Fortune 500 CEO on her professional heartbreak by Rupali Arora @FortuneMagazine October 9, 2014, 3:03 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Lynn Good was picked as Duke Energy’s ”DUK” CEO in July 2013. The promotion was a complete surprise to Good, she told Fortune assistant managing editor Leigh Gallagher on Wednesday at Fortune‘s Most Powerful Women Summit. Good was previously the $24.6 billion utility giant’s CFO; today, she’s the company’s first female chief in its 150-year history and one of a small handful of women who head power companies in the U.S.Good has a relatively down-to-earth approach to her career, which she credits to professional heartbreak. She spent the first half of her career at Arthur Andersen — then one of the “big five” accounting firms — and was eventually named a senior partner. Due to its affiliation with Enron, the firm was indicted in 2002 and disappeared about six to eight weeks later.The change caused Good to question her identity. “The way you defined yourself disappeared overnight,” she said. “It changed the way I thought about my career and realized that you are not your career; you are the asset.” Her advice: Don’t define yourself as your career. Instead define yourself as a professional, a mother, a friend and colleague—and pursue what you are passionate about.Good faced another professional challenge in February. On Super Bowl Sunday, a pipe broke at one of Duke’s power plants in North Carolina, releasing 39,000 tons of coal ash into the Dan River. The engineering problem quickly grew into an environmental issue and called into question the storage of ash in the country.“When you’re in a crisis, there’s really no playbook,” Good said. “It’s important to keep your long term perspective and communicate well both externally and internally. In such situations it’s best to adapt and change, and to stay calm and carry on, but with some urgency.”Good also learned some useful lessons from GM’s Marry Barra, who was also dealing with corporate challenges of her own. As Duke continues to clean up the spill and prepares to close its 32 ash basins in North Carolina, Good is focused on shifting to renewable energy by exploring shale gas—which is changing the landscape for the energy industry.