Conduct a site suitability analysis

A Colorado-based wind energy company has hired you to identify several new sites within the state for the installation of high-efficiency wind turbines. This site must meet several characteristics:

  • Located within the state of Colorado
  • In counties where the population as of 2010 is at least 20,000
  • In areas where the wind power class is at least 4 (Annual wind speeds in these areas at 10 meters off the ground are generally at least 5.6 meters per second [12.5 mph], and at 50 meters off the ground, are generally 7.0 meters per second [15.7 mph].)
  • Within 10 miles of existing power lines that have a capacity of at least 400 kilovolts (kV)
  • Within 5 miles of existing wind farms containing turbines where the rotor diameters span at least 100 feet

To meet these criteria, you'll save a copy of the map and then explore the data you have on population, existing wind farms and power lines, and average wind speeds around the state. Next, you'll start querying these layers to narrow down locations with the characteristics you want. Finally, you'll combine these into a single layer that you can conduct a multicriteria analysis on to locate a few viable sites.

Save a copy of the map

In this section, you'll open a map illustrating current wind turbine locations and wind power potential across the state of Colorado. The map will familiarize you with the features and attributes you'll be using to locate a new site for the development of a high-efficiency wind farm. After exploring this map, you'll save your own version of the map for further analysis.

  1. Open the ArcGIS Online group Perform a Site Suitability Analysis for a New Wind Farm.

    This group contains one item—a web map titled Wind Power Study in Colorado Starting Point by Learn_ArcGIS.

  2. Click the thumbnail to open the web map.

    Wind Power Study in Colorado Starting Point map thumbnail

    The map opens to the state of Colorado.

  3. If you aren't signed in, click Sign In and sign in to your ArcGIS organizational account.

    Note:

    If you don't have an organizational account, you can sign up for an ArcGIS free trial.

  4. On the Details pane, click Content.

    Switch Legend to Content

    The map contains data on existing wind farms in Colorado. Before exploring the map and the layers you'll query and analyze, you'll create a personal copy of the map.

  5. Click the Save button and choose Save As.

    Save map

  6. In the Save Map window, for Title, type Optimal Wind Farm Locations.
  7. For Summary, type Best locations for a new High-Efficiency wind farm.
  8. For Save in folder, verify that you are saving to your own folder.

    Save map as Optimal Wind Farm Locations

  9. Click Save Map.

    A copy of the map is now saved to your Content folder. You can access it at any time through the Content tab on the home page. Now that you've saved your map, you'll look at the data you have available to work with.

Check wind farm data

The map has five layers: the state boundary, Colorado counties, the locations of current wind turbines and power lines, and the average strength of the wind based on geographical location. Now you'll evaluate the available data to see if it is enough to satisfy the criteria listed above.

  1. In the Contents pane, check the Counties layer to turn it on.

    The Counties layer has population data for all 64 counties in Colorado. Some counties have higher population densities than others, which means higher energy demands. Because building new transmission lines is costly and detrimental to the environment, you want to identify locations with high demand for power to reduce the need to build additional transmission lines. This layer contains data that will allow you to check the first and second criteria: that the wind farm site is in the state of Colorado and has a high enough population density.

  2. Click a few counties along the Front Range (the mountain range west of Denver) between Fort Collins and Pueblo and note their population densities.

    These counties, including Boulder and Denver, have the highest population densities in the state.

    Identify Front Range counties

  3. Close the pop-up.
  4. In the Contents pane, uncheck the Counties layer to turn it off, and turn on the Wind Power Class layer.

    Display wind power classes

  5. For the Wind Power Class layer, click Show Legend.

    Explore wind power classes

    The Wind Power Class layer data is classified into 7 classes. These classes represent average (mean) wind speed as calculated for heights of 10 meters (33 feet) and 50 meters (164 feet). Wind speed is a good indicator of the power generating capacity of wind. Generally, the higher the wind speed, the greater the power generating capacity at a location.

