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A photoelectric effect (the emission of electrons from the surface of metal in response to light), occurs when semiconducting materials, such as the Silicon in some PV solar panels, are exposed to light. This defines the basic process in which PV solar panels convert sunlight to electricity.
The particles that make up sunlight, or photons, contain varying amounts of energy which correspond to the different wavelengths of the solar spectrum. Whenever photons hit the cells on PV solar panels, they are either reflected or absorbed, or pass right through the cells of a PV solar panel. However, only the photons that remain in the cells of the PV solar panels, through absorption, produce electricity by transferring energy on to an electron in the atoms of the semiconductor in the PV solar panel. These electrons then move on from their normal position, within the atoms of the semiconductor, and create an electrical current in the PV solar panel.
PV systems, such as PV solar panel systems, are made up of various components: PV modules, which are usually referred to as panels; batteries; charge regulators for stand-alone systems; inverters for utility-grid-connected systems and when alternating current is required, as opposed to direct current; wiring and the mounting framework.
There are four main types of solar energy technologies:
1. Photovoltaic (PV) systems (i.e. PV solar panels)
2. Concentrating solar power (CSP) systems
3. Solar water heating systems
4. Transpired solar collectors or “solar walls”
About 180 kilowatt-hours per square meter can be generated by PV solar panels that maintain a 10% efficiency rate. The majority of PV solar panels are capable of lasting up to between 20 to 30 years and usually only degrade at rates of less than 1% per annum.
Today’s PV solar panels are only capable of capturing a small portion of the light spectrum in sunlight, causing them to maintain a low efficiency rate – usually between 7% and 17%. In comparison to PV solar panels, a traditional fossil fuel generator has an efficiency of about 28%.The term “energy conversion efficiency” defines the amount of energy produced in relation to the amount of energy available to the PV solar panel.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

Nevertheless, efforts are being made to increase the efficiency of PV solar panels and therefore the amount of energy they can produce. In systems where solar heat is converted to a transfer medium like water, such as in solar thermal devices, efficiency decreases. In these systems, a lot of the heat is reflected away before it can even be used. Some PV cells in modern PV solar panel development projects are able to convert up to 40% of the light captured into electricity.

What are PV Solar Panels? is a post from: Crystalline Silicon

What are PV Solar Panels? is from Crystalline Silicon

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General knowledge of how these cells actually work is limited, however, and in this article we intend to shed some light on some of the basics of how PV cells are put together and how they function. PV is short for photovoltaic and the word is a fusion of the Greek word for light and the name of the Italian physicist and great contributor towards the study of electricity, Allesandro Volta. Hence it should be clear that that PV cells convert solar (or any other type of light for that matter) into electricity.
PV modules are formed when groups of PV cells are connected together. The PV cells are comprised of a positive layer of silicon, called the P-type, as well as a negative layer, known as the N-type. These layers create electric fields that capture the photons that are present in sunlight. The photons are first absorbed into the PV cells via the negative type silicon and later reach the positive type silicon where their energy is released in the form of electrons. The energy is then passed back to the negative layer and flows through the connecting wire as a direct current (electricity). The direct current can then be transformed to alternating current by means of an inverter in order to supply all of our modern household appliances (as well as thousands of other types of apparatus) with electricity.
PV cells are commonly joined to form panels that are easily attached to devices that require electricity or installed around domestic houses to power all sorts of household appliances. The PV cells’ ability to produce electrical energy from sunlight also depends on the amount of sunlight received. Different parts of the world receive varying amounts of sunlight and therefore the potential to generate more or less electricity is also affected by global position. Nevertheless, a standard home only needs to capture around 8 kilowatts per square meter of sunlight to produce enough electricity for general consumption. This can easily be done by 10 square meters of solar panels and most parts of our planet received a sufficient amount of sunlight for this.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

PV cells, or rather, photovoltaic panels are an excellent solution for taking advantage of the free solar energy our planet receives and powering all our electricity-based equipment. A conversion to this form of power generation from our traditional use of fossil fuels will definitely reduce global carbon dioxide emissions and help us all save a lot of money in the long run.

What are PV Cells and what are they used for? is a post from: Crystalline Silicon

