green environment


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green environment

  1. 1. Green Environment INTRODUCTION Environmental technology (envirotech), green technology (Genentech) or clean technology (cleantech) is the application of one or more of environmental, green chemistry, environmental monitoring and electronic devices to monitor, model and conserve the natural environment and resources, and to curb the negative impacts of human involvement. The term is also used to describe sustainable energy generation technologies such as photovoltaics, wind turbines, bioreactors, etc. Sustainable development is the core of environmental technologies. The term environmental technologies is also used to describe a class of electronic devices that can promote sustainable management of resources. Of the 52 percent of the country’s population that lives in rural areas, 22 percent reside in or near forests. A majority of these people rely on forest resources for their livelihood, making sustainable land and forest management a critically important challenge for the Philippines. This section presents the major trends in land and forest resources management in the country over the past five to ten years. While there has been some increase in forest cover owing to reforestation efforts and natural regeneration, per capita forest cover in the Philippines is still the lowest in Asia. Moreover, the remaining primary or intact forests remain under threat.  The term is also used to describe sustainable energy generation technologies such as photovoltaic’s, wind turbines, bioreactors, etc. Sustainable development is the core of environmental technologies.  Green Energy – “any sustainable energy source that comes from natural environment.”  Some Aspects of Renewable Energy  It exists perpetually and in abundant in the environment  It is a clean alternative to fossil fuels  “energy that is derived from natural process that are replenished constantly”. Dept Of Electrical Engineering 1
  2. 2. Green Environment Contribution of Renewable Energy in World Electricity Production:- Fig-1 Contribution of Renewable Energy in World Electricity Production. Major Renewable Energy Sources:-  Solar Energy  Wind Energy  Hydro Energy  Biomass Energy  Tidal Energy  Geothermal Energy  Wave Energy  Bio-fuel  Biogas Fig-2 Major Renewable Energy Sources. Dept Of Electrical Engineering 2
  3. 3. Green Environment PRESENT INSTALLED CAPACITY OF RENEWABLE ENERGY SOURCES IN INDIA:- The installed capacity in respect of RES is as on 30.06.2012 is based on MNRE email of dated 12.07.2012 from the Ministry of Renewable Energy where cumulative Grid interactive power installed capacity has been indicated as 25409.33 MW. Reconciliation of installed capacity of Hydro capacity resulted in transfer of 135 MW from conventional to SHP-RES and retrieval of installed capacity of 67.20 from SHP-RES to conventional Hydro has resulted in net addition of 67.8 MW to SHP under RES. Also 30 MW of capacity in the nature of Waste Heat Recovery Power Plant at Goa Energy Private Limited under U&I category of RES. Out of this installed capacity due to wind and small hydro amounting to 508.67 MW appearing in captive capacity has been deducted to arrive at installed capacity of utilities in respect of RES.(25409.33- 508.67+67.8+30=24998.46). Sector MW %age State Sector 86,881.13 41.51 Central Sector 62,373.63 29.66 Private Sector 60,321.28 28.82 Total 2,09,276.04 Fuel MW %age Total Thermal 140206.18 66.99 Coal 120,103.38 57.38 Gas 18,903.05 9.03 Oil 1,199.75 0.57 Hydro (Renewable) 39,291.40 18.77 Nuclear 4,780.00 2.28 RES** (MNRE) 24,998.46 11.94 Total 2,09,276.04 100.00 Table-1 Total Installed Capacity in India Dept Of Electrical Engineering 3
  4. 4. Green Environment Renewable Energy Source Present Installed Capacity Wind 10200 MW Small Hydro 2100 MW Bagasse 750 MW Biomass 620 MW Solar 2 MW Total RE Installed Capacity – 13672 MW Table-2 Total Installed Capacity of Renewable Energy in India SOLAR ENERGY:- Solar power is by far the Earth's most available energy source, easily capable of providing many times the total current energy demand. Solar power is the conversion of sunlight into electricity. Two main commercial ways of conversion of sunlight into electricity.  Concentrating Solar Thermal Plant (CSP)  Photovoltaic Plants (PV) CSP and PV both have their markets. PV is very successful in decentralized applications, whereas CSP offers advantages for central and large-scale applications. CSP power plants are the most cost-efficient way to generate and to store dispatch able CO2 -free electricity. However, there is no competition between both. Rather, they have to be seen as complementary technologies. PLF of CSP – In the range of 20 % to 30 % PLF of PV – In the range of 15 % to 20 % Photovoltaic systems (PV system) use solar panels to convert sunlight into electricity. A system is made up of one or more solar photovoltaic (PV) panels, an AC/DC power converter (also known as an inverter), a racking system that holds the solar panels, and the interconnections and mounting for the other components. A small PV system may provide energy to a single consumer, or to an isolated device like a lamp or a weather instrument. Large grid-connected PV systems can provide the energy needed by many customers. Solar cells can be electrically connected in series or in parallel to give any Dept Of Electrical Engineering 4
