PG&E announced rotating power outages could affect the Stanford Redwood City campus from 4 p.m. to 9 p.m. on Tuesday. 

Power is expected to be restored around 11 p.m. in some Redwood City neighborhoods which lost power earlier tonight, the Palo Alto Daily Post reported. Outages typically last one to two hours but can be longer, postponed or canceled based on energy conservation efforts, according to PG&E’s announcement.

Rotating outages occur when demand for electricity is too high on the power grid, such as during a heat wave. California is currently experiencing a heat wave, with an Excessive Heat Warning in effect since Saturday morning and through next Tuesday. 

The California Independent System Operator (CAISO) decides when rotating outages are necessary to avoid wider outages. Rotating outages are not Public Safety Power Shutoff (PSPS), which PG&E decides to enact to help prevent wildfires. 

Based on electricity demand, PG&E selects blocks of customers subject to rotating outages. The entire Stanford Redwood City campus, including the Stanford Medicine Outpatient Center, are in blocks that could be affected by today’s outage.

Updates on locations affected by rotating outages can be found on the PG&E website.