    The table below illustrates wind speed for heights at 10 meters (33 feet) and 50 meters (164 feet).

    Wind power classWind power density10 m (33 ft.)Speed10 mSpeed33 ft.Wind power density50 m (164 ft.)Speed50 mSpeed164 ft.

    1

    100

    4.4

    9.8

    200

    5.6

    12.5

    2

    150

    5.1

    11.5

    300

    6.4

    14.3

    3

    200

    5.6

    12.5

    400

    7.0

    15.7

    4

    250

    6.0

    13.4

    500

    7.5

    16.8

    5

    300

    6.4

    14.3

    600

    8.0

    17.9

    6

    400

    7.0

    15.7

    800

    8.8

    19.7

    7

    1000

    9.4

    21.1

    2000

    11.9

    26.6

    Note:

    The degree of certainty with which the wind power class can be specified depends on three factors: the abundance and quality of wind data, the complexity of the terrain, and the geographical variability of the resource.

    A certainty rating was assigned to each grid cell based on these three factors and is included in the Wind Energy Resource Atlas of the United States.

    Notice that the wind power class is generally light to moderate in the western part of the state, with a narrow windy zone on the lee (east) side of the continental divide (running generally north-south in the central part of the state) a lower wind power class in a band to the east of this, and then changing to windier conditions as you get closer to the borders of Kansas and Nebraska.

  6. In the Contents pane, point to the Wind Power Class layer and click Show Table.
  7. On the right side of the table, click Show/Hide Columns and then check All Columns.

    Show all columns

    Wind power class is stored in an attribute named GRIDCODE, and the corresponding mean wind speeds are given in miles per hour.

    • Areas designated as Gridcode 1 (Class 1) are generally not suitable, although a few locations with adequate wind resource for wind turbine applications may exist in some class 1 areas.
    • Areas designated Gridcode 2 (Class 2) are marginal for utility-scale applications but may be suitable for rural applications.
    • Areas designated Gridcode 3 (Class 3) or greater are suitable for most utility-scale wind turbine applications.

    The prevalence of high wind speeds indicates that you have the wind power needed to satisfy the third requirement.

  8. In the Contents pane, uncheck Wind Power Class to turn it off, and turn on Wind Turbines in Colorado.
  9. On the ribbon, click Bookmarks and click various places to explore.

    Explore bookmarks

    Bookmarks allow you to zoom quickly to various parts of the state where there are existing turbines. The Wind Turbines in Colorado layer shows the location of several large installations of turbines within the state boundaries. To build the infrastructure that these wind farms need to run and to have a staff to keep them running, it is easiest to clump them together. Most of these clumps are in the eastern part of the state, where you saw greater wind speeds.

  10. Click the bookmark for Limon.

    Limon is a small community in northeastern Colorado that has a sizable number of wind turbines located nearby.

    Wind turbines located near Limon

  11. Zoom in until you see individual turbines.
  12. On the ribbon, click Measure and click Distance. Click one turbine, and then double-click one next to it.

    The turbines near Limon tend to be between 0.18 and 0.25 miles apart. Newer high-efficiency wind turbines have a very long rotor diameter, sometimes over 100 meters (328 feet), and require extra logistical and spatial considerations. Next you'll examine the rotor diameter of installed turbines represented in the Wind Turbines in Colorado layer.

  13. For the Wind Turbines in Colorado layer, click Show Table to display layer attributes.

    Show layer attributes

  14. In the attribute table, locate and examine the rotor_dia (rotor diameter) field.
  15. Right-click the rotor_dia field and choose Sort Descending.

    Sort Rotor Diameter field

    Several existing turbines have rotor diameters of 100 feet. This, along with the many clusters you observed in the state, signifies that there are several areas that may satisfy the fourth criteria.

  16. Close the attribute table and use the Colorado bookmark to zoom to the state.
  17. Turn on the Platts Transmission Lines layer.

