Windfarm Locator needs an internet connection to retrieve local results so with the iPod Touch a Wi-Fi connection is required.
The iPod touch provides your approximate location using information based on your proximity to known Wi-Fi networks but the feature is not available in all areas. Known Wi-Fi networks are predominantly in urban areas.
If your location is not found automatically tapping the search icon at topright left of the main screen will allow you to specify the City or ZIP code.