The dictionary meaning of ‘alternative energy’ is as follows:
al·ter·na·tive en·er·gy noun Energy generated in ways that do not deplete natural resources or harm the environment, esp. by avoiding the use of fossil fuels and nuclear power. (http://www.google.com/#hl=en&q=alternative+energy&tbs=dfn:1&tbo=u&sa=X&ei=OBFfTooGhsqsB5_bqL4P&ved=0CCMQkQ4&bav=on.2,or.r_gc.r_pw.&fp=756c45c4808f223d&biw=1366&bih=688>)
Alternative energy in today’s terms means ‘Renewable Energy’ i.e. the energy obtained from sources that are indefatigable unlike fossil fuels of which there is a finite supply. Renewable energy sources include geothermal, wood, waste, photovoltaic and wind energy.
According to the map on the left, we see that SOLAR energy is available almost everywhere on earth and also is free to be used by anyone.
SOLAR energy can be converted to electrical energy by two methods: SOLAR Thermal/Electric Power Plants or by using Photovoltaic (PV) Cells.
SOLAR Thermal/Electric Power Plants generate electricity by focusing sunlight to heat a fluid and produce steam which powers a generator. Photovoltaic Cells convert sunlight directly into electricity. Individual PV cells are grouped into panels and arrays of panels that can be used in a wide range of applications ranging from single small cells that charge calculator and watch batteries, to systems that power single homes, to large power plants covering huge areas
The main advantage of using PV cells is that they do not produce any pollutants while converting sunlight to electricity. This will greatly impact the environment by reducing the load of waste emissions and greenhouse gasses.
Sunlight is composed of photons. Photons are particles packed with SOLAR energy which contain numerous amounts of energy corresponding to the different wavelengths of the SOLAR spectrum.
A PV cell is mostly made from silicon alloys. When a photon hits a PV cell, it is either reflected back, absorbed or it passes through the cell. Only those photons which are absorbed can be utilized to generate electric current. Upon collection of sufficient photons, electrons from the semiconductor in the cell start to move freely and get attracted to the specially treated front surface. The special treatment attracts more electrons to the front surface thus making it easier for the electrons to travel towards the surface.
When the electrons leave their position, they leave behind an empty space. With many electrons accumulating negative charge at the front surface of the cell, potential difference is created like the negative and positive terminals of a battery. When the two surfaces are connected through an external load, electricity flows.
One PV cell is the basic building block of a PV system. Individual cells can vary in size from about 0.5 inches to about 4 inches across. Although, one cell only produces 1 or 2 watts (which quiet a small quantity as compared to 50 watt light bulbs), they can be connected together into modules which can be further connected into arrays and arrays can be further networked into power plants. The number of modules/arrays can vary depending on the energy needs.
The performance of a PV array is depends on the intensity of sunlight available. Climatic conditions (such as clouds or fog) have a direct impact on the efficiency of a PV array. The efficiency of most available PV modules ranges from 5% to 15.
The success of PV technology, paved the path for its usage today. These days, the most basic application is in calculators and wrist watches. More complicated systems provide electricity to pump water, power communications equipment, and even provide electricity to our homes.
PV cells are similar to conventional batteries. They generate direct current (DC), which is generally used for small electronic equipment. For commercial applications, it must be converted to alternating current (AC) using inverters, solid state devices that convert DC power to AC.
Over the next fifty years, the demand for energy will continue to increase rapidly whereas the fossil fuel reserves will continue to decline until exhaustion. Here is where solar energy comes into the picture. Predicting the condition of the world energy economy in the next fifty years is useless as we have no idea of what turns it will take in the upcoming five years.
As we see that the Non-OCED will be requiring the most energy in the future world energy economy. This is because Non-OCED is mostly developing countries which will require more energy as they develop. Total world energy use rises from 495 quadrillion British thermal units (Btu) in 2007 to 590 quadrillion Btu in 2020 and 739 quadrillion Btu in 2035
As we see in the graphs, the world need for energy has almost doubled in 40 years from 1990 till 2030. As the predicted readings show, the usage of renewable energy sources will begin to meet the world energy demands.
