WHAT IS SOLAR POWER AND HOW DOES IT WORK

Solar power is the conversion of sunlight to electricity or steam. Every day the earth only gets about 2/billionths (2/1,000,000,000) of the sun’s light and energy, but that is the same amount of energy that the earth could consume in 30 years! The US Energy Administration has predicted that between 2003-2030, the world demand for energy will be double the amount of energy the world uses now. Charles Fritts created the first solar cell in the 1880s. Devices used to convert sunlight into various useful things are photovoltaic cells or solar thermal collectors. The heat of the sun can turn water running through solar thermal collectors into steam. Photovoltaic cells turn light into energy by using the photoelectric process by absorbing photons of the sunlight and putting out electrons. These electrons are then collected and can be used as a source of electricity. The assorted transformed energy is then processed into generators and/or turbines to create electricity. Batteries can also be solar powered by the sun and recharged by it too. Automobiles such as cars and boats can be powered by solar power and can save a lot of gasoline from polluting the earth’s atmosphere. Already 20,000 homes in the United States totally rely on solar power. However, most of these houses are in rural or isolated places. Scientists have predicted that solar energy will become more and more popular in the future when the price of the technology has lowered.
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Figure 1: Photovoltaic Cells

Photovoltaic Cells and Solar Thermal Collectors

One way the sun’s light can be captured and converted into energy is with solar thermal collectors, which are placed on the tops of buildings and peoples’ houses. Solar thermal collectors have tubes on them where water circulates through them. These tubes are placed where the sun shines. The sunrays have the energy to turn the water in the tubes into steam, which is then used to power motors in a turbine. Scientists have predicted
that eventually when the price of solar thermal collectors is cheaper, most skyscrapers and tall buildings will use them collectors and have them built on the outside rather than glass. AT&T’s Bells Laboratories created the Photovoltaic cells in 1954.Photovoltaic cells are used to turn sunlight into energy. As seen in figure one, the sunlight that hits the glass is strong enough to go through it to hit the metal contact sensors. The metal contacts then create millions of electrons that run in silicone holes or strips with a negative type and a positive type. Photovoltaic cells can be attached to many things like calculators and solar cars. Batteries to run generators can also be charged and powered by photovoltaic cells. When the sun is up, the sunlight can just power the batteries while the sun is shining. At noontime, the sun gives more energy than needed so then the batteries will charge while still being powered. Then in the evening or at night, the batteries can run on the charge energy from the sun collected at noontime. For this reason, batteries that use photovoltaic cells are used to power many things like big generators that may power some elevators.

Solar Farms

Areas that have an abundant source of solar thermal collectors are called solar farms. Solar farms produce lots of energy for the outside world so you can sort of think of it as an energy plant. Solar farms almost look like fields of crops because each panel is placed side by side and the panels have little grids on them. Solar farms can be located anywhere where there is enough land to place the panels. There is actually a big solar farm located in Swabia, Germany.

Solar Powered Vehicles and Events

There are many events involving solar powered automobiles such as solar cars (sun racers) or solar powered boats. There is an event that is held every three years that involves sun racers in Australia from Darwin to Adelaide and the distance between is about 3000 kilometers (1860 miles). These races contain about 40 cars and they determine which solar powered car is the best.
Australian doctor Robert Dane created a boat with sails that used both energy from the wind and the sun. The sails can be controlled and moved by a computer in the boat and in various weather situations, they could fold on top of the boat. Robert Dane’s boats use 100 percent solar and wind power but are not 100 percent dependable when moving large groups of people or cargo. For this reason, most boats have a hybrid engine for backup in case the solar power is not enough or it malfunctions. Even though these engines require fuel, they only use 1/10 of the amount of diesel gas used to power a regular boat.
On May 8, 2007 a boat arrived at the New York harbor after leaving Europe for an experiment. This boat was known as the Sun21and it was powered 100 percent by the sun and could go up to 7 knots of speed (8 miles per hour or 13 kilometers per hour). The sun21 was designed by a Swiss doctor named Mark Wust. It was also part of the Swiss Boat-Manufacturing Company. Scientists have also calculated that this boat had saved 988 gallons (3744 liters) of diesel gasoline on that trip!
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Figure 2: Solar powered car or a Sun Car.

Concentrating Solar Power

Concentrating solar power systems use large mirrors or lenses to take a large area of sunlight into a small concentrated beam of light. This is also called solar thermal energy and is almost the same concept on how a magnifying glass works. This light is then used to power a heat engine (usually a steam turbine) which is connected to an electrical power generator. Some scientists debate on if Archimedes used a burning glass to concentrate sunlight on the Roman fleet invading Syracuse. In 1973, a Greek scientist called Dr. Loannis Sakkas was curious whether or not the Archimedes’ principle was true. So he lined up 60 Greek sailors on a ship, each holding a mirror to concentrate sunlight to a tar-covered plywood silhouette 160 feet away. The whole ship caught on fire in a few minutes.

Other Sources of Natural Energy

The sun is not the only source in nature to get energy. Wind can also give you energy. The concept of wind energy is very similar to the concept of turbines. In fact, there are many different types of turbines and one of them is a wind turbine. When the wind is blowing, it causes the blades of the windmill to spin. The blades spin which then creates the electric generator to spin and it produces energy. Water can also be a source of energy. In the river, there could be a setup of a generator so when the water flows down, the water can push the generator, which could be connected to something else to produce energy.

Glossary

Photovoltaic Cells: Cells that are mostly made out of silicone and have glass on the outside. Under them are tiny metal sheets that take the electrons from the energy of the sun are separated as negative charges and positive charges.
Solar Thermal Collector: A panel that has tubes of flowing water in them and when the sun heats the water up, it becomes steam therefore running the angled blade of a turbine.
Turbine: An engine where fluid (steam) is used to spin an angled blade that spins an electric generator.

Citations

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