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


Used-cigarette butts offer energy storage solution
A group of scientists from South Korea have converted used-cigarette butts into a high-performing material that could be integrated into computers, handheld devices, electrical vehicles and wind turbines to store energy.

'Wetting' a battery's appetite for renewable energy storage
Sun, wind and other renewable energy sources could make up a larger portion of the electricity America consumes if better batteries could be built to store the intermittent energy for cloudy, windless days. Now a new material could allow more utilities to store large amounts of renewable energy and make the nation's power system more reliable and resilient.

Stanford study shows how to power California with wind, water and sun
Imagine a smog-free Los Angeles, where electric cars ply silent freeways, solar panels blanket rooftops and power plants run on heat from beneath the earth, from howling winds and from the blazing desert sun.

Bats use polarized light to navigate
Scientists have discovered that greater mouse-eared bats use polarisation patterns in the sky to navigate - the first mammal that's known to do this.

Researchers led by Stanford engineer figure out how to make more efficient fuel cells
Solar power and other sources of renewable energy can help combat global warming but they have a drawback: they don't produce energy as predictably as plants powered by oil, coal or natural gas. Solar panels only produce electricity when the sun is shining, and wind turbines are only productive when the wind is brisk.

Ancient ocean currents may have changed pace and intensity of ice ages
Climate scientists have long tried to explain why ice-age cycles became longer and more intense some 900,000 years ago, switching from 41,000-year cycles to 100,000-year cycles.

New study uses blizzard to measure wind turbine airflow
A first-of-its-kind study by researchers at the University of Minnesota (UMN) using snow during a Minnesota blizzard is giving researchers new insight into the airflow around large wind turbines.

Wind turbine payback
US researchers have carried out an environmental lifecycle assessment of 2-megawatt wind turbines mooted for a large wind farm in the US Pacific Northwest.

Sopcawind, a multidisciplinary tool for designing wind farms
The SOPCAWIND tool is a piece of software that facilitates the design of wind farms, bearing in mind not only the aspects of energy productivity but also the possible impact the wind farm may have on the environment, radars or other telecommunications systems in the vicinity.

A new concept to improve power production performance of wind turbines in a wind farm
Wind energy is one of the most promising renewable energy resources in the world today. Dr. Hui Hu and his group at Iowa State University studied the effects of the relative rotation directions of two tandem wind turbines on the power production performance, the flow characteristics in the turbine wake flows, and the resultant wind loads acting on the turbines.
More Wind Turbines Current Events and Wind Turbines News Articles

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 small-scale wind...

Wind Turbines: Fundamentals, Technologies, Application, Economics

Wind Turbines: Fundamentals, Technologies, Application, Economics
by Erich Hau (Author), Horst von Renouard (Translator)


Wind Turbines addresses all those professionally involved in research, development, manufacture and operation of wind turbines. It provides a cross-disciplinary overview of modern wind turbine technology and an orientation in the associated technical, economic and environmental fields. It is based on the author's experience gained over decades designing wind energy converters with a major industrial manufacturer and, more recently, in technical consulting and in the planning of large wind park installations, with special attention to economics. The second edition accounts for the emerging concerns over increasing numbers of installed wind turbines. In particular, an important new chapter has been added which deals with offshore wind utilisation. All advanced chapters have been extensively...

Build Your Own Small Wind Power System

Build Your Own Small Wind Power System
by Kevin Shea (Author), Brian Clark Howard (Author)


A STEP-BY-STEP GUIDE TO BUILDING A SMALL WIND POWER SYSTEM FROM THE GROUND UP Written by renewable energy experts, this hands-on resource provides the technical information and easy-to-follow instructions you need to harness the wind and generate clean, safe, and reliable energy for on-site use. Build Your Own Small Wind Power System shows you how to install a grid-connected or off-grid residential-scale setup. Get tips for evaluating your site for wind power potential, obtaining permits, financing your project, selecting components, and assembling and maintaining your system. Pictures, diagrams, charts, and graphs illustrate each step along the way. You'll also find out how you can help promote wind-friendly public policies locally. Save money and reduce your carbon footprint with help...

Wind Turbine Technology (Renewable Energies)

Wind Turbine Technology (Renewable Energies)
by Ahmad Hemami (Author)


Wind energy is a rapidly growing and the demand for trained technicians is high. WIND TURBINE TECHNOLOGY, is a comprehensive and well illustrated book on the theory and operations of wind turbines that generate electricity for power companies. This book is written as an introduction to wind energy technology. It prepares readers for a career as wind energy technicians who are responsible for maintaining, servicing and troubleshooting turbines on wind farms. This is an inclusive book that covers the main subjects associated with wind turbines. Dr. Hemami uses a practical, step-by-step manner with many examples and applications to help you to have a better understanding of the material. The book is divided into 17 progressive chapters. The book is divided into progressive sections,...

