Research at the Caltech Field Laboratory for Optimized Wind Energy, directed by John Dabiri, suggests that arrays of closely spaced vertical-axis wind turbines produce significantly more power than conventional wind farms with propeller-style turbines. (Credit: John Dabiri, Caltech)

Conventional wisdom suggests that because we’re approaching the theoretical limit on individual wind turbine efficiency, wind energy is now a mature technology. But California Institute of Technology researchers revisited some of the fundamental assumptions that guided the wind industry for the past 30 years, and now believe that a new approach to wind farm design — one that places wind turbines close together instead of far apart — may provide significant efficiency gains.

This challenges the school of thought that the only remaining advances to come are in developing larger turbines, putting them offshore, and lobbying for government policies favorable to the further penetration of wind power in energy markets.

“What has been overlooked to date is that, not withstanding the tremendous advances in wind turbine technology, wind ‘farms’ are still rather inefficient when taken as a whole,” explains John Dabiri, professor of Engineering and Applied Science, and director of the Center for Bioinspired Engineering at Caltech. “Because conventional, propeller-style wind turbines must be spaced far apart to avoid interfering with one another aerodynamically, much of the wind energy that enters a wind farm is never tapped. In effect, modern wind farms are the equivalent of ‘sloppy eaters.’ To compensate, they’re built taller and larger to access better winds.”

But this increase in height and size leads to frequently cited issues such as increased cost and difficulty of engineering and maintaining the larger structures, other visual, acoustic, and radar signatures problems, as well as more bat and bird impacts.

Dabiri is focusing on a more efficient form of wind ‘farm’ design, relegating individual wind turbine efficiency to the back seat. He describes this new design in the American Institute of Physics’ Journal of Renewable & Sustainable Energy.

“The available wind energy at 30 feet is much less abundant than that found at the heights of modern wind turbines, but if near-ground wind can be harnessed more efficiently there’s no need to access the higher altitude winds,” he says. “The global wind power available at 30 feet exceeds global electricity usage several times over. The challenge? Capturing that power.”

The Caltech design targets that power by relying on vertical-axis wind turbines (VAWTs) in arrangements that place the turbines much closer together than is possible with horizontal-axis propeller-style turbines.

VAWTs provide several immediate benefits, according to Dabiri, including effective operation in turbulent winds like those occurring near the ground, a simple design (no gearbox or yaw drive) that can lower costs of operation and maintenance, and a lower profile that reduces environmental impacts.

Two of the primary reasons VAWTs aren’t more prominently used today are because they tend to be less efficient individually, and the previous generation of VAWTs suffered from structural failures related to fatigue.

“With respect to efficiency issues, our approach doesn’t rely on high individual turbine efficiency as much as close turbine spacing. As far as failures, advances in materials and in predicting aerodynamic loads have led to new designs that are better equipped to withstand fatigue loads,” says Dabiri.

Field data collected by the researchers last summer suggests that they’re on the right track, but this is by no means ‘mission accomplished.’ The next steps involve scaling up their field demonstration and improving upon off-the-shelf wind turbine designs used for the pilot study.

Ultimately, the goal of this research is to reduce the cost of wind energy. “Our results are a compelling call for further research on alternatives to the wind energy status quo,” Dabiri notes. “Since the basic unit of power generation in this approach is smaller, the scaling of the physical forces involved predicts that turbines in our wind farms can be built using less expensive materials, manufacturing processes, and maintenance than is possible with current wind turbines.”

A parallel effort is underway by the researchers to demonstrate a proof-of-concept of this aspect as well.

American Institute of Physics (2011, July 20). Bold new approach to wind ‘farm’ design may provide efficiency gains. ScienceDaily http://www.sciencedaily.com­ /releases/2011/07/110713131644.htm

The Original Post is Located Here: A New Approach to Wind ‘Farm’ Design

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World Can Be Powered by Alternative Energy, Using Today’s Technology, in 20-40 Years, Experts Say

If someone told you there was a way you could save 2.5 million to 3 million lives a year and simultaneously halt global warming, reduce air and water pollution and develop secure, reliable energy sources — nearly all with existing technology and at costs comparable with what we spend on energy today — why wouldn’t you do it?

According to a new study coauthored by Stanford researcher Mark Z. Jacobson, we could accomplish all that by converting the world to clean, renewable energy sources and forgoing fossil fuels.

