The term black start refers to the ability of a power plant to restart itself after a complete power failure - a so-called blackout - without an external power supply and to gradually rebuild the power grid. This feature is of key importance to ensure security of supply in the event of a large-scale power outage. Power plants that have this capability are equipped with special auxiliary systems to enable them to operate even in a gridless state.

A black start is made possible by systems that rely either on battery systems, emergency generators or mechanical storage such as flywheels to provide the necessary energy. These systems must be able to operate autonomously in order to generate the necessary base load and thus begin to rebuild the power grid. In Austria, where the electricity supply has become increasingly decentralized in recent years due to the expansion of renewable energies, black start capabilities are of crucial importance, as the failure of large power plants could have serious consequences for grid stability.

In the event of a large-scale blackout, the grid must be rebuilt in an orderly and gradual manner. Power plants with black start capability are essential in this phase. They are commissioned first in order to create a stable basis for the gradual commissioning of further power plants. There are a number of hydropower plants in Austria that are designed for black start. These power plants, which are usually supported by pumped storage plants, play a crucial role as they are ready for operation again relatively quickly and offer a high degree of flexibility.

A well-known example in Austria is the Kölnbreinsperre pumped storage power plant in Carinthia, which is considered a key element in the black start capability of the Austrian electricity grid. With its ability to supply electricity quickly and stabilize the grid, it is an indispensable component of the safety grid for potential blackouts.

The regulatory authority E-Control monitors measures to increase grid security in Austria, including the expansion of black start capability. An important challenge in this context is the integration of renewable energies, in particular wind and solar energy. As a rule, these systems cannot carry out a black start as they are dependent on continuous weather conditions. It is therefore crucial that traditional power plants or flexible storage systems continue to act as the backbone of grid stability.

The expansion of intelligent grids (smart grids) also plays an important role in improving black start capacities. Smart grids enable better coordination between the various energy sources and help to make the process of recovery after a blackout more efficient. For example, flexible control of the grid load can help to optimize the recommissioning of generation plants and accelerate grid reconstruction.

In summary, black start is an indispensable part of modern energy infrastructure, especially at a time when renewable energy is playing an increasingly important role. While the majority of renewable energy sources are not black-start capable, conventional power plants and flexible storage solutions ensure that the power grid can be restored quickly and efficiently even after an outage. In Austria, hydropower plants make a significant contribution to ensuring this security and therefore play a key role in national energy policy.