Presentation by Michelle Taormino, Brittany Musolino, and Stephanie Sink

1. Solar Power is important to Earth. It is the power of life. Plants use solar energy to photosynthesize, humans use the sun to make vitamin D and it heats up the earth to allow organism to survive, especially out of the water. Photosynthesis provides food to the lowest level of the food chain and thus is the food and power source to every other organism. Throughout time and death, fossil fuels and other organic fuels (wood) were created. But this would not have happened if it weren’t originally from the sun’s energy. We too can benefit from the energy the sun provides us. Presentation by Michelle Taormino, Brittany Musolino, and Stephanie Sink

2. Barriers that make Solar Energy less attractive: -Fossil Fuel priced very cheap -Large subsidies given to fossil fuels and nuclear power -Little technology and development is invested into developing solar-based technology -Present infrastructure is energy inefficient and fossil fuel based -Denial that the end of the fossil fuel age is here Arguments to Barriers/Advantages of Solar: -Fossil Fuel prices are cheap because they do not include cost to health damage, environmental damage, conflict and war, and climate change -Renewable as long as the lifetime of the sun -Able to be mass produced in large and small scale -Eliminates air pollution, -Reduces climate change, oil spills etc. -Reduces conflict over energy resources because it is widely available -Applicable to businesses and commercial use on a large scale as well as communities and individuals on a small scale. -Contributes to decentralizing the energy production system and in turn making energy more dependable and less vulnerable

3. Passive Solar • More initial cost but will save on energy bills permanently. • Can be implemented into the design of any newly constructed building and has a very long life span. • Less dependent on utility companies for providing energy to heat the home. • More beneficial in suburb and rural areas than urban areas where buildings block the sun’s rays.

4. Direct Gain • Windows dominantly on the South side of the building • Windows 10-20% of floor area • Overhang to protect from summer sun • Light colors of walls and ceiling reflect more light • Use of stone, mason, concrete, brick etc. stored heat throughout the day to radiate thermal heat back at night • Can be about 75% effective

5. Indirect Gain • Use of a thermal body to create thermal heat that air currents will circulate throughout the living area. • Ex. Trombe Wall

7. Isolated Gain • Attached sunroom or greenhouse to gain thermal heat that then can be transported throughout the living space. • Sunrooms and greenhouses have high initial cost and the return of investment can take many years.

8. Active Solar Based on 1 kWh of energy=3413 Btu 6 hours of sun with 40% collector efficiency= 8,191 Btu. For 7 days=57,338 Btu = .4 gallon of crude oil (1 gal. = 140,000 Btu) Electrical Power plant is only 33% efficient.

9. Solar Panel • 40% total efficiency • 20% loss due to convection • 4% loss due to conduction • 8% loss due to reflection and glaze absorption • 8% loss due to reflection • Solar Panel has about a 10 year life span • $30-80 per square foot of panel

10. Worldwide • Germany produces about half the world’s solar energy, even though they have abundant cloudy days. • Spain requires new buildings to have solar panels and use solar energy as a portion of their energy needs. • South Korea in 2008 completed the world’s largest solar plant. • China has more solar panel manufacturers then the rest of the world put together. • Investing in the solar power can end the U.S. demand on foreign oil by 2050.

11. Solar Thermal Power Plants • Solar Thermal (heat) Energy is a carbon-free, renewable alternative to the power we generate with fossil fuels like coal and gas • Between 1984 and 1991, the United States built nine plants in California’s Mojave Desert • They continue to provide a combined capacity of 354 megawatts annually, power used in 500,000 Californian home

12. In solar thermal power plants the incoming radiation is tracked by a number of large mirror fields, which concentrate the energy towards absorbers.

