“It is defined as ability or capacity to do work”We use energy to do work and make all movements. Energy lights our cities,powers our vehicles, and runs machinery in factories. It warms and cools ourhomes, cooks our food, plays our music, and gives us pictures on television.
1. Renewable energy-Energy that comes from naturally sources such as Sun , wind etc. which is inexhaustible or naturally replenished2. Non renewable energy-Energy sources that can’t be reproduced ,generated or replenished. Once depleted there is no more for future use.
• Wood –Generally used in rural area• Coal- widely used as energy source• Petroleum-used in auto mobiles• Oil and Natural gas-used in lpg cylinder Most of them are non renewable.
• Non sustainable• Environmental impact• Extraction of coal, oil and gas is dangerous and increasingly expensive.
Energy conservation refers to efforts made to reduce energy consumption. Energy conservation can be achieved through increased efficient energy use, in conjunction with decreased energy consumption or reduced consumption from conventional energy sources. Energy conservation act was passed in 2001 in India. Bureau of energy efficiency (BEE)-Govt. body regulating energy efficiency. BEE ratings for electrical appliances to indicate energy efficiency and conservation. Trivial things like switching off the electrical appliances also help in conserving energy.
• Produced by fission or fusion of atoms.• Fission- When the nucleus splits nuclear energy is release in the form of heat.• Fusion- Energy is also release when atoms combine at high speed.• Power is generated in nuclear reactor by fission.
• Lower carbon dioxide (and other greenhouse gases) released into the atmosphere in power generation.• Low operating costs (relatively).• Large power-generating capacity able to meet industrial and city needs.
• Non renewable energy.• Expensive to mine, refine and transport.• High construction costs due to complex radiation containment systems and procedures.• Waste (including greenhouse gasses) are generated during extraction and generation.• Radiation risk are high.• Waste lasts 200 – 500 thousand years.• Risk of terrorism.
o Solar energy is the energy derived from the sun through the form of solar radiation.o Solar energy is the energy force that sustains life on the earth for all plants, animals, and people. The earth receives this radiant energy from the sun in the form of electromagnetic waves, which the sun continually emits into space.o This solar energy can be tapped directly as concentrating solar power(CSP) (solar thermal energy)and photovoltaic(PV) cells.
o Solar Cell: The PV cell is the component responsible for converting light to electricity. Some materials (e.g., silicon is the most common) produce a photovoltaic effect, where sunlight frees electrons striking the silicon material. The freed electrons cannot return to the positively charged sites (‘holes’) withou flowing through an external circuit, thus generating current.o Solar cells are designed to absorb as much light as possible and are interconnected in series and parallel electrical connections to produce desired voltages and currents.o PV is best suited for remote site applications that have small to moderate powe requirements, or small power consuming applications even where the grid is in existence.
• Solar cells are long lasting sources of energy which can be used almost anywhere.• Solar cells are totally silent and non-polluting.• Solar cells provide cost effective solutions to energy issues in places where there is no mains electricity.• As they have no moving parts, they require little or no maintenance at all, and have a long lifetime.• Solar cells can easily be installed on roofs, which means no new space is needed and each user can quietly generate their own energy.
• The initial cost is quite high.• Most types of solar cells require large areas of land to achieve average efficiency.• Air pollution and weather can also have a large effect on the efficiency of the cells.• The silicon used in cells is also very expensive.
Hydropower is power that is derived from the force or energy ofmoving water, which may be harnessed for useful purposes. Prior tothe development of electric power, hydropower was usedfor irrigation, and operation of various machines, such aswatermills, textile machines, sawmills, dock cranes, anddomestic lifts.
Hydropower available = ρQHWhere ρ-density of water, g-acceleration due to gravity,Q-discharge of water, H-head
• Hydropower is clean. It does not emit any of the waste gases that contribute to air pollution, acid rain, and global warming.• No fuel is required.• Hydropower is reliable. As long as there is water, there will be an energy source.• Hydropower is extremely efficient.
o Hydropower dams disrupt the natural flow of rivers.o A large area for reservoir construction.o Building a dam on a river has major implications for the biota found in the river system.o If dam breaks it would be a disaster causing heavy floods affecting nearby habitat.
• During high tide, water flows from sea to bay.• Turbine produces power.• During low tide, water flows from bay to sea.• Another set of turbine produces power.• Common turbines can also be used.•Power generated similar to hydropower.
o Utilization of organic waste to produce energyo Chemical energy stored in plants and animals or in the animal waste is called bio-energyo Burning of the biomass will release the energy in the form of heato Can also be converted into other energy source such as bio-fuel
o Theoretically inexhaustible fuel source.o The use of waste materials reduce landfill disposal and makes more space for everything else.
o On the contrary, biomass crops are seen as occupying agricultural land.o Could contribute to global warming and particulate pollution if directly burned
The energy is derived from biological carbon fixation, Biofuels include a wide range of fuels which are derived from biomass.There are two types of bio-fuel- (i)First generation bio-fuels a. Bio-alcohols(fermentation of sugar) b. Bio-diesel (transesterification of oils or fats) c. Green diesel (fractional distillation of oil) d. Bio-ethers(dehydration of alcohol made from organic material) e. Bio-gas(anaerobic digestion of organic material)
(ii) Second generation bio-fuel Many second generation biofuels are under development suchas Cellulosic ethanol, Algae fuel.Gaseous biofuels include biogas, landfill gas and synthetic gas.
It is eco friendly. The biofuels are much safer to handle and the health effects are also much lesser as compared to fossil fuels. The biofuels can help to reduce the global warming
Biofuels have a lower energy output than traditional fuels and therefore require greater quantities to be consumed in order to produce the same energy level Lots of cost required to produce biofuels on technological processes. There might be bad smell which is the outcome of the biofuel production cycle.
Natural heat extracted from the earths crust. For electricity, steam is formed using the heat which rotates the turbine fitted to generator and at last, electricity is generated.
Geothermal energy generally involves low running costs since it saves 80% costs over fossil fuels and no fuel is used to generate the power Being the renewable source of energy , geothermal energy has helped in reducing global warming and pollution. Geothermal systems does not create much pollution as it releases some gases from deep within the earth which are not very harmful to the environment.
To get geothermal energy, requires installation of power plants, to get steam from deep within the earth and this require huge one time investment. electricity towers, stations need to set up to move the power from geothermal plant to consumer. It is only suitable for regions where temperature below the earth are quite high and can produce steam over a long period of time.
Bagasse is the fibrous matter that remains after sugarcane or sorghum stalks arecrushed to extract their juice
• It is currently used as a biofuel and in the manufacture of pulp and paper products• It can also be used for making boards resembles like Plywood or Particle board• Low cost Dusts from the processing of bagasse can cause the chronic lung condition pulmonary fibrosis
• Biofuels ,bagasse, biomass, geothermal etc. are low power yielding sources.• Hydro power is the cheapest compared to all other energy sources
• To make sure we have plenty of energy in the future, its up to all of us to use energy wisely.• We must all conserve energy and use it efficiently. Its also up to those who will create the new energy technologies in the future.