Use Of Solar Energy example essay topic

Introduction Our world has been in existence for billions of years and throughout all those years we have used the sun for basic energy needs. So why not be able to harness that energy and use it to power things like our homes or our cars? Many scientist have been developing alternate forms of energy called "Green Energy". Green power is the solution to creating a cleaner, sustainable energy system. Renewable energy -- power from the sun, wind, plants, and moving water -- is a natural way to meet our energy needs and protect the environment. Here are some forms of green energy: o Wind energy converts the power available in moving air into electricity.

Wind power does not produce air emissions, generate solid waste, or use water. o Biomass is energy from trees and plants. This includes crops that are grown specifically for energy production and organic wastes, such as wood residues from paper mills and methane from landfills. Using biomass to generate electricity reduces global warming emissions if new plants are grown to replace those that are harvested. o Geothermal energy uses heat from inside the earth to make clean power. o Solar power captures the heat and light of the sun to generate electricity. Solar energy does not produce air emissions, generate solid waste, or use water. o Hydroelectric power captures the energy in falling water. It does not produce emissions or solid waste, but can have a relatively low or high impact on the environment, depending on the site-specific factors such as maintenance of water flow and water quality, fish impacts, and other land use issues.

For the most part the cost has been a limiting factor. Whether it be the cost of the technology, or just the cost of replacing our fossil fuels and nuclear power plants it will be expensive none the less. There are many downfalls to nuclear and fossil fuel energy that solar energy can replace: o about two-thirds of the annual US emissions of sulfur dioxide, the main cause of acid rain and of very small soot particles. These fine particles are believed to be responsible for the largest share of the 50,000-100,000 deaths caused by air pollution in the United States each year. o about 30 percent of the nitrogen oxides, which combine with organic compounds in sunlight to form smog, and which stress forest ecosystems. High smog levels can trigger heart and respiratory problems and contribute to air pollution deaths. o about one-third of the carbon dioxide, the leading heat-trapping gas that causes global warming, which may lead to increased droughts, flooding, disease, ecosystem disruption, and severe weather. o toxic metal emissions (such as mercury and lead) and nuclear waste. My project will be on the uses and possibilities of solar power in today's society and how it will function.

I will explain how solar energy can be used to power our homes and all the benefits and downfalls of using solar power. With this change in our energy system we can make the world a cleaner and more efficient place to live. Welcome to the world of Solar Energy. History Although practical solar cells have only been available since the mid 1950's, scientific investigation of the photovoltaic effect started in 1839, when the French scientist, Henri Becquerel discovered that an electric current could be produced by shining a light onto certain chemical solutions. The effect was first observed in a solid material (in this case the metal selenium) in 1877. This material was used for many years for light meters, which only required very small amounts of power.

A deeper understanding of the scientific principles, provided by Einstein in 1905 and Schottky in 1930, was required before efficient solar cells could be made. A silicon solar cell which converted 6% of sunlight falling onto it into electricity was developed by Chapin, Pearson and Fuller in 1954, and this kind of cell was used in specialized applications such as orbiting space satellites from 1958. Today's commercially available silicon solar cells have efficiencies of about 18% of the sunlight falling on to them into electricity, at a fraction of the price of thirty years ago. There is now a variety of methods for the practical production of silicon solar cells (amorphous, single crystal, polycrystalline), as well as solar cells made from other materials (copper indium diselenide, cadmium telluride, etc). Research The main topic will be on photovoltaics, or PV which is (photo = light, voltaic's = electricity).

PV is a semiconductor-based technology used to convert light energy into direct current (dc) electricity, using no moving parts, consuming no conventional fuels, and creating no pollution. Solar cells are devices which convert solar energy directly into electricity, either directly via the photovoltaic effect, or indirectly by first converting the solar energy to heat or chemical energy. The most common form of solar cells are based on the photovoltaic (PV) effect in which light falling on a two layer semi-conductor device produces a photo voltage or potential difference between the layers. This voltage is capable of driving a current through an external circuit and thereby producing useful work. The development of solar cell use in Australia has been stimulated by: o the need for low maintenance, long lasting sources of electricity suitable for places remote from both the main electricity grid and from people; e.g. satellites, remote site water pumping, outback telecommunications stations and lighthouses; o the need for cost effective power supplies for people remote from the main electricity grid; e.g. Aboriginal settlements, outback sheep and cattle stations, and some home sites in grid connected areas. o the need for non polluting and silent sources of electricity; e.g. tourist sites, caravans and campers o the need for a convenient and flexible source of small amounts of power; e.g. calculators, watches, light meters and cameras; o the need for renewable and sustainable power, as a means of reducing global warming. Together, these needs have produced a growing market for photovoltaics which has stimulated innovation.

