Solar Energy

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:

* Wind energy converts the power available in moving air into electricity. Wind power does not produce air emissions, generate solid waste, or use water.

* 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.

* Geothermal energy uses heat from inside the earth to make clean power.

* 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.

* 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:

* 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.

* 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.

* 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.

* 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 1950s, 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, voltaics=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 photovoltage 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:

* the need for low maintenance, long lasting sources of electricity suitable for places remote from both the main electricity grid and from people; eg satellites, remote site water pumping, outback telecommunications stations and lighthouses;

* the need for cost effective power supplies for people remote from the main electricity grid; eg Aboriginal settlements, outback sheep and cattle stations, and some home sites in grid connected areas.

* the need for non polluting and silent sources of electricity; eg tourist sites, caravans and campers

* the need for a convenient and flexible source of small amounts of power; eg calculators, watches, light meters and cameras;

* 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