“Based on our findings, there are no technological or economic barriers to converting the entire world to clean, renewable energy sources,” said Jacobson, a professor of civil and environmental engineering. “It is a question of whether we have the societal and political will.”

He and Mark Delucchi, of the University of California-Davis, have written a two-part paper in Energy Policy in which they assess the costs, technology and material requirements of converting the planet, using a plan they developed.

The world they envision would run largely on electricity. Their plan calls for using wind, water and solar energy to generate power, with wind and solar power contributing 90 percent of the needed energy.

Geothermal and hydroelectric sources would each contribute about 4 percent in their plan (70 percent of the hydroelectric is already in place), with the remaining 2 percent from wave and tidal power.

Vehicles, ships and trains would be powered by electricity and hydrogen fuel cells. Aircraft would run on liquid hydrogen. Homes would be cooled and warmed with electric heaters — no more natural gas or coal — and water would be preheated by the sun.

Commercial processes would be powered by electricity and hydrogen. In all cases, the hydrogen would be produced from electricity. Thus, wind, water and sun would power the world.

The researchers approached the conversion with the goal that by 2030, all new energy generation would come from wind, water and solar, and by 2050, all pre-existing energy production would be converted as well.

“We wanted to quantify what is necessary in order to replace all the current energy infrastructure — for all purposes — with a really clean and sustainable energy infrastructure within 20 to 40 years,” said Jacobson.

One of the benefits of the plan is that it results in a 30 percent reduction in world energy demand since it involves converting combustion processes to electrical or hydrogen fuel cell processes. Electricity is much more efficient than combustion.

That reduction in the amount of power needed, along with the millions of lives saved by the reduction in air pollution from elimination of fossil fuels, would help keep the costs of the conversion down.

“When you actually account for all the costs to society — including medical costs — of the current fuel structure, the costs of our plan are relatively similar to what we have today,” Jacobson said.

One of the biggest hurdles with wind and solar energy is that both can be highly variable, which has raised doubts about whether either source is reliable enough to provide “base load” energy, the minimum amount of energy that must be available to customers at any given hour of the day.

Jacobson said that the variability can be overcome.

“The most important thing is to combine renewable energy sources into a bundle,” he said. “If you combine them as one commodity and use hydroelectric to fill in gaps, it is a lot easier to match demand.”

Wind and solar are complementary, Jacobson said, as wind often peaks at night and sunlight peaks during the day. Using hydroelectric power to fill in the gaps, as it does in our current infrastructure, allows demand to be precisely met by supply in most cases. Other renewable sources such as geothermal and tidal power can also be used to supplement the power from wind and solar sources.

“One of the most promising methods of insuring that supply matches demand is using long-distance transmission to connect widely dispersed sites,” said Delucchi. Even if conditions are poor for wind or solar energy generation in one area on a given day, a few hundred miles away the winds could be blowing steadily and the sun shining.

“With a system that is 100 percent wind, water and solar, you can’t use normal methods for matching supply and demand. You have to have what people call a supergrid, with long-distance transmission and really good management,” he said.

Another method of meeting demand could entail building a bigger renewable-energy infrastructure to match peak hourly demand and use the off-hours excess electricity to produce hydrogen for the industrial and transportation sectors.

Using pricing to control peak demands, a tool that is used today, would also help.

Jacobson and Delucchi assessed whether their plan might run into problems with the amounts of material needed to build all the turbines, solar collectors and other devices.

They found that even materials such as platinum and the rare earth metals, the most obvious potential supply bottlenecks, are available in sufficient amounts. And recycling could effectively extend the supply.

“For solar cells there are different materials, but there are so many choices that if one becomes short, you can switch,” Jacobson said. “Major materials for wind energy are concrete and steel and there is no shortage of those.”

Jacobson and Delucchi calculated the number of wind turbines needed to implement their plan, as well as the number of solar plants, rooftop photovoltaic cells, geothermal, hydroelectric, tidal and wave-energy installations.

They found that to power 100 percent of the world for all purposes from wind, water and solar resources, the footprint needed is about 0.4 percent of the world’s land (mostly solar footprint) and the spacing between installations is another 0.6 percent of the world’s land (mostly wind-turbine spacing), Jacobson said.

One of the criticisms of wind power is that wind farms require large amounts of land, due to the spacing required between the windmills to prevent interference of turbulence from one turbine on another.

“Most of the land between wind turbines is available for other uses, such as pasture or farming,” Jacobson said. “The actual footprint required by wind turbines to power half the world’s energy is less than the area of Manhattan.” If half the wind farms were located offshore, a single Manhattan would suffice.

