Science Current Events | Science News | Brightsurf.com
 

Wind-turbine placement produces tenfold power increase, Caltech researchers say

July 13, 2011

PASADENA, Calif.-The power output of wind farms can be increased by an order of magnitude-at least tenfold-simply by optimizing the placement of turbines on a given plot of land, say researchers at the California Institute of Technology (Caltech) who have been conducting a unique field study at an experimental two-acre wind farm in northern Los Angeles County.

A paper describing the findings-the results of field tests conducted by John Dabiri, Caltech professor of aeronautics and bioengineering, and colleagues during the summer of 2010-appears in the July issue of the Journal of Renewable and Sustainable Energy.

Dabiri's experimental farm, known as the Field Laboratory for Optimized Wind Energy (FLOWE), houses 24 10-meter-tall, 1.2-meter-wide vertical-axis wind turbines (VAWTs)-turbines that have vertical rotors and look like eggbeaters sticking out of the ground. Half a dozen turbines were used in the 2010 field tests.

Despite improvements in the design of wind turbines that have increased their efficiency, wind farms are rather inefficient, Dabiri notes. Modern farms generally employ horizontal-axis wind turbines (HAWTs)-the standard propeller-like monoliths that you might see slowly turning, all in the same direction, in the hills of Tehachapi Pass, north of Los Angeles.

In such farms, the individual turbines have to be spaced far apart-not just far enough that their giant blades don't touch. With this type of design, the wake generated by one turbine can interfere aerodynamically with neighboring turbines, with the result that "much of the wind energy that enters a wind farm is never tapped," says Dabiri. He compares modern farms to "sloppy eaters," wasting not just real estate (and thus lowering the power output of a given plot of land) but much of the energy resources they have available to them.

Designers compensate for the energy loss by making bigger blades and taller towers, to suck up more of the available wind and at heights where gusts are more powerful. "But this brings other challenges," Dabiri says, such as higher costs, more complex engineering problems, a larger environmental impact. Bigger, taller turbines, after all, mean more noise, more danger to birds and bats, and-for those who don't find the spinning spires visually appealing-an even larger eyesore.

The solution, says Dabiri, is to focus instead on the design of the wind farm itself, to maximize its energy-collecting efficiency at heights closer to the ground. While winds blow far less energetically at, say, 30 feet off the ground than at 100 feet, "the global wind power available 30 feet off the ground is greater than the world's electricity usage, several times over," he says. That means that enough energy can be obtained with smaller, cheaper, less environmentally intrusive turbines-as long as they're the right turbines, arranged in the right way.

VAWTs are ideal, Dabiri says, because they can be positioned very close to one another. This lets them capture nearly all of the energy of the blowing wind and even wind energy above the farm. Having every turbine turn in the opposite direction of its neighbors, the researchers found, also increases their efficiency, perhaps because the opposing spins decrease the drag on each turbine, allowing it to spin faster (Dabiri got the idea for using this type of constructive interference from his studies of schooling fish).

In the summer 2010 field tests, Dabiri and his colleagues measured the rotational speed and power generated by each of the six turbines when placed in a number of different configurations. One turbine was kept in a fixed position for every configuration; the others were on portable footings that allowed them to be shifted around.

The tests showed that an arrangement in which all of the turbines in an array were spaced four turbine diameters apart (roughly 5 meters, or approximately 16 feet) completely eliminated the aerodynamic interference between neighboring turbines. By comparison, removing the aerodynamic interference between propeller-style wind turbines would require spacing them about 20 diameters apart, which means a distance of more than one mile between the largest wind turbines now in use.

The six VAWTs generated from 21 to 47 watts of power per square meter of land area; a comparably sized HAWT farm generates just 2 to 3 watts per square meter.

"Dabiri's bioinspired engineering research is challenging the status quo in wind-energy technology," says Ares Rosakis, chair of Caltech's Division of Engineering and Applied Science and the Theodore von Kármán Professor of Aeronautics and professor of mechanical engineering. "This exemplifies how Caltech engineers' innovative approaches are tackling our society's greatest problems."

"We're on the right track, but this is by no means 'mission accomplished,'" Dabiri says. "The next steps are to scale up the field demonstration and to improve upon the off-the-shelf wind-turbine designs used for the pilot study." Still, he says, "I think these results are a compelling call for further research on alternatives to the wind-energy status quo."

This summer, Dabiri and colleagues are studying a larger array of 18 VAWTs to follow up last year's field study. Video and images of the field site can be found at http://dabiri.caltech.edu/research/wind-energy.html

California Institute of Technology


Related Wind Turbines Current Events and Wind Turbines News Articles


Harnessing solar and wind energy in one device could power the 'Internet of Things'
The "Internet of Things" could make cities "smarter" by connecting an extensive network of tiny communications devices to make life more efficient.

Gone with the wind: Argonne coating shows surprising potential to improve reliability in wind power
Despite the rigors of scientific inquiry and the methodical approaches of the world's most talented researchers, sometimes science has a surprise in store.

Graphene composite may keep wings ice-free
A thin coating of graphene nanoribbons in epoxy developed at Rice University has proven effective at melting ice on a helicopter blade.

