The head of the Energy Department’s cybersecurity office said she doesn’t feel confident that U.S. utilities are prepared enough to defend against cyberattacks from Russia and North Korea.

Karen Evans, the department’s head of the Cybersecurity Energy Security and Emergency Response Office, told House lawmakers “there are a lot of opportunities for utilities to improve” their cybersecurity preparedness.

The Energy Department cyber office was first formed in May, and Evans was sworn in a month ago.

The U.S. utility sector faces millions of attempted cyber intrusions a day. In March, the Department of Homeland Security revealed...