    In the layer, transmission lines have been symbolized by voltage capacity. Lines with a capacity of 138 to 500 kV have the thickest line symbol, while lines with a capacity of 10 kV or less have the thinnest line symbol.

    Display transmission lines

    These high-voltage lines are present throughout the state, but they are especially concentrated toward the eastern half. This suggests that your fifth criteria, for sites to be within 10 miles of an existing power line, could be met.

    Now that you have explored the data layers necessary to identify new sites for high-efficiency wind turbines, you are ready to perform the analysis to identify specific sites. The Public Energy Commission has defined several site-specific criteria that you should consider.

    An ideal site should meet these conditions:

    • Located within the State of Colorado
    • In a county where the local or target population is at least 20,000, to ensure an adequate demand
    • Within 10 miles of existing power lines that have a capacity of at least 400 kilovolts (kV), to take advantage of nearby existing energy infrastructure
    • Within 5 miles of existing wind farms containing turbines where the rotor diameters span at least 100 meters
    • In areas where the wind power class is at least 4 (Annual wind speeds in these areas at 10 meters off the ground are generally at least 5.6 meters per second [12.5 mph], and at 50 meters off the ground, are generally 7.0 meters per second [15.7 mph].)

Combine layers for analysis

Because you have all the necessary data, you can now start the site selection analysis. To make sure all the criteria are being met, you ultimately want to merge all the layers into a single layer that you can query using the Find Existing Locations tool. To prepare for that, you'll start combining layers. The Colorado Counties layer, with the population data, and the Wind Power Class layer only require queries, so first you'll combine them using the Union tool. The requirements for the Turbines and Transmission Lines layers both specify certain distances from existing features, so you'll use the Buffer tool to calculate those distances. Then you'll use the Union tool to combine the layers.

  1. In the Contents pane, point to Wind Power Class and click Perform Analysis.

    Perform Analysis button

  2. In the Analysis pane, click Manage Data and choose Overlay Layers.

    Overlay Layers

  3. In the Overlay Layers tool pane, verify that Choose input layer is set to Wind Power Class.
  4. For Choose overlay layer, choose Counties, and for Choose overlay method, click Union.

    Union of Counties and Wind Power Class layers

  5. For Result layer name, type Union of Wind Power Class and Counties and add your initials to make the name unique in your organization. Then click Run Analysis.

    Union of Counties and Wind Power Class layers

    The resulting layer shows the combination of County and Wind Power Class features. This combined layer allows you to select all locations with wind power classes greater than and equal to 4 and counties with populations greater than 20,000.

    Next, you'll buffer the transmission lines layer. Since the transmission line data shows all lines in the state, you'll need to apply a filter. The first of your analysis criteria is to filter out transmission lines with a voltage of at least 400 kilovolts.

  6. In the Contents pane, turn on the Platts Transmission Lines layer and turn off the Union of Wind Power Class and Counties layer.
  7. In the Contents pane, point to the Platts Transmission Lines layer and click Filter.

    Layer selection using Filter tool

    Filter expressions use the general form of <Field_name> <Operator> <Value, Field or Unique>.

  8. In the Filter window, on the Create tab, click the arrows to create the expression VOLTAGE is at least 400.

    Transmission line filter expression

  9. Click Apply Filter.

    The filtered view is displayed on the map.

    400-volt transmission lines

    The layer has now been filtered to only display transmission lines that have a voltage of 400. Now you'll generate a 10-mile buffer zone around these transmission lines using the Create Buffers tool.

  10. In the Contents pane, point to Platts Transmission Lines and click Perform Analysis.

    Perform Analysis

  11. In the Perform Analysis pane, click Use Proximity and click Create Buffers.
  12. For Choose layer containing features to buffer, ensure that the layer is set to Platts Transmission Lines.
  13. For Enter buffer size, type 10 and set the units to Miles.

