Introduction
Wind is caused by temperature and pressure fluctuations in the atmosphere as the sun warms the earth. Alaska's wind resources are abundant, especially on the western coastal regions of the state.
Wind devices are powered by air. Air moving relative to an object such as the blades of a wind turbine (or the wings of a plane) imparts a force on that object.
Wind turbines use this aerodynamic force to convert the kinetic energy of the wind into mechanical energy that can be harnessed for use. The energy in the wind can be defined for a specific unit of area that the wind is flowing through in a unit of time. Wind energy is directly related to the area swept by the turbine blades, air density, and the cube of wind speed. A doubling of the wind speed increases the power from the wind by eight times. For this reason, the most important factor in calculating wind power is determining wind speed. This fact is important when considering the integration of wind into existing power systems. In most instances we need our power to be constant, and wind energy is as variable as the blowing wind.
V17 Wind Turbine
How Wind Energy Works
A wind turbine generator (WTG) uses a wind turbine rotor, with turbine blades to transform wind energy into mechanical energy; and a generator, to transforms that mechanical energy into electrical energy. Many different types of wind turbines are available. Sizes vary. Small (10 kW or less) wind turbines which are typically used for individual homes or small businesses. Medium-sized (50kW - 1000kW) ones are used for remote communities and other grid-connected, distributed generation. Large turbines (1MW or more) are generally used in large wind farms.
This section focuses on medium and large wind turbines without addressing the application of small wind turbines. More information on small wind turbine applications can be found on the Wind Powering America small wind website, or the Alaska Energy Authority website. Various publications like Wind Power: Renewable Energy for Home, Farm, and Business, by Paul Gipe (2004), might also be helpful.
Wind Energy in Alaska
In rural communities now using diesel generators, it is important to understand that wind energy alone cannot replace diesel generation. In most applications, when the wind is blowing, wind energy is used to reduce dependence on and consumption of diesel fuel. Diesel power is relied on when available wind energy is insufficient. These types of power systems are described in greater detail in the wind-diesel section.
Alaska has significant potential for wind technology development throughout the state, but the best resources are concentrated near the coast and on the large coastal plains and river deltas, like the Yukon-Kuskokwim region. Communities in interior Alaska may also have wind resources, but they are generally confined to passes, hills, or ridge tops. In nearly all cases, specific assessments will likely be required.
Click on the map image to see an Alaska wind resource map at 50 meters (map courtesy of National Renewable Energy Laboratory (NREL) and Alaska Energy Authority (AEA).
To see a list of current wind projects in Alaska, go here.
Challenges of Wind Energy
Obvious opportunities exist, but there are environmental and technical challenges related to the deployment of wind devices in Alaska. Some of these challenges are common to installations in any location, while others are more specific to Alaska. Most environmental concerns relate to potential impacts on birds. Often, coastal regions with good wind resources also have strong bird populations, including the King Eider, Black Scoter, and the Steller’s Eider, which is an endangered species. Two general laws govern turbine impacts on birds, the Endangered Species Act and the Migratory Bird Treaty Act. At this point there is a limited amount data on the impacts of Alaska’s current wind projects on local species and population.
Survivability and performance of turbines in the Arctic is another consideration. Wind turbine performance in Alaska has been good, however there is relatively limited information due to the small number of installed wind systems. Additionally there is little in-state maintenance support for most wind turbines at this time, however, with the continued growth of wind power in Alaska, this expertise is being developed. Some areas of Alaska are also subject to substantial amounts of rime icing and extremely low temperatures, these conditions may have a significant impact on wind turbine performance and reliability.
Challenges still exist with the integration of wind technologies into new or existing diesel power plants. Combined systems can be complex, and care must be taken during the development of the project to insure that the resulting system will perform satisfactorily. Also, the operational complexity of the system changes as the amount of wind energy increases as compared to the load.
Although a wind map has been completed for the state, additional local wind assessments are required to justify project development on any meaningful scale. The installation of an anemometer and collection of enough data to understand the local wind resource can take over a year.
Wind Technology
| Technology Snapshot: Wind | |
|---|---|
| Installed Capacity (Worldwide) | Over 100,000 MW |
| Installed Capacity (Alaska) | Approximately 10MW installed; a couple more MWs under construction during the next year |
| Resource Distribution | Potentially available to communities in all regions of Alaska although generally focused in coastal areas and throughout low-lying delta plains. |
| Number of communities impacted | At least 134 rural communities have viable wind resource. Additional communities along the Railbelt have yet to be assessed. |
| Technology Readiness | Wind-diesel systems are commercial to early-commercial depending on level of wind penetration to existing load. Larger turbines appropriate for the Railbelt are fully commercial. |
| Environmental Impact | Impacts on local and migratory bird populations although little impact currently documented. Potential for noise and visual impacts when sited close to a community. Most impacts can be minimized by appropriate siting, design, and operation. |
| Economic Status | Wide disparity on payback. For rural areas payback is highly dependent on associated balance of system costs and price of offset diesel fuel. |
| Case Studies | Toksook Bay, Saint Paul, Wales, High Penetration Hybrid Power System |
| Wind Working Group | Recommendations, References |
| News | DOE & Wind Powering America News |
To learn more about wind technology, click on the link below:
WIND TECHNOLOGY
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Links and Resources
- Alaska Wind-Diesel Applications Center. The Alaska Center for Energy and Power (ACEP) at the University of Alaska has developed a Wind-Diesel Applications Center. This Center represents a partnership between ACEP, AEA, several other state organizations involved in wind-diesel technologies, and NREL. The Center’s mission is to advance technology in wind energy and wind-diesel integration for the benefit of Alaskans.
- Renewable Energy Alaska Project (REAP) has created a Community Wind Toolkit as a guide for those looking to begin wind energy projects in rural Alaska.
Wind News
DOE Wind News