Making green fuels, no fossils required
Using solar or wind power to produce carbon-based fuels, which are commonly called fossil fuels, might seem like a self-defeating approach to making a greener world.

Offshore wind farms could be more risky for gannets than previously thought, study shows
Offshore wind farms which are to be built in waters around the UK could pose a greater threat to protected populations of gannets than previously thought, according to a new study by researchers at the universities of Leeds, Exeter and Glasgow.

New technology could reduce wind energy costs
Engineers from the University of Sheffield have developed a novel technique to predict when bearings inside wind turbines will fail which could make wind energy cheaper.

Study finds price of wind energy in US at an all-time low, averaging under 2.5¢/kWh
Wind energy pricing is at an all-time low, according to a new report released by the U.S. Department of Energy and prepared by Lawrence Berkeley National Laboratory (Berkeley Lab). The prices offered by wind projects to utility purchasers averaged under 2.5¢/kWh for projects negotiating contracts in 2014, spurring demand for wind energy.

Wind energy provides 8 percent of Europe's electricity
EU's grid connected cumulative capacity in 2014 reached 129 GW, meeting 8% of European electricity demand, equivalent to the combined annual consumption of Belgium, the Netherlands, Greece and Ireland.

Silent flights: How owls could help make wind turbines and planes quieter
An investigation into how owls fly and hunt in silence has enabled researchers to develop a prototype coating for wind turbine blades that could significantly reduce the amount of noise they make.

Renewable energy's record year helps uncouple growth of global economy and CO2 emissions
Renewable energy targets and other support policies now in place in 164 countries powered the growth of solar, wind and other green technologies to record-breaking energy generation capacity in 2014.
More Wind Turbines Current Events and Wind Turbines News Articles

Power Generation Collection: Go Off-Grid with Solar Air Heater, Micro Wind Turbine, Solar Panels and Wind Power: (Solar Power, Wind Power)

Power Generation Collection: Go Off-Grid with Solar Air Heater, Micro Wind Turbine, Solar Panels and Wind Power: (Solar Power, Wind Power)


Getting Your FREE Bonus
Download this book, read it to the end and see "BONUS: Your FREE Gift" chapter after the conclusion.
Power Generation Collection: Go Off-Grid with Solar Air Heater, Micro Wind Turbine, Solar Panels and Wind Power
Book 1. DIY Solar Heaters with Basic Materials: Water Heater, Air Heater, Solar Oven Tutorials
Book 2. Building A Micro Wind Turbine: Go Off-grid with the Wind Power Generator
Book 3. Solar Power: Proven Methods To Build Your Own Solar Power System That You Can Afford
Book 4. Power Generation: The Ultimate Guide on Building Your Own Wind Power Generating System
Download your E book "Power Generation Collection: Go Off-Grid with Solar Air Heater, Micro Wind Turbine, Solar Panels and Wind Power" by scrolling up and clicking...

Wind Power For Dummies

Wind Power For Dummies
by Ian Woofenden (Author)


The consumer guide to small-scale wind electricity production!

Maybe you're not T. Boone Pickens, but you can build your own home-sized wind-power empire right in your back yard. Wind Power For Dummies supplies all the guidance you need to install and maintain a sustainable, cost-effective wind generator to power your home for decades to come. This authoritative, plain-English guide walks you through every step of the process, from assessing your site and available wind sources to deciding whether wind power is the solution for you, from understanding the mechanics of wind power and locating a contractor to install your system to producing your own affordable and sustainable electricity. Guides you step by step through process of selecting, installing, and operating a...

Off-Grid Living: How To Build Wind Turbine, Solar Panels And Micro Hydroelectric Generator To Power Up Your House: (Wind Power, Hydropower, Solar Energy, Power Generation)

Off-Grid Living: How To Build Wind Turbine, Solar Panels And Micro Hydroelectric Generator To Power Up Your House: (Wind Power, Hydropower, Solar Energy, Power Generation)
by Andy Anderson (Author), Arnold Thompson (Author), David Shwarz (Author)


Getting Your FREE Bonus Download this book, read it to the end and see "BONUS: Your FREE Gift" chapter after the conclusion. Off-Grid Living: How To Build Wind Turbine, Solar Panels And Micro Hydroelectric Generator To Power Up Your House (FREE Bonus Included) Book 1: Go Off Grid And Go Green With Micro Hydro System: How A Micro Hydro System Can Provide Your Off-Grid Home With Electricity When we think of renewable energy, most of us think solar or wind, but another choice does exist, hydroelectric. Using water for power goes back to water wheels and culminates in huge hydroelectric dams. There is middle ground too; small hydroelectric systems can power a home as efficiently as solar power. Stop paying enormous electric bills and never worry about the power going out again! It is...