As the market has grown, the cost of cells and systems has declined, and new applications have been discovered. To fully understand how solar power energy is created we need to look at how silicon solar cells are made by using either single crystal wafers, polycrystalline wafers or thin films. Single crystal wafers are sliced, (approx. 1/3 to 1/2 of a millimeter thick), from a large single crystal ingot which has been grown at around 1400 ^0 C, which is a very expensive process. The silicon must be of a very high purity and have a near perfect crystal structure.

Polycrystalline wafers are made by a casting process in which molten silicon is poured into a mould and allowed to set. Then it is sliced into wafers. As polycrystalline wafers are made by casting they are significantly cheaper to produce, but not as efficient as mono crystalline cells. The lower efficiency is due to imperfections in the crystal structure resulting from the casting process.

Almost half the silicon is lost as saw dust in the two processes mentioned above. Amorphous silicon, one of the thin film technologies, is made by depositing silicon onto a glass substrate from a reactive gas such as silane (SiH 4). Amorphous silicon is one of a number of thin film technologies. This type of solar cell can be applied as a film to low cost substrates such as glass or plastic. Other thin film technologies include thin multi crystalline silicon, copper indium diselenide / cadmium sulphide cells, cadmium telluride / cadmium sulphide cells and gallium arsenide cells. There are many advantages of thin film cells including easier deposition and assembly, the ability to be deposited on inexpensive substrates or building materials, the ease of mass production, and the high suitability to large applications.

In solar cell production the silicon has dopant atoms introduced to create a p-type and an n-type region and thereby producing a p-n junction. This doping can be done by high temperature diffusion, where the wafers are placed in a furnace with the dopant introduced as a vapour. There are many other methods of doping silicon. In the manufacture of some thin film devices the introduction of dopant can occur during the deposition of the films or layers. A silicon atom has 4 relatively weakly bound (valence) electrons, which bond to adjacent atoms.

Replacing a silicon atom with an atom that has either 3 or 5 valence electrons will therefore produce either a space with no electron (a hole) or one spare electron that can move more freely than the others, this is the basis of doping. P-type doping, the creation of excess holes, is achieved by the incorporation into the silicon of atoms with 3 valence electrons, most often boron and n-type doping, the creation of extra electrons is achieved by incorporating an atom with 5 valence electrons, most often phosphorus (see figure 2). Figure 2 Silicon Crystal Lattice with Dopant Atoms. Once a p-n junction is created, electrical contacts are made to the front and the back of the cell by evaporating or screen printing metal on to the wafer. The rear of the wafer can be completely covered by metal, but the front only has a grid pattern or thin lines of metal otherwise the metal would block out the sun from the silicon and there would not be any output from the incident photons of light.

Applications The ability to produce electricity directly from the sun's energy is a revolutionary development. The technology involved in the production of these silicon cells is complicated and the efficiencies are still not even close to those of thermal solar applications, but these unique energy devices are now seen in places as common as the yard (solar powered lights), the highways (solar powered traffic lights and sign lights), and of course the common calculator. Photovoltaics is the direct conversion of light into electricity. Some materials exhibit a property, known as the photoelectric effect, that causes them to absorb photons of light and release electrons. When these free electrons are captured, an electric current results that can be used as electricity.

This diagram illustrates the operation of a basic photovoltaic cell, also called a solar cell. When light energy strikes the solar cell, electrons are knocked loose from the atoms in the semiconductor material. If electrical conductors are attached to the positive and negative sides, forming an electrical circuit, the electrons can be captured in the form of an electric current -- that is, electricity. This electricity can then be used to power a load, such as a light bulb or a water pump.

