Supply shortages are perhaps the rarest type of outage. These outages happen when there is simply not enough electricity to meet demand. In most parts of the country, this type of outage is most likely to occur on the hottest summer days when people are increasing their air conditioning usage and electricity demand is at its peak. This type of outage can also occur when equipment or appliances are used and/or installed without notifying PG&E and allowing us to complete a load evaluation to determine if existing transformer, equipment, and infrastructure is adequate to support the additional load.