Some wind turbines have been installed by the wind companies themselves with conventional financing from banks and leasing companies. Studies by electric utilities have found that it costs about 1 cent per kilowatt-hour to operate and maintain modern wind power plants. Wind power plants are in regular commercial service in California, Canada, Denmark, Germany, Great Britain, Ireland, India, and the Netherlands. It's unlikely that all of the machines will be operating at the same time because of variations in the wind and differences between turbines. Often there will be turbines out of service for routine maintenance.
Wind speeds vary with the terrain, season, and time of day.
They turn themselves on when conditions are right, and they turn themselves off when the winds are too strong, or when they sense a problem. Most turbines change directions as the wind changes. The Eggbeater or Darrieus turbines accept the wind from all directions. An operator at the console is then able to turn the turbines on and off at will, similar to that at most modern power plants. No one knows for sure.