Green Power Homes - Quick Guide To : Electricity From Solar Panels ; Solar Water Heating ; Wind Turbine Technology ; Geothermal Heating And Cooling

Green Power Homes - Quick Guide To : Electricity From Solar Panels ; Solar Water Heating ; Wind Turbine Technology ; Geothermal Heating And Cooling
by William Dollinger


Green Power Homes - Quick And Easy Guide to Wind, Solar and Geothermal Energy


If you have heard the concepts of Sustainable energy, Sustainable
living, Eco energy, Green homes and never knew what it is all about,
then this quick guide will introduce you to these concepts.

Ever wondered what Wind power is all about  ?  How to heat
your water with Solar panels ? Is it possible to cool your home using
geothermal forces ?


In this quick guide you'll find  :

About The History Of Wind EnergyHow Wind Turbines Work And The Advantages And Disadvantages Of
Wind PowerAnswers To Common Questions Such As  : How Much Does A Wind
System Cost?Case StudiesAbout The History Of Solar EnergyWhat Is Passive Solar...

My Light

My Light
by Molly Bang (Illustrator)


Caldecott Honor artist Molly Bang celebrates the many wonders of the sun, with radiant words and images that illuminate the myriad ways in which the sun gives us energy and power from its light.

Often taken for granted, the sun gives us more than its light. Here, acclaimed author and illustrator Molly Bang presents a celebration of the wonder and power of the sun and its radiance. With dazzling paintings and a simple poetic text, MY LIGHT follows the paths of the sun's rays, showing the many ways in which we obtain energy from its light. As in COMMON GROUND (Giverny Award for Best Science Picture Book), Bang uses a story to explain the basic concepts behind electricity and our energy resources--a compelling and easily-accessible way to present a non-fiction subject.


Wind Power, Revised Edition: Renewable Energy for Home, Farm, and Business

Wind Power, Revised Edition: Renewable Energy for Home, Farm, and Business
by Paul Gipe (Author)


In the wake of mass blackouts and energy crises, wind power remains a largely untapped resource of renewable energy. It is a booming worldwide industry whose technology, under the collective wing of aficionados like author Paul Gipe, is coming of age. Wind Power guides us through the emergent, sometimes daunting discourse on wind technology, giving frank explanations of how to use wind technology wisely and sound advice on how to avoid common mistakes. Since the mid-1970s, Paul Gipe has played a part in nearly every aspect of wind energy’s development—from installing small turbines to promoting wind energy worldwide. As an American proponent of renewable energy, Gipe has earned the acclaim and respect of European energy specialists for years, but his arguments have often fallen on...

How to build a micro wind turbine

How to build a micro wind turbine


"How to build a micro wind turbine" is a practical manual full of pictures, plans, tables and comments to learn how to build a 100W wind turbine and 6 metre tower from scratch, for less than 250 USD. The design is based on very reliable, efficient and easy to build Piggott's turbines. This micro turbine with five blades is appropriated to power a boat, a shelter, a RV or an household in a developing country. A design to build a simple and low cost wind controller is included. The book "A wind turbine recipe book" from Hugh Piggott is strongly recommanded as a complement to this manual. The units are international metrics.

Wind Turbine Maintenance Level 1 Volume 1 Trainee Guide (Contren Learning)

Wind Turbine Maintenance Level 1 Volume 1 Trainee Guide (Contren Learning)
by NCCER (Author)


This exceptionally produced trainee guide features a highly illustrated design, technical hints and tips from industry experts, review questions and a whole lot more! Key content includes: Introduction to Wind Energy, Introduction to Wind Turbine Safety, Climbing Wind Towers, Introduction to Electrical Circuits, Electrical Theory, Electrical Test Equipment, and Electrical Wiring.     Instructor Supplements Instructors: Product supplements may be ordered directly through OASIS at http://oasis.pearson.com. For more information contact your Pearson NCCER/Contren Sales Specialist at http://nccer.pearsonconstructionbooks.com/store/sales.aspx.   ·    Annotated Instructor's Guide (AIG) Paperback (Includes access code for Instructor Resource Center) 978-0-13-272049-6 ·  ...

Homebrew Wind Power

Homebrew Wind Power
by Dan Bartmann (Author), Dan Fink (Contributor), Mick Sagrillo (Contributor)


Have you ever wondered how wind turbines work and why they look like they do? Are you interested in adding wind power to your off-grid electric system, but have been put off by the high cost of equipment and installation? Well, now you can build and install your own wind turbine! Harnessing the wind can be a tricky business, but in this groundbreaking book the authors provide step-by-step, illustrated instructions for building a wind generator in a home workshop. Even if you don't plan on building your own turbine, this book is packed with valuable information for anyone considering wind energy. It covers the basic physics of how the energy in moving air is turned into electricity, and most importantly, will give you a realistic idea of what wind energy can do for you--and what it can't.

© 2014 BrightSurf.com