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What is renewable energy


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I st year seminar - applied phy

I st year seminar - applied phy

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  • 1. sWhat is renewable energy ?<br />Main Sources of renewable energy…<br />Renewable energy <br />Wind power<br />Water power<br />Solar power <br />Biomass <br />Geothermal power<br />1 Wind power<br />Blowing wind spins the blades on a wind turbine -- just like a large toy pinwheel. This device is called a wind turbine and not a windmill. A windmill grinds or mills grain, or is used to pump water. <br />The blades of the turbine are attached to a hub that is mounted on a turning shaft. The shaft goes through a gear transmission box where the turning speed is increased. The transmission is attached to a high speed shaft which turns a generator that makes electricity <br /> <br />Wind power is a renewable energy source used to generate electricity by converting wind energy into useful mechanical energy. This mechanical energy is then converted into electricity by the use of an electric generator located within each individual wind machine. <br />Rated power output: 1.5 MW - 3 MW <br />Locations preferred for wind farms: <br /> Areas where winds are stronger and more constant, such as offshore and high altitude sites,are preferred locations for wind farms. <br />Contribution in global energy: Currently provides less than 0.5% of global energy <br />Annual growth rate of energy: near 30% <br />Long-term technical potential of wind energy: <br /> It is believed to be five times total current global energy production, or 40 times current electricity demand. <br />Wind power is renewable and produces no greenhouse gases during operation, such as carbon dioxide and methane. <br />2 Water power<br /> Energy of water (in the form of motive energy or temperature differences) is called as water power and it can be harnessed and used. Since water is about 800 times denser than air,even a slow flowing stream of water, can yield considerable amounts of energy <br />Water power <br />Wave power <br />Hydroelectric energy <br />OTEC <br />Tidal power <br /> Hydroelectric energy is the electricity produced by the conversion of kinetic energy from falling water using a generator. <br />The water behind the dam flows through the intake and into a pipe called a penstock. The water pushes against blades in a turbine, causing them to turn. But instead of using steam to turn the turbine, water is used. <br />The turbine spins a generator to produce electricity. The electricity can then travel over long distance electric lines to your home, to your school, to factories and businesses <br />Wave power The concept of capturing and converting the energy available in the motion of ocean waves to energy <br /> Tidal power is the Power obtained by catching the energy of moving water masses due to tides. <br /> Tidal movement is caused by the gravitational pull of the moon on the earth. As the moon orbits the earth, water is dragged around the globe. <br />Ocean thermal energy conversion (OTEC) is electricity generation by making use of the temperature difference between the top and bottom layers of the ocean to convert a fluid to vapour, which in turn powers a turbine generator. OTEC has not been field-tested on a large scale. <br />3 Solar energy <br />Indirectly, the sun or other stars are responsible for ALL our energy. Even nuclear energy comes from a star because the uranium atoms used in nuclear energy were created in the fury of a nova - a star exploding. <br />What is solar energy ?<br />"solar energy" refers to energy that is collected from sunlight. <br />Solar energy <br />solar cells <br />Solar updraft tower <br />solar-thermal panels <br />solar power satellites <br />solar chimneys <br />solar ovens <br />Generate electricity using photovoltaic solar cells <br />We can also change the sunlight directly to electricity using solar cells. <br />Solar cells are also called photovoltaic cells - or PV cells for short - and can be found on many small appliances, like calculators, and even on spacecraft. They were first developed in the 1950s for use on U.S. space satellites. They are made of silicon, a special type of melted sand. When sunlight strikes the solar cell, electrons (red circles) are knocked loose. They move toward the treated front surface (dark blue color). An electron imbalance is created between the front and back. When the two surfaces are joined by a connector, like a wire, a current of electricity occurs between the negative and positive sides. <br />Generate electricity by heating trapped air which rotates turbines in a Solar updraft tower <br />Heat foodstuffs, through solar ovens. <br />Box type, parabolic type, panel type<br />Heat water or air for domestic hot water and space heating needs using solar-thermal panels. <br />Generate electricity in geo-synchronous orbit using solar power satellites. <br />Heat and cool air through use of solar chimneys. <br />“The first of a multi-post series on building a Green House with a Solar Chimney to act as a passive air-loop ventilation system. “ <br />4 Bio-mass<br />Simply defined, biomass is all plant material, or vegetation, either raw or processed, wild or cultivated. <br />Bio-mass <br />Liquid bio-fuel <br />Solid bio-mass <br />Biogas <br />Types of biomass : wood , crops, Garbage, landfill gases ,Alcohol fuels<br />What is bio-mass or bio-matter ?<br />Plants use photosynthesis to grow and produce biomass. Also known as biomatter, biomass can be used directly as fuel or to produce liquid biofuel. Agriculturally produced biomass fuels, such as biodiesel, ethanol and bagasse (often a by-product of sugar cane) can be burned in internal combustion engines or boilers. Typically biofuel is burned to release its stored chemical energy. <br /> Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work. <br />Liquid biofuel<br /> Liquid biofuel is usually either a bioalcohol such as ethanol or a bio-oil such as biodiesel and straight vegetable oil. <br /> Biodiesel can be used in modern diesel vehicles with little or no modification to the engine and can be made from waste and virgin vegetable and animal oil and fats (lipids). <br /> Virgin vegetable oils can be used in modified diesel engines. <br /> The use of biodiesel reduces emission of carbon monoxide and other hydrocarbons by 20 to 40%. <br /> In some areas corn, cornstalks, sugarbeets, sugar cane, and switchgrasses are grown specifically to produce ethanol (also known as grain alcohol) a liquid which can be used in internal combustion engines and fuel cells. <br /> Ethanol is being phased into the current energy infrastructure. <br /> E85 is a fuel composed of 85% ethanol and 15% gasoline that is sold to consumers. <br /> Biobutanol is being developed as an alternative to bioethanol. <br />Solid biomass <br /> Sugarcane residue, wheat chaff, corn cobs and other plant matter can be, and are, burned quite successfully. The net carbon dioxide emissions that are added to the atmosphere by this process are only from the fossil fuel that is often currently consumed to plant, fertilize, harvest and transport the biomass. <br />Solid biomass can also be gasified, and used as biogas. <br />Bio-gas<br /> Biogas can easily be produced from current waste streams, such as: paper production, sugar production, sewage, animal waste and so forth. These various waste streams have to be slurried together and allowed to naturally ferment, producing methane gas. This can be done by converting current sewage plants into biogas plants. When a biogas plant has extracted all the methane it can, the remains are sometimes better suitable as fertilizer than the original biomass. <br />5 Geothermal energy <br />Geothermal Energy has been around for as long as the Earth has existed. "Geo" means earth, and "thermal" means heat. So, geothermal means earth-heat <br />For every 100 meters you go below ground, the temperature of the rock increases about 3 degrees Celsius. Or for every 328 feet below ground, the temperature increases 5.4 degrees Fahrenheit. So, if you went about 10,000 feet below ground, the temperature of the rock would be hot enough to boil water. <br />Geothermal Energy has been around for as long as the Earth has existed. "Geo" means earth, and "thermal" means heat. So, geothermal means earth-heat <br />For every 100 meters you go below ground, the temperature of the rock increases about 3 degrees Celsius. Or for every 328 feet below ground, the temperature increases 5.4 degrees Fahrenheit. So, if you went about 10,000 feet below ground, the temperature of the rock would be hot enough to boil water. <br />The future is ours, but we need energy to get there .<br />To make sure we have plenty of energy in the future, it's up to all of us to use energy wisely. <br />We must all conserve energy and use it efficiently. It's also up to those who will create the new energy technologies of the future. <br />