A Breezy Guide to Help You Navigate WINDExchange Resource Maps
Jan. 30, 2023
An article by Emily Mercer for WINDExchange
Anyone who’s felt Chicago’s frigid breeze sweeping up from Lake Michigan wouldn’t dare question its nickname as America’s “Windy City.” But the so-called Windy City doesn’t even land among the top 10 windiest cities in the United States. According to wind speed data, Boston tops the podium with an average annual wind speed of 12.3 miles per hour—2 miles per hour faster than Chicago’s.
Wind resource maps show that America’s strongest winds don’t blow in cities. Rather, they hug coastlines, spills off mountain ranges, and expand across the Great Plains.
And wind resource maps can do far more than refute a city's nickname or show the best rural spots for flying a kite; they also help advance wind energy development by pinpointing where wind resources are most abundant.
Offering more than 300 wind resource maps and counting, the U.S. Department of Energy Wind Energy Technologies Office’s WINDExchange website serves as a hub of wind data for large and small wind energy projects alike, including those offshore. The comprehensive (and colorful) collection of wind resource maps is not only fun to browse, but it also serves as a useful step in the wind energy development planning process.
Long before putting wind turbines in the ground or in the ocean, government and business decision makers rely on snapshots of wind resources to determine if wind power is a viable option in a specific region. Even rural homeowners looking to install residential wind energy on their land can use wind resource maps to help estimate if there is enough wind where they live to produce the amount of electricity they need or want.
But maps aren’t very helpful if you don’t understand where to find them and how to use them. Read on to learn all about the WINDExchange resource maps.
How to Read a Wind Resource Map
At first glance, WINDExchange maps may look like other maps you’ve seen, with geographic boundaries (like state and county lines) and topographic features (such as mountain ranges and lakes). But wind resource maps show an additional feature: the quality of wind resources—or the potential amount of wind available—at a specific distance above the ground.
Searching through hundreds of maps to find the one you’re looking for could feel like battling a strong headwind. Luckily, these maps can be easily filtered by both region and turbine hub height (the distance from the ground to a turbine’s hub, or the point around which a turbine’s blades rotate). WINDExchange resource maps are labeled and grouped into the below categories, but you can also find all the available maps and wind energy information for a given state using the interactive U.S. map.
WINDExchange Maps Explained by Category
30-Meter Residential Wind Speed Maps
Produced using a combination of weather data and computer modeling, these maps estimate the average annual wind speeds 30 meters above the ground. They’re useful in determining if a location may be suitable for small wind power projects, which are typically installed at a 15- to 40-meter hub heights in areas with annual average wind speeds around 4 meters per second or greater and can be used for home-based renewable power systems.
50-Meter Community Power Density Maps
This type of map displays the estimated wind power density, which is the average annual power available per square meter of the area swept by a turbine’s blades. Wind power density is an older type of wind resource data that has been replaced by wind speed data to accommodate technology advancements in the wind energy industry. Providing the estimated wind power density at 50 meters above the ground, these maps are suitable for distributed wind energy, which powers nearby users, such as communities looking to lower utilities costs or transition to clean energy.
80-Meter Land-Based Wind Speed Maps
Displaying the average annual wind speeds 80 meters above the ground, these maps provide useful data for utility-scale wind energy development. The average wind turbine hub height is growing, so turbines with 80-meter hub heights are among the smallest utility-scale, land-based turbines today. At 80-meter heights, areas with annual average wind speeds around 6.5 meters per second or greater are generally considered to have a resource suitable for wind energy plant development.
90- and 100-Meter Offshore Wind Speed and Water Depth Maps
In addition to providing the estimated average annual wind speed 90 and 100 meters above the ocean surface, the WINDExchange offshore wind resource maps also display varying water depths. Because the depth of water impacts the type of wind turbine structure required (fixed-bottom or floating turbines), this information is important for offshore wind development planning. For additional data, check out the offshore wind potential tables, which break down wind resources by annual wind speed, water depth, and distance from shore.
100-Meter Wind Speed Maps
As of January 2023, the WINDExchange database features maps displaying wind speeds at 100 meters above the ground for all 50 U.S. states. Researchers at the U.S. Department of Energy’s National Renewable Energy Laboratory developed these maps using the Wind Integration National Dataset Toolkit. Using three different sources of data and turbine power calculated for more than 126,000 sites in the United States, the toolkit provides powerful information for the next generation of wind energy development.
110-Meter Wind Potential Maps
The maps in this category, along with the 140-meter potential maps, show land areas meeting a minimum “gross capacity factor.” This represents the total amount of wind energy actually produced versus the total amount of wind energy that could theoretically be produced in a region based on wind speed data and turbine specifications.
These maps display land areas with a gross capacity factor of at least 35%, which was the average capacity factor for wind energy in the United States in 2021. Calculations for the 110-meter potential wind capacity maps were performed using a 2014 industry-standard wind turbine installed on a 110-meter tower, which represents plausible wind resource potential with then-current wind turbine technology.
140-Meter Wind Potential Maps
The maps in this category again display land areas with a gross capacity factor of 35% and higher; however, calculations for the 140-meter potential wind capacity maps were performed using a 2014 industry-standard wind turbine installed on a 140-meter tower. This represents wind resource potential that would likely be accessible with then-future wind turbine technology.
Now You’re Ready to Put Wind Resource Maps to Use!
Although the WINDExchange maps show wind resources across the United States, wind energy developers should carefully evaluate detailed wind measurements in their area of interest as well as other site selection criteria before launching their project.
Whether your goal is to develop wind energy on your land or perhaps just to engage in a spirited, data-based debate about whose town is windier, with the help of this guide, these maps might just blow you away.
For more information, check out our wind resource maps video tutorial, find detailed descriptions below individual maps and charts, and read about wind resource assessment and characterization.