A measure of the remaining physical capability in a transmission network for commercial activity, over and above that already committed to users for both commercial transactions and system reliability.

Unit of measure for the transfer capability remaining in the physical transmission network for further commercial activity, over and above committed uses.

a measure of the transfer capability remaining in the physical transmission network for further commercial activity over and above already committed uses. ATC is defined as the total transfer capability ( TTC), less the transmission reliability margin ( TRM), less the sum of existing transmission commitments (which includes retail customer service) and the capacity benefit margin (CBM). see also capacity benefit margin