By Bruce Mohl

Paul Hibbard is stepping down as chairman of the state Department of Public Utilities and being replaced by a top aide to Ian Bowles, the secretary of energy and environmental affairs.

Bowles made the announcement in an email to state workers on Friday. He said Hibbard first broached the idea of leaving in December “as his kids approach college age” but was convinced to stay on several months longer. Bowles said Ann Berwick, the undersecretary of energy, will serve out the remainder of Hibbard’s four-year term.

The DPU regulates the state’s investor-owned electric utilities, approving their rates and some of their power contracts. National Grid, for example, is currently negotiating a long-term power contract with Cape Wind. The terms of any eventual deal will have to be approved by the DPU.

Late last year, the DPU lopped $67 million off a $111 million hike in distribution rates sought by National Grid. It also disallowed $33 million NStar was seeking as its share of benefits associated with customer savings initiatives.

Bruce Mohl oversees the production of content and edits reports, along with carrying out his own reporting with a particular focus on transportation, energy, and climate issues. He previously worked...