Putting The Wind To Work

The use of wind to generate electricity continues to grow at an astonishing rate. For each of the last three years, new wind power facilities coming online in America have set records.

According to the American Wind Energy Association, our nation added another 5,244 megawatts of wind-powered generating capacity during 2007. That brought the total working wind capacity up to 16,818 megawatts by last January.

Wind power projects still under construction and new projects planned for the rest of 2008 are much larger. By the end of this year, wind power could be generating about 48 billion kilowatt-hours of electricity—that’s enough for about four and a half million homes.

These are impressive numbers—yet wind power by the end of this year will still supply only about 1 percent of America’s demand for electricity.

What will it take to increase this percentage by substantial amounts?

That’s just what the Electric Power Research Institute (the electric utility research organization) asked when it conducted an extensive survey about how technology could help reduce greenhouse gas emissions between now and mid-century.

The report, compiled two years ago and released the middle of last year, pointed out that before wind power can be used even more widely and efficiently, a lot of problems must be solved.

EPRI’s PRISM report, a summary of all their findings for reducing greenhouse gas emissions, noted two major areas in which wind power will need aggressive development and implementation of advanced technology.

One area that needs improvement is the nation’s electric utility infrastructure, the interlocking grid of transmission and distribution lines.

A key concern is managing the flow of electricity through the grid from wind power plants. As more wind power generating facilities are added, the present infrastructure will need to be upgraded to accommodate some of the unique features of wind power. The impact of increased generation from wind power resources will vary in any particular geographic area, depending on how large a portion of that region’s generating mix depends on wind.

When wind power supplies up to about 10 percent of the electricity in a regional system, it’s fairly easy for grid system managers to shift the flow of electricity seamlessly when that wind power varies.

When wind generates between 10 and 20 percent of the electricity within a system, managers and grid operators will need much better computer software to control the flow of electricity coming from all sources so consumers have a steady supply of electricity at all times. If a regional system installs so much wind generating capacity that wind provides more than 20 percent of the power mix, even greater changes will be necessary.

Another concern about adapting the electric utility infrastructure to using more wind power involves the location of wind power plants. Since many areas with good wind resources are located far from densely populated areas, new transmission lines will be needed to bring that electricity to where it is needed.

As important as the infrastructure issues are, at the moment there is much more interest in the second area that EPRI investigated in its study of wind power: developing better technology to harvest wind power. The devices that operate in the wind to convert that energy to electricity must be improved. Designing more efficient wind turbines that can be used in a variety of situations is quite a challenge.

Let’s take a look at the different ways wind power can be used, and see how Kentucky is playing a role in the development of cutting-edge technology for wind power.

Big wind, little wind
The tricky issue with wind as an energy source is that, when you want to use electricity or other energy, you want it immediately. But the wind may not be blowing, or not blowing hard enough.

Wind blows at different speeds in different parts of the country. In any particular spot, the wind may blow at one speed early in the day or late during the night, but very little in mid-afternoon. And it can change from season to season.

This variation means that some locations with plentiful and predictable winds throughout the year are more suitable for huge wind farms. Large arrays of many wind turbines are grouped together over many acres. Together, they can generate electricity measured in hundreds of kilowatts. Electricity from these wind power facilities can be added into the grid as a regular resource. Such “utility scale” installations need big winds most of the time to be cost efficient to build.

These utility-scale wind power systems reduce greenhouse gases in an important way. Whenever the wind is generating enough electricity to supply power to the regional grid of power lines, the equivalent amount of electricity is not being generated from conventional fossil fuel power plants. Grid operators can move electricity from wind through the grid while the other plants are in stand-by mode. Wind power plants do not emit greenhouse gases when they operate, so using them can result in a big reduction in emissions.

But there’s another way to reduce greenhouse gas emissions, and reduce use of nonrenewable energy, by using the wind.

Even in areas with lighter or more variable wind resources that aren’t suitable for utility-scale wind projects, wind power can still be an important option. These spots could be just right for simpler, lower kilowatt projects, known as “small wind.” A single wind turbine, or a little group of wind turbines, can produce electricity to directly meet a local need, such as power for a small office building or manufacturing plant.

These small wind projects are not connected to the electric utility transmission grid.

When the wind is blowing at the correct speed to generate electricity, the user gets power directly from the on-site small wind installation instead of from the utility company electric grid. When there isn’t enough wind to generate power from this on-site system, the user’s electricity does come from the grid.

Every time the wind blows enough to operate the small wind system, the user doesn’t have to buy power from the local utility’s connection to the grid. When a utility company’s fossil fuel power plant doesn’t have to supply electricity to this user, it runs at lower capacity and uses less fossil fuel—so that reduces greenhouse gas emissions, too.

Testing new technology
There are two main ways to catch the power of wind and use it to generate electricity. Most people have seen a horizontal axis wind power device. It looks like an airplane propeller mounted on a very tall flagpole. It works best in areas with high-speed prevailing winds. These devices are typically grouped together in large arrays for utility-scale power generation.

Although Kentucky doesn’t have the wind resources for such big wind projects, the Bluegrass State is playing an important role in advancing wind technology. Two companies here are developing and testing new wind power solutions that make use of horizontal wind power devices. These are more suitable for small wind projects.

Jim Fugitte, chairman and CEO of Wind Energy Corporation headquartered in Elizabethtown, says, “Big wind is dominated by turbines that make use of the propeller lift system. They require consistent prevailing wind speeds between 20 and 40 miles per hour to spin the blades at a high number of revolutions per minute. Our product is different—it has a different shape and can operate in lower winds. Our target is to develop our product as a 25-kilowatt rated generator with peak generating capacity at 35 kilowatts.”

There are two major styles of vertical axis wind turbines, the Savonius model and the Darrieus model. A Darrieus wind turbine looks a lot like an upside-down eggbeater. Savonius-style wind turbines can have different shapes. The two most common styles look like a large sail with a spiral twist in it, or a big version of a child’s pinwheel toy. Researchers at Western Kentucky University in Bowling Green participated in some of the early design tests for Wind Energy’s Savonius models.

Fugitte says, “Our product is a sail design. We’ve done all the laboratory tests with wind tunnels and we’re very satisfied with the mechanism. Our system is efficient at lower wind speeds.”

Later this year, Wind Energy will begin a “small wind” test project to provide power directly to a site in Weslaco, Texas. Food retailer H-E-B wants to use local wind power to provide as much electricity as possible at its retail support center. This test will answer a lot of questions about the practicality of small wind projects.

“We have two distinct objectives in Texas,” Fugitte says. “We want to evaluate the performance of our turbine, and also determine what the wind resources are in that location. We’re putting up a meteorological station along with the turbines to record wind speeds and direction all the time.”

Unlike propeller wind turbines that, due to their design, only turn when the wind is coming from a certain direction, Wind Energy’s new device can harvest wind from any direction. Fugitte notes that in their early research they discovered there aren’t any minute-by-minute records of wind statistics kept in the United States. Gathering local wind data at the test site will be an important part of this new project.

Wind Energy will manufacture its turbines in Morgantown for this test and other projects. “By July this year, we hope to employ about 30 people,” Fugitte says, “and we’ll have the space to manufacture about 60 turbines each year.”

Another Kentucky company, Dynastrosi Laboratories, Inc., headquartered in Bowling Green, helped with much of the initial design and testing of Wind Energy’s new turbines. President and CEO Ronald Jones says, “Our company specializes in products manufactured from advanced composite materials, such as carbon fibers.”

Wind turbine design is a very competitive field right now, with different companies pursuing different design approaches for different situations around the world.

Jones notes that the turbine designed for Wind Energy is for point-of-use applications, while that for a company based in California is intended for use in a European country’s utility grid. Tall and slim, this innovative experimental vertical design may blend in visually much better than a large horizontal wind axis turbine.

Jones notes that his company is now working with the Bowling Green staff of Kenmold (a company headquartered in China) to develop a manufacturing facility in mainland China to produce these unique wind turbines for the California based entrepreneur.