Jacobson said that about 1 percent of the wind turbines required are already in place, and a lesser percentage for solar power.

“This really involves a large scale transformation,” he said. “It would require an effort comparable to the Apollo moon project or constructing the interstate highway system.”

“But it is possible, without even having to go to new technologies,” Jacobson said. “We really need to just decide collectively that this is the direction we want to head as a society.”

Jacobson is the director of Stanford’s Atmosphere/Energy Program and a senior fellow at Stanford’s Woods Institute for the Environment and the Precourt Institute for Energy.

Stanford University (2011, January 27). World can be powered by alternative energy, using today’s technology, in 20-40 years, experts say. ScienceDaily. Retrieved January 27, 2011, from http://www.sciencedaily.com­ /releases/2011/01/110126091443.htm

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The Original Post is Located Here: World Can Be Powered by Alternative Energy

At present, wind power can be harnessed to produce electricity. This is basically done by erecting a tall tower, with a propeller on top. The wind makes the propeller rotate, and the rotating mechanisms then in turn generate electricity. A wind farm is an area with several such towers operating, which, combined, produce enough energy to provide power to a whole area.

The more wind towers there are, the more electricity is produced. Location is key to maintaining a productive wind farm. The area should have steady, strong winds, blowing at all times. Ideal regions include coastal areas, open plains, hills tops, and mountain gaps. Some wind farms are located offshore. The average wind velocity should be approximately 25 km per hour.

Aside from the location, the size of the propeller is an essential factor as well. The bigger the propeller, the larger the volume of wind that can be harnessed, in order to extract energy. The blades can be angled, so as to cope best with the wind speed.

Some wind towers are designed to turn their propellers with the direction of the wind. There designs utilize vertical turbines. The height of the towers should also be set to the wind’s strongest point. In some areas, the land below is used as farmland. That maximizes the space and productivity of the area and ensures that the land is not be wasted at all.

Pros and Cons of Using Wind Power

There are disadvantages to using wind power. When the wind isn’t blowing, a farm won’t produce power. Another disadvantage is that many suitable areas have a high real estate value, especially in the case of coastal lots. Some don’t like it when the wind towers block scenery, and consider windmills as eyesores. Wind generators are noisy, which can be very disturbing to some.

Wind power has its advantages as well. Some wind farms are tourist attractions and bring visitors into an area. Remote areas which are off the main energy grids can use the wind, for a supply of electricity to their communities. The power itself is free, and the turbines don’t any fuel power in order to operate. It also produces no harmful side effect, and doesn’t emit any dangerous gases into the air.

While it is true that there are drawbacks to using this form of energy, however, it is also true that the disadvantages involved with the uses of polluting fossil fuels are far more harmful and problematic in the long run.

The Original Post is Located Here: Harnessing Clean Energy: Wind Power

Recent environmental concerns have made way for the return of wind power, and in its wake came a host of myths, mistruths and misunderstandings. This article aims to dispel some of the common myths of wind power.

Wind turbines are only efficient in high winds
This is a common misconception regarding wind turbines. Obviously the more wind there is the more electricity each wind turbine will generate, but even in a light breeze both large commercial wind turbines and the smaller residential wind turbines will generate an acceptable amount of electricity. As the wind speed changes, the angle of the turbines blades will adjust themselves accordingly to achieve maximum efficiency, regardless of wind speed.

Wind turbines are noisy
This may have been true in the past as many early wind turbines had no noise emission guidelines to adhere to. Also, wind turbine manufacturers and wind power companies didn’t really consider the impact a large scale wind farm would have on nearby residential areas. These early wind turbines are the source of the current ‘wind turbines are noisy’ myth. Over the last decade wind turbine technology had progressed considerably, rendering mechanical noise almost undetectable.

Wind farm planners have strict guidelines to adhere to in order to protect nearby residential areas from noise emissions. This doesn’t mean that wind farms are silent as there is an audible ‘swoosh’ as the turbines blades pass the tower; however this is only heard at a relatively close range.

Wind farms are not cost effective
Twenty to thirty years ago, wind farms and wind turbine technology was a victim of trial and error to a certain extent. Let us not confuse older, noisier and more costly wind farms with their modern counterparts. In the early 1980′s over 5000 wind turbines were put in place at the Tehachapi Pass in California. These days wind farms consist of fewer, larger wind turbines which have proved not only more cost effective but more attractive on the eye than the early wind farms which dotted the landscape with hundreds of smaller wind turbines.

