Power outage

Power outages can occur for various reasons, including severe weather conditions (e.g. storms, hurricanes, or blizzards), earthquakes, equipment failure, grid overload, or planned maintenance.

Blackouts are also used as a public safety measure, such as to prevent a gas leak from catching fire (for example, power was cut to several towns in response to the Merrimack Valley gas explosions), or to prevent wildfires around poorly maintained transmission lines (such as during the 2019 California power shutoffs).

[2] In that case, the short-term economic benefit of keeping the individual customer happy increases the likelihood of large-scale blackouts.

The Senate Committee on Energy and Natural Resources held a hearing in October 2018 to examine "black start", the process of restoring electricity after a system-wide power loss.

To maintain supply frequencies within tolerable limits during this process, demand must be reconnected at the same pace that generation is restored, requiring close coordination between power stations, transmission and distribution organizations.

It has been argued on the basis of historical data[4] and computer modeling[5][6] that power grids are self-organized critical systems.

This phenomenon has been attributed to steadily increasing demand/load, the economics of running a power company, and the limits of modern engineering.

The term critical point of the system is used here in the sense of statistical physics and nonlinear dynamics, representing the point where a system undergoes a phase transition; in this case the transition from a steady reliable grid with few cascading failures to a very sporadic unreliable grid with common cascading failures.

[8] The practice of operating these systems much closer to their maximum capacity leads to magnified effects of random, unavoidable disturbances due to aging, weather, human interaction etc.

Leaders are dismissive of system theories that conclude that blackouts are inevitable, but do agree that the basic operation of the grid must be changed.

[9] Others advocate greater use of electronically controlled high-voltage direct current (HVDC) firebreaks to prevent disturbances from cascading across AC lines in a wide area grid.

[16] The effects of trying to mitigate cascading failures near the critical point in an economically feasible fashion are often shown to not be beneficial and often even detrimental.