Wind Farm, Columbia River Gorge, USA (image) Stanford University Caption Grid operators routinely shut down wind farms that produce surplus clean electricity. Credit Charles Barnhart, Stanford University Usage Restrictions Photographs, videos and other images provided by the Precourt Institute for Energy at Stanford University are to be used -- with appropriate credit -- for editorial purposes only. Flopping, editing, altering or otherwise embellishing these images in any way that changes the images' editorial content is prohibited. Photographs and images provided for web use must be resized to low resolution. Permission is for one-time use only. Supplied photo/video/image file must be deleted after use. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.