Specialists emphasize that this type of total blackout—an exceptional and infrequent event—is also a security mechanism of the electricity system itself. Maintaining grid balance is the responsibility of the system operator, who monitors parameters such as electrical frequency, voltage, and load from substations in real time. The grid, unable to balance such a sharp drop between generation and demand, protected itself by automatically disconnecting both internally and from the rest of the European grid. Second, there are interconnections with neighboring countries’ grids, which allow energy to be imported or exported as needed to balance generation and demand. Finally, there is something called “mechanical inertia.” Synchronous generators—the large spinning machines that generate electricity in power stations—also store a lot of energy in their very large rotating parts.