This excerpt taken from the AEP 10-K filed Feb 28, 2008.
Transmission Equalization Agreement: APCo, CSPCo, I&M, KPCo and OPCo operate their transmission lines as a single interconnected and coordinated system and are parties to the TEA, defining how they share the costs and benefits associated with their relative ownership of the extra-high-voltage transmission system (facilities rated 345kV and above) and certain facilities operated at lower voltages (138kV up to 345kV). The TEA has been approved by the FERC. Sharing under the TEA is based upon each company’s “member-load-ratio.” The member-load-ratio is calculated monthly by dividing such company’s highest monthly peak demand for the last twelve months by the aggregate of the highest monthly peak demand for the last twelve months for all east zone operating companies. The respective peak demands and member-load-ratios as of December 31, 2007 are set forth above in the section titled ELECTRIC GENERATION – AEP Power Pool and CSW Operating Agreement.
The following table shows the net (credits) or charges allocated among the parties to the TEA during the years ended December 31, 2005, 2006 and 2007: