"Utilities know their system can meet predictable but variable load," says Brian Parsons, project manager for wind applications at the National Wind Technology Center. "If you think of wind as an added variable -- not something in isolation -- but in the context of running an entire portfolio, it is attractive. Look at how other generation resources can adjust. Any new generator will have issues but wind is different. It is variable. But we are displacing gas and other fuels. That's the main value."

The California Public Utility Commission underwrote a report that found the top 18 wind units there underperformed in July 2006 during some of the hottest days. Succinctly, 608 megawatts were available after transmission congestion was subtracted. But, during a five day period from 3 p.m. to 4 p.m., the units only produced 145-533 megawatts. While the report does say the analysis is "rough," it is nevertheless concerned - creating "some uncertainty in the reliability of wind units during times of system need."

Proponents of wind shrug off the report, noting that all generation forms must be backed up with other types of power in case they go down. They add that new technologies are always emerging and make wind not just environmentally beneficial but also cost effective and increasingly reliable.

Utilities were paying 5 cents a kilowatt hour, although it amounted to 3 cents per kilowatt hour with the production tax credit given to wind producers. Prices are now rising, largely because manufacturers can't produce enough turbines to meet demand. In any event, experts say that if the price of natural gas is above $5 per million Btus, wind is competitive. And wind is also viable with newer coal plants that use the latest technologies, although it is not with the older facilities.

Today's land turbines average about 1.5 megawatts each, although the development is underway to gradually increase that power to as much as 5 megawatts each and all by 2012. General Electric, for example, is now working with national researchers to complete the design of blades that will work better and cheaper, both on land and at sea. Experts say that would cut the price of wind exponentially in the coming years.

"If you double the diameter of the blade, you will get four times the output," says Parsons. But the cost will not quadruple. At the same time, taller towers are able to capture more of the wind, he adds -- all research that the center is now tackling.

Fast Development

The U.S. wind energy industry installed 2,454 megawatts of new generating capacity in 2006, an investment of approximately $4 billion. That total investment is second only to natural gas facilities. The total U.S. installed wind energy capacity climbed by 27 percent to 11,603 MW, greater than the 10,000 MW milestone reached in August 2006.

And the power source could expand even faster if not for the high demand and subsequent market constraints. GE Wind Energy supplies 60 percent of the turbines and says that its plants are at capacity through 2007. Meanwhile, Clipper Windpower is gearing up and planning to produce a total of 250 wind turbines by 2007.

GE Energy Financial Services, a unit of General Electric and a sister to the wind energy division, is committing to invest in a 410-megawatt wind farm portfolio, on top of the 3,100 megawatts it now owns. The $270 million will go to six wind farms in California, Illinois, New Mexico and Pennsylvania. All the facilities will be completed by year-end.

Altogether, new utility-scale turbines from all sources were installed in a total of 20 states across the country, from Maine to New Mexico to Alaska. Texas accounted for nearly a third of the new wind power installed in 2006, with California second. Still, the developers can't evade the permitting process or the technological realities.

That is, the transmission infrastructure is not adequate and the power generated is therefore difficult to harness and transport. The wind, for example, blows hardest offshore and in the states of Montana, the Dakotas and Wyoming -- all of which are problematic when it comes to building new transmission lines. There are other places where the wind is not as strong but the infrastructure does exist -- from the northeast to the Mid Atlantic regions.

Then there's the issue of winning public approval. No one really wants a wind farm -- a power plant -- near where they live. In West Virginia, for example, residents forced a subsidiary of U.S. Wind Force to withdraw its permit application. By contrast, environmental groups in the same state tried unsuccessfully to prevent Chicago-based Invenergy from going forward with a 124-tower facility. In all cases, opponents argue the sites would spoil views while hurting tourism and property values.

The strong demand for wind power is a function of national mood. That desire for clean energy, in turn, has prompted about 20 state legislatures to enact laws requiring utilities to hold more green energy in their portfolios. But, those demands are running headfirst into the age-old dilemma of resistant neighborhoods as well as the stark truth that the wind does not blow on demand and can't easily get hooked into the grid. As the industry proves its case both environmentally and economically, those obstacles will fall.