Home wind turbines are a waste of time and money
The smaller home wind turbines are more often than not used in combination with an array of solar panels. The wind turbine will continue to charge the batteries through the night even in a light breeze meaning a steady trickle of electricity is potentially available 24 hours a day. Prices of home wind turbines vary depending on the output power and installation cost. A small residential wind turbine will reduce an average electricity bill by around 20-35%. Or to put it another way, a residential wind turbine would save around half a ton of CO2 each year.

Wind farms kill birds
It is true that a considerable number of birds have flown into the blades of wind turbines and as a result have been injured or even killed. Saying that, it is also true that a large number of birds are killed each year as a result of flying into tall buildings or are hit by cars, trains, trucks and buses. It is an unfortunate fact that human impact on the environment does take its toll on wildlife to a certain extent; however, wind farms do not pose any considerable threat to birds or any other form of wildlife.

The Original Post is Located Here: Blowing Away the Myths of Wind Power

Countries like Denmark and Spain have already successfully harnessed wind power to supply a portion of their electric power. In London, a vast wind farm expected to become the largest in the world has already begun construction, a physical manifestation of the country’s efforts towards encouraging the renewable energy sector. Elsewhere in the United States are several wind farms established for power generation, such as those in Pampa, Texas and in Fond du Lac County in Wisconsin. In Wyoming, there is the Happy Jack Windpower Facility that already began its commercial operations in September 2008.

Another renewable energy source is also being used to generate power and for other practical purposes as well—solar power. In states filled with sunshine the whole year through, such as California and Nevada, solar thermal power plants are being constructed with the aim of supplying power to a large percentage of households. However, the largest photovoltaic plant in the world is found in Germany and is expected to become operational in 2009. Several communities in the United States are also implementing plans of purchasing and installing their own photovoltaic farms to supply renewable energy to its households.

Many places all over the world are also harnessing geothermal energy for power supply. In the United States, the latest projects of this kind have been initiated in Beaver County, Utah and in New Mexico. The former has a geothermal power plant called Thermo while the latter has just begun construction on the Lightning Dock Geothermal Power Plant.

Wave power is also being tapped as potential source of renewable source, with the opening of a large wave farm in Portugal in September 2008. This first of its kind facility is expected to generate more than 2 MW of electricity. In Oahu, Hawaii, the US Navy has funded and taken active participation in the development of a wave energy technology expected to generate about 1 MW of electricity.

And elsewhere in the world, car manufacturers, legislators, and private individuals have taken interest and commitment to reduce carbon dioxide emissions through the use of more energy efficient automobiles. Most of these vehicles are also capable of using the biofuel ethanol, which is certainly affordable and produces no pollutants into the atmosphere.

With most of the countries in the world and environmental organizations pushing for the use of renewable energy resources and for the development of supporting technologies, there is an expected trend of consumer preference toward renewable energy supply. Because of these, it is also expected that the renewable energy sector will continue to increase and expand with more investments from capitalists all over world. With these developments, the goals of reducing the world’s dependence of fossil fuels and enjoying cleaner environment are slowly reaching realization.

The Original Post is Located Here: Developments in the Renewable Energy Sector

Much renewable energy is harnessed for the production of electricity to power homes and offices. While biofuels, wind, and solar energy are making strides in Canada, wave and tidal power has not received the same amount of attention. This may soon change due to the amount of ocean available on both coasts and to the north. In fact, these coasts are capable of producing a quarter of Canada’s annual electricity consumption through wave and tidal power. And because the waves and tides are a consistent natural force, wave-powered energy production is more dependable than that provided by the intermittent sun and wind.

The perception that Canada is lagging in the wave and tidal power department is partially due to its overshadowing accomplishments in solar and wind power. In actuality, Canada trails only the United States and United Kingdom in wave power development. Natural Resources Canada is helping future wave and tidal projects by creating an atlas that points to useful locations in which to construct wave and tidal power plants.

Nunavut is one such location. Meaning “our land” in Inuktitut, it became independent of the Northwest Territories in April of 1999 and comprises a large portion of northern Canada. Consisting of just over 29,000 residents spread over a region the size of Western Europe, it is an ideal location upon which to set up onshore wave and tidal power systems. Because the residents that live along Nunavut’s water do not use the shores for recreation, the concrete and steel structures of a wave powered turbine would not interfere with swimmers or boaters. Furthermore, in the waters of Nunavut and Canada’s eastern and western coasts, there are plenty of available oceans for offshore wave and tidal power systems.

