The state moved back to a Stage Two power alert Thursday evening, after previously being under a Stage Three emergency for only the second time in history. The highest alert is issued when electricity reserves drop below 1.5 percent. Customers in the program receive a 15 percent to 20 percent rate reduction, but are first on the list when blackouts are called and will have their power cut for hour-long periods until the situation ends. Most of the VIP customers are large industrial power users. Should blackouts among these customers fail to improve power levels during a Stage Three emergency, utility companies would begin rolling blackouts.
Blackouts are an emergency measure to prevent a collapse of the power grid.
Rolling blackouts involve switching off entire neighborhoods for about an hour at a time to relieve the strain on the system. The ISO blamed the low power situation on heavy rain, cold temperatures and high surf along the coast. State power production fell more than 15,000 megawatts, or one-third of all available power, as the storm battered the state. One megawatt is enough to power 1,000 homes for an hour. The plant, like many others along the coast, uses vacuums to bring in cold water to cool its systems.