    Set 10-mile radius

  14. Expand Options and change the buffer type from Overlap to Dissolve.
  15. For Result layer name, type Transmission Lines 10 Mi Zone. Add your name or initials to make sure the name is unique within your organization.

    Save buffer

  16. Click Run Analysis.

    The tool may take a moment to complete. When the operation finishes, the Transmission Lines 10 Mi Zone layer is added to the map.

    Resultant transmission line buffers

    The Transmission Lines 10 Mi Zone layer represents both the location of high-capacity transmission lines and a 10-mile zone around them. The location of your new wind farm should be within one of these 10-mile zones close to a high-capacity transmission line.

  17. Turn off the Platts Transmission Lines and Transmission Lines 10 Mi Zone layers.

    To take advantage of existing infrastructure, now you'll need to find locations within 5 miles of existing wind farms. Specifically, these wind farms must contain turbines with rotor diameter spans of at least 100 meters. As you did before, you'll filter and then buffer the layer.

  18. In the Contents pane, point to the Wind Turbines in Colorado layer and click Filter.
  19. In the Filter window, use the arrows to create the expression roto_dia is at least 100.

    Filtering wind turbines

  20. Click Apply Filter.

    Your layer now displays only existing wind turbines with a rotor diameter of 100 meters or greater. There are four turbine clusters.

    Map of filtered wind turbines

    Next, you'll generate 5-mile zones around the filtered turbines.

  21. In the Contents pane, point to the Wind Turbines in Colorado layer and click Perform Analysis.
  22. In the Perform Analysis pane, click Use Proximity and click Create Buffers.
  23. For Choose layer containing features to buffer, ensure the layer is set to Wind Turbines in Colorado.
  24. For Enter buffer size, change the buffer size to 5 miles.
  25. Expand Options and change the buffer type from Overlap to Dissolve.
  26. For Result layer name, type Turbine 5 Mile Zone YourInitials.
  27. Click Run Analysis.

    Buffer wind turbines

    The buffer layer is added to your map. There are four turbine clusters, three of which appear to meet your criteria so far. To finalize your selection, look at the populations of the counties in which these clusters are located. Now you'll combine the buffered transmission lines and the buffered wind turbines into a new layer using the Union tool.

  28. In the Contents pane, point to the Turbine 5 Mile Zone layer and click Perform Analysis.
  29. In the Perform Analysis pane, click Manage Data and click Overlay Layers.
  30. For Choose input layer, choose Turbine 5 Mile Zone, and for Choose overlay layer, choose Transmission Lines 10 Mi Zone.
  31. For Choose overlay method, choose Union.

    Union tool wind turbines and transmission lines

  32. For Result layer name, type Union of Turbine 5 Mile Zone and Transmission Lines 10 Mi Zone.
  33. Click Run Analysis.

    Union of buffered wind turbines and transmission lines

    The resultant layer now contains all the buffered features for the transmission lines as well as the buffered wind turbine locations. Using this layer you'll be able to select all locations within 10 miles of a 400-volt transmission line as well as within 5 miles of wind turbines with a rotor diameter of 100 feet. Next, you'll combine the two union layers into a single layer from which your final site selection can be made. This final layer will have all the criteria necessary for you to select suitable sites for your client to consider developing and installing high-capacity wind turbines.

Find locations for wind farms

Now that you've combined several of the layers and filtered them, you'll use the Find Existing Locations tool, which is designed to select existing features in your study area that meet a series of criteria you specify from a single layer. These criteria can be based on attribute queries (for example, wind power class areas with generating capacity greater than 4) and spatial queries (for example, areas within 10 miles of current transmission lines with a voltage greater than 400).

