Public Safety Power Shutoffs Explained

Why do PSPS events happen?

Utilities are required to ensure clearance between energized power lines and foliage that might make contact with the lines. When trees or branches hit power lines, either the branch can cause a short circuit between two lines, or the branch can push lines together to cause a short circuit directly between the lines. In either case, a short circuit can cause branches to catch fire, or cause sparks or molten metal to drop on and ignite surrounding bushes or grass. Another way tree strikes can occur is when power lines sag into trees. This can happen when lines are overloaded, causing them to overheat, stretch, and expand. PSPS events de-energize electrical equipment during high fire and wind conditions to lower the risk of starting fires. In California, certain utilities failed to conduct the maintenance required to reduce the risks of electrical equipment resulting in historic wildfires and widespread PSPS events.

Where are PSPS events happening?

While PSPS events began in California, climate change is increasing the frequency and intensity of extreme weather across the U. S., leading more utilities to adopt PSPS events. Examples of this shift include:

• Oregon utilities have implemented PSPS events and energy regulators adopted PSPS guidelines in May 2022
• A Hawaiian utility, which announced its new PSPS program in July 2024
• An Idaho utility, which implemented PSPS in the Treasure Valley in July 2024
• A Colorado utility implemented a PSPS event in Boulder in April 2024

How long is a PSPS?

PSE Healthy Energy has conducted analysis on PSPS shutoffs in California, which has the most publicly-available data given their history in the state. In California, the average duration is almost two days, with some outages extending longer than six days. In general, the duration of a PSPS outage is driven by two factors:

• The duration of the weather event triggering the need to de-energize.
• The amount of time it takes the utility to determine the event is over and inspect the lines to ensure they can be safely re-energized.

How do PSPS events affect individuals?

Any extended power outage has the potential to result in disruptions to individual productivity, economic hardships, and risks to public health and safety. For example, extended power outages can result in a range of impacts, including food spoilage, missed work or school, and the inability to charge cell phones and computers. For individuals who depend on electrically-powered medical, mobility, or other essential devices, loss of electricity can be life threatening.

Learn more about PSPS

If you are experiencing a power outage or have questions about your local utility’s power outage policies, we recommend contacting your utility directly. To access research on the trends and impacts of public safety power outages from PSE Healthy Energy scientists, explore our related research below.

Stay informed!

Join our email list to receive updates
on PSE's work and news.