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Reliability Improvements

Making Energy More Reliable and Strengthening the Grid

Our customers depend on us for reliable electric service to manage their daily lives, feel safe and comfortable in their homes and businesses, and protect them during times of emergency. They expect uninterrupted service and, when an outage does occur, fast service restoration with regular communication. To meet these expectations and continue to serve our customers, we make prudent investments in our infrastructure. These investments have shown proven improvements to our customer reliability scores. 


How We Measure Reliability

Liberty measures customer reliability through the industry performance metrics SAIDI and SAIFI (System Average Interruption Duration Index or SAIDI and System Average Interruption Frequency Index or SAIFI).


SAIDI and SAIFI Explained

SAIFI is the average number of sustained power interruptions per customer during a year. It is the ratio of the annual number of interruptions to the number of consumers.

SAIFI = (Total number of sustained power interruptions in a year) / (Total number of customers)

SAIDI is the average duration of power interruptions per customers during a year. It is the ratio of the annual duration of interruptions (sustained) to the number of customers. 

SAIDI = Total duration of sustained interruptions in a year / total number of consumers


Operation Toughen Up

In 2010, Liberty developed a multi-year plan to construct system improvements to improve the reliability of their total electric system. This reliability plan is often referred to as Operation Toughen-Up. Liberty is in the midst of the implementation of this plan.


2020 Reliability Investments

In 2020, an additional 20 circuits were sectionalized and 1,549 poles were reinforced or replaced.  Additionally, approximately 3,000 devices have received wildlife guards to protect against animal related outages. 


Improved Reliability Scores

In 2020, Liberty customers experienced a high level of service reliability. The 2020 reliability performance metrics were as follows; SAIDI of 103.54 and SAIFI of 0.941. These scores were positively influenced by favorable weather, but largely possible due to Liberty's infrastructure investments, ongoing vegetation clearing and Operation Toughen Up projects.



Aged poles after removal

Liberty performs a routine system aerial inspection to ensure reliability

Crews install a protective wildlife cover above a transformer to help prevent animal and bird-related outages

New sectionalization switching devices are shown on structure