 Under deregulation, many vertically integrated utilities were separated into generation owners, transmission and distribution owners, and retail providers.In order to recover capital costs, operating costs, and earn a return on investment, a transmission revenue requirement (TRR) is established and approved by a national agency (such as the Federal Energy Regulatory Commission in the United States) for each transmission owner.The TRR is paid through transmission access charges (TACs), load-weighted fees charged to internal load and energy exports for use of the transmission facilities.