  1. In the Contents pane, point to the Union of Turbine 5 Mile Zone and Transmission Lines 10 Mi Zone layer and click Perform Analysis.
  2. In the Perform Analysis pane, click Manage Data and click Overlay Layers.
  3. Verify that Choose input layer is set to Union of Turbine 5 Mile Zone and Transmission Lines 10 Mi Zone.
  4. For Choose overlay layer, choose Union of Wind Power Class and Counties.
  5. For Choose overlay method, choose Union.
  6. For Result layer name, type TargetSitesYourInitials and click Run Analysis.

    Combined analysis layers

    The resulting layer displays the combination of all features and their attributes that you would need to include in your analysis to determine suitable locations for your client. Now you'll use the Find Existing Locations tool, which allows you to combine the attribute and spatial selections in a single statement by adding a set of expressions, one at a time. These selection criteria can be based on attribute queries (for example, counties with a population greater than 20,000) and spatial queries (locations 10 miles from transmission lines).

  7. In the Contents pane, point to TargetSites and click Perform Analysis.
  8. In the Perform Analysis pane, click Find Locations and click Find Existing Locations.
  9. Verify that the layer for Choose layer containing features you want to find using attribute and spatial queries is set to TargetSites.
  10. In Build a query to find features, click Add Expression.

    The Add Expression window opens. You can add multiple expressions to the query box as needed. Click the Run Analysis button to execute the list of expressions. Features in your input layer are then filtered through each expression, and those features that satisfy the expressions are written to a results layer.

    Find Existing Locations query builder

    Like you did earlier, you'll build expressions, but these will query the TargetSites layer. You'll start with two spatial expressions to locate suitable sites within the 5-mile zone of turbines and the 10-mile zones of transmission lines. A spatial expression establishes a relationship between two layers. In this case, you're searching for all target sites in the first layer that are completely within the second layer, the 5-mile buffer zone of 100-foot rotor diameter wind turbines.

  11. In the Add Expressions window, ensure TargetSites is the first layer.

    The analysis layer (TargetSites) represents the source layer you are selecting from.

  12. Choose Completely within for the spatial relationship.

    Choose a spatial relationship

    Choosing Completely within specifies that if a feature in the first layer is completely within a feature in the second layer, the location is included in the output. Once you establish a spatial relationship to other layers, they will be listed in the drop-down menu.

  13. For the second layer, choose Turbine 5 Mile Zone and click Add.

    The first expression has been added to the expressions query box in the Find Existing Locations pane.

    Expressions in the query box

    Now you'll build the expression to locate target sites completely within the Transmission Lines 10 Mi Zone layer.

  14. Click Add Expression and ensure that TargetSites is specified as the first layer.
  15. Choose Completely within for the spatial relationship, and choose Transmission Lines 10 Mi Zone for the second layer.
  16. Click Add.

    The second spatial expression is added to the expression query box and is combined with the first expression by the connector and. In queries, the operator and requires that each expression or condition must be true for a location to be selected. The other operator, or, requires that one or the other condition, but not both conditions, can be true for a location to be selected.

    Adding a second expression
    Note:

    Click the operator to switch between and and or.

    Now you'll add a series of attribute selection expressions to further refine the locations that will be selected within the 5- and 10-mile zones.

  17. Click Add Expression and build the expression TargetSites where STATE_NAME is Colorado.
  18. Click Add.

    The third expression is added to the expression query box and is combined with the first and second expressions by the and connector.

    Query expressions

  19. Click Add Expression and build the query TargetSites where POP2010 is greater than 20,000, and then click Add.

    There will be four expressions in the query box list. The final expression you need to add will filter only the highest wind speeds.

  20. Click Add Expression and build the query TargetSites where GRIDCODE is between 4 and 7, and then click Add.

    The final expression is added to the query box.

    Completed query expressions

    Note:

    The order of the expressions does not affect the result of the analysis.

  21. In Results Layer name, type SuitableSites and click Run Analysis.
  22. On the Contents tab, turn off TargetSites and all other analysis layers except for SuitableSites and the basemap. Turn on the State Line layer if necessary.

    Suitable locations

    The two final sites are in the northeast corner of the state.

