World energy production in 1995 was estimated at 5 million MWh/year from over 22,000 wind turbines with an installed capacity of around 4,000 MW. The American Wind Energy Association set a very optimistic goal for the United States of 10,000 MW by the year 2000. This was not achieved, although there was a lot of activity in other states outside of California due to the new incentive of the production tax credit (PTC) for 1990-1995. The PTC was $0.015/kWh for 10 years, with an inflation factor for wind farms installed in later years. The PTC was extended a number of times; however, late extension meant hardly any installations during that year.
Sandia Labs managed the DOE program for VAWTs. A 34 m VAWT test bed, 500 kW, was tested at USDA-ARS, Bushland, Texas, from 1988 to 1998 (Figure 10.10). The DOE program, managed by the National Wind Technology Center, NREL, was changed to assistance and R&D for the U.S. industry to meet the foreign competition through the Advanced Wind Turbine Program [45-47]. Also in the United States, there was the EPRI/DOE Wind Turbine Performance Verification Program, which was to provide a bridge from utility-grade development programs to commercial purchases. The 1995 goal of the U.S. Department of Energy Advanced Wind Turbine Program was to develop wind turbines for class 3 wind regimes (5-5.5 m/s average at 10 m height), which would produce electricity at $0.03-0.04/kWh, with O&M costs of $0.005/kWh. Another DOE R&D project goal was for cost of energy from wind of $0.025/kWh or less at sites with 6.7 m/s winds by 2002.
Government regulations and incentives in Europe, especially in Germany, resulted in rapid expansion of industry and installation of wind turbines. There was more consolidation, and some manufacturing shifted from Denmark.
The manufacturers of two-blade, light-weight machines went out of business, for example, Carter. However, prototypes are still being used in testing, and Vergnet in France is selling a commercial machine. There were not any vertical-axis wind turbines being produced for the wind farm market. This period was characterized by:
1. Continued rapid growth of the wind industry. Size of wind turbines increased from 200 kW to megawatt size. Countries outside the United States and Europe installed wind farms, with 1,220 MW installed in India by the end of 2000.
2. European manufacturers dominated the market for large wind turbines.
3. Offshore wind farms were installed in Europe.
4. Development of large wind turbines with no gearboxes.
5. Only one manufacturer of large wind turbines in the United States. Kenetech went out of business, leaving only one manufacturer of large turbines, Zond. Zond was then purchased by Enron and renamed Enron Wind.
The Utility Wind Integration Group in the United States published a number of brochures  on all aspects of the wind industry. This information is primarily for planners in utilities and policy makers in state governments.
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Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.