08-10-2012, 10:58 AM
Overview of Wind Energy in California
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In the year 2004, wind energy in California produced 4,258 million kilowatt-hours of electricity, about 1.5 percent of the state's total electricity. That's more than enough to light a city the size of San Francisco.
More than 13,000 of California's wind turbines, or 95 percent of all of California's wind generating capacity and output, are located in three primary regions: Altamont Pass (east of San Francisco - a portion of which is shown on the right in this photo from NREL), Tehachapi (south east of Bakersfield) and San Gorgonio (near Palm Springs, east of Los Angeles). In 1995, these areas produced 30 percent of the entire world's wind-generated electricity.
According to the Electric Power Research Institute, the cost of producing wind energy has decreased nearly four fold since 1980. The levelized cost of energy from wind turbines in 1993 was about 7.5 cents per kilowatt/hour. With current wind research and development efforts, the Energy Commission estimates that newer technologies can reduce the cost of wind energy to 3.5 cents per kilowatt-hour.
Wind energy also creates jobs. The America Wind Energy Association estimated that through the early 1990s, 1,200 direct jobs in California's wind industry, with as many as 4,000 indirect jobs, were created. Total private investment in wind energy in California amounted to $3.2 billion through 1991.
Smaller turbines can be used by farms, homes and businesses in windy locations, such as along the coast. They can also be used (like solar cells) in areas where it is not feasible to run power lines because of the cost.
Wind Energy Production
Wind power plants are turbines which use the energy in the motion of the wind to make mechanical energy, which is then converted to electrical energy.
The components of a utility-scale "wind farm" include wind turbines, an underground power transmission system, control and maintenance facilities, and a substation that connects the farm with the utility power grid. Utility-scale wind turbines are classified by size as follows: small (less than 50 kilowatts [kW]); intermediate (50 to 500 kW); and large (above 500 kW). Small and intermediate turbines make up the bulk of the older installed turbine base, but new turbines installed in the late 1990s are generally 600 kW and larger.
Utility-scale wind farms are generally located in areas with average annual wind speeds of at least 13 miles per hour. Wind power is more available during certain seasons because climatic conditions affect wind speed. In California, wind speeds are highest in the hot summer months, and approximately three-fourths of all annual wind power output is produced during the spring and summer.
Another application of wind is in distributed use systems, which provide on-site power in either stand-alone or grid-connected configurations. Most such systems range in size from one to 25 kW. Distributed wind systems are applicable to industry, water districts, rural residences, agricultural use, and a wide variety of isolated power uses located in good wind resource areas.
Wind power for utility-scale applications is considered to be commercially available under most conditions. The technology is considered to be mature, and there are several system suppliers. The federal government encourages electricity production from wind farms with a 1.5-cent per kilowatt-hour tax credit. California also offers incentives through the Existing Renewables Program ($70.2 million for Tier 2, wind) and the New Renewables Program (nearly 1,000 megawatts of new, installed capacity is being added under this program).
Wind power for distributed applications is considered to be commercially available under limited conditions. Distributed wind systems can be a cost-effective option in remote locations where a utility connection would not be economically feasible. The California Energy Commission supports grid-connected small wind systems or 10 kW or less through the Emerging Renewable Rebate Program.
While the power produced by many of California's older wind turbines is not cost-competitive with other forms of electricity generation, some of the newest wind turbine designs may be able to match or beat the power prices from many coal and nuclear plants.
Permitting Issues.
Some of the potential issues associated with windfarm development include:
• Use of large tracts of land. (The average windfarm requires 17 acres of land to produce one megawatt of electricity. However, simultaneous land uses such as agriculture and cattle grazing occur often.)
• Erosion in desert areas.
• Changes in visual quality (since windfarms tend to be located at or just below ridge lines).
• Disturbances to wildlife habitats.
• Avian mortality due to collisions with wind turbines and associated wires (research is on-going to reduce bird deaths).
• Noise (wind turbines generate both audible and low frequency [deep base vibration] sound waves).
• Grass or brush fires caused by shorts in the electrical cables in the unlikely event that they become stretched or twisted when the turbines turn to catch the wind.