What are PV Cells and what are they used for? is from Crystalline Silicon

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Internationally, there are several producers of polysilicon and monocrystalline silicon. The majority of production goes towards the semiconductor and photovoltaic cell industries.
Polysilicon is primarily used as a resource in two industries: firstly, the semiconductor industry, where monocrystalline silicon wafers are made, and in the photovoltaic industry, in order to make solar cell panels. Non-essential materials that are not used up by the first industry are usually purchased by the photovoltaic industry.
Investment in polysilicon has remained strong over recent years with prices on the increase between 2006 and 2008. Among the many “new energy” industries, the polysilicon industry has become quite popular. Local governments in China have prioritized investments in polysilicon and have created conditions that should attract more manufacturers. Polysilicon bases in China include: Sichuan Leshan, Chongqing, Wuhan and Luoyang in the West and Xuzhou, Yangzhou and Lianyungang in the East.
The province of Jiangsu has constructed a project that aims at reaching a capacity of 30,000 tons of polysilicon in 2011 – 6 times the production capacity in place in the whole of the country in 2008.
The forecast for Chinese production of polysilicon is approximately 60,000 tons in 2011 and over 100,000 in 2012.
A conservative estimate of global production in 2012 is 240,000 tons. In 2008, total production by the 7 largest manufacturers was 120,000 tons.
In 2008, international supply of cell modules was 5.5GW. The amount in 2012 is estimated to reach 12GW. Modern technology allows for 6 grams of cell modules to generate 1W. Therefore, 72,000 tons of polysilicon will be required in 2012. There is currently an oversupply of the product in the world.
Over 10 fabrication plants have been rebuilt in China since 2008.
Large amounts of capital are required for investments in polysilicon. Around USD 143 million is necessary for the production of 1,000 tons of polysilicon. Over USD 14 billion in polysilicon investment projects has been planned for China over the last few years.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

Average production costs for the largest Chinese polysilicon producers currently lies around 40 USD/Kilo and 70 USD/Kilo. In 2008, the average production cost for all Chinese companies was around 450 USD/Kilo. The average cost at present is around 70 USD/Kilo and 80 USD/Kilo. Even the most advanced polysilicon producers have seen their profits being reduced. Nevertheless, manufacturers can still up their returns if they invest in technology and manage costs well. The average return on investment period for polysilicon projects is around 3 to 4 years.

Outlook of the Chinese Polysilicon Industry is a post from: Crystalline Silicon

Outlook of the Chinese Polysilicon Industry is from Crystalline Silicon

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Amorphous solar panels offer a much lower efficiency rating (5% to 8%), but do reveal some advantages in the heating department, due to the reduced amount of silicon used to manufacture them, granted their 1 micron thickness. These thinner amorphous panels degrade at an alarming rate over time in the sun. Many companies attempt to market these panels at exaggerated prices, insinuating that they offer more advantages than they really do. These modules only generate a fraction of the electricity that polycrystalline versions do.
Polycrystalline modules will undoubtedly last longer than any other version of solar panels on offer currently. This is primarily due to their crystalline configuration. One vital factor for ensuring their durability, however, is the presence of appropriate ventilation for the polycrystalline panels, so that no excessive heating occurs during sunlight exposure. Panels that are not cooled sufficiently may suffer damage to their mounting equipment, as well as to any other components that are not designed to handle heat.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

All in all we can gather that polycrystalline solar panels are the product of choice when a photovoltaic solar system is required. Not only do they offer advantages in regards to durability, but they also have a more attractive appearance.

Polycrystalline vs Monocrystalline Solar Panels is a post from: Crystalline Silicon

Polycrystalline vs Monocrystalline Solar Panels is from Crystalline Silicon

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The term “photovoltaic” in photovoltaic solar panels is composed of two parts: “photo”, derived from the Greek word for light (or sunlight in this context) and “voltaic”, which makes its way back to the Italian physicist Alessandro Volta and his pioneering study of electricity. Hence we arrive at the conclusion that photovoltaic energy is the production of electricity through the transformation of sunlight.
The photovoltaic cells in photovoltaic solar panels provide them with the capability of capturing sunlight and transforming it into the electrical energy we have become accustomed to for powering the general conveniences we have in our homes. Photovoltaic cells contain two or more layers of oppositely charged (positive and negative) semiconductors. Silicon is very common example of a semiconductor used in photovoltaic solar panels.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

When sunlight arrives at the semiconductors in a cell, the electrical field produced where the oppositely charged layers of the semiconductor meet causes an electrical current to be created.
The amount of sunlight that hits the cells of photovoltaic solar panels varies on any given day. Radiation will most likely start out low and the gradually increase until it reaches a peak at midday before then slowly decreasing towards the end of the day. The more sunlight the photovoltaic solar panel receives, the greater the production and flow of electricity within the panel.
There is currently a wide range of varying photovoltaic solar panels on offer. A very welcome addition to existing panels on the market has been the PV tiles that can be fitted onto any standard roof. These photovoltaic solar panels or tiles have a reduced visual impact when compared to other older paneling systems.
In principle, the power received from photovoltaic solar panels systems in Direct Current (DC). However, through the addition of an inverter, this DC current is transformed into an Alternating Current (AC) in order to provide you with the electricity your general household appliances require.
The electricity produced from the light captured by photovoltaic solar panels reaches the mains box via the fuse board. As expected, it is possible to measure and record the amount of electricity produced by the photovoltaic solar panel with a meter. In many areas, any excess electricity produced by the solar panels can be sold on to the local electricity supplier, making these systems quite economical in the long terms, as well as causing all solar powered homeowners to be great contributors towards a much more environmental friendly society.
Location is the main determining factor for the amount of energy that can be received by photovoltaic solar panels. Midday or noon is used as the basis for calculation of the availability of solar radiation and the daily average hours of maximum radiation is determined from this.
Merely 10m² of photovoltaic solar paneling is required to powering the average home entirely from solar powered electricity. Should you wish to discover how many photovoltaic solar panels would e necessary in order to completely move your house off-grid, solar calculators can be are available and can be used for this purpose.

