Prepared by five wind energy experts, this paper examines and summarizes wind integration experience in the United States. U.S. wind capacity has nearly tripled since 2005, and the wind power integration issue is attracting increasing attention. The paper begins with a description of time scales of grid operation; discusses estimated grid impacts based on wind integration studies and operating experience; summarizes estimated wind integration costs; considers literature on how to determine the capacity value of wind; describes potential solutions and means of accommodating higher levels of wind power; discusses recent grid outages involving wind power; and closes with a summary.