It was on her watch in 2006 that Oregon's largest utility severed ties with the bankrupt Enron Corp. and issued its common stock as an independent company.
Hundreds of PGE employees lost nearly all their 401(k) retirement investments that had been held mostly in what became worthless Enron stock.
She has been CEO since April 2000 and will be succeeded Jan. 1 by Jim Piro, the chief financial officer, who has 28 years with PGE. She said she will spend the interim two months on vacation. The company said it plans to replace Piro as CFO by the end of the year.
The utility serves about 814,000 residential and commercial customers in Oregon.
The utility says Fowler will remain on the board and is involved in various community and business activities.
In 2006, Fowler saw her annual salary rise 59 percent, from $383,764 to $610,000, according to documents filed with the U.S. Securities and Exchange Commission.
Fowler, 57, said that the timing is right. "We've put many major issues behind us and we've built a strong foundation for growth and have a strong executive team in place."
She said her husband retired 10 years ago and she wanted more time together. "Golf would be nice," she said, adding that she had considered retirement for some time.
She joined PGE as a chemist in 1974.
Piro said the company will continue to develop wind and solar energy projects and to promote all-electric cars.
Fowler appeared with Gov. Ted Kulongoski to promote all-electric vehicles as the governor revealed his 2009 legislative energy conservation and efficiency agenda.
Piro would not comment on whether PGE will seek to absorb other companies, saying the company does not comment on merger plans.