Hawaii wrapped up a two-day energy security exercise Thursday that simulated a cyberattack and physical attack on the state’s electrical grid.

Hawaii, Colorado, Idaho and Maryland were the four states chosen by the National Governors Association to be a part of the biennial exercise, known as GridEx, which began Wednesday and attempted to determine how the state would respond to a major power outage caused by either cyberattack or some other event, such as a natural disaster.

Participating agencies and organizations included the Hawaiian Electric Co., the Hawaii State Energy Office, the state Office of Homeland Security and the U.S. Indo-Pacific Command. All had to communicate with each other to respond to a scenario presented to them.

“We appreciate the National Governors Association’s inclusion of Hawaii in this important exercise at a time when increasing attention is being focused on grid security,” said Hawaii Chief Energy Officer Scott Glenn. “We look forward to sharing Hawaii’s unique experience with its isolated electric grids and learning about the best practices being employed by other states as they deal with grid security issues.”

The exercise was primarily a virtual simulation that involved role-playing, but Dolores Cook, administrator for OHS, thought Hawaii’s participation would help address problems it might experience.

If a major power outage did happen in Hawaii, Cook said, “Nobody’s going to come to our defense for a couple days probably, where on the mainland, if you had something happening, you’re going to have folks lined up to support each other.”

OHS and the energy office jointly applied to participate in the exercise. The North American Electric Reliability Corporation conducts the exercise on electrical grids across the continent.

Cook also said the exercise is important for Hawaii because the electric grid is linked to the water supply, transportation and other infrastructure.

“It’s important to have all the agencies together in one room, because we all have to be reliant on each other if something did happen,” said Shannon Tangonan, spokeswoman for HECO. “We sort of have to be self-sufficient.”

Tangonan said HECO has done drills with other agencies and works regularly with them.

The exercise was primarily a virtual simulation that involved role-playing, but Dolores Cook, administrator for the state Office of Homeland Security, thought Hawaii’s participation would help address problems it might experience.