The TSO (Transmission System Operator) is the key player responsible for the operation, maintenance, and development of the high and extra-high voltage electricity transmission network.
Its role is to guarantee the secure, continuous, and balanced flow of electricity between generation sites (power plants, wind farms, solar arrays, etc.) and the distribution networks (DSO), while maintaining the stability of the electrical system. The TSO also ensures real-time equilibrium between electricity supply and demand, which is essential to prevent network outages or overloads. In Canada, this role is primarily undertaken by provincial entities such as Hydro-Québec TransÉnergie in Quebec, or independent system operators like the Independent Electricity System Operator (IESO) in Ontario.
The TSO is a strategic link in the integration of renewable energies and the broader energy transition.