  5. 5. Green Environment desired voltage and current output. Photovoltaic cells are typically sold in modules (or panels) of 12 volts with power outputs of 50 to 100+ watts. These are then combined into arrays to give the desired power or watts. Fig-3 PV Cells FUNCTIONING OF PV CELLS:- PV functionality relies upon the absorption of light within a bulk or semiconductor material, most commonly a silicon pn diode, providing a medium in which incident photons can be converted to energy, usually in the form of heat. When absorbed, a photon transfers energy to an electron in the absorbing material and if the magnitude of incident photon energy is greater than the electron’s work function, the photon may raise an electron’s energy state or even liberate an electron. Once liberated, the electrons are then free to move around the semiconductor material influenced by present phenomena of diffusion, temperature, and electric field. The quantum theory of semiconductor devices states that all semiconductors have a gap between their valence and conduction bands. The valence band represents all allowable energies of valence electrons that are bound covalently to neighboring host atoms, and the conductive band represents all allowable energies of electrons which have received some form of energy and are no longer bound to host atoms. Semiconductors, characterized as being perfect insulators at absolute zero, become increasingly conductive as temperature is increased. As temperature becomes greater, sufficient energy is transferred to a small fraction of electrons, causing them to move from the valence band to the conduction band and holes to move from the Dept Of Electrical Engineering 5
  6. 6. Green Environment conduction band to the valence band. The increase in temperature responsible for this entire process is a direct result of external energy; in the case of PV systems, it is incident photons due to illumination. Under the photoelectric effect, because photons incident upon a pn diode can create electron-hole pairs at a cross material junction, an electric potential difference across this junction can be established. Under no illumination, electrons and holes are separated at n and p regions respectively due to the diode characteristic unidirectional current path. When illuminated, PV cells are impacted by incident photons which bombard cell electrons creating electron hole pairs. These electron hole pairs then separate in response to the electric field created by the cell junction, causing electrons to drift back into the n region, and holes into the p region. A bidirectional current path is created and energy can be harnessed. With basic PV function understood, a solar cell can now be designed. Fig-3 Function of PV Cell WIND ENERGY:- Wind power is the conversion of wind energy into a useful form of energy, such as using: wind turbines to make electrical power, windmills for mechanical power, wind Dept Of Electrical Engineering 6
  7. 7. Green Environment pumps for water pumping or drainage, or sails to propel ships. A large wind farm may consist of several hundred individual wind turbines which are connected to the electric power transmission network. Offshore wind farms can harness more frequent and powerful winds than are available to land-based installations and have less visual impact on the landscape but construction costs are considerably higher. Small onshore wind facilities are used to provide electricity to isolated locations and utility companies increasingly buy surplus electricity produced by small domestic wind turbines Wind power, as an alternative to fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation and uses little land. Any effects on the environment are generally less problematic than those from other power sources. As of 2011, Denmark is generating more than a quarter of its electricity, and 83 countries around the world are using wind power on a commercial basis. In 2010 wind energy production was over 2.5% of total worldwide electricity usage, and growing rapidly at more than 25% per annum. The monetary cost per unit of energy produced is similar to the cost for new coal and natural gas installations. Although wind power is a popular form of energy generation, the construction of wind farms is not universally welcomed due to aesthetics. Wind power is very consistent from year to year but has significant variation over shorter time scales. The intermittency of wind seldom creates problems when used to supply up to 20% of total electricity demand, but as the proportion increases, a need to upgrade the grid, and a lowered ability to supplant conventional production can occur. Power management techniques such as having excess capacity storage, dispatch able backing supplies (usually natural gas), storage such as pumped- storage hydroelectricity, exporting and importing power to neighbouring areas or reducing demand when wind production is low, can greatly mitigate these problems.  Differential heating of the earth’s surface and atmosphere induces vertical and horizontal air currents that are affected by the earth’s rotation and contours of the land and generates WIND. A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades. The amount of energy which the wind transfers to the rotor depends on the density of the air, the rotor area, and the wind speed. PLF of Wind Farm is normally in the range of 20 % to 30% depending upon the site conditions and WTG rating. Dept Of Electrical Engineering 7