How Photovoltaic Solar Panels Work is a post from: Crystalline Silicon

How Photovoltaic Solar Panels Work is from Crystalline Silicon

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Most systems that convert sunlight into electrical energy contain photovoltaic solar cells as their basic component. Originally, photovoltaic solar cells were only used in homes where panel systems were employed in order to convert sunlight into electricity or heat. However, in today’s world, photovoltaic solar cells are useful components in a number of different kinds of apparatus and therefore assume various forms, depending on their exact application.
The first photovoltaic solar cells were made up of generally simple pieces. The most common photovoltaic solar cells consisted of a flat square with a glass or plastic panel placed over a crystalline silicone substance. Metal wires were then found to be imbedded within the silicone. The neutrons were set off by getting the sun’s rays to hit the silicone. In this process, the neutrons would generate a small electrical current that could be picked up by the wires. The electricity produced was in the form of Direct Current (DC), which was then converted to an Alternating Current (AC) by an inverter. The power produced could then either be stored in batteries or passed on to the local power grid.
The biggest disadvantage with the first photovoltaic solar cells was that they were not very efficient. The first photovoltaic solar cells held efficiency rates of between 1% and 6%. To aggravate this inefficiency, more power would be lost during the conversion from direct to alternating current. Although these primitive photovoltaic solar cells worked, a very large number of them were required in order to generate enough electricity.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

With improvements in technology, photovoltaic solar cells became more efficient. Silicone was still used as the primary semi-conductor, even though it was gradually altered so that it could transform more spectrums of sunlight. The costs if installing, using and maintaining photovoltaic solar cells also decreased as the improvements in technology increased – it was now possible to produce more energy with fewer photovoltaic solar cells in a panel. Nevertheless, efficiency levels were still not at an optimum and it was still evident that traditional fossil fuel power supplies were cheaper.
Modern trends seem to be deviating from the traditional concept of photovoltaic solar cells. New platforms, such as options that include nanotechnology, in which quantum dots are utilized in order to transform sunlight into electrical energy, are being developed. In future, these dots could become a part of the paint we use to cover the outside walls of our houses. In theoretical terms, these dots could still be considered as cells (even though they do not represent what one general associates with that term “cells”). Germanium is used in other solutions as an alternative semi-conductor, but it has not replaced silicone entirely as of yet.
The future of photovoltaic solar cells is very uncertain as companies race to develop new and more efficient methods of converting our suns energy into the electricity we require to power the conveniences we have become accustomed to in our homes.

A Glance At The Evolution Of Photovoltaic Solar Cells is a post from: Crystalline Silicon

A Glance At The Evolution Of Photovoltaic Solar Cells is from Crystalline Silicon

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Although initial investments are generally more costly than other common forms of power supply, the installation of photovoltaic panels can eventually end up saving you money. The primary reasons for this are the fact that once the equipment has been paid for and installed there are no further costs for the energy supply, as well as the possibility for selling excess power that has been generated off to the local power grid. This feature of photovoltaic panels also makes users of the same great contributors towards a more environmentally friendly national energy supply.
The production of photovoltaic panels has increased drastically in the recent past and the estimated generation of electricity by these means is expected to reach around twenty thousand megawatts. Since 2002, the fabrication and sales of photovoltaic panels have increased at a rate of 50% every 2 years. It is therefore the fastest growing renewable energy source in the world. Current technology used in the production of solar cells that make up photovoltaic panels is efficient enough to allow them to supply most of the energy for a modern home.
Photovoltaic panels make use of solar cells stored together in photovoltaic modules, which in turn are stored together to form photovoltaic arrays, in order to generate electric power. Silicon is the primary semiconductor used in the solar cells. Part of the sunlight received by the photovoltaic panels is absorbed by the semiconductor which ends up releasing the electrons found in the silicon. Photovoltaic cells possess electric fields that force the now free electrons to flow in a certain direction. This free flow of electrons is called electricity. Photovoltaic panels are often installed facing south in order to optimize the capture of sunlight. Modern advancements in technology have allowed for panels to track the direction of the sun however.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

Photovoltaic panels are put to extremely good use in areas which receive abundant sunlight. This type of technology is used for electricity production in over 100 countries around the world. Current progress in technology and design, and the ever increase rates of production and sales, have driven the costs of photovoltaic panels down ever since their first introduction. Recently, the initial costs of installing photovoltaic panels have been overlooked by homeowners, as these costs are easily surpassed not only by long term savings, but also by the infinite amount of benefits they provide in regards to environmental friendliness.
Seeing as our planet has not provided us with an endless supply of traditional energy sources (such as oil), and taking into account the detriment that the use of those resources have on our environment, the increased production and use of photovoltaic panels is a welcome option for us to continue with the conveniences we have become accustomed to, without having to change much of our common lifestyles.