A typical four-inch silicon solar cell produces about one-and-a-half watts of electricity in bright noon-time sunshine. Remote locations such as billboards, road signs and other areas where it is cost effective to install solar electric systems with battery backup are becoming more and more common. Solar cells are made of the same semiconductor materials (usually silicon) used in the microelectronics industry. For solar cells, a thin semiconductor wafer is specially treated to form an electric field, positive on one side and negative on the other. The basic components of a solar electric array are the photovoltaic panels, battery storage and other sub-assemblies that regulate the storage and release of the sun's electric current. There is a tendency to dismiss the use of solar-generated electricity because of its relatively high price per kilowatt-hour as compared to traditional sources of energy, especially grid- supplied electricity.

However, the issue is not so much what solar electricity costs, but rather what the service it provides is worth to the user. Input This is a great way of producing energy for all of mankind. There are many reasons for this. As most scientist have discovered the world will one day run out of natural resources, which power our homes and modes of transportation and we will need a alternate form of energy when this happens. Not to mention it is 100% cleaner and safer than other forms of fossil fuels and nuclear power plants. Unless we develop new forms of energy production, our world will be in complete chaos.

Sure there are other natural ways to produce energy, as stated above, but compared to the rest solar energy out performs all competitors. Solar energy is the most productive and cheapest form of green energy. Wind energy is not capable of producing as much energy and takes up much more space than solar panels. Not to mention it is less predictable than the sun its self and can not be relied on as a main source.

Geothermal is capable of producing a lot of energy, but sites that make this energy possible are lacking in number. Also major plants have to be constructed to harness this energy, that not only destroy the environment but are quite costly. Along with hydroelectric energy that is probably the most used source of green energy today, but has many downfalls. First off, there needs to be a river or some sort of moving body of water to make this possible. Not all places in the world have this, but just about every place in the world has sun. In terms of the environment it is quite atrocious since it controls the flow of water it can mess a whole environmental cycle and destroy the homes of the aquatic life.

Now on to what the project is really about, Solar Power. There are many convieneces to solar power, but of course nothing is perfect. It is more convien et for the consumer because they will not have to purchase things to run their house or car, they could just have the solar panels themselves and be independent. The one and major inconvenience of solar power is what do you do on a cloudy day? Or if one place does not get a lot of sun how can it run? Advantages: Solar energy is a renewable resource that is environmentally friendly.

Unlike fossil fuels, solar energy is available just about everywhere on earth. And this source of energy is free, immune to rising energy prices. Solar energy can be used in many ways - to provide heat, lighting, mechanical power and electricity. Disadvantages: It can overheat if the windows and thermal mass are not balanced. Large amounts of south-facing glass can cause problems with glare and privacy.

The thermal mass used for heat storage should not be covered by carpet or blocked by furnishings. Furnishings and fabrics exposed to ultraviolet radiation from the sun can degrade or change color. South-facing windows need summer shading and a nighttime insula tive covering in winter. Nighttime insulation can be provided by exterior-mounted panels, interior draperies, shutters, pop-in panels, or other insulating window treatments. One day I believe the whole world will run off of this source of energy and humans will be even more dependant on the sun than they are today. Everything will be run by solar power; our homes, our cars, our street lights, to any basic tool that needs energy to function.

We are going to have to invest more into this source of energy because right now it is not capable of running the world we live in. I fear we will wait too long to invest and will be stuck in a "dark age" and I mean that literally too. Also we need to advance it further because we are going to need it to be able to store energy on the days that it is cloudy. It is capable of doing that today but not anywhere near the efficiency we need it to be.

Advertising This is a source of energy that is not widely advertised, heard of but not advertised. I would run a whole campaign starting from, posters, bumper stickers, to commercials, clubs, and political compromising. The commercial would have a dark setting, with things that are just barley visible, then all of a sudden it shows oil pumps stop pumping, power plants shutting down, cars not moving, and the world at almost a complete stand still. Then a voice will say, "Where will the world be when our natural resources run out.

(Pause) Absolutely nowhere!" Then a ray of light will shine down on the dark world and every thing will start moving again, just like normal. Then some sort of statement will come on about investing in solar power and how it is the way of the future. Posters and bumper stickers will have some catchy phrase and be in wide production. They will be handed out for free and be in production everywhere to try and get people familiar with what needs to be done for the future. Posters will have some computer generated art with blazing beams of sunlight coming out of them, like holograms of some sort. Then if I can get a wide enough cohilition I can start a political party that promotes the use of solar energy.

If I can get it to be big enough we will be the determining factor in many elections for House and Senate and that is when we will really start to see things moving.