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Wind Energy

In the early 1980’s, the Department of Non-conventional Energy Sources (DNES) came into existence with the aim to reduce the dependence of primary energy sources like coal, oil etc in view of the Country’s energy security. The DNES became Ministry of Non-conventional Energy Sources (MNES) in the year 1992 and now from 2006, the Ministry was renamed as Ministry of New & Renewable Energy (MNRE). The growth of Renewable Energy in India is enormous and Wind Energy proves to be the most effective solution to the problem of depleting fossil fuels, importing of coal, greenhouse gas emission, environmental pollution etc. Wind energy as a renewable, non-polluting and affordable source directly avoids dependency of fuel and transport, can lead to green and clean electricity.

With an installed capacity of 24088.36 MW (August 2015) of wind energy, Renewable Energy Sources (excluding large Hydro) currently accounts for 13.37 % of India’s overall installed power capacity of 276782.62 MW. Wind Energy holds the major portion of 65.09 %(of 37010.25GW total RE capacity) among renewable and continued as the largest supplier of clean energy.

The Government of India has announced a laudable Renewable Energy target of 175GW by 2022 out of which 60GW will be coming from wind power. The Wind Potential in India was first estimated by National Institute of Wind Energy (NIWE) at 50m hub-height i.e. 49 GW but according to the survey at 80m hub height, the potential grows as much as 102 GW. Further a new study by NIWE at 100m height has estimated a potential 302GW. One of the major advantages of wind energy is its inherent strength to support rural employment and uplift of rural economy. Further, unlike all other sources of power, wind energy does not consume any water-which in itself will become a scarce commodity.

Overall the future of Wind Energy in India is bright as energy security and self-sufficiency is identified as the major driver. The biggest advantage with wind energy is that the fuel is free, and also it doesn’t produce CO2 emission. Wind farm can be built reasonably fast, the wind farm land can be used for farming as well thus serving dual purpose, and it is cost-effective as compare to other forms of renewable energy. (Numerical Data Source: CEA, NIWE, MNRE)

Wind Energy - What is it?
Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. The earth’s surface is made of different types of land and water. These surfaces absorb the sun’s heat at different rates, giving rise to the differences in temperature and subsequently to winds. 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 in to take its place, creating winds. At night, the winds are reversed because the air cools more rapidly over land than over water. In the same way, the large atmospheric winds that circle the earth are created because the land near the earth's equator is heated more by the sun than the land near the North and South Poles. Humans use this wind flow for many purposes: sailing boats, pumping water, grinding mills and also generating electricity. Wind turbines convert the kinetic energy of the moving wind into electricity.

map Basic technology

Wind electric generator converts kinetic energy available in wind to electrical energy by using rotor, gearbox and generator.


The Basic Process-

The wind turns the blades of a windmill-like machine. The rotating blades turn the shaft to which they are attached. The turning shaft typically can either power a pump or turn a generator, which produces electricity. Most wind machines have blades attached to a horizontal shaft. This shaft transmits power through a series of gears, which provide power to a water pump or electric generator. These are called horizontal axis wind turbines. There are also vertical axis machines, such as the Darrieus wind machine, which has two, three, or four long curved blades on a vertical shaft and resembles a giant eggbeater in shape. The amount of energy produced by a wind machine depends upon the wind speed and the size of the blades in the machine. In general, when the wind speed doubles, the power produced increases eight times. Larger blades capture more wind. As the diameter of the circle formed by the blades doubles, the power increases four times.


Why Wind Energy-
  • The project is environment friendly.
  • Good wind potential to harness wind energy.
  • A permanent shield against ever increasing power prices. The cost per kwh reduces over a period of time as against rising cost for conventional power projects.
  • The cheapest source of electrical energy. (on a levelled cost over 20 years.)
  • Least equity participation required, as well as low cost debt is easily available to wind energy projects.
  • A project with the fastest payback period.
  • A real fast track power project, with the lowest gestation period; and a modular concept.
  • Operation and Maintenance (O&M) costs are low.
  • No marketing risks, as the product is electrical energy.
  • A project with no investment in manpower.

The main advantages of power generation from wind energy are-

  • The capital cost is comparable with conventional power plants. For a wind farm, the capital cost ranges between 4.5 crores to 6.85 crores per MW, depending up on the type of turbine, technology,size and location.
  • Construction time is less.
  • Fuel cost is zero.
  • & M cost is very low.
  • Capacity addition can be in modular form.
  • There is no adverse effect on global environment. The whole system is pollution free and environment friendly.

Limitation-

Wind machines must be located where strong, dependable winds are available most of the time. Because winds do not blow strongly enough to produce power all the time, energy from wind machines is considered "intermittent," that is, it comes and goes. Therefore, electricity from wind machines must have a back-up supply from another source. As wind power is "intermittent," utility companies can use it for only part of their total energy needs. Wind towers and turbine blades are subject to damage from high winds and lighting. Rotating parts, which are located high off the ground can be difficult and expensive to repair. Electricity produced by wind power sometimes fluctuates in voltage and power factor, which can cause difficulties in linking its power to a utility system. The noise made by rotating wind machine blades can be annoying to nearby neighbours. People have complained about aesthetics of and avian mortality from wind machines.