RIYADH — Many cities in the western and southern parts of Saudi Arabia experienced a power outage for several hours on Thursday night. The Saudi Electricity Company (SEC) said in a statement on Friday that a technical breakdown in the power grid disrupted operations at several plants and feeding stations, causing the partial blackout. It said electricity was restored to 90 percent of subscribers after several hours and the company's engineers and technicians had been working on an emergency footing to restore the supply to the remaining subscribers. The SEC apologized to the subscribers for their suffering in extreme summer heat.