The graph on the right again shows that renewables, nuclear and gas will eventually become the backbone of the world energy economy.
Production of electricity from PV cells does not require oversized and noisy generators and also does not produce any harmful by-products. PV arrays can be installed quickly and in any size and also require very less space. The environmental impact is minimal, requiring no water for system cooling and generating no by-products.
While usage of solar energy may not produce any health hazards, the production of a PV panel produces silicon tetrachloride (a corrosive and toxic waste product of poly-silicon manufacturing), dusts, and greenhouse gases like sulphur hexafluoride. Silicon tetrachloride can make land barren and infertile for ever by making the soil too acidic for plants, causes severe irritation to living tissues, and is highly toxic when ingested of inhaled. This disturbs the balance of the ecosystems and is also ethically immoral because we are creating pollutants not only for humans, but also for other organisms.
Usage of fossil fuels in the first place is environmentally wrong. Fossil fuels are stored carbons which are supposed to release into the atmosphere slowly. By using them as fuel, we are disturbing the balance by releasing those carbons in harmful quantities.
Usage of alternative energy sources will result in healthier economies of an individual and in the long run of a country as PV systems only requires an initial investment and then there is a free supply of power.
So in the years to come, Roof top solar panels will be more common than oil spills in the Pacific Ocean.
Bibliography
"Asia-Pacific Must Invest Up to $9.7 Trillion by 2030 to Meet Energy Needs | Asian Development Bank." Asian Development Bank (ADB). N.p., n.d. Web. 29 Aug. 2011. <http://beta.adb.org/news/asia-pacific-must-invest-97-trillion-2030-meet-energy-needs>.
"BP Statistical Review of World EnergyJune 2011." BP Global | BP. N.p., n.d. Web. 30 Aug. 2011. <www.bp.com/assets/bp_internet/globalbp/globalbp_uk_english/reports_and_publications/statistical_energy_review_2011/STAGING/local_assets/pdf/statistical_review_of_world_energy_full_report_2011.pdf>.
"Biomass Energy Pros And Cons." Biomass, Biomass Fuel, Biomass Energy. N.p., n.d. Web. 2 Sept. 2011. <http://www.biomass.net/Biomass-Energy-Pros-And-Cons.html>.
"Cars produced in the world - Worldometers." Worldometers - real time world statistics. N.p., n.d. Web. 1 Sept. 2011. <http://www.worldometers.info/cars/>.
"Chemistry of Petroleum 1." Heavy Oil Science Center Home Page. N.p., n.d. Web. 30 Aug. 2011. <http://www.lloydminsterheavyoil.com/petrochem01.htm>.
"Danger: Solar Panels Can Be Hazardous to Your Health | CleanTechnica." CleanTechnica. N.p., n.d. Web. 2 Sept. 2011. <http://cleantechnica.com/2009/01/14/danger-solar-panels-can-be-hazardous-to-your-health/>.
"Energy Outlook 2030 | Statistical Review 2011 | BP." BP Global | BP. N.p., n.d. Web. 1 Sept. 2011. <http://www.bp.com/sectiongenericarticle800.do?categoryId=9037134&contentId=7068677>.
"File:Oil Reserves.png - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 31 Aug. 2011. <http://en.wikipedia.org/wiki/File:Oil_Reserves.png>.
"Fossil fuel - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 30 Aug. 2011. <http://en.wikipedia.org/wiki/Fossil_fuel>.
"Google." Google. N.p., n.d. Web. 1 Sept. 2011. <http://www.google.com/#hl=en&q=alternative+energy&tbs=dfn:1&tbo=u&sa=X&ei=OBFfTooGhsqsB5_bqL4P&ved=0CCMQkQ4&bav=on.2,or.r_gc.r_pw.&fp=756c45c4808f223d&biw=1366&bih=688>.