Riding the waves in order to create the pressure needed to move electricity-producing turbines, the bobbers and hoses of a wave power system require no power besides the renewable energy of the earth’s waves to operate. Canada has more than enough water power on its shores to make wave and tidal power a priority.

The Original Post is Located Here: Canada Looking To Ride The Waves To Electricity Production

You may not know this, but wind turbines are becoming a great alternative to run power at many home across our country. While it cost you to own one initially, but in the long term, you will eventually recoup your costs. And if you were to utilize wind turbines that are powered with solar panels, the two items are a powerful force in creating low cost energy.

Solar energy by itself is totally free. However, if you are not careful, the price and maintenance of a solar panel can be very expensive so you need to consider whether your want to build one or buy one to use at home.

Another potential source of free electricity is nuclear power. This kind of power is already developed in many different countries. The initial price of setting up this system is very expensive. But the bad concern with nuclear power is that people are afraid of the risks because of the incidents at Chernobyl and Three Mile Island. While it is not entirely impossible, using a nuclear power plant to run the power of the most part of the earth is expensive and risky.

When you consider all the power sources that we have mentioned here, it appears that the wind power is the most affordable. You just need to have a windy environment to effectively run the electricity. A gentle breeze will do for as long as it will keep the turbine running.

Wind turbines are very affordable. In fact, many companies today are selling wind turbines on an increasing scale. Capturing free power from the wind will only require that you install a wind turbine generator at your home.

A wind turbine can be constructed from auto parts (either new or old). Put the wind turbine at the highest place in your house as possible. Winds turbine is actually a good substitute for places that do not have access to the local power utility. Anyone who has knowledge with auto workshop and mechanic can actually build one wind turbine for himself.

The Original Post is Located Here: Wind Power Is The Best Choice

The #1 Question:

How much does it cost? Is all the equipment of a windmill expensive?
With patience, one could pick up all materials needed and build one for less than $200.00. Some of the materials can even be found for free.

How difficult is it to build?
Today? Not very difficult at all with all the homemade wind generator resources out there. Find a set of plans that are easy, step by step instructions. Make sure there are plenty of diagrams and pictures. And make sure you can understand it. Terminology in layman’s terms obviously is the best. With all the proper pieces, your wind generator can be built in less than a day.

How much wind is needed?
Very light winds between 5-15 mph. There is a cut in range, when the blades are beginning to produce power and a survival range, the max wind speed it can handle before the blades "fly off the handle"

How much space do I need?
Wind generators that are homemade take up a small footprint. Using an old homeowners radio tower or TV antenna, many times these items are unnoticeable being now immune to our eyes as part of the landscape. If you are storing electricity in batteries, you will need the space of a small trunk to more if your windmill is larger.

How do I save money?
Obviously, the less power you have to buy from your local power company, the more you will save.

Can I make money by going to a wind generator?
Yes, if you live in a location that offers to buy your excess power. This is called net metering. Check with your local power company to see if they offer incentives such as net metering, credits or rebate programs.

Is it safe?
Energy in any form is inherently dangerous. Just as with any industry, there are hazards for those who work with wind energy, dealing with high winds, heights, and moving machinery such as the spinning of the wind turbine rotor. The damage caused by wind energy is evidenced everywhere. When wind kills, it is well known. Building your own wind generator is safe as long as you put safety 1st.

The Original Post is Located Here: Frequently Asked Questions When Considering Using Wind Power for Your Home

Here are just a few easy, yet effective, changes you can start making today.

1. Make sure your furnace is ready for the winter ahead. Arrange to have a qualified HVAC professional check and clean your heating unit. Once you start operating your heating unit regularly make sure that you change your filters monthly. If the filter becomes dirty it will restrict the airflow making the heating unit use more energy as it has to work harder.
2. Add a programmable thermostat, so that you can set it to automatically adjust the temperature settings at certain times of the day and certain days of the week. This way the temperature in your home will automatically go down during the day when no one is home, or at night when everyone is under covers. It can also raise the temperature shortly before you get out of bed in the mornings.
3. Maintain your fireplace. Make sure the chimney is cleaned, in good repair and clear of any obstructions. If you use your fireplace more than once a week you should have it professionally cleaned every year. It is also prudent to install a cap or screen at the top of your chimney to prevent birds from building nests.
4. Seal around your windows and doors. The more heat loss you can prevent the less your furnace will have to work, and that will save you money all season long. Window kits are another way to help prevent heat loss from older windows. Glass is a big conductor of heat, so it is always helpful to have some heavy drapes across the windows to minimise the heat loss through the windows.
5. Try some wind power on a small scale, (think home windmill) along with the above winterizing tips and you will be ahead of the game in cutting your long term heating and electric bills.