How to Build a Micro Wind Turbine: A Guide for Beginners: (Wind Power, Power Generation)

How to Build a Micro Wind Turbine: A Guide for Beginners: (Wind Power, Power Generation)
by Daniel Hopkins (Author)


Getting Your FREE Bonus Download this book, read it to the end and see "BONUS: Your FREE Gift" chapter after the conclusion. How to Build a Micro Wind Turbine A Guide for Beginners Welcome to Building a Micro Wind Turbine: For Beginners, a D.I.Y. book designed to help you build and understand your first wind turbine both in aerodynamics and electricity. Many books assume you know how electricity works and just show you how to build one or two types of wind turbines, maybe even more. The problem with such books is that if you don't know how the turbine actually works, you won't be able to make a wind turbine that serves your needs. This is why this book is mostly dedicated to helping you understand all the working parts so you can take the building plans into your own hands. Download your...

Do-it-Yourself Solar and Wind Energy System: DIY Off-grid and On-grid Solar Panel and Wind Turbine System

Do-it-Yourself Solar and Wind Energy System: DIY Off-grid and On-grid Solar Panel and Wind Turbine System
by Eric Layton (Author)


Eric Layton, an engineer in the solar industry who installs solar panels, wrote this guide for readers that are trying to build their own solar or wind system. Using pictures, this do-it-yourself (DIY) solar and wind system was built with a battery back-up system. His new book is a comprehensive guide on the design, thought process, equipment, and technique on designing this DIY system. Using photographs taken throughout the building process, he covers why he chose certain components in addition to any issues building and installing. This book was written to help fellow solar and wind enthusiasts, as well as inspire those who would like to build their own solar and wind DIY system.

Building a Micro Wind Turbine: Go Off-Grid with the Wind Power Generator: (Wind Power, Power Generation)

Building a Micro Wind Turbine: Go Off-Grid with the Wind Power Generator: (Wind Power, Power Generation)
by Michael Fair (Author)


Getting Your FREE Bonus Download this book, read it to the end and see "BONUS: Your FREE Gift" chapter after the conclusion. Building a Micro Wind Turbine Go Off-Grid with the Wind Power Generator If you wish to off-grid and generate electricity by harnessing the power of the wind, then you have certainly come to the right place. We have come up with a highly comprehensive guide that will let you build a well-equipped and functioning wind power generator in no time. Wind energy is one of the most prominent renewable sources of energy and by constructing wind turbines you can harness it without any hassle. A turbine can convert the mechanical energy of the wind into electricity. Don’t worry! It is really easy. In this informative guide, we have provided an in-depth walkthrough for...

The Renewable Energy Home Handbook: Insulation & energy saving, Living off-grid, Bio-mass heating, Wind turbines, Solar electric PV generation, Solar water heating, Heat pumps, & more

The Renewable Energy Home Handbook: Insulation & energy saving, Living off-grid, Bio-mass heating, Wind turbines, Solar electric PV generation, Solar water heating, Heat pumps, & more
by Lindsay Porter (Author)


The Renewable Energy Home Handbook is biased towards the practical, and covers the installation of all leading types of alternative domestic energy sources - from ground- and air-source heat pumps, PV solar electricity generation and solar water heating, to bio-mass domestic heating systems and wind turbines. Discussing the pros and cons of each technology, it also provides you with a clear overview of what's genuinely required and the benefits to be gained from each system.The author, Lindsay Porter, is best known for his books on motor vehicle technology, making car mechanics and body repairs easy to understand and carry out. But alternative energy and conservation have long been a passion for him and his wife, Shan, so this manual is very much a labour of love. Here, Lindsay applies...

A Wind Turbine Recipe Book

A Wind Turbine Recipe Book
by Hugh Piggott (Author)


A Wind Turbine Recipe Book (Jan 2009 English Units edition) This is the latest edition of Mr. Piggott's 'axial flux windmill plans' as used in the courses he teaches worldwide. The Recipe Book replaces his older plans 'How to Build a Wind Turbine' (2005). The Recipe Book is a much better structured document than the older 2005 plans. Rather than evolving 'organically' it is carefully planned to include six different sizes of turbines. Each section offers general advice combined with specific dimensions and diagrams for each of these six sizes and a range of operating voltages. During 2008 the Recipe book was only available in metric units, but in 2009 a new 'English Units' edition is also available (written specifically for North American readers who prefer to use Inches and AWG sizes for...

Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering

Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering
by David A. Spera (Editor)


This state-of-the-art guide to wind turbine engineering lets you: examine the real-life choices made by inventors, designers, and builders of turbines; absorb their practical lessons; and synthesize the experiences of a wide range of wind-energy professionals. You get technical expertise on a wide range of material, including advances in aerodynamics, structural dynamics and fatigue, wind characteristics, acoustic and electromagnetic emissions, commercial wind power applications, and utility power systems. Packed with applications-oriented advice -- and including numerous graphics and numerical examples -- this authoritative volume provides uniform terminology, nomenclature, and graphic style, as well as widespread cross-referencing. Covering design concepts and philosophies, research and...

Small Wind Turbines: Analysis, Design, and Application (Green Energy and Technology)

Small Wind Turbines: Analysis, Design, and Application (Green Energy and Technology)
by David Wood (Author)


Providing software and techniques on analysis, design and installation, this volume illustrates how to build small wind turbines. While serving as a reference for student projects and detailed design studies, the text also provides important background material for engineers.

© 2017 BrightSurf.com