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Wind power is one of the fastest growing technologies in electric power generation
and is a renewable power resource, driven by the sun. (An estimated 1 to 3
percent of the energy from the sun is converted into wind energy.) Wind resources
in the United States are significant, with many in Northern California. In
January 2005, Alameda Power & Telecom (Alameda P&T) purchased the output
from 10 megawatts (MW) of wind capacity and hopes to achieve an average of
3 MW of wind power from the High Winds Project in Solano County (one megawatt
is equal to the electric use of about 1,000 homes).
What is Alameda Power & Telecom's Electric Load?
The City of Alameda's electric load is fairly constant year-round but with a slightly higher usage during winter.
Alameda's peak electric load is about 70 MW and our minimum load is 35 MW. Most of California has a very high summer peak load -
sometimes two or three and one-half times that of the utilities' minimum load.
Alameda P&T's electric load in kilowatts (one thousand kilowatts = one megawatt)
Does Alameda Power & Telecom have any wind power?
Yes, we have recently completed a purchase of wind power from the High Winds Project in Solano County, located near the Bay Area.
Power delivery from this site started in December 2004 and will continue until June 2028, a total of 23 years.
The total amount of the wind purchase is 10 MW, but because high winds are not always available,
the actual capacity amount will vary from 0 to 7 MW and average at about 3 MW a year.
The output of a wind turbine generator is not constant; it varies depending upon the amount of wind.
Another limitation is that it is not dispatchable, in other words, you cannot control the output or timing of the generation.
While wind is not a perfect solution to Alameda P&T's generation needs, it plays a partial role in our generation because it is
economical and because it is a renewable resource.
For additional information on the Solano High Winds Project, visit the following websites:
What is the environmental impact of the wind turbine generators at the Solano High Winds Project?
In some locations the wind farms are considered an eyesore; to mitigate this, the Solano High Winds Project is located in an
agricultural area far from businesses and homes. The generators pay $2,500 to $4,000 a year to the landowners to lease the space,
which is about 2% of their farmland. In this way the wind farm does not displace agriculture but instead adds value to the farms.
Unlike the turbines at the Altamont Wind site, the Solano High Winds Project uses large wind turbine generators in which the blades
move much slower, so fewer birds get caught in the blades. The California Energy Commission is doing a study on avian mortality
associated with wind farms.
What is wind power and how does it work?
- A wind turbine generator (WTG) usually consists of three blades on top of a tower with the blades facing into the wind.
The wind turns the blades, which spins a shaft that is connected to a generator that produces electricity.
The electricity is sent to a transmission line or a distribution system line.
Illustration courtesy of US DOE's Wind & Hydropower Technologies Program
- WTGs range in size from a unit to pump water for cattle to utility size. The most cost-effective sizes are the utility
size - 600 kilowatts to 2 1/2 MW.
- WTG technology has matured into a reliable and competitively priced power resource.
- WTGs are getting larger and taller - the wind speed is greater at higher elevations such as 50 and 70 meters.
- Currently there are 24,000 MW of installed WTG worldwide, 1,700 MW in California alone.
Most of the California WTGs are located at Altamont, Tehachapi, and San Gorgonio.
| General Overview of a 1-MW WTG |
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| Capital Cost for a 1-MW WTG | $1,175,000 |
| Average Generation | 2,890,500 kWh/year |
| Estimated Lifetime | 20 years |
| Warranty | 3 to 5 years |
| Estimated Operations and Maintenance costs: |
| 1 - 10 years | 1 to 2% of the WTG cost |
| 10 - 20 years | 4 to 5% of the WTG cost |
Is there Potential for Wind as a Future Power Supply in Alameda?
- Typically class 4+ to 5 winds (17 to 27 mph) are required for a site to be considered for WTG.
Although there are some WTG that are being developed for lower wind speeds, such as class 3 (14 to 16 mph),
Alameda is a class 1 (0-12 mph) site.
- While modern wind turbines begin operation in winds as low as 14 mph, the efficiency is low.
Efficiencies don't become economically viable until there is a constant wind speed of 17 mph.
- Reference the following website for California's wind information -
www.energy.ca.gov/maps/wind.html and for more information on Alameda wind speed go to
http://sfports.wr.usgs.gov/cgi-bin/WindTide.cgi
What are the benefits of Wind Power?
- Free renewable fuel source. The wind will always be available at certain times of the day and year,
and is not subject to fuel price increases
- No air, water, or soil pollution
- Competitively priced with natural-gas generated energy
- Wind farms provide an additional revenue source for farmers and other landowners that ranges from $2,500-4,000
per turbine per year
- WTG are modular, and therefore fast to build
- Federal tax credits for wind generation
What are the disadvantages of Wind Power?
- Intermittent power supply, not dispatchable, and not appropriate for base load.
- Avian mortality: an estimated 400 to 900 birds are killed every year at Altamont Pass.
Even though this issue is not resolved, it is known that Altamont is an avian pathway and a good hunting place for raptors.
Some studies indicate that the lower the blade speed, the less avian mortality,
such as with the WTGs at the Solano High Winds Project site.
- Wind farms tend to be located on ridges that are readily visible from miles around.
Many people do not want WTG as part of their view.
- Noise problems have been associated with older WTGs; the newer units are much quieter.
- Most wind projects, as with many renewable power supplies, are located far from transmission lines and
from where the electric demand is. Fortunately, the Solano High Winds Project is next to a high voltage transmission line.
However, the Bay area has problems with line congestion and potential high cost of power delivery.
The cost to fix these problems is high and therefore increases the cost of power from renewable resources.
What Are Wind and Renewable Energy Credits?
Renewable Energy Credits (RECs) represent the environmental attributes associated with a particular renewable resource.
For each megawatt-hour of energy produced, a REC is also generated.
For the most part, RECs remain bundled with their energy component and the resulting energy is represented as renewable.
However, in some cases the REC can be disassociated from the energy and sold to a third party.
In so doing, the seller relinquishes the right to claim the environmental attributes of that particular resource for the term of the sale.
The Buyer assumes the ability to market the REC as they see fit. This transaction does not affect the amount of delivered energy.
A great deal of effort has been devoted to developing a REC market to facilitate REC trading and encourage renewable
generation development.
Summary
Wind power is a viable part of California's growing electric supply. To help ensure reliability,
California must have a diversity of power supplies and increase the development of renewable power supplies.
No one renewable power supply can provide for all of our power needs. Wind power is appropriate when certain conditions are met:
where there is not a need for base load, when wind can compliment other power supplies that are dispatchable like hydroelectric,
or where solar power can fill in the voids of the summer peak in midday and is compatible with the electric demand.
Wind power projects should be located carefully:
- Away from avian migratory paths and habitats
- In a place where it will not be considered an eyesore
- Near transmission lines
- Location should be compatible with the existing land use such as ranch land and farms when possible
Such sites do exist in California, such as the Solano High Winds Project.
Transmission of renewable power supplies to high-demand areas is a long-term problem however, and will be costly to solve.
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