Wind energy - how it works

Page - November 10, 2006
Wind power, the world's fastest growing energy source, is a deceptively simple technology. Behind the tall, slender towers and steadily turning blades lies a complex interplay of lightweight materials, aerodynamic design and computer controlled electronics. Power is transferred from the rotor through a gearbox, sometimes operating at variable speed, and then to a generator (although some turbines avoid a gearbox by use of direct drive).

Clean energy is the solution for our planet's future.

Wind power today

Twodecades of technological progress have resulted in state-of-the-artwind turbines that are modular and rapid to install. Today, a singlemodern wind turbine is 100 times more powerful than its equivalent twodecades ago, and now wind farms provide bulk power equivalent toconventional power stations.  

By the beginning of 2004, globalwind power installations had reached a level of 40,300 MW. Thisprovides enough power to satisfy the needs of around 19 million averageEuropean households, close to 47 million people.  

Asthe market has grown, wind power has shown up to a 50 percent drop inproduction costs over the past 15 years.  Now, at optimum siteswind can be competitive with new coal-fired plants and in somelocations can challenge gas.

Wind power by 2020

Withinstalled wind capacity growing at 30 percent over the past few years,it is an entirely realistic goal to for wind to provide 12 percent ofthe world's energy by 2020.  Along the way, this would create twomillion jobs, and save more than 10,700 million tonnes of carbondioxide emissions.

Thanks to continuing improvements in theaverage turbine size and capacity, by 2020 the cost of wind power ongood sites is expected to drop to 2.45 euro cents per kilowatt hour(kWh) - 36 percent less than its 3.79 euro cents/kWh cost in 2003. Gridconnection is not included in these costs, but is a factor forvirtually any new energy site, not just wind.

Wind power beyond 2020

Theworld's wind resources are extremely large and well distributed acrossalmost all regions and countries. Using current technology, wind powercould supply an estimated 53,000 Terawatt hours (TWh) per year. This ismore than twice the projected world energy demand in 2020 - leavingsubstantial room for growth in the industry even decades fromnow.   The US alone has enough wind potential to supply itsenergy needs three times over.

Advantages of wind:

Environmentallyfriendly - A reduction in the levels of climate change causing carbondioxide emissions is the most important environmental benefit from windpower generation.  However, it is also free of the other of otherpollutants associated with fossil fuel and nuclear plants.  

Extremelygood energy balance - The carbon dioxide emissions related to themanufacture, installation and servicing over the average 20 yearlifecycle of a wind turbine are "paid back" after the first three tosix months of operation - which means more than 19 years of energyproduction at virtually no environmental cost.

Quick todeploy - Construction of a wind farm can be completed within a matterof weeks, with large cranes installing the turbine towers, nacelles(housing) and blades on top of reinforced concrete foundations.

Reliableand renewable resource - Wind to drive the turbines will always be freeof charge, and unaffected by swings in the price of fossil fuels. It also doesn't need to be to be mined, drilled for or transported tothe generating station.  As world fossil fuel prices rise, so doesthe value of wind power, and its generating costs will only drop.  

Furthermore,in larger projects, using proven medium sized turbines, an operationalavailability of 98 percent is consistently achieved using wind. Meaningonly a two percent down time for repairs - a far better performancerecord than what can be expected from a conventional power plant.  

Variability of wind

Thevariability of the wind has produced far fewer problems for electricitygrid management than sceptics had anticipated.  Swings in energydemand and the need to protect against failures of conventional plantsactually require more flexibility of the grid system than wind power,and real world experience has shown that national power systems are upto the task.  On windy nights, for example, wind turbines accountfor up to 50 percent of power generation in the western part ofDenmark, but the load has proved manageable.  

The creationof super-grids also reduces the problem of wind variability by allowingchanges in wind speed in different areas to be balanced against eachother.

Moving forward

Despiteits recent rapid growth the future of wind power is notguaranteed.  Although there is some wind power today in 50countries, most of the progress so far has been thanks to the effortsof just a few, led by Germany, Spain, and Denmark.  Othercountries will need to improve their wind power industries dramaticallyif global targets are to be met.  Therefore, the prediction of 12percent of the world's energy from wind power by 2020 should not beseen as a sure thing, but as a goal - one possible future we can choseif we are willing.

Find out how you can help on our Take Action page.


More information:

www.yes2wind.com - Includes answers to common myths about wind power.

Greenpeace report: Windforce 12