It was a second helping of bad news for Democrats searching for a key statewide victory on a day when Democrat Jim Martin's effort to unseat Republican U.S. Saxby Chambliss fell short. The party had thrown its support behind the "two Jims," parading the candidates across the state.
McDonald's victory thwarted the Democratic Party's bid to muscle its way onto the commission, which regulates Georgia utilities and is firmly in GOP hands. All five members of the panel, along with outgoing commissioner Angela Speir, are Republicans.
McDonald, a former state legislator who served on the commission for four years, stressed his experience in public office and private business throughout the campaign. Powell vowed to be an independent voice for Georgia consumers.
With most precincts reporting, McDonald held a comfortable lead over Powell with about 56 percent of the vote.
For Powell, the runoff defeat marks the end of a particularly challenging election bid in which he struggled to simply keep his name on the ballot.
Republican Secretary of State Karen Handel disqualified Powell days before the July primary on grounds that he didn't meet his district's residency requirements, forcing the Democrat to file a flurry of legal challenges to stay in the race.
A judge allowed Powell's name to remain on the ballot, and Georgia's top court later issued a stinging decision concluding that Handel "committed an error" by ousting him. The ruling was greeted warmly by Powell, who claimed that Handel disqualified him for political reasons.
Sara Doyle also claimed a victory over Mike Sheffield in her bid for an open seat on the Georgia Court of Appeals. Doyle carved out a narrow lead over Sheffield, grabbing about 52 percent of the vote.
In the primary, Doyle captured just over 22 percent of the vote, while Sheffield drew roughly 21 percent in the November election. The other five candidates split the remaining votes.