15. Power Plants Vs. Solar • In 2008, the “average” nuclear power plant generated about 12.4 billion kilowatt-hours (kWh). There were 65 nuclear power plants with 104 operating nuclear reactors that generated a total of 808.97 billion killowatt-hours, or almost 20% of the nation’s electricity. • There are two main types of technologies for converting solar energy to electricity: photovoltaic (PV) and solar-thermal electric. In 2008, less than1% of the nation's electricity was from solar power

18. Disadvantages • Power producing plants adjust to solar energy only being available during the day. • Energy conversion rates or efficiencies are low compared to other energy sources. Low energy conversion rates to electrical energy in both solar thermal and photovoltaics are being addressed by increasingly stronger research and development activities of key companies. • High capital cost requirement for the procurement or production of materials and installation of solar energy systems or facilities.

19. Advantages • Use of cheap barren lands not frequently affected by climatic changes and that typically have sunny weather condition throughout the year. • Reduced operating cost given the fact that solar power is free. • Reduced harmful effects to the environment (reduced carbon emissions) are compared to using other sources of energy like crude oil. • Reduced dependency on imported crude oil.

20. Photovoltaic Cells

21. History of Photovoltaic Cells • French physicist Edmond Becquerel first described the photovoltaic effect in 1839. • Photovoltaic’s were first studied in solids (Selenium) though only at a 1-2% efficiency. Later moved to pure crystalline silicon – 6% efficient. • “Photovoltaic” comes directly from “photo” meaning light and “voltaic” meaning electricity.

22. PV Cells • Found in calculators and satellites. • First used exclusively in space but have become more common in homes. • Now made of semiconductors such as silicon.

23. How They Work • Light strikes the cell and is absorbed within the semiconductor. • Energy from the light is then transferred to the semiconductor. • Energy knocks the electrons loose and lets them flow freely. • Cells have electron fields that force the freed electrons in one direction.

24. How They Work • This flow of electron causes a current. • By placing metal contacts on the top and bottom of the PV cells, electricity can be drawn from them. • The current with the cell’s voltage defines the amount of power or wattage the solar cell can produce. • Typically mounted on southern facing roofs.

26. http://www.youtube.com/watch?v=x2zjdtxrisc

27. Grid-Tie System • Solar PV panels produce DC electricity which then runs through an inverter producing AC electricity and is fed back to your power company. • Users of the system can receive a credit when they produce more electricity than they use. • Causes their meters to go backwards.

28. Grid Tie System

29. PV Worldwide • Production of photovoltaics jumped to 3,800 mega watts worldwide in 2007, up to 50% since 2006. • Has been growing an average of 48% each year since 2002. • World’s fastest growing energy source. • Top five PV producing countries are: Japan, China, Germany, Taiwan and United States.

30. PV in U.S. • Growth installation in the U.S. increased 20% in 2005 to 31% in 2006, primarily driven by California and New Jersey. • Incentives such as tax credit of up to $2,000 helped to achieve an 83% growth in 2007. • Could power the entire United States.

31. Cost • The cost for a PV module excluding installation has dropped from $100 per watt in 1974 to less than $4 per watt.

32. Advantages • Sun gives off 1,000 watts of energy per square meter, could easily power our homes and offices for free of the sun. • Gas prices rice and resources dwindle but energy from the sun will never cease to exist. • Many times government gives incentives for people who have them installed. • Minimal maintenance and are extremely safe (no moving parts). • Long service lifetimes.

33. Disadvantages • Still quite expensive to purchase compared to available electricity. • Depending on location, PV may not be as efficient. • Surface area requirement for PV installations are typically somewhat large.

34. The sun’s energy has enough power to meet the energy needs of the world. • Incentives are utilized to promote solar power but more incentives will promote solar power better. • Sustainable because there are no pollution, particulates or greenhouse gases as emissions, global climate change will be reduced, and conflicts over energy resources will be radically reduced. Also, the environment will be more intact because no mining, or drilling or oil spills would occur to harm organisms of that area.

35. Conclusion • The sun’s energy has enough power to meet the energy needs of the world. • Incentives are utilized to promote solar power but more incentives will promote solar power better. • Sustainable because there are no pollution, particulates or greenhouse gases as emissions, global climate change will be reduced, and conflicts over energy resources will be radically reduced. Also, the environment will be more intact because no mining, or drilling or oil spills would occur to harm organisms of that area.