Cells Are Noiseless
As compared to the usual sources of energy, the solar power cells, which are generally used in a solar powered grid, are noiseless in nature. Hence, if you are using solar generated power for your household uses, you are indirectly saving your environment from excessive noise pollution. At the same time, the energy which is generated is never wasted and can be easily stored for future use.
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The forecast for the solar power industry is rather cloudy.
On the one hand, we have governments globally trying to give the industry the impetus it needs, through subsidies and incentives, to fulfill its potential and become a mainstream energy source. On the other hand, the fundamentals for the industry are currently far from sunny.
But just because there’s cloud cover, doesn’t mean that solar panels don’t make energy. And even though the markets conditions have changed, doesn’t mean we can’t make money here. Let’s take a closer look at the solar sector to see where the best opportunities are for investors.
The Global Solar Industry
Only last year, it was bright sunny skies for the solar industry. Demand for photovoltaic panels had been growing at 45 percent annually from 2000 to 2008.
And industry growth had actually been hampered by tight supplies of the raw material polysilicon, causing prices to soar 40-fold between 2001 and 2008.
However, the industry underwent an aggressive expansion at the wrong time – just as the credit squeeze and the global economic slowdown kicked in. Today there is plenty of polysilicon, plunging prices, and few buyers.
The supply/demand fundamentals and pricing for the industry are not good.
On the supply side, finished solar panel capacity is at about 9,000 megawatts, while demand for such panels has contracted from about 6,000 megawatts last year to 4,500 megawatts this year. And analysts at technology research firm iSuppli predict the panel glut will not end until 2012.
Much of the blame for the slowdown in demand lies in Spain. Sunny Spain accounted for nearly half of global installations last year. This year Spanish demand is expected to fall from 2,500 megawatts to only 300 megawatts as government subsidies were slashed due to the recession.
Demand for solar is still lagging in much of the rest of the world. The high cost of solar power continues to hold it back from becoming more widely used around the world as a power source. For example, electricity produced using solar energy can be four times as expensive as electricity produced using traditional power plants run on natural gas. So for the foreseeable future, solar power will continue to need government support in order to be a viable energy choice.
Solar Power in China and the United States
Despite the current problems in the solar industry, there are two countries that are attempting to play catch-up to Europe, which leads in the solar power industry – China and the United States.
China is already the world’s biggest producer of solar panels. However, China still exports 90 percent of the solar panels it produces to markets such as Germany, Spain, Japan and the United States.
China is striving to become a meaningful market for solar energy and has adopted the European model of subsidizing the industry in an attempt to get it off the ground.
The official target for total installed capacity by the end of 2011 was recently raised 15-fold to 2 gigawatts and the target for 2020 was upped from 1.8 gigawatts to 20 gigawatts.China has started moving toward these goals by breaking ground on its first commercial solar power station.
It is the United States, however, which has recently attracted the most attention globally from the solar industry. Legislation is a sure way to increase the use of solar power. Therefore, much attention followed on the heels of the Obama Administration’s stimulus package which contained grants and tax breaks for solar power.
Demand for renewable sources of energy, such as solar, is growing in the United States as utilities must comply with state (and soon federal) standards. These standards will require a double-digit percentage of power production that must come from renewable sources. Since solar only accounts for about 1 percent of current U.S. energy produced, government standards have increased demand for solar power in the United States.
The United States is already the fourth largest solar market behind Germany,Spain and Japan. However, a recent report by Pike Research, a clean technology research group, says the United States may well lead the solar industry by 2014.
Jeff Smidt, general manager of Underwriters Laboratories energy business, commented “Most manufacturers around the world see the United States as the next big thing for solar.”
The Bottom Line
Many solar power companies were profitable before the recent economic downturn. But this mainly due to government subsidies as governments globally continue to give the solar industry a push to becoming a major energy source.
But with many component prices dropping and other problems, pressure has been put on profit margins at many solar manufacturers and there is downward pressure on these companies’ stocks.
It seems that the solar industry’s gold rush mentality and over-reliance on government subsidies have come home to roost.
Owners of solar power stocks such as First Solar (FSLR), Suntech Power (STP), Sunpower (SPWR), along with the solar ETFs – Van Eck Solar Energy ETF (KWT) and the Claymore Global Solar ETF (TAN) should be very cautious.
If investors want to buy solar stocks, they need to do the research and buy only the companies that will be the major beneficiaries of government spending on solar in the United States. Otherwise, investors who hold large positions in solar stocks may want to consider scaling back their positions or at least, tighten up any trailing stops on the stocks.
