The main thing BGE customers will see as a result of today’s approval by the Maryland Public Service Commission of Exelon’s purchase of Constellation Energy Group is a one-time cut in electric rates.

A condition of the merger is for a $100 credit to be applied to all BGE customers within 90 days of its completion.

This provision was hammered out by Gov. Martin O’Malley in a settlement between the state and Exelon two months ago that paved the way for the PSC’s approval today.

Originally, the PSC rejected the $7.9 billion merger as not consistent with the public interest and demanded that it “include benefits and no harm to ratepayers.”

Besides the rate credit, today’s approval requires Exelon to develop 285-300 megawatts of new power generation in Maryland to protect consumers from higher rates that could result from Exelon’s increased market power.

A longer-range result of the merger will be a new skyscraper that Exelon agreed to build in Baltimore to house its energy trading, renewable energy and other operations.

The site selected by Exelon, on the property of the ex-Allied Chemical works near Harbor East, has been the subject of controversy among Baltimore real estate factions.

Exelon’s pick has solidified the empire of baker-turned-builder John Paterakis Sr. at the expense of the Inner Harbor, whose interests had clamored for the Exelon building to be located near Pratt and Light streets.

BGE will continue to serve area customers under its own name, while Constellation Energy will disappear from public view, becoming a subsidiary of Exelon with no publicly traded stock.

The final step for the merger’s completion is the approval of the Federal Energy Regulatory Commission, which is expected in the near future.