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     Gobar times: Environment for Beginners

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C O V E R  S T O R Y

ALTERNATIVE ENERGY

Green Energy

WIND POWER

Wind power harnesses the energy of the wind to propel the blades of wind turbines. These turbines cause the rotation of magnets, which creates electricity. Wind towers are usually built together on wind farms.

In India
India ranks fourth amongst the wind-energy-producing countries of the world, after Germany, Spain and USA. The country’s estimated potential is around 45000 MW at 50m above ground level. By 2012, the country aims to produce 5000 MW of it. Wind-farms have been installed in more than nine states. Also, wind-solar and wind-diesel hybrid systems have been installed at a few places.

Verdict: Wind power is a renewable energy source, which has no waste by-products, and causes no pollution. But it is quite ‘unpredictable’. When wind speed is low, less electricity is generated.


SOLAR POWER

It involves using sunrays to:
Convert sunlight into electricity, using solar cells
  • Heat water or air, using solar thermal panels
  • Heat water and produce steam, using parabolic mirror
  • For passive solar heating of a building from the sunlight entering windows.
In India

India gets over 5,000 trillion kWh of solar energy per year. And the daily average over different parts of India is about 4-7 kWh per square metre, depending on the location. While, the largest solar photovoltaic (PV) plant in India has 200kwp capacity currently.

Verdict: Solar power is a renewable resource, which causes no pollution, and has no fuel costs and waste by-products. But currently, it is very expensive to produce.


HYDROELECTRIC ENERGY

Hydropower or hydraulic power is the force or energy of moving water. And hydroelectricity is a form of hydropower, which is most widely used as form of renewable energy. Most of it comes from the potential energy of dammed water driving a water turbine and generator.

In India

India has immense amount of hydro-electric potential – estimated at 84,000MW at 60 per cent load factor (1,48,701 MW installed capacity). It ranks 5th in terms of exploitable hydro-potential on global scenario. India has considerable potential. But unfortunately, some major projects have sparked controversy.

Verdict: Hydroelectricity produces no primary waste or pollution. But, construction of dams can have grave environmental impact on the surrounding areas.

TIDAL POWER

Tidal power or tidal energy is a form of hydropower that converts the energy of tides into electricity. A water turbine is placed in a tidal current, which turns an electrical generator, or a gas compressor that stores the energy until needed.

As tides are more predictable than wind energy and solar power, some consider it to have the potential for future electricity generation.

In India
India is surrounded by sea on three sides. So, its potential to harness tidal energy is huge. The identified economic tidal power potential in India is about 8000-9000 MW.

The most potent sites to produce tidal energy include the Gulf of Cambay (7000 MW approx.) and the Gulf of Kachchh (1200 MW approx.) on the west coast, and the Ganges Delta in the Sunderbans in West Bengal (less than 100 MW).

Verdict: Tides are a source of clean and renewable source of energy. But the energy generation may have serious environmental impacts like water salinity and sediment movement.

WAVE ENERGY

Wave power systems convert the motion of the waves into usable mechanical energy, which in turn, can be used to generate electricity. These systems can be floating or fixed to the seabed offshore, or may be constructed at the edge on a suitable shoreline.

Wave energy is being extensively researched in several industrial countries, particularly Japan, Norway, UK and USA. The largest concentration of potential wave energy is located between the 40 and 60 latitudes in both the northern and southern hemispheres.

In India
In 1982, the research and development activity for exploring wave energy started at the Ocean Engineering Centre, Indian Institute of Technology, Madras.

It is estimated that the annual wave energy potential along the Indian coast is about 60000 MW approximately (between 5 MW to 15 MW per meter).

Verdict: Though wave power has great potential, its generation is not currently a widely employed commercial technology because of the high costs.


BIOMASS
Biomass is all plant material or vegetation, raw or processed, wild or cultivated. It is essentially stored solar energy that can be converted to electricity, fuel, and heat.

Biomass energy comes from three sources – agricultural crop residues, municipal and industrial waste, and energy plantations. It consists of fast growing trees and grasses, agricultural residues like used vegetable oils, wheat straw or corn, wood waste like paper trash, yard clippings, sawdust or wood chips, and methane that is captured from landfills, livestock, and municipal waste water treatment.

In India
Indian rural economy is a biomass subsistence economy in which forest plays a major role in supporting rural livelihood. Urban Indians purchase 14-20 million tones of firewood every year, worth over Rs. 500 crore. Gobar (cow dung) is only used in the domestic sector, but crop residues are used in the industrial sector too.

Verdict: Biomass is abundant and renewable source of energy, available throught the world. It is a good example of recycling resources.


GEOTHERMAL ENERGY

Geothermal energy harnesses the heat energy present underneath the Earth.
  • Two wells are drilled.
  • One well injects water into the ground.
  • The hot rocks heat the water, and produce steam.
  • The steam shoots back up the other hole
  • It is purified and used to drive turbines, which power electric generators.
In 1997, the world’s geothermal electricity generation capacity was 8000 MW and another 12000 MW for thermal applications. Italy, New Zealand, USA, Japan, Mexico, Philippines, and Indonesia are some of the countries that are using geothermal energy for electricity generation and thermal applications.

In India
Exploration and study of geothermal fields started in 1970. The Geological Survey of India (GSI) has identified 350 geothermal energy locations in the country. The most promising of these is in Puga valley of Ladakh. Although, there are seven geothermal provinces in India – the Himalayas, Sohana, West coast, Cambay, Son-Narmada-Tapi (SONATA), Godavari, and Mahanadi. The estimated potential for geothermal energy in India is about 10000 MW.

Verdict: Geothermal energy causes no pollution, and has low deployment costs. It has a lesser impact on the environment than tidal or hydroelectric plants. But, some geothermal stations have created geological instability, even causing earthquakes.

NUCLEAR ENERGY

Nuclear power stations use nuclear fission to generate energy from the reaction of Uranium-235 (an isotope of uranium). The atoms of uranium rods are split in the process, releasing a large amount of energy. The process continues as a chain reaction with other nuclei. The released heat boils up water to create steam, which spins a turbine generator, producing electricity.

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