Basin Electric Power Cooperative
Wind Facts
We get asked a lot of questions about wind energy. This page may help you better understand this vast renewable resource.
- How is a location chosen for a wind project?
- How is it possible my neighbor has “better” wind than me?
- How can I find out if the wind on my land is desirable?
- If it’s not windy all the time, how do power companies use wind energy?
- How do transmission lines affect wind projects?
- Are wind turbines noisy?
- Can a wind turbine’s shadow be disruptive?
- Could I put up a wind turbine and make electricity for my home?
- Why can’t we completely rely on wind turbines for electricity?
- If the wind isn’t blowing in one area, it must be blowing somewhere else, right?
How is a location chosen for a wind project?
The two primary requirements are transmission availability and, of course, wind.
The economics of wind projects are very tight right now, given the current high costs of wind turbines. The cost of a wind project has doubled from $1 million a megawatt to more than $2 million a megawatt in the last five years. Those high costs dictate that we start with the best locations for wind since the production of power is significantly higher.
Another issue we are concerned about is the potential environmental regulations related to whooping cranes through the area during their migration. The U.S. Fish and Wildlife Service is currently looking at the potential impact of wind projects on whooping cranes and that issue may affect where we can erect wind turbines.
There are many environmental and social issues that need to be addressed in the siting of a wind power facility, including: Is the site’s geology suitable and appropriate for a wind project? Will noise and aesthetics be issues for the local community? Will the turbines obstruct the flight path of local air traffic, radar or microwave communications?
How is it possible my neighbor has “better” wind than me?
A minimum average annual wind speed of 17-18 miles per hour is desired. It's important to understand the energy available in the wind is a function of the cube of its speed. For every doubling of the wind speed, the wind energy potential increases by a factor of 8. That means a site with an average wind speed of 18 mph could have the potential to produce 40 percent more power than a site with an average wind speed of 16 mph. Such a difference in available energy dramatically affects the cost of a wind project and its competitiveness with other sites, as well as other energy sources.
Wind turbines do not operate efficiently in turbulent, swirling gusts of wind. They operate best in areas of steady wind. Additionally, the air density at higher elevations can be lighter, resulting in slightly less energy in the flowing air.
How can I find out if the wind on my land is desirable?
Wind monitoring devices to record the site’s wind characteristics need to be installed with preferred measuring heights of roughly 200 feet or higher. Wind developers prefer at least 24 months of reliable wind monitoring data before considering the investment of many millions of dollars in a project. A listing of consultants specializing in wind resource assessments can be found at the American Wind Energy Association web site: http://www.awea.org.
If it’s not windy all the time, how do power companies use wind energy?
When the wind blows, the electric industry backs down a gas-fueled or coal-based facility somewhere, reducing fuel consumption. The savings from reducing fuel consumption can vary greatly. If you back down a coal plant, you’re not saving much money because coal is a low-cost fuel. Other fuels such as natural gas and diesel are much more expensive. For example, if you save the coal used to generate one kilowatt hour, the system saves only about one penny. In contrast, the savings from the amount of natural gas would amount to five to nine cents per kilowatt-hour, depending on the volatile price of natural gas. Diesel fuel is even more expensive, but is rarely used in our region.
How do transmission lines affect wind projects?
The proximity of a project to existing transmission lines affects the project cost. For example: A 100 MW wind project typically requires a 115-kV to 230-kV interconnection. The cost of a 230-kV interconnection line to connect to the nearest 230-kV transmission line is estimated to be more than $300,000 per mile. If a substation is not available, a new 230-kV substation can cost roughly $4 million. Costs for a 115-kV interconnection are projected at roughly 70 percent of the cost of a 230-kV interconnection.
Even if a transmission line is nearby, that line may already be fully committed during parts of the year. In that case, the cost of upgrading the grid system to obtain firm transmission service can be enormous. Alternatively, the risk of accepting non-firm service can be unacceptable to developers and financing agencies, since any transmission interruptions involve not only the loss of the power sales revenue, but also the loss of the production tax credit (which can be larger than the power sales revenue).
Are wind turbines noisy?
Some turbines built in the early 1980s were so noisy it was annoying to hear them from a mile away. Turbines are now built much quieter. Today, an operating wind project at a distance of 750 to 1,000 feet is no noisier than a kitchen refrigerator or a moderately quiet room.
Can a wind turbine’s shadow be disruptive?
“Shadow flicker” is the term used to describe what happens when rotating turbine blades come between the viewer and the sun, causing a moving shadow. For some residences close to wind turbines, shadow flicker can occur under certain circumstances and can be annoying when trying to read or watch television. However, the effect can be precisely calculated to determine whether a flickering shadow will fall on a given location near a wind project, and how many hours in a year it will do so.
Normally, shadow flicker should not be a problem in the U.S. because at U.S. latitudes (except Alaska) the sun’s angle is not very low in the sky. If any effect is experienced, it is generally short-lived, as in a few hours over a year’s time. Most developers take steps while designing a wind project to minimize “shadow flicker” wherever possible.
Could I put up a wind turbine and make electricity for my home?
Yes. However, a small wind project lacks the economy of scale found in a large project, making it very expensive.
In our region, typically half or more of the residential electric bill is for the "wires" (the electrical distribution system and the high-voltage electrical grid from the central station power plants). Unless you are planning to disconnect from the system and put in backup generation to provide power when the wind doesn't blow, you will need to remain connected to the system and may still need to pay the costs of the wires and the backup generation that would continue to serve you. Otherwise, the costs of the infrastructure to serve you would be borne by the other consumers on the system.
Why can’t we completely rely on wind turbines for electricity?
Renewable generating resources like wind energy need a back-up source for power when, for example, the wind doesn’t blow. Even the excellent wind resources in our region are only able to generate about 40 percent of their rated capacity on average throughout the year. The rest of the time electricity must be produced from other sources, such as coal or gas. Wind resources can be an excellent fuel saver during time when high prices make natural gas (or other volatile fuels) unattractive.
Basin Electric recognizes the vast wind resource within our member service territory. Wind energy has significant challenges - just as conventional generation resources do – and the new wind projects we are building reflect our determination to overcome those challenges.
It is important to recognize that Basin Electric is counting on the sale of the renewable energy credits (a.k.a. green tags) to help support the economics of those renewable resources we have developed or will develop.
If the wind isn’t blowing in one area, it must be blowing somewhere else, right?
People think the wind must be blowing somewhere all the time. But that just doesn’t happen. Across the region, the wind generally rises and falls about the same time. Basin Electric tracks ten wind projects spread out over hundreds of miles, from Minnesota to North Dakota to south-central South Dakota. Generally the wind rises and falls in a similar pattern across the region. Although there is some diversity in wind energy available at different sites, there are usually several times each month when the winds are calm and all ten sites generate little or no power. At other times, all ten sites are generating close to their maximum. This lack of diversity in how the wind blows is of concern and Basin Electric is continuing to study this issue.
Developed with assistance from the American Wind Energy Association.
Basin Electric Power Cooperative
1717 East Interstate Ave.
Bismarck, ND 58503-0564 USA
701.223.0441