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

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...

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...

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.

Sixteen Wind Turbines: Crystal seas, blase prairielands, and......

Sixteen Wind Turbines: Crystal seas, blase prairielands, and......
by BookRix


The memoirs of my first trip to Cornwall in over forty years, and the first ever to the North Cornish Coast. It was here that I finally found where heaven was.

Like so many prairielands in the UK, Cornwall is not short of paradise for the hardened rambler.

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 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...

Wind Turbine Technology: Principles and Design

Wind Turbine Technology: Principles and Design
by Muyiwa Adaramola (Editor)


This important book presents a selection of new research on wind turbine technology, including aerodynamics, generators and gear systems, towers and foundations, control systems, and environmental issues. This informative book: • Introduces the principles of wind turbine design • Presents methods for analysis of wind turbine performance • Discusses approaches for wind turbine improvement and optimization • Covers fault detection in wind turbines • Describes mediating the adverse effects of wind turbine use and installation

Wind Energy Handbook

Wind Energy Handbook
by Tony Burton (Author), David Sharpe (Author), Nick Jenkins (Author), Ervin Bossanyi (Author)


As environmental concerns have focused attention on the generation of electricity from clean and renewable sources wind energy has become the world's fastest growing energy source. The Wind Energy Handbook draws on the authors' collective industrial and academic experience to highlight the interdisciplinary nature of wind energy research and provide a comprehensive treatment of wind energy for electricity generation. Features include: An authoritative overview of wind turbine technology and wind farm design and development In-depth examination of the aerodynamics and performance of land-based horizontal axis wind turbines A survey of alternative machine architectures and an introduction to the design of the key components Description of the wind resource in terms of wind speed frequency...

How to Install a Small to Mid Size Solar & Wind Power Generation System

How to Install a Small to Mid Size Solar & Wind Power Generation System


How to Install a
Small to Mid size
Solar Power and Wind Generation System

Using/Installing Solar Panels plus info on Wind Generator Installation

Most people think that solar power is only used to power huge inverters to attach to the power grid and feed extra power back into the grid. Well yes you can do this IF you have thousands and THOUSANDS of dollars to spend.

Most people don’t even think or realize how much you can do with 12 volt power.
I have 98% of all the lights inside and outside my home are 12 volt LED’s. Most of my LED lights use only 3 watts or 6 watts of power.
I have a 12 volt Evaporative (swamp) Cooler to cool my home on hot summer days.
I have a 12 volt coffee pot to make my coffee in the...

And Soon I Heard a Roaring Wind: A Natural History of Moving Air

And Soon I Heard a Roaring Wind: A Natural History of Moving Air
by Bill Streever (Author)


A thrilling exploration of the science and history of wind from the bestselling author of Cold.

Scientist and bestselling nature writer Bill Streever goes to any extreme to explore wind--the winds that built empires, the storms that wreck them--by traveling right through it. Narrating from a fifty-year-old sailboat, Streever leads readers through the world's first forecasts, Chaos Theory, and a future affected by climate change. Along the way, he shares stories of wind-riding spiders, wind-sculpted landscapes, wind-generated power, wind-tossed airplanes, and the uncomfortable interactions between wind and wars, drawing from natural science, history, business, travel, as well as from his own travels.

AND SOON I HEARD A ROARING WIND is an effortless personal narrative...

© 2016 BrightSurf.com