Small wind turbine

Small wind turbines may be as small as a fifty watt generator for boat or caravan use. Small units often have direct drive generators, direct current output, aeroelastic blades, lifetime bearings and use a vane to point into the wind. Larger, more costly turbines generally have geared power trains, alternating current output, flaps and are actively pointed into the wind. Direct drive generators and aeroelastic blades for large wind turbines are being researched.

A small wind turbine can be installed on a roof. Installation issues then include the strength of the roof, vibration, and the turbulence caused by the roof ledge. Small-scale rooftop wind turbines have been known to be able to generate power from 10% to up to 25% of the electricity required of a regular domestic household dwelling. [ [http://www.timesonline.co.uk/tol/news/uk/article706123.ece Rooftop wind turbines able to power up to 25% of domestic energy requirements] ]

Smaller scale turbines for residential scale use are available, they are usually approximately 7 feet (2 m) to convert|25|ft|m|0 in diameter and produce electricity at a rate of 900 watts to 10,000 watts at their tested wind speed. Some units have been designed to be very lightweight in their construction, e.g. 16 kilograms (35 lb), allowing sensitivity to minor wind movements and a rapid response to wind gusts typically found in urban settings and easy mounting much like a television antenna. It is claimed that they are inaudible even a few feet under the turbine. [ [http://marquix.homelinux.net/catalog/product_info.php/cPath/243/products_id/314 One of the most silent Micro Wind Turbines: Zephyr Airdolphin Z1000] ] Dynamic braking regulates the speed by dumping excess energy, so that the turbine continues to produce electricity even in high winds. The dynamic braking resistor may be installed inside the building to provide heat (during high winds when more heat is lost by the building, while more heat is also produced by the braking resistor). The location makes low voltage (around 12 volt) distribution practical.

In the United States, residential wind turbines with outputs of 2-10 kW, typically cost between $12,000 and $55,000 installed ($6 per watt), although there are incentives and rebates available in 19 states that can reduce the purchase price for homeowners by up to 50 percent, to ($3 per watt). [ [http://www.nytimes.com/2007/12/13/garden/13wind.html?em&ex=1197954000&en=57b42d0a2f9ce2be&ei=5087%0A Homespun Electricity, From the Wind - New York Times] ] The US manufacturer "Southwest Windpower," [ [http://www.windenergy.com/index_wind.htm Southwest Windpower] ] estimates a turbine to pay for itself in energy savings in 5 to 10 years. [ [http://www.windenergy.com/news/news_Rapid_City_Journal_2-20-08.html Wind turbine, a powerful investment] ]

The American Wind Energy Association has released several studies on the small wind turbine market in the U.S. and abroad, showing that the U.S. continues to dominate the Small Wind industry. [http://www.awea.org/smallwind/documents/AWEASmallWindMarketStudy2007.pdf] According to another organization, the World Wind Energy Association, it is difficult to assess the total number or capacity of small-scaled wind turbines, but in China alone, there are roughly 300,000 small-scale wind turbines generating electricity. [http://www.wwindea.org/home/images/stories/pdfs/pr_statistics2006_290107.pdf World Wind Energy Association Statistics] ]

The dominant models on the market, especially in the United States, are horizontal-axis wind turbines (HAWT).

There have been a number of recent developments of small turbines which could be adapted to home use, including:
* Jacobs Wind International Jacobs Wind.
* The AeroTecture vertical-axis turbine [ [http://www.aerotecture.com/products.html AeroTecture] ]
* The AeroVironment Architectural Wind Project [cite news| title = Energy Technology Center: Project Architectural Wind | publisher = AeroVironment Inc |date=2006 | url=http://www.avinc.com/energy_lab_project_detail.php?id=85 ] [ [http://news.com.com/Micro+wind+turbines+are+coming+to+town/2100-11398_3-6037539.html 'Micro' wind turbines are coming to town, CNET, February 10, 2006, Martin LaMonica] ]
* The piezoelectric windmill project [cite news | title = Piezoelectric Windmill: A novel solution to remote sensing | publisher = Japanese Journal of Applied Physics, v. 44 no. 3 p. L104-L107|date=2005 | author = Shashank Priya et al | url =http://mse.uta.edu/Priya/Piezoelectric%20Windmill.pdf ]
* The Swift home wind turbine. [ [http://www.renewabledevices.com/swift/index.htm Swift Turbines] ] The Swift project peaked in 2004 and has had some implementation difficulties while promising to be a low-noise/safe roof-mount/low-cost alternative [ [http://www.bettergeneration.co.uk/wind-turbine-models/the-swift-rooftop-wind-energy-system.html Better Generation: Swift Rooftop wind energy system discussion] ]
* The Motorwave micro-wind turbine [ [http://www.inhabitat.com/2007/03/21/micro-wind-turbines-small-size-big-impact/ Motorwind] ] [ [http://edition.cnn.com/2007/BUSINESS/04/15/ft.gambarota/index.html Lucien Gambarota: Alternative energy pioneer, CNN, 16 April 2007] ] [ [http://www.motorwavegroup.com/new/motorwind/index.html Motorwind Turbines] ]

Loopwing

Loopwing turbine is a low-noise, low-vibration and self-stabilizing devices. It is specifically designed for quiet home use. It requires only a mph|1.6 breeze to get started [http://www.metaefficient.com/renewable-power/loopwing-wind-turbine-at-japanese-tradeshow.html] .

