Power Grids and Cross-Border Energy Interconnection

Electricity grids are organized into synchronous zones, groups of interconnected systems that operate at the same alternating-current frequency and can share power seamlessly, and into high-voltage direct current (HVDC) links, which are typically used to move large amounts of power over very long distances or to connect grids that are not synchronized with one another, since HVDC lines lose less energy over distance than AC lines and can link systems running at different frequencies or phases. Continental Europe's grid, coordinated by the European Network of Transmission System Operators for Electricity (ENTSO-E), forms one of the largest synchronous zones in the world, spanning most of the continent and allowing electricity to be traded and balanced across national borders in close to real time.