  23. On the ribbon, click Bookmarks and explore the Limon and NE Colorado sites.

    These sites both meet the criteria you need:

    • Located within the state of Colorado
    • In counties where the population as of 2010 is at least 20,000
    • In areas where the wind power class is at least 4 (Annual wind speeds in these areas at 10 meters off the ground are generally at least 5.6 meters per second [12.5 mph], and at 50 meters off the ground, are generally 7.0 meters per second [15.7 mph].)
    • Within 10 miles of existing power lines that have a capacity of at least 400 kilovolts (kV)
    • Within 5 miles of existing wind farms containing turbines where the rotor diameters span at least 100 feet
  24. On the ribbon, click Save. In the menu, click Save again.

Next, you'll create drive-time routes to each site to help make your final decision. Because transportation to and maintenance of the site are important, it should be easily accessible.


Route to prospective sites

Previously, you explored site selection criteria for siting high-efficiency wind turbines and identified two potential sites in the state of Colorado. Selecting an appropriate site is key to the success of any renewable energy project and affects its financial viability. Next, you'll be performing a drive-time analysis between the potential sites and the company headquarters based in Denver. This will be an important consideration, as engineers and other logistic staff involved in the installation and maintenance of the wind turbines are based at located in the company headquarters and not on-site in remote locations. Therefore, minimizing drive time and the availability of fast and efficient transportation routes to and from a new site are crucial to successfully maintaining and running equipment at these sites.

Add map notes

Now that you have identified suitable sites for the wind turbines, you need to conduct site visits and access routes between the sites and the company headquarters. First, you'll add map notes, and then you'll conduct drive-time analyses.

  1. On the ribbon, click Bookmarks and choose Limon.
  2. On the ribbon, click Add and choose Add Map Notes.

    Add Map Notes

  3. In the Add Map Notes window, name the notes Optimal Wind Farm Sites and click Create.

    Name Map Notes layer

    The Map Notes template allows you to create basic shapes and symbols. There are other options in the menu, including Citizen Requests, Disasters, and Oil and Gas Infrastructure, that provide additional specialized symbols.

  4. In the Add Features pane, click the pushpin.

    Choose Pushpin

  5. On the map, click and add a pushpin anywhere within the Limon wind farm sites.

    Add a pushpin at Limon

    When you have placed a pin, a pop-up dialog box opens for you to add additional location information.

  6. In the Points pop-up, for Title, type Site 1- Limon.

    Title the pushpin point

  7. Click Change Symbol and click Use an Image. For URL, paste http://downloads.esri.com/learnarcgis/perform-a-site-suitability-analysis-for-a-new-wind-farm/wind-farm.png and press Enter.

    Change pushpin symbol

  8. Click OK.

    The point feature is now symbolized as a windmill.

  9. In the Points window, click Close to save the point.
  10. Click the bookmark for NE Colorado and add a pushpin anywhere within the Fleming wind farm site.
  11. In the Points window, for Title, type Site 2- Fleming.
  12. Click Change Symbol, then click Use an Image. For URL, type http://downloads.esri.com/learnarcgis/perform-a-site-suitability-analysis-for-a-new-wind-farm/wind-farm.png and press Enter.
  13. Click OK to update the symbol.
  14. In the Points window, click Close to save the point.
  15. On the ribbon, click Details.

Calculate drive time

Now that you have point locations for each site, you can perform the drive-time analysis. You are now ready to compute the optimal route so that you can visit the sites.

  1. On the ribbon, click Analysis.
  2. Click Use Proximity and choose Plan Routes.

    The Plan Routes tool determines how to efficiently route a vehicle to the stops that you specify.

  3. In the Plan Routes pane, for Choose point layer representing stops to visit, choose Optimal Wind Farm Sites.
  4. For Travel mode for routes, choose Driving Time and accept the current date and time for all routes.

    The current date and time are the default settings.

