Windpower

Mike W gave us an insight into the subject of windpower. Starting with a brief survey of windmills and anemometer types, Mike turned to the operational details for modern wind-powered generators.

The latest designs incorporate variable-pitch blades of composite material. Long- term site surveys have to be done before any installation can be started.

One of the most important points brought out in Mike’s talk, which never seems to be covered in the media, is that the generators need to extract run-up power off the grid itself – so they cannot be considered simply as stand-alone items just contributing power to the grid. Thus they need a reserve of power before they can become available The generators are not multi-pole machines, they are induction motor/generators.

The operating sequence is that an on-site anemometer detects suitable wind threshold. The generator brake is released, a yaw circuit positions the blades into the wind, blade pitch is set to minimum. The blades are driven up to speed via power from the grid, as the motor/generator reaches synchronous speed, blade pitch is coarsened, torque then reverses as the unit changes from motoring to generating. Pitch controls attempt to keep the unit at constant speed and yaw controls keep it into the wind.

It would seem that existing designs are not going to be the easy solution to the energy gap that some suggest.