The document summarizes the pros and cons of various renewable energy sources including solar, wind, hydro, and biomass energy. It discusses that while solar and wind are free sources of energy, they have limitations based on weather and location. Hydroelectric power is inexpensive once dams are built but can damage ecosystems. Biomass energy utilizes waste but production and storage of raw materials is expensive. The document also provides examples of energy innovations and news articles on renewable energy projects.

10. Comparison s

15. Inventions in Energy Conservation

16. Solar The Juice Bag Solarjo Power Purse SeV Solar Panel Jacket

17. Solar Powered Contact Lenses Solar Panels Solar Powered Ships

18. Solar powered cars of the future Solar Powered Calculator

19. Wind Tree-Hugging Wind Turbine Wind Turbines

20. Wind Powered Generator for your home Wind Powered Car

21. Hydro Water powered Car Water Powered Clock Water powered jetpack Hydrogen run car

22. Biomass Biomass Run Car

23. How do they work?

24. Solar thermal: The most common solar concentrators is parabolic troughs —long, curved mirrors that concentrate sunlight on a liquid inside a tube that runs parallel to the mirror. The liquid, at about 300 degrees Celsius, runs to a central collector, where it produces steam that drives an electric turbine.

25. Photovoltaics In 1839, French scientist Edmund Becquerel discovered that certain materials would give off a spark of electricity when struck with sunlight. This photoelectric effect was used in primitive solar cells made of selenium in the late 1800s. In the 1950s, scientists at Bell Labs revisited the technology and, using silicon, produced solar cells that could convert four percent of the energy in sunlight directly to electricity. Within a few years, these photovoltaic (PV) cells were powering spaceships and satellites. The most important components of a PV cell are two layers of semiconductor material generally composed of silicon crystals.

26. Wind energy system

27. Typical hydroelectric powerplant Hydroelectric energy is produced by the force of falling water. The capacity to produce this energy is dependent on both the available flow and the height from which it falls. Building up behind a high dam, water accumulates potential energy. This is transformed into mechanical energy when the water rushes down the sluice and strikes the rotary blades of turbine. The turbine's rotation spins electromagnets which generate current in stationary coils of wire. Finally, the current is put through a transformer where the voltage is increased for long distance transmission over power lines. (Source: Environment Canada )

28. News Time!

33. Interesting Facts about Alternative Energy

34. 600 percent: The highest average efficiency of a ground source heat pump in the winter, compared to 250 percent for air-source pumps. 15: Percentage of the average household electricity bill that goes toward lighting alone. 9: Lowest wind speed (in miles per hour) from which it’s efficient to harness wind power. 750: Number of electricity providers that offer a green alternative. 280,475: Number of photovoltaic cells shipped domestically in 2007. 7: Percent of energy that came from renewable sources in 2007. 53: Percent of that renewable energy that was drawn from biomass fuels, the largest supplier, followed by hydroelectric (36%); solar, geothermal, and wind energy all contributed 5% or less.

35. Alternative Energy Rap!

36. Perry, Z. "Advantages and Disadvantages of Wind Power." Hubpages . N.p., 10/09. Web. 2 Mar 2010. http://hubpages.com/hub/advantages-disadvantages-wind . "Pros And Cons Of Solar Energy." Clean Energy Ideas . N.p., 2009. Web. 2 Mar 2010. http://www.clean-energy-ideas.com/articles/pros_and_cons_of_solar_energy.html . Nathan Crawford, Katie Marshall, Ben Pope, And Zeya Wagner, . "Pros and Cons." Water Project . N.p., n.d. Web. 2 Mar 2010. http://drake.marin.k12.ca.us/stuwork/rockwater/Upload%20this%20doc--dams%20and%20hydropower%20report/pros%20and%20cons.html . Ghosh, Suvamita. "Biomass Energy Pros and Cons." Buzzle . Buzzle.com, 2009. Web. 2 Mar 2010. http://www.buzzle.com/articles/biomass-energy-pros-and-cons.html . Copeland, Blythe. "Interesting Facts about Alternative Energy." Planet Green . Planet Green, n.d. Web. 9 Mar 2010. http://planetgreen.discovery.com/go-green/alternative-energy/alternative-energy-numbers.html . Bibliography Jake’s:

37. &quot;Energy Inventions.&quot; Energy Inventions . Web. 8 Mar. 2010. <http://www.alternative-energy-news.info/technology/inventions/>. † InventorSpot . Web. 8 Mar. 2010. <http://inventorspot.com/portable_solar_power>. † NewScientist Tech . Web. 8 Mar. 2010. <http://www.newscientist.com/article/dn16395-invention-treehugging-wind-turbine.html>. † TFOT: The Future Of Things . Web. 8 Mar. 2010. <http://thefutureofthings.com/news/1011/water-powered-car-demonstrated.html>. † Water Powered Car Demonstrated . Web. 8 Mar. 2010. <http://thefutureofthings.com/news/1011/water-powered-car-demonstrated.html>. Bibliography Kira’s:

38. “ Water Science for Schools.” USGS . Web. 8 Mar. 2010. <http://ga.water.usgs.gov/edu/wuhy.html>. “ How Solar Energy Works”. Clean Energy. Web. 8 Mar. 2010. <http://www.ucsusa.org/clean_energy/technology_and_impacts/energy_technologies/how-solar-energy-works.html>. Bibliography Tian’s:

39. http://www.nytimes.com/cwire/2010/03/02/02climatewire-companies-work-to-harness-the-power-of-waves-5213.html http://www.windenergynews.com/content/view/1576/43/ http://www.firstcoastnews.com/news/local/news-article.aspx?storyid=152644&provider=rss http://www.wral.com/news/local/story/7139474/ Bibliography Albert’s:

40. The End. Thank you!