  8. 8. Green Environment Fig-4 Wind Turbine. Hydro Energy :- Hydro power plants are based on a rather simple concept Hydro power plants harnes water's energy and use simple mechanics to convert that energy into electricity. Water flowing through a dam turns a turbine which turns a generator. Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity consumption, and 3,427 terawatt-hours of electricity production in 2010, which continues the rapid rate of increase experienced between 2003 and 2009. Hydropower is produced in 150 countries, with the Asia-Pacific region generating 32 percent of global hydropower in 2010. China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use. There are now three hydroelectricity plants larger than 10 GW: the Three Gorges Dam in China, Itaipu Dam in Brazil, and Guri Dam in Venezuela. The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour.[1] Hydro is also a flexible source of electricity since plants can be ramped up and down very quickly to adapt to changing energy demands. However, damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and Dept Of Electrical Engineering 8
  9. 9. Green Environment wildlife.[1] Once a hydroelectric complex is constructed, the project produces no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants.  Dam - Most hydropower plants rely on a dam that holds back water, creating a large reservoir. Often, this reservoir is used as a recreational lake  Intake - Gates on the dam open and gravity pulls the water through the penstock, a pipeline that leads to the turbine. Water builds up pressure as it flows through this pipe  Turbine - The water strikes and turns the large blades of a turbine, which is attached to a generator above it by way of a shaft. The most common type of turbine for hydropower plants is the Francis Turbine, which looks like a big disc with curved blades. A turbine can weigh as much as 172 tons and turn at a rate of 90 revolutions per minute (rpm)  Generators - As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate past copper coils, producing alternating current (AC) by moving electrons.  Transformer - The transformer inside the powerhouse takes the AC and converts it to higher-voltage current  Power lines - Out of every power plant come four wires: the three phases of power being produced simultaneously plus a neutral or ground common to all three  Outflow - Used water is carried through pipelines, called tailraces, and re-enters the river downstream Dept Of Electrical Engineering 9
  10. 10. Green Environment Fig-5 Hydro Energy BIOMASS ENERGY:- Biomass is a renewable energy source that is derived from living or recently living organisms. Biomass includes biological material, not organic material like coal. Energy derived from biomass is mostly used to generate electricity or to produce heat. Thermal energy is extracted by means of combustion, torrefaction, pyrolysis, and gasification. Biomass can be chemically and biochemically treated to convert it to a energy-rich fuel. Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel. In the first sense, biomass is plant matter used to generate electricity with steam turbines & gasifiers or produce heat, usually by direct combustion. Examples include forest residues (such as dead trees, branches and tree stumps), yard clippings, wood chips and even municipal solid waste. In the second sense, biomass includes plant or animal matter that can be converted into fibers or other industrial chemicals, including biofuels. Industrial biomass can be grown from numerous types of plants, including miscanthus, switchgrass, hemp, corn, poplar, willow, sorghum, sugarcane, bam boo, and a variety of tree species, ranging from eucalyptus to oil palm (palm oil). Dept Of Electrical Engineering 10
  11. 11. Green Environment Fig-6 Sources of Biomass BIOGAS ENERGY:- Biogas is clean environment friendly fuel that can be obtained by anaerobic digestion of animal residues and domestic and farm wastes, abundantly available in the countryside. Biogas is an important renewable energy resource for rural areas in India Biogas generally comprise of 55-65 % methane, 35-45 % carbon dioxide, 0.5-1.0 % hydrogen sulfide and traces of water vapor. Average calorific value of biogas is 20 MJ/m3 (4713 kcal/m3 ). Biogas like Liquefied Petroleum Gas (LPG) cannot be liquefied under normal temperature and pressure. Critical temperature required for liquefaction of methane is -82.1o C at 4.71MPa pressure, therefore use of biogas is limited nearby the biogas plant. An estimate indicates that India has a potential of generating 6.38 X 1010 m3 of biogas from 980 million tones of cattle dung produced annually. The heat value of this gas amounts to 1.3 X 1012 MJ. In addition, 350 million tones of manure would also produce along with biogas. Dept Of Electrical Engineering 11
  12. 12. Green Environment Table-3 Biogas Production From Different Material CONCLUSION:- Environmental Technology (envirotech), green technology (greentech) or clean technology (cleantech) is the application of one or more of environmental science, green chemistry, environmental monitorin and electronic devices to monitor, model and conserve the natural environment and resources, and to curb the negative impacts of human involvement. The term is also used to describe sustainable energy generation technologies such as photovoltaics, wind turbines, bioreactors, etc. Sustainable development is the core of environmental technologies. The term environmental technologies is also used to describe a class of electronic devices that can promote sustainable management of resources. Dept Of Electrical Engineering 12
  13. 13. Green Environment REFERENCES:  Environmental and Renewable Energy Innovation Potential among the States: State Rankings. Applied Research Project. Texas State University.  Hermann Scheer “Energy Autonomy: The Economic, Social & Technological Case for Renewable Energy”  Mark Diesendorf “Greenhouse Solutions with Sustainable Energy”. Dept Of Electrical Engineering 13