"Google Images." Google. N.p., n.d. Web. 28 Aug. 2011. <http://www.google.com/imgres?q=world+renewable+energy+potential&um=1&hl=en&sa=X&biw=1366&bih=688&tbs=isz:l&tbm=isch&tbnid=P_FTyMCBdgLbuM:&imgrefurl=http://bigthink.com/ideas/37727&docid=WMmwcuyBLLApiM&w=9500&h=3800&ei=5qVfTuDzC87xrQeE25yqDw&zoom=1>.
"Google Images." Google. N.p., n.d. Web. 29 Aug. 2011. <http://www.google.com/imgres?q=sunniest-places-in-the-world2.jpg&hl=en&sa=G&biw=1366&bih=688&gbv=2&tbm=isch&tbnid=UWtu82CYNAFqAM:&imgrefurl=http://pointfocus.com/images/charts/&docid=VUdDLb6CMWSYjM&w=1437&h=921&ei=mKZfTtjrMMimrAeq8t2gDw&zoom=1>.
"International Energy Outlook 2010 - Highlights." U.S. Energy Information Administration. N.p., n.d. Web. 28 Aug. 2011. <http://205.254.135.24/oiaf/ieo/highlights.html>.
"International Petroleum (Oil) Production ." U.S. Energy Information . N.p., n.d. Web. 31 Aug. 2011. <www.eia.gov/emeu/international/oilproduction.html>.
"OECD 50." OECD Country Websites. N.p., n.d. Web. 2 Sept. 2011. <www.oecd.org/countrieslist/0,3351,en_33873108_33844430_1_1_1_1_1,00.html>.
"Oil reserves - Wikipedia, the free encyclopedia." Wikipedia, the free encyclopedia. N.p., n.d. Web. 30 Aug. 2011. <http://en.wikipedia.org/wiki/Oil_reserves#OPEC_countries>.
Potter, Seth, and New York University. "SOLAR ENERGY." Formal Reasoning Group . N.p., n.d. Web. 2 Sept. 2011. <http://www-formal.stanford.edu/jmc/progress/solar.html>.
"Statistical Review of World Energy 2011 | BP." BP Global | BP. N.p., n.d. Web. 1 Sept. 2011. <http://www.bp.com/sectionbodycopy.do?categoryId=7500&contentId=7068481>.
"Renewable Solar." energy KIDS U.S. Energy Information. N.p., n.d. Web. 28 Aug. 2011. <http://205.254.135.24/kids/energy.cfm?page=solar_home-basics>.
"Renewable Solar." energy KIDS U.S. Energy Information. N.p., n.d. Web. 28 Aug. 2011. <http://205.254.135.24/kids/energy.cfm?page=solar_home-basics>
"Renewable Solar." energy KIDS U.S. Energy Information. N.p., n.d. Web. 28 Aug. 2011. <http://205.254.135.24/kids/energy.cfm?page=solar_home-basics>
"Statistical Review of World Energy 2011 | BP." BP Global | BP. N.p., n.d. Web. 1 Sept. 2011. <http://www.bp.com/sectionbodycopy.do?categoryId=7500&contentId=7068481>.
OECD: Organization for Economic Cooperation and Development (Australia, Austria, Belgium, Canada, Chile, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Japan, Korea, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Poland, Portugal, Slovak Republic, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom, United States)
"OECD 50." OECD Country Websites. N.p., n.d. Web. 2 Sept. 2011. <www.oecd.org/countrieslist/0,3351,en_33873108_33844430_1_1_1_1_1,00.html>.
"Energy Outlook 2030 | Statistical Review 2011 | BP." BP Global | BP. N.p., n.d. Web. 1 Sept. 2011. <http://www.bp.com/sectiongenericarticle800.do?categoryId=9037134&contentId=7068677>.