Wind power

Posted: 27 November 2007

A wind turbine converts the energy in the wind into electrical energy or mechanical energy to pump water or grind grain. Wind turbines are rated by their maximum power output in kilowatts (kW) or megawatts (MW - 1000 kW). For commercial utility-sized projects, the most common turbines sold are in the range of 600 kW-1000 kW (one megawatt) - large enough to supply electricity to 600-1000 homes. The newest commercial turbines are rated at 2 megawatts. A typical 600 kW turbine has a blade diameter of 35 metres and is mounted on a 50-metre concrete or steel tower.

  • The power that can be generated from a modern wind turbine is usually related to the square of the windspeed. This means that a site with twice the windspeed of another will generate four times as much energy.

  • Over the past ten years, global wind power capacity has continued to grow at an average cumulative rate of over 32 per cent. In 2006 alone, close to 15,000 MW (Megawatts) of new capacity were installed around the world, a market worth around €18 billion (US$23 billion).

    Wind power expansion
    Wind power expansion
    By the end of 2006, the capacity of wind turbines installed globally had reached a level of more than 74,000 MW. Source: Global Wind Energy Council
  • By the end of 2006, the capacity of wind turbines installed globally had reached a level of more than 74 GW. Today, wind energy meets the electricity needs of more than 25 million households worldwide.

  • Generation costs have fallen by 50 per cent over the last 15 years, moving closer to the cost of conventional energy sources. Modern wind turbines have improved dramatically in their power rating, efficiency and reliability.

  • Europe has historically been the strongest market for wind energy development, with over 48 GW of installed capacity. In 2006, the European Union saw another record year with installations above 7 GW, thereby reaffirming its undisputed status as the world's biggest wind market. Germany is the world's leader in terms of installed capacity. The total share of wind energy in the total electricity consumption in Germany now stands at approximately 5.5 per cent.

  • Wind energy now contributes 13 per cent of national energy consumption in Denmark, the highest proportion of any country in the world. When the wind blows strongly, wind energy supplies more than half the electricity in the western half of the country.

  • The US wind energy industry shattered all previous annual installation records in 2006, adding more than 2,400 MW. It will add a further 3 GW in 2007. From 9.8 GW installed at the end of 2006, it is estimated to reach 31.6 GW by the end of 2010. The facilities already produce about 0.7 per cent of the country's electricity generation, enough to power the equivalent of 2.9 million average American households.

  • A modern wind turbine annually produces 180 times more electricity at less than half the cost per unit (kWh) than its equivalent twenty years ago. At good locations wind can compete with the cost of both coal and gas-fired power. The competitiveness of wind power has been further enhanced by the recent rise in the price of fossil fuels.

  • The cost of generating electricity from wind energy currently ranges from approximately4-5 €cents (2.7-3.5 US cents)/kWh at high wind speed sites up to approximately 6-8 €cents (4-5.5 US cents)/kWh at sites with low average wind speeds. However, over the past 15 years the efficiency of wind turbines has been increasing by 2 per cent to 3 per cent annually.

  • Good windspeed data is critical to determining the economic feasibility of a wind project; prime windsites have average windspeeds greater than 7.5 metres/sec (27 km/hr).

    Horns Rev offshore wind farm, Denmark
    Horns Rev offshore wind farm, Denmark
    Vestas' offshore wind farm at Horns Rev at Jutland's west coast supplies two per cent of Denmark's energy consumption. Credit: Danish Ministry of Foreign Affairs

  • Offshore sites provide excellent opportunities for wind turbines. The very first UK offshore windfarm, in the North Sea off Blyth on the Northumberland coast, was commissioned in December 2000. The offshore wind sector has grown to 13 projects totalling over 1,155 MW. Of these, three projects with a total capacity of 210 MW are already generating for the grid: North Hoyle, off the coast of North Wales; Scroby Sands, off the coast of Great Yarmouth in Norfolk; and the newly commissioned Kentish Flats off Whitstable in Kent. Another project is under construction, the 90 MW Barrow off the Cumbrian coast.

See Winds of change