In grids with high wind power penetration, the System Operator may curtail the power injected at critical moments for security reasons. An intermediate operator can optimize this power reduction for a group of wind farms under its control, attending to their controllability. In this way, resources may be used efficiently, and in cooperation with the system operation. In this paper, an optimization-based procedure is proposed to allocate the power reductions among the wind farms of a region. Application examples based on the Spanish situation are shown, because in that country, these intermediate entities (called Delegated Dispatches) are about to begin their full operation. Copyright © 2008 John Wiley & Sons, Ltd.