Although each electric utility is autonomous concerning the supply of electricity within a certain area, the high-voltage grids of Western Europe are joined together into an international system. The Union for Coordination of Generation and Transport of Electrical Energy in Western Europe (UCPTE) is responsible for coordinating the operation of this interconnected system. The advantages of this system, which include an optimal energy exchange between all partners and increased effectiveness through common operation and coordinated planning, are discussed. Coordination and execution of the system depends on an active exchange of information on an international basis, but owing to the separate development of individual utilities, a homogeneous information exchange system does not exist, despite efforts by UCPTE. The UCPTE-recommended data-transfer protocol, based on the ISO standards for open systems interconnection, is discussed.