The winds of change are blowing over Buffalo Ridge in this corner of northwestern Iowa, where nearly as far as the eye can see gigantic propeller blades atop 200-foot steel towers move slowly in the breeze, casting darting shadows over corn and soybean fields like the wings of hundreds of prehistoric birds.

The scene somehow looks oddly out of place for the heartland of America. It seems more suited to California, where generating power with windmills first took hold in the early 1980s amid much derision and skepticism over it ever becoming a cost-effective source of alternative energy.

But federal energy officials, who have called the Great Plains states "the Saudi Arabia of wind power," helped dedicate the world's largest single wind power project here yesterday, setting the Midwest on a course policymakers hope will soon propel the region past California as the U.S. leader in wind turbine power. Another wind power project was dedicated Friday at Lake Benton, Minn.

"There's nothing more American than farmers in the Midwest," Energy Secretary Bill Richardson said in an interview. "I think that once people see so much wind power in the heartland, you'll see more support for it all across the country."

Richardson noted that seven of the 10 states ranked highest for wind energy potential, as measured by the constancy of the prevailing winds and factoring in environmental and land use exclusions, are in the Midwest--the Dakotas, Kansas, Nebraska, Oklahoma, Minnesota and Iowa--and that the Dakotas and Texas alone have sufficient wind resources to provide electricity for the entire nation. Paradoxically, California is 17th on the list because most of its best sites for wind power have already been used and because of land use restrictions. Texas is No. 2, with a potential for revenue of about $30 billion a year from wind.

The problem is the same one that has bedeviled alternative energy advocates for decades: lowering the cost of wind power to the point where it can compete with conventional energy sources such as coal (the leading nonrenewable energy source), natural gas, and hydroelectric and nuclear power. Wind turbines have been so expensive to build and they each produce such a small amount of electricity that they have not been able to compete with the conventional sources.

However, federal energy officials say that shortcoming is falling away rapidly and that recent research breakthroughs, spurred in part by the development of highly efficient wind turbines in Europe, have reduced the cost of wind energy from 40 cents per kilowatt hour in 1980 to between 4 and 5 cents a kilowatt hour now.

With sufficient congressional backing for additional research and development, coupled with production tax credits, the cost could be reduced to 2 1/2 cents a kilowatt hour by 2002, approximately equal to today's cost of natural gas power plants, according to Dan Reicher, assistant energy secretary for renewable energy. He said the Department of Energy is seeking $40 million in fiscal 2000 for research and development of wind power.

"It'll take a lot of work and a genuine policy commitment, but it's not just a pipe dream anymore, it's an attainable goal," Reicher said. He cited a goal that Richardson announced in June of putting 10,000 megawatts of wind power on line by 2010, or enough electricity to meet the needs of 3 million households.

Richardson's "Wind Powering America Initiative" envisions at least 5 percent of the nation's electricity needs being filled by wind power by 2020, an increase from the less than 1 percent of total power currently generated by wind. While the percentage increases may seem small compared with the nation's total energy consumption, Richardson noted that in 1980 the United States had less than 10 megawatts of wind power, compared with the 2,500 megawatts on line today. Worldwide, about 10,000 megawatts of wind power are replacing conventional fuel.

Energy Department officials said one key to reducing per-kilowatt costs is a proposed four-year extension of the production tax credit for wind power development, which is part of the Republican tax cut bill that President Clinton is expected to veto for reasons unrelated to wind.

Although California still leads the nation in the number of wind towers connected to power grids--16,000, compared with fewer than 500 elsewhere in the United States--most of the older California windmills have relatively small, 50-kilowatt turbines, compared with the massive 750-kilowatt turbines that are operating here and at Lake Benton, about 60 miles northeast of this farming community.

The 259 wind turbines at the Storm Lake facility, located 80 miles east of the South Dakota border, generate 193 megawatts of power for the MidAmerican Energy Co. of Des Moines and Alliant Energy of Cedar Rapids. That is enough electricity to serve 72,000 households, or 192,000 people, according to officials of Enron Wind Corp. of Tehachapi, Calif., developer of the project.

Enron, a pioneer in wind energy, also built and is operating two facilities at Lake Benton for the Minneapolis-based Northern States Power Co., one with 138 turbines generating 104 megawatts and another with 143 turbines producing 107 megawatts.

The turbines here are a far cry from the cumbersome old windmills that used to dot the landscape across rural America, drawing water from underground wells.

The lattice towers each weigh 57 tons and are topped with a housing nacelle the size of a fuselage of a small plane, large enough for a technician to stand inside while working on the gears, drive shaft, generator and other equipment. The three fiberglass blades are nearly 80 feet long, creating a rotor diameter equivalent to the wingspan of an MD-11 jumbo jet. The turbines are set on a track 17 miles long and 8 miles wide.

As the blades turn one revolution every two or three seconds, they power the generator that sends electricity through underground cables to nearby substations, which in turn feed it into the utility's power grid.

Mike Kelly, the Iowa facility's superintendent, said that as the output increases with the speed of the wind, it allows the purchasing utility to either "ramp down its fossil fuel plant somewhere" or export its excess load to another buyer.

Kelly said that Buffalo Ridge, a barely discernible rise that runs along the watershed divide between the Missouri and Mississippi rivers, was selected for the site because of the consistency of the 18-mph winds and its proximity to high-voltage power transmission lines.

"There's great wind here, but it's not just the average annual wind speed that's important. It's the frequency distribution of the wind over the time periods when the utility needs it the most," Kelly said.

Enron officials said that if coal were burned to generate the same amount of electricity produced in the wind turbines here, more than 300,000 tons a year would be needed. They also said 502,000 tons of carbon dioxide, which is associated with the greenhouse effect of global warming, and 2,600 tons of sulfur dioxide, a major cause of acid rain, would be produced if fossil fuels were used instead of wind.

However, Enron and Energy Department officials were quick to point out that neither the Iowa nor the Minnesota projects were driven by market forces or a groundswell of public environmental demands, but instead by legislatures. In Minnesota, the legislature mandated that if Northern States Power wanted to continue storing spent nuclear fuel on its controversial Prairie Island site, it had to provide some renewable energy such as wind power. Iowa's legislature mandated that at least 1.5 percent renewable energy be produced by each utility. After a lengthy legal battle, the requirement was upheld by the Federal Energy Regulatory Commission.

But officials said that even so the projects bode well for a rapid growth in wind energy in the Midwest. And farmers here, who collectively stand to earn more than $500,000 in annual payments and a percentage of production revenue by leasing their land to Enron, generally have been enthusiastic supporters of the project. One reason is they can plant crops right up to the bases of the windmills.

"I would have thought small midwestern towns might be resistant to change like this," said Hap Boyd, Enron's director of governmental affairs. "But they are great stewards of their land, and this is a great combination of environmental consciousness and good business sense."

Jim Gossett, executive director of the Storm Lake Area Development Corp., said initially there was some local resistance to the idea of hundreds of wind towers dotting the landscape. But he said it faded quickly in the face of an increased tax base and the prospect of new jobs.

"Some areas may decide they don't want all these turbines, but I think they can look to this area five years down the road and find a comfort level with the residents who accepted wind power," Gossett said.

"Besides," he added, "we don't have people come here to look at the cornfields anyway."

Harnessing the Wind

The largest single wind power project in the world is getting underway in Iowa, where wind is plentiful.

These are the 15 states with the greatest wind energy potential:

(BILLIONS OF KILOWATT-HOURS)

North Dakota: 1,210

Texas: 1,190

Kansas: 1,070

South Dakota: 1,030

Montana: 1,020

Nebraska: 868

Wyoming: 747

Oklahoma: 725

Minnesota: 657

Iowa: 551

Colorado: 481

New Mexico: 435

Idaho: 73

Michigan: 65

New York: 62

SOURCE: American Wind Energy Association

CAPTION: Storm Lake superintendent Mike Kelly stands beside nacelle that sits atop 200-foot windmills with 80-foot propellers.