There is great capacity for turbine power. Many manufacturers of this recent phenomenon are from foreign markets and have penetrated the US market. There is a growing demand for more manufacturers, however, the market is limited due to the uncertainty in federal PTCs. The graph below outlines who the major manufacturers are over the course of the past 3 years. GE is the leading manufacturer. Table 4. Annual Turbine Installations, by Manufacturer Source: AWEA project database.