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May 11
21
Solving Solar Power Issues
Certainly, no one would accept only having electricity during the day, and then only on clear days, if they have a choice. We need energy storage — batteries. Unfortunately, batteries add a lot of cost and maintenance to the PV system. Currently, however, it’s a necessity if you want to be completely independent. One way around the problem is to connect your house to the utility grid, buying power when you need it and selling to them when you produce more than you need. This way, the utility acts as a practically infinite storage system. The utility has to agree, of course, and in most cases will buy power from you at a much lower price than their own selling price. You will also need special equipment to make sure that the power you sell to your utility is synchronous with theirs — that it shares the same sinusoidal waveform and frequency. Safety is an issue as well. The utility has to make sure that if there’s a power outage in your neighborhood, your PV system won’t try to feed electricity into lines that a lineman may think is dead. This is called islanding.
How to Produce Electricity at Home
If you decide to use batteries, keep in mind that they will have to be maintained, and then replaced after a certain number of years. The PV modules should last 20 years or more, but batteries just don’t have that kind of useful life. Batteries in PV systems can also be very dangerous because of the energy they store and the acidic electrolytes they contain, so you’ll need a well-ventilated, non-metallic enclosure for them.
Although several different kinds of batteries are commonly used, the one characteristic they should all have in common is that they are deep-cycle batteries. Unlike your car battery, which is a shallow-cycle battery, deep-cycle batteries can discharge more of their stored energy while still maintaining long life. Car batteries discharge a large current for a very short time — to start your car — and are then immediately recharged as you drive. PV batteries generally have to discharge a smaller current for a longer period (such as all night), while being charged during the day.
The most commonly used deep-cycle batteries are lead-acid batteries (both sealed and vented) and nickel-cadmium batteries. Nickel-cadmium batteries are more expensive, but last longer and can be discharged more completely without harm. Even deep-cycle lead-acid batteries can’t be discharged 100 percent without seriously shortening battery life, and generally, PV systems are designed to discharge lead-acid batteries no more than 40 percent or 50 percent.
Also, the use of batteries requires the installation of another component called a charge controller. Batteries last a lot longer if care is taken so that they aren’t overcharged or drained too much. That’s what a charge controller does. Once the batteries are fully charged, the charge controller doesn’t let current from the PV modules continue to flow into them. Similarly, once the batteries have been drained to a certain predetermined level, controlled by measuring battery voltage, many charge controllers will not allow more current to be drained from the batteries until they have been recharged. The use of a charge controller is essential for long battery life.
The other problem besides energy storage is that the electricity generated by your PV modules, and extracted from your batteries if you choose to use them, is not in the form that’s used by the electrical appliances in your house. The electricity generated by a solar system is direct current (DC), while the electricity supplied by your utility (and the kind that every appliance in your house uses) is alternating current (AC). You will need an inverter, a device that converts direct current (DC) to alternating current (AC). Most large inverters will also allow you to automatically control how your system works. Some PV modules, called AC modules, actually have an inverter already built into each module, eliminating the need for a large, central inverter, and simplifying wiring issues.
Throw in the mounting hardware, wiring, junction boxes, grounding equipment, overcurrent protection, DC and AC disconnects and other accessories and you have yourself a system. Electrical codes must be followed (there’s a section in the National Electrical Code just for PV), and it’s highly recommended that the installation be done by a licensed electrician who has experience with PV systems. Once installed, a PV system requires very little maintenance (especially if no batteries are used), and will provide electricity cleanly and quietly for 20 years or more.
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May 11
21
Energy Loss in a Solar Cell
Visible light is only part of the electromagnetic spectrum. Electromagnetic radiation is not monochromatic — it is made up of a range of different wavelengths, and therefore energy levels.
One way efficiency has been improved is to use two or more layers of different materials with different band gaps. The higher band gap material is on the surface, absorbing high-energy photons while allowing lower-energy photons to be absorbed by the lower band gap material beneath. This technique can result in much higher efficiencies. Such cells, called multi-junction cells, can have more than one electric field.
