Characteristics of source of energy

Transcription

1 Energy Sources

2 Characteristics of source of energy Provide adequate amount of useful energy at a steady rate over a long period of time. It should be safe & convenient to use economical & easy to store and transport

3 Renewable vs Non-renewable sources of energy Non-conventional Obtained continuously over a long period of time Natural and will never get exhausted Sources can be regenerated Conventional Cannot be obtained continuously Natural but will get exhausted over time Cannot be regenerated Sun. wind, flowing water (hydro), bio mass, tides, oceans, geo thermal & nuclear fuel Coal, petroleum, natural gas

4 Renewable source - Sun Main source Nuclear fusion generates huge energy radiated continuously in all directions Solar constant average solar energy reaching the upper atmosphere per second on area 1 m 2 Contributes winds, storms, rains, photosynthesis Production Solar cell Solar power plant

5 Solar Energy production Solar cell Converts solar energy into electrical (d.c) energy Semiconductors silicon & gallium are used Conductivity of semiconductor increases with increase in impurity & temperature This creates a potential difference of approx. 0.5 volt Many cells together is a solar panel Electrical energy can be stored in battery Used to supply electricity, satellite, street lighting, calculator, watches etc. Advantages No maintenance, lasts long, low running cost, suitable for remote/inaccessible area, no pollution Disadvantage High initial cost, efficiency of conversion is very low, only d.c. electricity

6 Solar Energy production Solar power plant Large concave reflectors focuses concentrated heat Water placed at focus converts to steam Steam runs the turbine Turbine rotates the armature of the generator

7 Renewable source - Wind Large mass of moving air has kinetic energy Due to unequal heating of different areas of earth Rotation of earth Local convection current Uses: remove husk from grain, propelling sail boats, wind mills Wind drives the turbine of wind mill Turbine rotates the armature of generator to produce electricity Advantages No pollution Everlasting source Disadvantages Only near coastal areas (wind speed > 15 kmph) Large area of land needed Setting up wind farm is expensive

8 Renewable source Flowing water kinetic energy possessed by flowing water Used for rotating wheels of water mill to drive flour mill, transport heavy logs downstream Hydro electricity water flowing down dam drives turbine Turbine drives armature of generator that gives electricity Advantages No pollution Renewable source Dams irrigation & controls flood Disadvantages Flowing water unavailable everywhere Ecological imbalance

9 Renewable source Bio mass Bio mass (wastes, dead parts of plants, trees & animals) Contains carbon compounds in them Chemical energy contained is bio energy Used to produce bio gas 65% methane and 35% - CO 2, H & H 2 S Two types of gobar gas plant (mixture of animal dung and water) Floating gas holder type Fixed dome type Anaerobic respiration (decay) Uses: electricity, run engine, cooking

10 Renewable source - Tides High tide (rise of ocean) & low tide (fall of ocean) Tidal wave occurs twice a day energy possessed is tidal energy Harnessed by constructing a dam across a narrow opening to the sea Disadvantages Rise & fall of sea water is not enough to generate electricity Very few sites for building tidal dams

11 Renewable source - Ocean Ocean thermal Surface gets heated water deeper is cold Difference in temperature up to 20 o C Thermal energy available is ocean thermal energy Ocean thermal energy conversion power plant Oceanic waves energy Waves move at high speed due to wind KE possessed by fast moving waves is oceanic waves energy Only models are made to generate electricity

12 Renewable source Geo thermal Some places - rocks below are very hot Hot rocks convert water into steam runs turbine Holes are drilled to the hot spots and pipes are placed for steams to pass

13 Renewable source - Nuclear Uranium nucleus is bombarded with slow neutron Uranium-235 nucleus splits into light nuclei (fission) Emits neutron + releases large amount of energy Chain reaction Cadmium rods controls by absorbing neutrons Heat energy released is absorbed by coolant and exchanged with water in heat exchanger Water in heat exchanger becomes steam and turns the turbine Turbine rotates the armature of generator and gives electricity Advantages Small amount of uranium > large energy, energy released for long period Disadvantages Harmful radiations, nuclear waste high degree of pollution

14 Judicious use of energy Limit fossil fuel use alternative Avoid wastage of energy Ban cutting trees & plant more trees Use energy in community (in groups) Use renewable energy in rural areas Use renewable energy Obtain nuclear energy from deuterium nuclei (sea water)

15 Energy degradation Gradual decrease of useful energy radiation loss, friction etc., Less than 25% of electrical energy is converted into light energy Fuel in vehicle major energy is wasted in heating, moving parts, working against friction While cooking heat radiated (sideways) Transmission of electricity energy is lost in the form of heat (in the lines/cables) Machines have efficiency of less than 1. fraction of input energy is used for useful work the balance is degraded Electrical appliances heat energy is wasted energy

16 Energy degradation