Introduction to Photovoltaic Panels is a post from: Crystalline Silicon

Introduction to Photovoltaic Panels is from Crystalline Silicon

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Solar cells made up of crystalline silicon require that pure crystalline silicon with high crystal quality be used. Four bonding electrons are held in the outer shell of a crystalline silicon atom. Two electrons from adjacent atoms in the crystal lattice must bond in order to form a stable electron formation. Crystalline silicon manages to obtain a noble gas configuration with 8 outer electrons by forming stable bonds with 4 neighboring electrons. The electrons are provided with the means to move freely when they are broken down with light or heat, which ends up leaving a hole in the crystal lattice. This process is known as intrinsic conductivity.
The process of intrinsic conductivity does not produce electricity, however. For the production of electricity, doping atoms (essentially impurities) are added into the crystal lattice of the crystalline silicon. These atoms usually possess an extra electron (such as phosphorous) or one electron less (as is the case of boron), in their outer shell, when compared to crystalline silicon. The term “negative doping” or “n-doping” is attributed to the method that uses phosphorous and the term “positive doping” or “p-doping” is used to describe the method that uses boron.

Pemco International 1911 – 2011 – A message from Marcel Zegger (CEO)

An electrical charge can be carried in the method using n-doping, as the electron can move about spontaneously in the crystal lattice of the crystalline silicon. There is a missing bonding electron for every bonding born atom in the crystal lattice in the p-doping method. This phenomenon allows the electrons from crystalline silicon atoms to fill in the gaps created by the missing bonding electrons, opening up a new hole elsewhere. Impurity conduction is the correct term used to describe this method that is based on these doping atoms.
A positive-negative junction is formed when both positively and negatively doped semiconductor layers are united. This coming together allows superfluous electrons from the n-semiconductor to diffuse into the positive semiconductor layer and form an area called the “space charge region”. Negatively charged doping atoms remain in the p-region, while positively charged doping atoms remain in the n-region of the transition. Opposing the movement of the charge carriers, an electrical field is formed which forces diffusion to eventually discontinue. This positive-negative semiconductor is what is commonly known as a solar cell. Photons are taken in by the electrons when light strikes the solar cell. Electron bonds are broken down by this gust of energy. The electrons that are released are pulled through the electrical field in the n-region. The holes that appear have a tendency to migrate in the opposite direction into the p-region. This process is what turns sunlight into electrical energy and is known as the photovoltaic effect.

How Crystalline Silicon Solar Cells Work is a post from: Crystalline Silicon

How Crystalline Silicon Solar Cells Work is from Crystalline Silicon

Source:  http://www.amnh.org

People see winter as a cold and gloomy time in nature. The days are short. Snow blankets the ground. Lakes and ponds freeze, and animals scurry to burrows to wait for spring. The rainbow of red, yellow and orange autumn leaves has been blown away by the wind turning trees into black skeletons that stretch bony fingers of branches into the sky. It seems like nature has disappeared.

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But when I went on a winter hiking trip in the Catskill Mountains in New York, I noticed something strange about the shape of the tree branches. I thought trees were a mess of tangled branches, but I saw a pattern in the way the tree branches grew. I took photos of the branches on different types of trees, and the pattern became clearer.

The branches seemed to have a spiral pattern that reached up into the sky. I had a hunch that the trees had a secret to tell about this shape. Investigating this secret led me on an expedition from the Catskill Mountains to the ancient Sanskrit poetry of India; from the 13th-century streets of Pisa, Italy, and a mysterious mathematical formula called the "divine number" to an 18th-century naturalist who saw this mathematical formula in nature; and, finally, to experimenting with the trees in my own backyard.

My investigation asked the question of whether there is a secret formula in tree design and whether the purpose of the spiral pattern is to collect sunlight better. After doing research, I put together test tools, experiments and design models to investigate how trees collect sunlight. At the end of my research project, I put the pieces of this natural puzzle together, and I discovered the answer. But the best part was that I discovered a new way to increase the efficiency of solar panels at collecting sunlight!

My investigation started with trying to understand the spiral pattern. I found the answer with a medieval mathematician and an 18th-century naturalist. In 1209 in Pisa, Leonardo of Pisano, also known as "Fibonacci," used his skills to answer a math puzzle about how fast rabbits could reproduce in pairs over a period of time. While counting his newborn rabbits, Fibonacci came up with a numerical sequence. Fibonacci used patterns in ancient Sanskrit poetry from India to make a sequence of numbers starting with zero (0) and one (1). Fibonacci added the last two numbers in the series together, and the sum became the next number in the sequence. The number sequence started to look like this: 1, 1, 2, 3, 5, 8, 13, 21, 34… . The number pattern had the formula Fn = Fn-1 + Fn-2 and became the Fibonacci sequence. But it seemed to have mystical powers! When the numbers in the sequence were put in ratios, the value of the ratio was the same as another number, φ, or "phi," which has a value of 1.618. The number "phi" is nicknamed the "divine number" (Posamentier). Scientists and naturalists have discovered the Fibonacci sequence appearing in many forms in nature, such as the shape of nautilus shells, the seeds of sunflowers, falcon flight patterns and galaxies flying through space. What’s more mysterious is that the "divine" number equals your height divided by the height of your torso, and even weirder, the ratio of female bees to male bees in a typical hive! (Livio)