Now is the best time to make some simple changes to help you cut your energy bills this winter. Take a few minutes now to save hundreds not only this winter but throughout the rest of the year and for years to come.

The Original Post is Located Here: Simple Tips to Winterize Your Home and Cut Energy Bills

Airborne turbines like these depicted in this illustration could generate electricity from strong high-altitude winds. Credit: Ben Shepard, courtesy Sky WindPower

“There is a huge amount of energy available in high-altitude winds,” said researcher Ken Caldeira at the Carnegie Institution’s Department of Global Ecology in Stanford, Calif. “These winds blow much more strongly and steadily than near-surface winds, but you need to go get up miles to get a big advantage. Ideally, you would like to be up near the jet streams, around 30,000 feet.”

All told, if wind turbines miles above the planet were tethered to 10 percent of the world’s land, there is enough energy in these jet stream winds to meet world demand 100 times over, researchers said.

Jet streams are meandering belts of fast winds at altitudes between 20,000 and 50,000 feet. They shift seasonally, but are otherwise persistent features in the atmosphere. Jet stream winds are generally steadier and 10 times faster than wind near the ground, making them a potentially vast and dependable source of energy.

But how to capture the wind so high?

Kites and tethers
A number of technological schemes have been proposed to harvest energy from these high-altitude winds, including tethered, kite-like wind turbines lofted miles high. Up to 40 megawatts of electricity could be generated by current designs and transmitted to the ground via tether.

Using 28 years of weather data, the researchers developed the first-ever global survey of high-altitude wind energy.

“We found the highest wind power densities over Japan and eastern China, the eastern coast of the United States, southern Australia, and north eastern Africa,” said researcher Cristina Archer, an atmospheric scientist at California State University in Chico.

These specific areas generate roughly 10 kilowatts per square meter or more. “This is unthinkable near the ground, where even the best locations have usually less than one kilowatt per square meter,” Archer added.

The analysis also looked at some of the world’s largest cities: Tokyo, New York, Sao Paulo, Seoul and Mexico City. New York proved a prime location, as did the East Asian cities.

“For cities that are affected by polar jet streams such as Tokyo, Seoul and New York, the high-altitude resource is phenomenal,” Archer said. “New York, which has the highest average high-altitude wind power density of any U.S. city, has an average wind power density of up to 16 kilowatts per square meter.”

Tokyo and Seoul also have high wind power density, as they are both affected by the East Asian jet stream. Since Mexico City and Sao Paulo are located at tropical latitudes, they are rarely affected by the polar jet streams and only occasionally by the weaker sub-tropical jets. As a result they see lower wind power densities than the other three cities.

Issues remain
Another issue is whether implementing such devices on a wide scale could alter general air circulation patterns and thus impact local and global climate. Their simulations hint that if carried to unlikely extremes, blanketing the entire planet with such devices would cool the Earth’s surface, reduce precipitation and boost sea ice levels. However, if deployed at levels comparable to total global electricity demand, there seemed to be no detectable effect on the climate even after 70 years.

Also, fluctuating wind strength still presents a challenge when it comes to exploiting this energy source on a large scale, just as it does on the ground.

“While there is enough power in these high altitude winds to power all of modern civilization, at any specific location there are still times when the winds do not blow,” Caldeira said. Even over the best areas, the wind can be expected to fail about 5 percent of the time.

“This means that you either need back-up power, massive amounts of energy storage, or a continental or even global scale electricity grid to assure power availability,” he added. “So, while high-altitude wind may ultimately prove to be a major energy source, it requires substantial infrastructure.”

Archer told LiveScience she did not think high-altitude wind power would solve the entire planet’s energy needs by itself — “you don’t want something that’s not 100 percent reliable. But I am positive that it could play an important role.”

Archer and Caldeira detailed their findings online May 26 in the journal Energies.

By Charles Q. Choi, Special to LiveScience

The Original Post is Located Here: Miles-High Kites Could Generate Electricity