Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
RENEWABLE ENERGY SOURCES SOLAR ENERGY Readily available and cheapest Non polluting Finding appropriate means for efficient utilisation of solar energy will reduce the use of non renewable energy source which will make the environment cleaner Output of sun–2.8x1023 kW Energy reaching the earth-1.5x1018KWh/year Insolation-The amount of incident solar power on a unit surface (KW/m2) Solar constant-1.37kW/m2 50% solar energy is in the form of thermal energy SOLAR ENERGY UTILISATION Direct solar power It involves only one step transformation into usable form eg: Sunlight hits photovoltaic cell generating electricity Sunlight directly converted into heat energy Indirect solar power It involves more than one transformation to reach a usable form Eg: vegetation uses photosynthesis to convert solar energy to chemical energy, which can later be burnt as fuel to generate electricity ADVANTAGES Pollution free, sustainable energy source Facilities can operate with little maintenance after initial setup Becoming economical Solar power can be viewed as a local resource because of regional climatic variance DISADVANTAGE Practical in areas of favourable climate Not available at night, reduced during cloud cover It must be converted into some other forms of energy to be stored Produces DC which must be converted into AC power WIND ENERGY Wind is a by-product of solar energy (2% of sun’s energy reaching earth) During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and rises, and the heavier, cooler air rushes into take its place, creating winds. Wind is used to turn the turbines Wind turbines classified into two types: (a)horizontal axis and (b) vertical axis WIND POWER ADVANTAGES It is a renewable energy, cleanest energy Wider adoption can reduce the dependence on fossil fuel Less air and water pollution as it does not release toxic gases or destroy environment Initial cost: cost of production is coming down steadily Creates more job: job opportunities of installation and maintenance DISADVANTAGES Higher initial investment Good wind sites are often located in remote areas Wind resource development may not be the most profitable use of the land Turbines may cause noise and sound pollution The turbine blades may damage local wild life HYDROELECTRIC POWER Generated by the flow of water through turbine Generator shaft turns, which generates electricity Components of hydel power 1. Dam/reservoir/large buffer tank 2. Penstock 3. Power house: Turbines, generators and step-up transformers Hydel power plants: large, small, Mini, Micro etc TIDAL POWER Tidal energy is the energy due to the water waves created in the ocean. Tidal energy is also called hydropower –Mainly due to rising and falling of waves The raising and falling waves are used to rotate the turbines Rising and falling is due to gravitational forces of sun and moon, and also due to rotation of earth ADVANTAGES Renewable energy, cleanest source Not expensive to operate and maintain compared to other Low noise pollution as any sound generated is transmitted through water High predictability as high tide and low tide can be predicted in advance Low visual impact as the tidal turbines are submerged beneath the water DISADVANTAGES Not always a constant source of energy as it depends on the strength and flow of tides Requires suitable site, where tides are strong Must be able to withstand forces of nature resulting in high capital, construction and maintenance costs May damage the fish and marine ecosystem Intermittent power generation GEOTHERMAL ENERGY Steam and hot water produced inside the earth is used to heat buildings or generate electricity Below the crust of the earth, the top layer of the mantle is a hot liquid rock called magma. Crust of earth floats on this liquid magma mantle. Water close to the hot rock (>10,000 feet from ground) can reach temperatures of more than 148°C. STRUCTURE OF EARTH TEMPERATURE VARIATION GEOTHERMAL POWER PLANTS GEOTHERMAL ENERGY ADVANTAGES renewable source of energy Non polluting and environmental friendly No waste generation or by-product Geothermal energy can be used directly Maintenance cost is comparatively low Geothermal power plants don’t occupy too much space and thus help in protecting natural environment Unlike solar energy, it is not dependent on weather conditions DISADVANTAGES Most geothermal sites are in remote areas Total generation potential is low There is always a danger of volcano Installation cost of steam power plant is very high There is no guarantee that the amount of energy which is produced will justify the capital expenditure and operation cost It may release some harmful, poisonous gases that can escape through holes drilled during construction