Light can be separated into different wavelengths, and we can see them in the form of a rainbow. Since the light that hits our cell has photons of a wide range of energies, it turns out that some of them won’t have enough energy to form an electron-hole pair. They’ll simply pass through the cell as if it were transparent. Still other photons have too much energy. Only a certain amount of energy, measured in electron volts (eV) and defined by our cell material (about 1.1 eV for crystalline silicon), is required to knock an electron loose. We call this the band gap energy of a material. If a photon has more energy than the required amount, then the extra energy is lost (unless a photon has twice the required energy, and can create more than one electron-hole pair, but this effect is not significant). These two effects alone account for the loss of around 70 percent of the radiation energy incident on our cell.
Why can’t we choose a material with a really low band gap, so we can use more of the photons? Unfortunately, our band gap also determines the strength (voltage) of our electric field, and if it’s too low, then what we make up in extra current (by absorbing more photons), we lose by having a small voltage. Remember that power is voltage times current. The optimal band gap, balancing these two effects, is around 1.4 eV for a cell made from a single material.
We have other losses as well. Our electrons have to flow from one side of the cell to the other through an external circuit. We can cover the bottom with a metal, allowing for good conduction, but if we completely cover the top, then photons can’t get through the opaque conductor and we lose all of our current (in some cells, transparent conductors are used on the top surface, but not in all). If we put our contacts only at the sides of our cell, then the electrons have to travel an extremely long distance (for an electron) to reach the contacts. Remember, silicon is a semiconductor — it’s not nearly as good as a metal for transporting current. Its internal resistance (called series resistance) is fairly high, and high resistance means high losses. To minimize these losses, our cell is covered by a metallic contact grid that shortens the distance that electrons have to travel while covering only a small part of the cell surface. Even so, some photons are blocked by the grid, which can’t be too small or else its own resistance will be too high.
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May 11
21
Anatomy of a Solar Cell
Before now, our silicon was all electrically neutral. Our extra electrons were balanced out by the extra protons in the phosphorous. Our missing electrons (holes) were balanced out by the missing protons in the boron. When the holes and electrons mix at the junction between N-type and P-type silicon, however, that neutrality is disrupted. Do all the free electrons fill all the free holes? No. If they did, then the whole arrangement wouldn’t be very useful. Right at the junction, however, they do mix and form a barrier, making it harder and harder for electrons on the N side to cross to the P side. Eventually, equilibrium is reached, and we have an electric field separating the two sides.
This electric field acts as a diode, allowing (and even pushing) electrons to flow from the P side to the N side, but not the other way around. It’s like a hill — electrons can easily go down the hill (to the N side), but can’t climb it (to the P side). So we’ve got an electric field acting as a diode in which electrons can only move in one direction.
When light, in the form of photons, hits our solar cell, its energy frees electron-hole pairs.
Each photon with enough energy will normally free exactly one electron, and result in a free hole as well. If this happens close enough to the electric field, or if free electron and free hole happen to wander into its range of influence, the field will send the electron to the N side and the hole to the P side. This causes further disruption of electrical neutrality, and if we provide an external current path, electrons will flow through the path to their original side (the P side) to unite with holes that the electric field sent there, doing work for us along the way. The electron flow provides the current, and the cell’s electric field causes a voltage. With both current and voltage, we have power, which is the product of the two.
There are a few more steps left before we can really use our cell. Silicon happens to be a very shiny material, which means that it is very reflective. Photons that are reflected can’t be used by the cell. For that reason, an antireflective coating is applied to the top of the cell to reduce reflection losses to less than 5 percent.
The final step is the glass cover plate that protects the cell from the elements. PV modules are made by connecting several cells (usually 36) in series and parallel to achieve useful levels of voltage and current, and putting them in a sturdy frame complete with a glass cover and positive and negative terminals on the back.
How much sunlight energy does our absorb? Unfortunately, the most that our simple cell could absorb is around 25 percent, and more likely is 15 percent or less.
| anatomy of a solar cell |
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May 11
21
How Silicon Makes a Solar Cell
Silicon has some special chemical properties, especially in its crystalline form. An atom of silicon has 14 electrons, arranged in three different shells. The first two shells, those closest to the center, are completely full. The outer shell, however, is only half full, having only four electrons. A silicon atom will always look for ways to fill up its last shell (which would like to have eight electrons). To do this, it will share electrons with four of its neighbor silicon atoms. It’s like every atom holds hands with its neighbors, except that in this case, each atom has four hands joined to four neighbors. That’s what forms the crystalline structure, and that structure turns out to be important to this type of PV cell.
We’ve now described pure, crystalline silicon. Pure silicon is a poor conductor of electricity because none of its electrons are free to move about, as electrons are in good conductors such as copper. Instead, the electrons are all locked in the crystalline structure. The silicon in a solar cell is modified slightly so that it will work as a photovoltaic solar cell.
