Commercial Wind Turbine Systems and Applications - Wind Turbine Technology: Fundamental Concepts of Wind Turbine Engineering - page 243

While new federal incentives were passed in 992, it was not until 999 that major
project deployment began again. This rapid increase in the installation of wind turbines is
shown graphically in Figure 4-27. The PTC proved to be effective at spurring growth in
200, 2003, and 2005 to 2008, but the extensions of the tax provisions were for only a year or
two and were passed too late to allow business continuity. Another - year extension of PTC
was passed in October 2008 but some projects planned for 2009 had already been canceled.
Despite these disruptive discontinuities in federal tax policies, by 2008 wind power installa-
tions had spread across the country with 6 states having more than 00 MW installed and
six states with ,000 to 4,500 MW. Total installed capacity in the United States in midyear
passed 20,000 MW.
Figure 4-27. Wind energy capacity installed in the U.S. from 982 to 2007. The bars
indicate the capacity installed per year and the line shows the cumulative capacity .
The business structure of a wind power station project is a complex relationship among
developers, investors, wind turbine manufacturers, utilities, insurers, and government entities
which must approve many aspects of the project. By 2007, the structure of the wind business
had changed substantially with increasing globalization. Companies like General Electric
(GE) and the Spanish firm Gamesa were selling equipment but no longer developing power
stations. GE had captured 45 percent of the U.S. market with their popular .5-MW turbine.
Other leading turbine suppliers and their market shares in 2007 in the United States include
Vestas at 8 percent; Siemens , 6 percent (following acquisition of Bonus ); Gamesa , per-
cent; the remaining approximately 0 percent by Mitsubishi , Suzlon , Clipper , and Nordex .