Special Wind Issue by Drew Lowell-Britt
"For the first time in more than a decade, the USA took over the number one position from Germany in terms of total installations.."
-World Wind Energy Report 2008
Making CO2 Valuable
Riverside County between the San Bernardino Mountains and the San Jacinto Mountains
3,218 turbines and more under construction
619 MW installed
California was the first U.S. state in which large wind farms were developed, beginning in the early 1980's. Today they are three major wind farms that produce 95% of California’s wind energy:
(south east of Bakersfield) - 666 MW installed – 1,663 GWh generated in 2007
- San Gorgonio
(near Palm Springs, east of Los Angeles) – 619 MW installed – 1,063 GWh generated in 2007
- Altamont Pass
(east of San Francisco) – 586 MW installed – 722 GWh generated in 2007
Total California Wind Power Capacity (2008)
Existing Capacity: 2,516.51 MW (about 5% of CA peak demand)
Projects under Construction: 275 MW
Rank in U.S. by Existing Capacity: 3
Potential Capacity: 6,770 MW (about 13.5% of CA peak demand)
U.S. Wind Capacity and Potential
The U.S. wind energy industry continued new installations at record pace in 2008, putting over 1,300 MW of new wind capacity in place. That brings the total installed capacity to 21,017 MW in 35 states. In addition, over 8,000 MW are under construction and expected to be completed this year. For the first time in more than a decade, the U.S. took over the number one position from Germany in terms of total installations.
Texas leads the nation in terms of installed wind power capacity with more than twice the capacity of the next state, Iowa. At the end of the third quarter of 2008, the states with the most cumulative wind power capacity installed were:
The Top Five Wind States
Texas: 7,906 MW
Iowa: 2,883 MW
California: 2,653 MW
Minnesota: 1,802 MW
Washington: 1,478 MW
Top Five States for Wind Energy Potential
(as measured by annual energy potential in the billions of kWh)
North Dakota: 1,210
South Dakota: 1,030
Offshore wind turbine technology is the frontier of commercial wind technolgy. The offshore wind energy potential in the U.S. is over 1,000 GW. The National Renewable Energy Laboratory estimates commercial deepwater technology is still 10 - 15 years away, but near term offshore experience in shallow water will accelerate deepwater technology. For example, companies such as GE, Vestas, and Enercon GmbH have developed 5 - 7 MW turbine prototypes that they expect to install 150 ft water by the summer of 2009.
The Costs of Wind Power Today - Small Wind
For a farm, ranch, village project, or remote home, or for backup power, a smaller turbine can be an attractive investment. Wind systems for single family homes in windy areas are less expensive than solar systems, while still eligible for the residential renewable energy tax credit of 30% of the installed cost with no maximum, and like solar systems, they can be net metered. In addition, utilities in your area may offer additional cash rebates. For example, residents living in California’s investor owned utility territories are eligible for the Emerging Renewables Program rebates.
The economics of a wind system are particularly sensitive to average wind speeds in the area, and to the prevailing prices for conventional electricity. A prospective turbine owner should have at least a 10 mph average wind speed and be paying at least 10 cents/kWh for electricity. Lesser values beware. As for turbine placement, the standard industry rule is that the lowest point of the turbine rotor should be at least 30 feet above anything within 500 feet, and taller is better. (The height of your turbine may be restricted by local ordinance, if not state code.)
In areas like the high desert near Victorville, California, household systems are sprouting up like dandelions. Remote locations are more ideal because of the ability to install tall towers essential for capturing the wind resource. If the conditions are right at your site, the cost of a small wind turbine may look something like this:
Southwest Whisper system rated at 3 kW
Gross Cost at $5.00/watt:
Emerging Renewables Program Rebate of $2.50/watt: $7,500
Tax Credit of 30%: $2,250
Net Cost $5,250
This particular wind turbine (Whisper 500) uses very efficient fiberglass and foam core blades (14’ diameter) that can start-up at low winds (7.5 mph). In consistent 12 mph winds the Southwest Wind Whisper 500 model turbine will deliver in excess of 385 kWh per month and will pay for itself in about 13 years. In 15 mph winds, the output increases to 535 kWh per month.
Other prominent wind turbine manufacturers for homes and farms are Bergey Wind Systems and Kestrel. George Bush senior has a Southwest Skystream at his Kennebunkport Maine compound.
Some innovative ideas and designs have brought more wind power into the urban environment such as vertical axis turbines and building integrated turbines. New parapet wind systems – such as Boston’s Logan International Airport – are attracting interest. Yale University is testing a similar system with 10 turbines on its Becton Center building. Yale estimates the 10 turbines will generate less than 1% of the Becton’s high energy consumption but pay for themselves in 8 years. These systems are promising, but actual field production figures are not yet published. One of the most extreme urban installations can be found at the new Bahrain World Trade Center which will have three turbines with a combined capacity of 1.3 MW.
There are many challenges to urban wind, mainly performance and safety.
- Buildings and other features in an urban setting tend to cause turbulence in the wind flow, thereby reducing wind speeds.
- Building & safety codes often require “a fall radius” that simply makes the installation of pole-mounted or parapet-mounted wind turbines impossible.
- The load on a roof caused by the weight of a spinning turbine is substantial
Wind and the Environment
Concerns with wind power do not end in the city, there are also concerns about the environmental impact of wind farms in rural areas. The primary concerns include, noise, visual impact, and the deaths of birds and bats.
Noise is evident when the turbines are producing, but much of it is masked by the wind itself. To reduce turbine noise, designers have made changes that increase efficiency whereby more wind is turned converted into rotational torque and less into acoustic noise. Additionally, proper siting and insulating materials are used to minimize noise.
Wind turbines are generally very visible because they are sited in exposed places where the winds are strong. Aesthetic issues are by nature subjective, however, with proper placement and the use of the latest efficient technologies, fewer turbines are needed in each location, partially avoiding aesthetic impact.
The mortality of birds and bats is perhaps the most controversial biological issue related to wind turbines. Birds occasionally collide with wind turbines like they do all tall structures. (A particular area of concern: the Altamont Pass in Northern California.) To address the issue, the wind industry and government officials have sponsored research on collisions and avian behavior. Developers are required to collect monitoring data at existing and proposed wind sites. Turbine manufacturers also now use tubular towers that do not attract as many birds as the older lattice towers that used to provide perches. Research and monitoring show that less than 1% of bird deaths result from turbines, compared to over 50% from their colliding with buildings.
Developers have to plan wind farms carefully, especially because a wind farm requires about 60 acres per MW of installed capacity, but the public needs to put the impacts into prospective. Only 5% (3 acres) or less of this area is actually occupied by turbines, access roads, and other equipment; 95% remains free for other compatible uses such as farming or ranching.