  5. On the ribbon, click Manage Bookmarks and choose Denver State Capitol.
  6. In the Plan Routes pane, for Routes begin at, click the Add point to map button and add a point at the Denver State Capitol building.

    Draw a route point at State Capitol

  7. For Routes end at, ensure Return to start is checked.
  8. For Maximum number of vehicles to route, type 1, and for Maximum number of stops per vehicle, type 2.
  9. For Time spent at each stop, type 120 minutes and uncheck the box next to Limit the total route time per vehicle.

    It will take you 2 hours, or 120 minutes, to inspect each site, but depending on the time of day you're using, the traffic might cause the total route time to vary.

    Routing steps

  10. For Result layer name, type Routes to Optimal Wind Farm Sites.
  11. Check Include route layers and save the result to your folder.
  12. Zoom to the Colorado bookmark and click Run Analysis.

    When your analysis has completed, change the basemap to Streets.

  13. On the ribbon, click Basemap and choose Streets.

    Resultant routes from Denver to Sites

    Note:

    Results may vary slightly depending on time of day and where each site point was created.

    The assigned stops for the route are numbered 1 to 4. The first and fourth stops are both located at the State Capitol. Since you set the Route to end option to Return to start, your route will visit all stops in sequence and return to the point of origin.

  14. For the Routes to Optimal Wind Farm Sites – Assigned Stops layer, click Show Table.

    This table contains 4 records, one for the start and end points, and one for each site under consideration. Your distances and times may vary slightly depending on where you placed your map notes.

  15. Turn the Routes to Optimal Wind Farm Sites layer on and off to change the route.
  16. For the Routes to Optimal Wind Farm Sites layer, click Show Table to display layer attributes.

    Routes to Optimal Wind Farm Sites table

    This table contains one record for your entire route. Note that it states that two stops are included, and that the total time is approximately 594 minutes. This includes travel time and service time to inspect the sites. Of the 594 minutes, your total travel time is 354 minutes and service time is 240 minutes, making up the 120 minutes you would use to inspect each site.

    If you subtracted your end time from your start time, you would notice that completing the route as planned would take around 10 hours. Therefore, even if you take a break from driving for 30 minutes, you would still be able to complete the travel and the site inspection in under one day.

    Your route analysis would need to be included in your report to your client, along with your recommended site. Now you'll evaluate the two sites and make a decision.

Recommend a site

After your initial inspection, other visits will need to be conducted to look for soils, drainage, and other site factors. GIS will be helpful for assessing climate, slope and aspect, land ownership, historical incidence of tornadoes, performance of existing wind turbines, permits and permissions, and other factors. When these factors are considered, you can make an additional recommendation of how many turbines each site can accommodate.

  1. For the SuitableSites layer, click Show Table to display layer attributes.

    If you can only choose one of the sites due to budget constraints, and you are told to choose the larger of the two, the southern site, near Limon, is 200.83 square kilometers or 77.5 square miles, as opposed to the site near Fleming, which is 102.34 square kilometers or 39.5 square miles.

    If you are instructed to choose the site that is closer to Denver and its major population, you could use the route results or the measure tool to get a straight-line distance.

  2. On the ribbon, click Measure, and then click Distance to determine the straight-line distance from both the Limon site and the Fleming site to Denver.

    Measure straight-line distances

    The Limon site is closer, approximately 70 miles (113 kilometers) straight-line distance, compared to approximately 133 miles (214 kilometers) for the Fleming site. In other respects, such as mean wind speed and population per square miles, the two sites are quite similar.

  3. On the ribbon, click Save.

    It is most likely that you would recommend the Limon site, but there are additional considerations. GIS will be critically important in the logistics of transporting large wind turbines to the site. This may be the most difficult part of the operation, because wind turbine blades often have to be transported by rail, and then by a convoy of two or three trucks, to accommodate the length. In this respect, the Fleming site may be better, because it is located near a major U.S. Highway (U.S. 6), whereas the Limon site, while near I-70, has no exits directly to the site, and is located largely off unimproved county roads.