The spiral on trees showing the Fibonacci Sequence

Aidan studied leaf arrangments

Aidan measuring the spiral pattern

In 1754, a naturalist named Charles Bonnet observed that plants sprout branches and leaves in a pattern, called phyllotaxis. Bonnet saw that tree branches and leaves had a mathematical spiral pattern that could be shown as a fraction. The amazing thing is that the mathematical fractions were the same numbers as the Fibonacci sequence! On the oak tree, the Fibonacci fraction is 2/5, which means that the spiral takes five branches to spiral two times around the trunk to complete one pattern. Other trees with the Fibonacci leaf arrangement are the elm tree (1/2); the beech (1/3); the willow (3/8) and the almond tree (5/13) (Livio, Adler).

I now had my first piece of the puzzle but it did not answer the question, Why do trees have this pattern? I had the next mystery to solve. I designed experiments that attacked this question, but first I had to do field tests to understand the spiral pattern.

I built a test tool to measure the spiral pattern of different species of trees. I took a clear plastic tube and attached two circle protractors that could be rotated up and down the tube. When I put a test branch in the tube, I aligned the zero degree mark on one compass to match up with the first offshoot branch. I then moved and rotated the second compass up to the next branch spot. The second compass measured the angle between the two spots. I recorded the measurement and then moved up the branch step-by-step.

I collected samples of branches that fell to the ground from different trees, and I made measurements. My results confirmed that the Fibonacci sequence was behind the pattern.

But the question of why remained. I knew that branches and leaves collected sunlight for photosynthesis, so my next experiments investigated if the Fibonacci pattern helped. I needed a way to measure and compare the amount of sunlight collected by the pattern. I came up with the idea that I could copy the pattern of branches and leaves with solar panels and compare it with another pattern.

Diagram of tree model that Aidan made with his computer.

I designed and built my own test model, copying the Fibonacci pattern of an oak tree. I studied my results with the compass tool and figured out the branch angles. The pattern was about 137 degrees and the Fibonacci sequence was 2/5. Then I built a model using this pattern from PVC tubing. In place of leaves, I used PV solar panels hooked up in series that produced up to 1/2 volt, so the peak output of the model was 5 volts. The entire design copied the pattern of an oak tree as closely as possible.

Aidan building his solar "tree" collector

The flat-panel collector

I needed to compare the tree design pattern’s performance. I made a second model that was based on how man-made solar panel arrays are designed. The second model was a flat-panel array that was mounted at 45 degrees. It had the same type and number of PV solar panels as the tree design, and the same peak voltage. My idea was to track how much sunlight each model collected under the same conditions by watching how much voltage each model made.

I measured the performance of each model with a data logger. This recorded the voltage that each model made over a period of time. The data logger could download the measurements to a computer, and I could see the results in graphs.

The two models collecting sunlight

Graph: Tree Design

Graph: Standard Solar

Winter test showing energy collection of the tree and the flat-panel collector

Graph comparing the two solar collector designs

A typical solar collector

I set the two models in the same location in my backyard facing the southern sky and measured their output over a couple of months. I moved the test location around to vary the conditions.

The sunlight conditions were also important. I started my measurements in October and tested my models through December. At that time of year the winter solstice was coming, and the Sun was moving into a lower declination in the sky. The amount of sunshine was shortening. So I was testing the Fibonacci pattern under the most difficult circumstances for collecting sunlight.

I compared my results on graphs, and they were interesting! The Fibonacci tree design performed better than the flat-panel model. The tree design made 20% more electricity and collected 2 1/2 more hours of sunlight during the day. But the most interesting results were in December, when the Sun was at its lowest point in the sky. The tree design made 50% more electricity, and the collection time of sunlight was up to 50% longer!

I had my first evidence that the Fibonacci pattern helped to collect more sunlight. But now I had to go back and figure out why it worked better. I also began to think that I might have found a new way to use nature to make solar panels work better.

I learned that making power from the Sun is not easy. The photovoltaic ("PV") array is the way to do it. A photovoltaic array is a linked collection of multiple solar cells. Making electricity requires as much sunlight as possible. At high noon on a cloudless day at the equator, the power of the Sun is about 1 kilowatt per square meter at the Earth’s surface (Komp). Sounds easy to catch some rays, right? But the Sun doesn’t stand still. It moves through the sky, and the angle of its rays in regions outside the equator change with the seasons. This makes collecting sunlight tricky for PV arrays. Some PV arrays use tracking systems to keep the panels pointing at the Sun, but these are expensive and need maintenance. So most PV arrays use fixed mounts that face south (or north if you are below the equator).

Fixed mounts have other problems. When a PV array is shaded by another object, like a tree or a house, the solar panels get backed up with electrons like cars in a traffic jam, and the current drops. Dirt, rain, snow and changes in temperature can also hurt electricity production by as much as half! (Komp)

I began to see how nature beat this problem. Collecting sunlight is key to the survival of a tree. Leaves are the solar panels of trees, collecting sunlight for photosynthesis. Collecting the most sunlight is the difference between life and death. Trees in a forest are competing with other trees and plants for sunlight, and even each branch and leaf on a tree are competing with each other for sunlight. Evolution chose the Fibonacci pattern to help trees track the Sun moving in the sky and to collect the most sunlight even in the thickest forest.