A solar cell has silicon withimpurities — other atoms mixed in with the silicon atoms, changing the way things work a bit. We usually think of impurities as something undesirable, but in our case, our cell wouldn’t work without them. These impurities are actually put there on purpose. Consider silicon with an atom of phosphorous here and there, maybe one for every million silicon atoms. Phosphorous has five electrons in its outer shell, not four. It still bonds with its silicon neighbor atoms, but in a sense, the phosphorous has one electron that doesn’t have anyone to hold hands with. It doesn’t form part of a bond, but there is a positive proton in the phosphorous nucleus holding it in place.
When energy is added to pure silicon, for example in the form of heat, it can cause a few electrons to break free of their bonds and leave their atoms. A hole is left behind in each case. These electrons then wander randomly around the crystalline lattice looking for another hole to fall into. These electrons are called free carriers, and can carry electrical current. There are so few of them in pure silicon, however, that they aren’t very useful. Our impure silicon with phosphorous atoms mixed in is a different story. It turns out that it takes a lot less energy to knock loose one of our “extra” phosphorous electrons because they aren’t tied up in a bond — their neighbors aren’t holding them back. As a result, most of these electrons do break free, and we have a lot more free carriers than we would have in pure silicon. The process of adding impurities on purpose is called doping, and when doped with phosphorous, the resulting silicon is called N-type (“n” for negative) because of the prevalence of free electrons. N-type doped silicon is a much better conductor than pure silicon is.
Actually, only part of our solar cell is N-type. The other part is doped with boron, which has only three electrons in its outer shell instead of four, to become P-type silicon. Instead of having free electrons, P-type silicon (“p” for positive) has free holes. Holes really are just the absence of electrons, so they carry the opposite (positive) charge. They move around just like electrons do.
The interesting part starts when you put N-type silicon together with P-type silicon. Remember that every PV cell has at least one electric field. Without an electric field, the cell wouldn’t work, and this field forms when the N-type and P-type silicon are in contact. Suddenly, the free electrons in the N side, which have been looking all over for holes to fall into, see all the free holes on the P side, and there’s a mad rush to fill them in.
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May 11
21
How Solar Cells Work
You’ve probably seen calculators that have solar cells — calculators that never need batteries, and in some cases don’t even have an off button. As long as you have enough light, they seem to work forever. You may have seen larger solar panels — on emergency road signs or call boxes, on buoys, even in parking lots to power lights.
Although these larger panels aren’t as common as solar powered calculators, they’re out there, and not that hard to spot if you know where to look. There are solar cell arrays on satellites, where they are used to power the electrical systems.
You have probably also been hearing about the “solar revolution” for the last 20 years — the idea that one day we will all use free electricity from the sun. This is a seductive promise: On a bright, sunny day, the sun shines approximately 1,000 watts of energy per square meter of the planet’s surface, and if we could collect all of that energy we could easily power our homes and offices for free.
In this article, we will examine solar cells to learn how they convert the sun’s energy directly into electricity. In the process, you will learn why we are getting closer to using the sun’s energy on a daily basis, and why we still have more research to do before the process becomes cost effective.
About the Author: Aldous, Scott. “How Solar Cells Work.” HowStuffWorks.com. http://science.howstuffworks.com/solar-cell.htm.
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In today’s world of improving technology, we need to understand the source of energy that the sun is and learn how to use that energy more efficiently. Did you know that you can lower your monthly utility bills by reducing the amount of regular electricity that you use at home? When you install a solar power kit at home you will be reducing the amount of fossil fuels that are being used which in turn helps to protect the environment.
If you want to convert your home to solar power, there are a few things that you should consider. How much energy do you use in your home? What types of appliances would you need to power? Do you have a good location to place the solar power panels?
Purchasing a good, reliable solar power kit is the first important step to converting your home to solar power. If you purchase a kit that comes together the installation will be much easier, then you won’t have to worry about trying to figure everything out and buy the individual pieces that are needed.
If you haven’t decided where to place the panels, you should consider putting them on the roof because it is a great place that is still discreet. The roof is closer to the sun so it makes it an ideal spot for them– the panels will need to be directly in the suns rays so that they can gather energy from the sun, then transfer that energy to a converter to store the energy until it is needed. It is very important to make sure that the solar power panels are placed in a location where they will be in direct contact with the sun as much as possible. Look at the surroundings around your house to avoid placing the panels in a spot that is covered by other buildings or over-hanging branches.
