Gov. Martin O'Malley said in an interview Tuesday that settlement talks between his office and Constellation Energy Group are over and vented frustration with the company that owns Baltimore Gas and Electric Co., the state's largest utility.

The governor tried to wrest concessions from Constellation as the company seeks state regulatory approval of a $4.5 billion deal to sell half its nuclear power business to French utility Electricite de France. Constellation offered to give customers a break by delaying requests for rate increases, but O'Malley said that didn't go far enough. He sought immediate electricity price reductions and other commitments.

"I wish, in retrospect, that they had never called me. I wish we had never met or even discussed a settlement," said O'Malley, a Democrat. "It took a lot of time. It took a lot of energy. And the only settlement they appeared willing to join in was one that would have fallen short."

Constellation spokesman Robert Gould declined to comment on the aborted settlement talks and said the company is "hopeful" that the Public Service Commission, the state's top energy regulator, will issue a final order as soon as possible. "We believe we've made a strong case that the proposed transaction will provide tremendous benefits for the state of Maryland," he said.

The PSC could reject the transaction, approve the deal or allow it to move forward if conditions are met. The PSC has held extensive hearings on the Constellation-EDF transaction, and it's unclear when the agency will render a decision. Final briefs from interested parties are due Monday.

Behind-the-scenes talks between Constellation and the governor's office began months ago and then stalled over disagreements about the details.

O'Malley wanted the company to extend one-time credits for residential customers, contribute to a program that helps low-income residents pay utility bills, and invest in environmentally friendly energy projects. The governor also criticized a lucrative golden parachute package for Constellation CEO Mayo A. Shattuck III.

While Constellation officials insisted the EDF deal wouldn't trigger any payout to Shattuck, they offered to cancel the package as part of their offer that was rejected. Constellation's proposal also included provisions to insulate BGE from negative impacts that could result from the deal.

O'Malley said his administration has been trying to create a comprehensive energy policy that the state has lacked. He has worked to set goals for reducing energy consumption, boosting renewable power and curbing greenhouse gas emissions. He failed this year to win approval in the General Assembly to re-regulate the electricity market but has vowed to resurrect the proposal.

Baltimore Sun reporter Hanah Cho contributed to this article.