I saw patterns that showed that the tree design avoided the problem of shade from other objects. Electricity dropped in the flat-panel array when shade fell on it. But the tree design kept making electricity under the same conditions. The Fibonacci pattern allowed some solar panels to collect sunlight even if others were in shade. Plus I observed that the Fibonacci pattern helped the branches and leaves on a tree to avoid shading each other.

My conclusions suggest that the Fibonacci pattern in trees makes an evolutionary difference. This is probably why the Fibonacci pattern is found in deciduous trees living in higher latitudes. The Fibonacci pattern gives plants like the oak tree a competitive edge while collecting sunlight when the Sun moves through the sky.

My investigation has created more questions to answer. Why are there different Fibonacci patterns among trees? Is one pattern more efficient than another? More testing of other types of trees is needed. I am testing different Fibonacci patterns now. I am improving my tree design model to see if it could be a new way of making panel arrays. My most recent tries with a bigger test model were successful.

The tree design takes up less room than flat-panel arrays and works in spots that don’t have a full southern view. It collects more sunlight in winter. Shade and bad weather like snow don’t hurt it because the panels are not flat. It even looks nicer because it looks like a tree. A design like this may work better in urban areas where space and direct sunlight can be hard to find.

But the best part of what I learned was that even in the darkest days of winter, nature is still trying to tell us its secrets!

BIBLIOGRAPHY

Adler, I., D. Barabe, and R.V. Jean. "A History of the Study of Phyllotaxis." Annals of Botany 80 (1997): 231-244.

Atela, P., C. Golé, and S. Hotton. "A Dynamical System for Plant Pattern Formation: A Rigorous Analysis." Journal of Nonlinear Science 12.6 (2002): 641-676.

Brockman, C. Frank. Trees of North America: A Guide to Field Identification. New York: Golden Guides from St. Martin’s Press, 2001.

Geisel, Theodor Seuss (Dr. Seuss). The Lorax. New York: Random House Publishers, 1971.

Jean, Roger V. Phyllotaxis: A Systematic Study in Plant Morphogenesis. New York: Cambridge University Press, 2009.

Komp, Richard J. Practical Photovoltaics: Electricity from Solar Cells. 3rd. ed. Ann Arbor, Michigan: Aatec Publications, 2001.

Livio, Mario. The Golden Ratio: The Story of Phi, The World’s Most Astonishing Number. New York: Broadway Books, 2002.

Posamentier, A., and I. Lehman. The (Fabulous) Fibonacci Numbers. New York: Prometheus Books, 2007.

Aidan–The Secret of the Fibonacci Sequence in Trees is a post from: Crystalline Silicon

Aidan–The Secret of the Fibonacci Sequence in Trees is from Crystalline Silicon

by Christian Roselund
July 20th, 2011

Intersolar North America 2011: Bigger than ever

On July 14th, 2011, the Intersolar North America trade show concluded in San Francisco, California, capping three days of conferences, exhibition and networking for manufacturers, installers, policymakers, financiers and advocates of the solar industry.

The lobby of the Moscone Center during Intersolar North America 2011; photo: Solar Promotion International GmbH

Everything at Intersolar was bigger this year. Not only did the exhibition feature 839 exhibitors, 17% more than last year, on 16,000 square meters of exhibition space in the city’s Moscone Center – a 30% increase, but the show reflected a larger industry. The global PV market more than doubled in 2010, bringing with it ambitious production capacity increases, ever larger projects, new technologies, and approaches to problems old and new.

Growing pains for the solar industry in 2011

However, six months after the close of this monumental year, the mood is very different. While many in the industry retain strong optimism for the long-term growth of the industry, short- and medium-term trends are more problematic.

Specifically, Intersolar North America 2011 came at the close of two quarters of weak demand in some of the world’s largest PV markets, an oversupply of PV modules, and collapsing prices. The smaller CSP market continues to grow in Spain, but ambitious CSP and PV projects in the United States have been delayed by financing difficulties and lawsuits. Solar heating and cooling markets have also faced difficulties, in part due to the ongoing recession.

This year’s conference saw an industry that is having to take a hard look at itself, and confront some of its more serious problems.

Energy storage

As PV capacities continue to grow throughout the world, the issue of energy storage looms large.

Sodium sulfur batteries have are currently the most popular choice to accompany large scale solar generation, but multiple other technologies are being investigated; photo: Hawaiian Electric Companies

And while the United States has lower levels of PV penetration than leading European markets, the larger scale of U.S. PV projects leads to greater risks from intermittent and variable output than distributed solar, and some U.S. PV companies are already taking energy storage seriously.

