BlackStart

Blackstart is the capability to restore electric power to a grid after a blackout without relying on external power sources. It refers to initiating generation and the transmission network from a state of zero or near-zero energy, using equipment and resources that can start and operate independently.

In practice, blackstart begins with one or more blackstart-capable units that can start without external electricity. These units supply initial power to start additional generators and energize transformers, substations, and transmission lines. Operators then gradually bring online other plants, synchronize their output to the grid, and carefully control frequency and voltage as the system is re-energized. The process requires careful sequencing, monitoring, and coordination to prevent instability as loads increase.

Common blackstart resources include hydroelectric plants with reservoirs or pumped-storage facilities, which can start quickly and provide sustained output. Some fossil-fueled plants with on-site starting capability (such as certain coal, gas, or diesel units) can also serve as starting points. Energy storage systems, especially large batteries, are increasingly considered to support blackstart by delivering rapid power and stabilizing frequency during reconstruction.

Planning and operations are essential for reliability. Grid operators designate and maintain blackstart-capable units, ensure adequate fuel or water supplies, and conduct regular drills and post-event analyses. Coordination with neighboring grids and transmission operators is often required to manage cross-border restoration.

Ongoing developments include integrating distributed energy resources, microgrids, and advanced storage to enhance resilience and shorten restoration times after outages.