The advantage of converting your home to solar power is to help protect the environment. Fossil fuels that are used such as coal and oil pollute the air and harm the environment, but the have no negative effects on the environment.
If you decide that you want to help protect the environment by converting your home, make sure that you purchase a good solar power kit that includes all of the necessary parts. It is a very easy process and you will be thrilled with the results!
Author Milos J Leonard is an expert that can help you find the perfect solar power kit. Find the cheapestsonline and save our earth by powering your home naturally.
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The Importance of Solar Power and Solar Panels
We have ways to heat our water, our homes and provide us with electricity. We probably take all of this for granted and if we lost them we would probably panic. We take for granted that these conveniences will be there for us from now on. We expect glitches to happen but we want them to be fixable without going long without all of these. We appreciate the heat in the winter when it snows outside and when the temperatures drop. We need water to live and although it is usually running under the ground we want the convenience of it running through our pipes and into our homes.
Solar power is everywhere because it comes from the sun. Solar power can be used to power electricity, pump water, to heat your home or office and power vehicles. With all that we can do with solar power you have to wonder why we don’t do enough to conserve the solar power. We could use it for almost anything and it would cost a fraction of what we are paying now. You can make a difference by doing your part is making solar power something you can use.
Preserving the earth helps when you use natural resources that don’t hurt the earths atmosphere and everything in it. If we continue to use the power that we use today we may pollute the atmosphere so much that the right amount of sun will not be able to make it down to the earth’s surface in the future. Then we will have no other choice but to rely on our man made abilities to produce something that will cost us more than what it already does now. Pollutants will also harm life on earth as it starts to close in and start to harm us. Cutting down on monthly and over all costs can save you a lot of money in the future.
Solar power is very important and provides a natural way to heat, obtain electricity and water with just a little more effort. In the future we may have no other choice but to look at natural resources in order to have these necessities and conveniences. Solar power is important now and in the future.
Solar panels importance
Solar panels can be different shapes and sizes but their main purpose is to convert the light in order to make electricity. Photovoltaic, or PV, is the process of converting the light into electricity. Photovoltaic cells are self generating and consist of a very thing film made of silver. This film is placed on a semiconductor layer that can be found on an iron substrate. The photovoltaic cells are very important in producing enough sunlight and heat in order to successfully produce the energy that is needed in order to heat up water, heat homes and power electricity.
Solar panels can be cheaper to use over general electricity in the long run and as long as the sun still rises up in the morning you will generate elec
| importance of solar power |
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Considering a Do It Yourself Solar Power System for Your Home?
Evaluating a do it yourself solar power system on your home? Imagine converting freely available solar power into electricity that can be used to power your home. The amount of electricity that will be generated depends on the number and wattage of the solar panels and the number of direct sun light the solar panels receive.
If the solar panels are producing more electricity that what is needed to run your home the excess solar power can be sold to the electric company. This is a great situation to be in, be selling electricity back to the utility district.
There are a few things that you need to consider before deciding on installing a solar power system on your house.
In order to recoup the initial investment you need to determine how long it will take. You don’t want to move out of the house before having recouped your investment.
Do you have a large enough space on your roof where the solar panels can be installed on that receives at least six hours of direct sun light each day? Solar cells work best in direct sunlight. If most of the south facing roof space is covered by nice large trees a photovoltaic system is not going to produce much electricity.
Pitch of your roof. Are you comfortable walking on your roof? Is it too steep for you? When installing a do it yourself solar power system you will be spending some time on the roof installing the solar panels and wiring them together. If you are not comfortable working on the roof for a day or two you might want to consider hiring someone to install the solar panels for you.
How to find do it yourself solar power retailers that you can work with. Start with the yellow pages and contact the local solar retailers in your area. Check out each retailer with the local BBB.
Another option is to search for solar retailer sites with the search phrase ‘do it yourself solar power system’. Check out the result sites. Be sure to verify that the site is reputable and secure.
Before purchasing a do it yourself solar power system from a retailer be they local or online there are a few questions you should ask them. Will they help you determine the load of your home and size the solar power system to your home’s electrical needs?
You are now ready to find the right retail outlet that will provide you with the best do it yourself solar power system and great customer service. Even if you decide not to install a solar power system yourself, consider hiring a local company that specializes in installing solar power systems in homes. It will be more expensive, but in the long run the cost savings will be well worth it.
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