Notable among these is SOLON Corporation, a subsidiary of SOLON SE, whose Director of Research and Development Bill Richardson presented at an energy storage panel on the first day of this year’s conference. SOLON has recently announced a new partnership with Tucson Electric Power Company (Tucson, Arizona, U.S.) the University of Arizona, to test multiple energy storage solutions to accompany PV generation.

"PV is getting bigger and bigger, it is getting higher penetration," Richardson of SOLON told Solar Server at the conference. "We have discovered that utilities are concerned about the effects of intermittency of PV in these large scale projects."

"And so we are looking out in the future, and saying OK, if utilities want control of the PV plants, then we should be experts in giving them that control. And that is going to require storage. And the way you become an expert at installing and integrating storage is you install, integrate and control the storage. You have to do it."

In terms of technologies, one thing that Richardson has emphasized is that there is no one-size-fits-all storage solution, and that the appropriateness of specific solutions is highly differentiated by both climatic conditions and the type of power control needed.

The conference also comes a few months after the commissioning of the Gemasolar plant, the first utility scale concentrating solar power (CSP) project to operate 24 hours continuously, thanks to its molten salt storage system. This technical feat shows the potential of CSP for energy storage at a lower cost than many battery systems, which has caused many in the industry to re-evaluate the potential of CSP.

(Solar Server featured the Gemasolar plant as its June 2010 Solar Energy System of the Month. To read more about the plant, see: www.solarserver.com/solar-magazine/solar-energy-system-of-the-month/concentrating-solar-energy-of-the-future-torresol-energys-molten-salt-power-tower-csp-plant-gemasolar.html)

Thin films on the rise

Among the more exciting technological developments since last year’s conference are a series of new efficiency records for thin film PV, particularly copper indium gallium selenium (CIGS or CIS) technology, and a new optimism among thin film suppliers.

Aerial view of Solar Frontier’s 1 GW Kunitomi CIGS manufacturing facility; photo: Solar Frontier K.K.

Perhaps no thin film manufacturer is as ambitious about taking market share from crystalline silicon as Solar Frontier K.K. (Tokyo, Japan), which officially opened its 1 GW CIS production facility in Miyazaki, Japan in April 2011.

Solar Frontier Americas Chief Operating Officer Greg Ashley spoke at  the July 13th, 2011 panel on thin-film technology improvements, noting that in addition to closing the gap with crystalline silicon efficiencies, CIS also offers other benefits, including broader spectra ratios and better performance in low light conditions and hot weather.

Ashley also noted that thin film technologies use a small fraction of the semiconductor material employed by crystalline silicon. He has also stated that CIS has the ability to compete with crystalline silicon prices.

Solar Frontier joins a number of companies that have been able to deliver big increases in CIS efficiencies, including Q-Cells subsidiary Solibro GmbH (Wolfen, Germany), and more recently XsunX Inc. (Aliso Viejo, California, U.S.).

While what is produced on the shop floor is always a step behind what is achieved in the lab, some of these companies – including Solibro and Solar Frontier – have also shown that they can mass-produce modules with impressive conversion efficiencies, 13.4% in the case of Solibro.

Clouds on the horizon in 2011 and 2012

Rising efficiencies and falling prices are more necessary than ever for PV to compete, as the industry faces a gloomy near-term outlook for world markets. At a panel discussion focused on the future of world PV markets, Both EuPD Research Director Daniela Schreiber and IHS iSuppli Photovoltaics Analyst Michael Sheppard released predictions that the aggregate global PV market would rally in the second half of 2011, but decline in 2011 and 2012.

The analysts pointed out that in both Germany and Italy – which together represented 60% of global PV demand in 2010 – market growth has exceeded national goals for PV capacities. Both researchers also predicted that the markets which represent the most hope for the future, including the United States and China, will not replace these markets for several years to come, even given the ongoing collapse in PV prices due to overproduction.

Big questions about the U.S. market

Paula Mints of Navigant Consulting; photo: Navigant Consulting

Other analysts, including Paula Mints of Navigant Consulting Inc. (Washington D.C., U.S.), have suggested that some of the more optimistic predictions of short-term growth in U.S. PV markets may not be taking all factors into account. The nation possesses enormous project pipelines for utility scale PV and CSP, but as Mints points out, "it is a long way from power points to power plants".

Mints and others have expressed concern about U.S. policy mechanisms, such as California’s Renewable Auction Mechanism, which rely on competitive solicitations instead of the set rates offered by feed-in tariffs. Both Mints and the CLEAN Coalition (Palo Alto, California, U.S.), which critically supported the policy, note that such mechanisms can lead to underbidding and projects that are never completed.

Political realities

Intersolar organizers called a national feed-in tariff for the United States at the conference. While this would be obviously beneficial for any solar technologies that would be included, the odds of such a proposal being implemented at the national level are slim to none in the nation’s current political climate.

The U.S. Republican Party has shown hostility to both carbon regulation and policies to support renewable energy at the national level; Image source: public domain

The return of the opposition Republican Party and the Tea Party movement in the U.S. Congress has already led to slashed funding for the DOE’s Office of Renewable Energy and Energy Efficiency and the Environmental Protection Agency, the latter as part of a concerted effort to prevent regulation of CO2. It is an irony that the feed-in tariff proposal was made at Intersolar during a Republican threat to not raise the nation’s debt ceiling – which could be disastrous for the United States’ economy and industries well beyond the solar industry.

