The Power of the Sun

1. By Anna and Gloria The Power of the Sun

2. First Discovery and Use • The Greeks and Romans were probably the first people to discover the power of the sun and put that energy to use. • Edmund Becquerel discovered the photovoltaic effect in 1839 wile experimenting with the electrolytic cell. • Russell Ohl was the first person to find a way to harness the sun’s energy when he invented the solar cell in 1941. • Gerald Pearson, Calvin Fuller and Daryl Chapin worked together to invent the first efficient solar panels.

3. When and where is was first used • The sun’s energy was first used in about 400 BC in Greece and Rome. • After Ohl discovered how to harness the sun’s energy through solar cells, satellites in space began to use them to produce electricity. • The efficient solar battery was first used in a telephone carrier system in Americus, Georgia on October 4, 1955

4. Why? • The Romans and Greeks developed the use of the sun’s energy to heat buildings and water. The Greeks also used it to grow vegetables in greenhouses. • Solar cells were first used to provide electricity for satellites and when cheaper alternatives were unavailable.

5. How? • The Greeks and Romans discovered that by building their houses a certain way would trap the heat inside and making darker colored pots would keep the contents warmer for longer. • Pearson, Fuller and Chapin put several strips of silicon the size of razorblades in the sunlight and captured the free electrons and turned them into an electrical current.

6. Diagram- Water

7. Diagram- Electricity

8. Steps of Solar energy production • The sun hits the solar panels • Solar panels collect energy from the sun • The collected solar energy is sent to the electric panel • The electric panel provides electricity for the building • Excess energy can be sold to the power company

9. Current Uses • Heat • Passive: Air is circulated past the solar heat surface and through the building by convection. • Active: A “collector” absorbs and collects solar radiation. Fans or pumps circulate the heated air. • Electricity • Thermal power plants • Parabolic trough: focuses the sun’s rays on a receiver pipe and moves with the sun as the day progresses • Solar dish: tracks the sun and points straight at it to receive concentrated solar energy • Solar power tower: focuses concentrated solar energy gathered by rotating mirrors on a tower- mounted heat exchanger/ receiver

10. Where is it currently used? • Residential and business buildings • Vehicles • Roadway signs • Heating water • Creating portable water

11. Future Plans • Storing excess energy • Creating a miniature “sun” on earth to help power solar cells when the sun is not shining

12. Benefits • It is renewable, which means it can never run out. • It is environmentally friendly because solar cells don’t produce pollutants. • Solar cells don’t make noise. • It is cheaper than electricity. • There is a large variety of solar panel systems available. • Can sell the excess electricity produced by the solar cells. • Government will provide a tax credit or incentive for purchasing solar energy systems.

13. Disadvantages • The initial cost of the equipment used to harness the sun’s energy • Large areas are needed for the equipment in order for the system to be efficient. This is inconvenient for people that live in areas where there is not a lot of space, or where space is expensive, such as inner cities. • Pollution can degrade the efficiency of photovoltaic cells • Solar panels only work when the sun is shining. This means that when it is cloudy or nighttime the solar panels are less effective. • The location of solar panels can affect performance, due to possible obstructions such as buildings or the landscape. • Toxic materials, chemicals, solvents and alcohols that are produced in the process of making PV cells • Large solar thermal power plants harm desert ecosystems if they are not properly managed. • Birds and insects can be killed if they fly into a concentrated beam of sunlight produced by the “solar power tower”

14. References • http://ezinearticles.com/?10-Benefits-of-Solar-Energy&id=2154024 • http://www.clean-energy-ideas.com/articles/disadvantages_of_solar_energy.html • http://www.eia.doe.gov/kids/energy.cfm?page=solar_home-basics • http://www.annesley.sa.edu.au/amep/energyconservation_solarenergy/history.htm • http://inventors.about.com/od/sstartinventions/a/solar_cell.htm • http://encyclobeamia.solarbotics.net/articles/photovoltaic.html • http://www.articlesbase.com/technology-articles/how-is-solar-energy-used-today-and-what-are-the-plans-for-the-future-1497115.html • http://dsc.discovery.com/videos/powering-the-future-clips-solar.html

15. Picture References • http://www.solargain.ca/EAC_solar.html • http://www.latrobeschool.com/about/facilities.html • http://nobelprize.org/nobel_prizes/physics/laureates/1903/becquerel-bio.html • http://www.solarpowerninja.com/solar-power-technology/recreating-the-sun-to-harness-solar-power-74901/ • http://portal.unesco.org/ci/en/ev.php-URL_ID=11543&URL_DO=DO_TOPIC&URL_SECTION=201.html • http://www.powertripenergy.com/pv_hist.htm • http://www.norcalblogs.com/watts/2006/12/post_1.html • http://inhabitat.com/wp-content/uploads/sunpower_main.jpg • http://www.trec-uk.org.uk/press/brussels/prince_hassan_presentation.html • http://www.huffingtonpost.com/alanna-zabel/the-hybrid-hype_b_618875.html • http://www.scientificamerican.com/article.cfm?id=how-to-use-solar-energy-at-night • http://www.markburrier.com/blog/2009/03/ominous-clouds/ • http://green-energy-center.blogspot.com/2008/08/grants-for-clean-energy-business.html