Non Conventional (Alternative) Energy Source-2

Non Conventional (Alternative) Energy Source

1) Shale gas

Shale refers to the soft finely stratified sedimentary rock that is formed from the compaction of small old rocks containing mud and minerals -such as quartz and calcite, trapped beneath earth's surface. These rocks contains fossil fuels like oil and gas in their pores. The fuel is extracted by a technique called hydraulic fracturing (drilling or well boring of sedimentary rocks layers to reach productive reservoir layers)

Environmental concerns of shale gas:

• i) Shale drilling could affect groundwater reserves, which can contaminate the drinking water resources and also affect the fertility of the soil.
• ii) Million gallons of water is needed to break and release the shale gas, which inturn can affect the water table.

2)Wind energy

The kinetic energy possessed by the wind is due to its high speed, that can be converted in to mechanical power by wind turbines.

The Wind energy can be used for:

• i) Generating electricity.
• ii) Run water pumps, flour mills etc.,
• iii) Rotatory motion of windmills is used to draw water from wells

Points to Know

• The world's largest and tallest wind turbine is situated in Hawaii.
• One wind turbine can produce electricity for 300 homes

3) Wind Mill :

Windmill is a machine that converts the enegy of wind into rotational energy by broad blade attached to the rotating axis. When the blowing air strikes the blades of the windmill, it exerts force and causes the blades of the windmill, it exerts force and causes the blades to rotate. The rotational movement of blades operate the generator and electricity is produced. The energy output from each windmill is coupled together to get electricity on a commericial scale.

• Advantages of Wind energy :
• Wind energy is free, eco-friendly, renewable source of energy
• It does not cause pollution
• Expenses on periodic maintenance is low when compared to the other power sources.

4) Water Energy :

Earth's surface is covered wtih nealry 71% of water. Harnessing the energy from the flowing water can be used to produce electricity. The technique to harness the water energy is called Hydropower.

5)Tidal Energy :

Tidal energy is the energy obtained from the movement of water due to ocean tides. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted on the oceans of the earth.

• A tidal stream is a fast flowing body of water created by tides.
• Turbines are placed in tidal streams.
• When the tides hit the turbine,the turbine rotates and converts tidal energy into electric energy.

Advantages of tidal energy

• Tidal energy does not produce any pollution.
• It does not use any fuel and does not produce any waste.
• Tides are predictable, so tidal energy can be produced at any time.
• Water is denser thatn air and therefore can generate electricity at lower speeds than wind turbines.

6) Rainwater Harvesting :

• Rain water hasrvesting is technique of collecting and storing rainwater for future use.
• It is a traditona method of storing rain water in undergournd tanks, ponds, lakes, check dams and used in future
• The main purpose of rainwter harvesting is to make the rainwater percolate under the ground so as to recharge groundwater level

• Methods of rainwater harvesting
• 1)Roof top rainwater harvesting :
• Roof tops are execellent rain catchers. The rain water that falls on the roof of the houses, apartments, commercial buildings etc., is collected and stored in the surface tank and can be used for domestic purpose
• 2)Recharge pit:
• In this method, the rainwater is first collected from the roof tops or open spaces and is directed into the percolation pits through pipes for filtration. After filtration the rainwater enters the recharge pits or ground wells

• i) Digging of tanks or lakes (Eris) : It is one of the traditional water hasrvesting system in Tamil Naudu.
• Eris are constructed in such a way that if the water in one eri overflows, it automatically get diverted to the eri of the next village, as these eris are interconnected
• ii) Ooranis: These are small ponds to collect rainwater. The water is used for various domestic purpose (drinking, washing and bathing). These ponds cater the nearyby villages.

• Advantages of rainwater harvesting
• 1) Overcome the rapid depletion of ground water level.
• 2) To Meet the increase demand of water
• 3) Reduces flood and soil erosion
• 4) Water sotred in ground is not contaminated by human and animal wastes and hence can be used for drinking purpose