If the right wing of the U.S. political spectrum maintains this momentum into 2012 elections, there is also a potential for national policy supports put in place by U.S. President Barack Obama to be removed. Most significantly, while Obama’s Treasury Grant Program (TGP) managed to survive budget negotiations in late 2010 for another year, there is no guarantee that this will happen again. In an interview during Intersolar Paula Mints of Navigant Consulting gave the TGP’s chances of extension to 2012 at 40-60 against.

The state-level policy environment is more complex. In the absence of strong federal action, U.S. states and even cities have taken the lead in implementing renewable energy mandates. In several states, including California, Texas and North Carolina, some Republican politicians have supported strong policies to support solar and other forms of renewable energy.

Hope springs eternal, part I: CPV

However, there are several trends that bode well for the U.S. and global solar markets. Falling PV prices mean pain for manufacturers, but also help close the gap between PV costs and grid parity. On a more positive note for the industry, the ongoing advance of technology and new approaches to the problem of financing could both be game-changers in certain markets.

Concentrix CPV module with tracker

After decades of development and years of small pilot projects, concentrating photovoltaics (CPV) is finally breaking out into the scale of projects over 100 megawatts.

Among this year’s exhibitors, Soitec SA’s (Bernin, France) Concentrix CPV technology has recently secured power purchase agreements (PPAs) for a total of 305 MW with San Diego Gas and Electric Company (SDG&E). These PPAs are much larger than any projects that have been completed to date. Soitec is also pursuing pilot projects and research and development collaborations in Morocco and Tunisia.

Much of the potential of CPV comes down to cost. For the right regions, including parts of Southern California and much of Northern Africa, CPV offers a lower levelized cost of electricity than competing technologies. Furthermore, Soitec and others are very confident of CPV’s potential to scale without complications.

During the Intersolar conference, Solar Server interviewed Hansjörg Lerchenmüller of Soitec, who co-founded Concentrix before its purchase by Soitec, which can be accessed here.

Hope springs eternal, part II: solar leasing

While much attention is paid to the technical problems of bringing efficiencies up and costs down, many of the solutions to growing PV markets come from other areas, notably policy and financing.

Policy analysts have noted that one of the chief weaknesses in the hundreds of diverse solar incentives in the United States, as compared to a system of feed-in tariffs, is that these combinations of incentives simply do not offer the same investment security, and that U.S. homeowners have difficulty securing loans at reasonable rates to address the high up-front costs installing PV systems.

This has created a booming market for companies including SolarCity Corporation (San Mateo, California, U.S.) and SunRun Inc. (San Francisco, California, U.S.) which lease solar systems to homeowners, with the option of little or no up-front costs. As this solution proves its utility, the field of companies offering such services broadens.

Centrosolar America Inc. (Scottsdale, Arizona, U.S.) has launched a solar lease program geared towards its network of residential installers, making it unique among original equipment manufacturers. The company  advertised its CentroLease solution at the Intersolar exhibition, along with its CentroPack "solar-in-a-box" system and its mounting and racking solutions.

U.S. Cities have also noted the potential benefits of financing programs. During the Intersolar conference the city of San Francisco unveiled a new solar group purchase and financing program for businesses and commercial property owners, "Solar at Work". SolarCity will assist with financing options for the program, which aims to install 2 MW by the end of 2011.

It remains to be seen how dramatic of an expansion in the U.S. market solar leases will enable, but industry analysts are already reporting that installations through solar lease programs are making up an increasingly greater portion of residential and small commercial markets.

Conclusion: many markets, many technologies

While there are many concerns for the global solar industry going into the second half of 2011, there is also cause for considerable optimism.

Even if things do not turn out as planned in specific national markets or market segments, there are many developing markets that offer mid- to long-term growth potential for grid-tied PV, CSP and CPV, as well as solar heating and cooling, beyond North America and Western Europe. These developing and potential markets include China, India, North Africa and the Middle East, Southeast Asia, Central and Eastern Europe, and Latin America.

Other regions offer great potential for off-grid solutions, for those developers that can adapt to different infrastructure, different markets and different demand.

The same can be said for technologies. Currently the solar industry offers a greater variety of real and potential solutions to our energy needs than any other technology. No one can say which technology or company will be the winner in any specific market or market segment in the years to come, but the signs of ever greater efficiencies, lower costs and more adaptive solutions are all positive.

The global solar industry continues to be a testament to the boundless creativity of humanity, and a growing means of addressing our greatest challenges. Nowhere is this as evident in the gathering of talent, ideas, technologies and solutions that was on display at Intersolar North America 2011.

Exhibition floor at the Intersolar conference; photo: Solar Promotion International GmbH

source: http://www.solarserver.com

Intersolar NA 2011: Challenges amid growth in the global solar industry is a post from: Crystalline Silicon

Intersolar NA 2011: Challenges amid growth in the global solar industry is from Crystalline Silicon