DIY Wind turbines

Some hobbyists have built wind turbines from kits, sourced components, or from scratch. Do it yourself or DIY-wind turbine construction has been made popular by magazines such as OtherPower and Home Power, [ [http://www.rebelwolf.com/essn/ESSN-Dec2005.pdf OtherPower and Home Power as popular diy microgeneration magazines] ] websites as Instructables, and by TV-series as Jericho and The Time Machine. DIY-made wind turbines are usually smaller (rooftop) turbines of ~ 1kW or less. [ [http://www.bwea.com/you/byo.html British Wind and Energy Agency's DIY wind turbines page] ] [ [http://www.otherpower.com/otherpower_wind_tips.html#reading Overview of wind turbine construction and info for proper building] ] [ [http://www.villageearth.org/pages/Appropriate_Technology/ATSourcebook/ VillageEarth AT SourceBook: Wind Generation] ] These small wind turbines are usually tilt-up or fixed/guyed towers. [ [http://www.homepower.com/view/?file=HP105_pg64_Woofenden Smaller wind turbines usually of tilt-up or fixed design] ] [ [http://greenterrafirma.com/DIY_Wind_Turbine.html Modified Chispito Wind Turbine] ] However, larger (freestanding) and more powerful windtubines are sometimes built as well. The latter can generate power of up to 10 kW. [ [http://www.rebelwolf.com/essn/ESSN-Apr2006.pdf DIY 10kw freestanding turbine (page 17)] ] In addition, people are also showing interest in DIY-construction of wind turbines with special designs as the Savonius, Panemone, wind turbine to boost power generation. [ [http://static2.instructables.com/id/Build-a-Savonius-Wind-Turbine-or-VAWT-to-make-elec/ Another DIY Savonious wind turbine] ] [ [http://static2.instructables.com/id/A-Home-Power-Plant---Wind-Power-Generator-Revised/ An improved design of a small savonious wind turbine] ] When compared to similar sized commercial wind turbines, these DIY turbines tend to be cheaper. [ [http://www.instructables.com/id/Ted-Baer_s-Bicycle-Wheel-Windmill/ DIY windturbine for less than 80 dollar] ] [ [http://www.solarshop.com.au/wind%20turbines%20page.htm Commercial wind turbine for 650 dollar] ] Through the internet, the community is now able to obtain plans to construct DIY-wind turbines. [ [http://peswiki.com/index.php/Directory:Home_Generation:Wind_Turbine Wind turbine plans from the PESN-database] ] [ [http://static2.instructables.com/id/DIY-1000-watt-wind-turbine/ DIY 1000 Watt windturbine example with pictures] ] [ [http://www.instructables.com/id/Ted-Baer_s-Bicycle-Wheel-Windmill/ another DIY windmill-example with pictures] ] [ [http://www.builditsolar.com/Projects/Wind/wind.htm#DIYWind Builditsolar wind turbine plans] ] [ [http://www.thebackshed.com/windmill/articles/GettingStarted.asp The Backshed Wind turbines plans] ] [ [http://www.rebelwolf.com/essn/ESSN-Jul2006.pdf DIY Wind turbine upgrading] ] and there is a growing trend toward building them for domestic requirements. The DIY-wind turbines are now being used both in developed countries and in developing countries, to help power residences and small businesses. At present, organizations as Practical Action have designed DIY wind turbines that can be easily built by communities in developing nations and are supplying concrete documents on how to do so. [ [http://practicalaction.org/?id=region_united_kingdom_turbine Practical action producing info to construct DIY wind turbines for the developing world] ] [ [http://www.rebelwolf.com/essn/ESSN-Aug2005.pdf Basics on diy small scale windturbines and domestic power consumption] ] To assist people in the developing countries, and hobbyists alike, several projects have been open-sourced (e.g. the Jua Kali wind turbine, Hugh Piggot's wind turbine, ForceField Wind Turbine, etc.). [ [http://peswiki.com/index.php/Directory:Jua_Kali_Micro_Wind_Turbines Jua Kali Wind Turbines open-sourced] ]

References

See also

* Wind turbine

External links

* [http://www.eesi.org/briefings/2008/061208_senate_smallwind/061208_senate_smallwind.html Small wind turbines] (Environmental and Energy Study Institute).
* [http://www.eesi.org/briefings/2008/061208_senate_smallwind/AWEA_factsheet.pdf Fact sheet] by American Wind Energy Association (AWEA) * [http://www.allsmallwindturbines.com/ World's small wind turbines]