Wind Energy - A renewable energy resourceThe natural movement of air is called wind. Wind is caused by uneven heating and cooling of the earth's surface and by the earth's rotation. Land and water areas absorb and release different amount of heat received from the sun. As warm air rises, cooler air rushes in to take its place, causing local land and sea breezes or winds. The rotation of the earth changes the direction of the flow of air.
Growing concern for the environmental degradation has led to the world's interest in renewableenergy resources. Wind is commercially and operationally the most viable renewable energy resource. wind energy is currently making a significant contribution to the installed capacity of power generation, and is emerging as a competitive option.
How is Wind Energy converted to Electrical EnergyWind electric generator converts kinetic energy available in wind to electrical energy by using rotor, gearbox and generator.
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, 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 has become popular
- Wind energy is generally '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.)
- Low cost Loans 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.
Pollution SavingThe pollution saving from a Wind Energy generator having an average output of 4,00,0.00 kWh per year has been estimated as:
- Sulphur - dioxide (SO2): 2 to 3.2 tonnes
- Nitrogen - oxide (NO) ; 1.2 to 2.4 tonnes
- Carbon - dioxide (CO2) : 300 to 500 tonnes
- Particulates : 150 to 280 kg.
Comparison between Fossil Fuels and Wind
- 'Availability:' Wind Energy is usable as it exists but Fossil fuel has to be procured and made usable through laborious and environmentally damaging processes.
- 'Limitation on availability:' Wind Energy is an inexhaustible resource but fossil fuels are limited in reserves, expected to get completely exhausted in the coming 60 years.
- 'Transportation:' Wind Energy is available in situ but fossil fuel have to be transported from the site for further processing exposing environment to danger and rise in cost.
- 'Use in production:' Wind Energy is zero emission but fossil fuels always release high levels of green house gasses.
- 'Geo-political Implications:' Wind energy helps in reducing our reliance on oil, safeguarding national security.
Therefore Wind energy has no adverse effect on global environment. The whole system is pollution free and environment friendly.
Limitations for using Wind Energy
- 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.}c
HEDON organizations working on wind energy
External links and references
- Wind Power - comprehensive site about grid connected wind energy
- Scoraig Wind Electric - self-built small wind turbines by Hugh Piggott.