MANILA, Philippines - The Department of Energy warns rotational power interruptions will continue in Mindanao until 2015. Energy Secretary Jericho Petilla says they are expecting two power plants to come on stream next year - a 350-MW facility from the Aboitiz group and a 200-MW plant from the Alcantara group - which should help address the supply shortage in the southern Philippines. He added this is why they have asked electric cooperatives to prepare contingency measures. "We expected it to happen this year. In fact, I'm surprised people are bringing this up, the rotational brownouts in Mindanao because based on our projection there is shortage of power in Mindanao until 2015 and we've been repeating that several times already," he told ANC. "Even without the blackout (last Thursday), we will have rotational brownouts," he added. Meanwhile, the DOE appears for understanding as it continues to look into last week's Mindanao blackout. Petilla said they have asked the Department of Science and Technology to come on board to help them look for answers. "People were saying, is there a sabotage? I said, this is not to hope for a sabotage. But if a tower is blown up, it's easy to trace it. If a tree fell on a transformer, it's physical. But if its electro-mechanical, you need all the data, you need all the logs of all the plants, all the logs of the NGCP," he said. "The logs are in nano-seconds. Sabi nila nagsabay-sabay bumagsak ang planta. But when you look at the logs, hindi sabay-sabay. Some of them were split-seconds. On our end, hindi sabay-sabay yan. Titingnan namin ang sequence, down to the last nano-second because it will spell the difference and give us answers," Petilla added. Parts of Mindanao suffered a blackout last Thursday, although the cause has yet to be determined. The suspected cause was equipment failure at a high-voltage switchyard, which then triggered the automatic shutdown of a nearby government-owned hydro power plant that draws its power from a dam. It then had a cascading effect on other power plants across the region. - ANC