wind power

Twisted Savonius wind turbine

Wind power – conversion of wind energy into a useful form of energy, such as using wind turbines to make electrical power, windmills for mechanical power, wind pumps for water pumping or drainage, or sails to propel ships.

Windmills are not new. They have been in use all around the world for centuries. Windmills were used in Persia (present-day Iran) as early as 200 B.C. The windwheel of Heron of Alexandria marks one of the first known instances of wind powering a machine in history. However, the first known practical windmills were built in Sistan, a region between Afghanistan and Iran, from the 7th century.

Windmills have been used in many countries to turn heavy stones that grind corn or wheat, or to pump water.

Wind turbine – there are a number of different wind turbine designs in use

  • Twisted Savonius wind turbine – (shown in the animation)

Here are some examples of wind power

  • World’s Biggest Offshore Wind Farm Switched On in Britain – 175 turbines. 630 megawatts. Half a million homes. 100 square kilometers. 450 kilometers of offshore cabling.
  • Harnessing the Wind and Tide in One Power Station – Darrieus vertical-axis wind turbine, submerged Savonius tidal turbine, and a central platform that’s home to a gearbox and generator which creates electricity from both the wind and tide that surround the platform.
  • Onshore wind power is currently the cheapest source of renewable energy. The article talks about geothermal and tidal power – two other sources of renewable energy.

Engineering ideas

  • Wind tree – Its steel trunk stands 36 feet tall and has 72 artificial leaf-like micro-turbines that spin vertically on an axis. Unlike industrial-sized turbines, it’s silent – all of its cables and generators are buried deep within its leaves and branches. And it can create power even from light breezes, allowing it to provide electricity for more than 280 days a year. If the prototype works as well as Michaud-Larivière hopes, it could blossom into a forest of turbines across Paris and beyond. Also in the works at his New Wind company: “foliage” that can be installed on rooftops or along roads, and a scaled down “wind bush.”

Energy 101: Wind Turbines – (video 2:16) See how wind turbines generate clean electricity from the power of the wind. Highlighted are the various parts and mechanisms of a modern wind turbine.

light detection and ranging (lidar) A tool to measure the shape and contour of the ground from the air. It bounces a laser pulse off a target and then measures the time (and distance) each pulse traveled. Those measurements reveal the relative heights of features on the ground struck by the laser pulses.

Meet the people in wind power Engineering

  • Kathryn Johnson puts wind to work to make renewable energy. She’s an electrical engineer and teaches at the Colorado School of Mines in Golden.

What’s the problem?

It could happen… “The return of sailing ships as a commercially viable transport system.” Even in the days of cloth sails and hemp rope, he said, clipper ships could convert 60 percent of the raw energy of the wind into useful work. With modern materials and design, they could capture more energy than they used en route. “When a fleet of ships got to port, they could not only deliver cargo but even put energy into the grid.” —George Dyson, 2013

  • Ask – Why was wind power one of the earliest forms of energy to be used?
  • Imagine – What were some of the engineering solutions that people came up with in ancient times? What were their inspirations?
  • Design, Build – What materials were available for early wind power? Using wood for masts and blades was common throughout history. Tall trees were prized as they were used to support wind generation and capture.
  • Improve – How have these old ideas been update for use today?

That’s engineering

  • Tip speed ratio – The ratio between the speed of the wind and the speed of the tips of the blades of a wind turbine. Modern wind turbines are designed to spin at varying speeds (a consequence of their generator design). Use of aluminum and composites in their blades has contributed to low rotational inertia. Newer wind turbines can accelerate quickly if the winds pick up, keeping the tip speed ratio more nearly constant. Operating closer to their optimal tip speed ratio during energetic gusts of wind allows wind turbines to improve energy capture from sudden gusts that are typical in urban settings.
  • generator – A device used to convert mechanical energy into electrical energy.
  • weather – Conditions in the atmosphere at a localized place and a particular time. It is usually described in terms of particular features, such as air pressure, humidity, moisture, any precipitation (rain, snow or ice), temperature and wind speed. Weather constitutes the actual conditions that occur at any time and place. It’s different from climate, which is a description of the conditions that tend to occur in some general region during a particular month or season.
  • wind turbine – A wind-powered device — similar to the type used to mill grain (windmills) long ago — used to generate electricity.

Engineering ideas

  • turbine, wind, tidal, gearbox, generator, ti[s speed ration, composite, rotational inertia, accelerate, energy capture

Do it
Here are some challenges for you to work on…

  • Design a windmill that can harness the power of the wind. – For centuries, people have used windmills to harness the power of the wind for such tasks as grinding grain and pumping water. Even today, some propose using wind farms as a form of “green” energy. As a design engineer, focus on the testing and redesign parts of the engineering design process. Learn about independent variables and data-driven design by testing various blade designs and configurations and placing them in a wind stream.
  • Blow Your Mind Design a prototype windmill – requires Shockwave
  • Make a paper windmill

Learn more…

  • Wind power is looking up – to the clouds. Researchers look to the skies in their search for airborne wind power. When scientists first came up with the idea of airborne wind power, some considered tapping into jet streams, says Cristina Archer, a civil and environmental engineer.
  • Wind Now Cost Competitive With Coal in India – renewables, such as wind and solar photovoltaic, use far less water than coal, nuclear, or natural gas power plants. Across the globe, water stress is growing within the energy industry and power plants have to partially shut down when there isn’t enough water for cooling. In India, water shortages just before monsoon season in 2012 forced hydro generation and thermal power plants to partially close.
  • Airborne Wind Energy (10:54) – Scientists and engineers are test-flying a kite-like tethered wing that may someday help revolutionize clean energy. Explore the potential of wind energy and new airborne wind turbines designed to harness the stronger and more consistent winds found at higher altitudes.
  • Airborne Wind Energy
  • 10 Wind Power Facts