    Thus, there are pros and cons about both sites. But spatial analysis with GIS helped to narrow the decision to these two sites.

    Are other considerations important? Certainly, and if you were truly choosing a site for a client, you would consider additional factors and conduct additional analysis to qualify your recommended site to the client.

You've considered logistics about your site visits, using spatial thinking and GIS in the process.


Create a web app

Previously, you calculated drive time to each of the sites. Now, your client has requested preliminary results of the high-efficiency wind turbines site analysis study you are conducting. One of the best ways to efficiently share your results is to create a web application to share results and to allow your client the ability to explore and investigate your data and analysis results.

Share results as a web app

A web app is a customized map that you can present to the client to include and symbolize the data as you feel would best enable the commission members to understand the problem and the solution. To create the web mapping application, you first need to share your map publicly. Once the map and layers are public, you can create a web app for the shareholders.

  1. On the ribbon, click Share.
  2. In the Share window, check Everyone (public).
    Note:

    If you are prompted to share layers, check Yes, update sharing.

  3. At the bottom of the Share window, click Create a Web App.

    Share as web app

    The Create a New Web App window appears. This window contains a list of configurable app templates, each tailored to a specific purpose. You'll use the Impact Summary template and modify it using Web AppBuilder for ArcGIS.

  4. On the Configurable Apps tab, click Show All.
  5. For Select a configurable app, choose Impact Summary.

    Choose Impact Summary app

  6. In the Impact Summary pane, click Create Web App.

    Click Create Web App

  7. In the Create a New Web App window, title the app Wind Turbines in Colorado Impact Study, and for Summary, type Optimal Wind Farm Sites.
  8. For Save in folder, choose Your Folder, and then click Done.

    The Impact Summary Web AppBuilder opens.

  9. In the Contents pane, click Layers.

    Configure web app legend

    In the Layers pane, you can choose the layers you want to be included in the web app. These should convey your story to the commission members without overwhelming them.

  10. Turn on the two route layers, SuitableSites, Wind Turbines in Colorado, Platts Transmission Lines, and State Line.

    Display legend

    Next, you'll configure the settings for your app, including the description and basemap.

  11. On the ribbon, click Application Settings.

    Application Settings

  12. For Application Description, type Wind turbine site selection study in Colorado based on the following criteria:
    • Located within the state of Colorado.
    • In a county where the local or target population is at least 20,000, to ensure an adequate demand.
    • Within 10 miles of existing power lines that have a capacity of at least 400 kilovolts (kV), to take advantage of nearby existing energy infrastructure.
    • Within 5 miles of existing wind farms containing turbines where the rotor diameters span at least 100 meters.
    • Wind power class is at least 4. (Annual wind speeds at 10 meters off the ground are 5.6 meters per second, or 12.5 mph, and at 50 meters off the ground are 7.0 meters per second, or 15.7 mph.)
  13. Click Save.

    Your application settings are now saved for the app. This web app is stored in your My Content folder in ArcGIS Online, and just like you can with your map, you can modify it whenever you want. The app points to your original web map, so any changes you make on the web map will be reflected in the web app.

  14. On the ribbon, click Save.

    Now you'll see a preview of the app.

  15. Click the Share button located in the upper right of your application.

    Share web app

    Your web app is already shared publicly, but in this window there is a map link you can send to your client to access your application. In addition, there is an Embed Map code you can use to embed your web application into external web pages and applications.

  16. On the ribbon, click Exit Builder to see the public version of your web app.

In this lesson, you examined spatial relationships to conduct a site suitability analysis. You ran a series of spatial analysis functions, determined how you would conduct site visits, and prepared a web app to communicate your results to your client.

For more information on wind farm siting, consult the AWEA website.

You can find more lessons in the Learn ArcGIS Lesson Gallery.