Biden is expected to name former Michigan Gov. Jennifer Granholm to head the Department of Energy, sources familiar with the decision confirmed to ABC News on Tuesday.

That would make Granholm, 61, the ninth woman Biden has nominated so far to serve in his cabinet. If confirmed by the Senate, the former two-term governor would be just the second woman to lead the Energy Department.

A source familiar with the transition team's thinking pointed to Granholm’s work with Biden in Michigan during the 2009 recovery that rescued the U.S. auto industry and led to investments in green energy jobs in the state -- something Biden’s ambitious infrastructure plan would also seek to invest in.

-ABC News' John Verhovek, Molly Nagle and Benjamin Siegel

Biden has announced his intention to nominate Pete Buttigieg to serve as his secretary of transportation, as earlier reported by ABC News.

If confirmed, Buttigieg, 38, would be the youngest pick yet for Biden’s cabinet and the first non-acting LGBTQ department head in history.

In a statement, Biden called Buttigieg a "patriot and a problem-solver," and said he was nominating the former mayor of South Bend, Indiana, "because this position stands at the nexus of so many of the interlocking challenges and opportunities ahead of us" -- jobs, infrastructure, equity and climate.

Buttigieg said he was honored to be asked to serve in the position.

"This is a moment of tremendous opportunity -- to create jobs, meet the climate challenge, and enhance equity for all," he tweeted following the announcement.

Biden touched down in Atlanta Tuesday afternoon to stump for Democratic Senate candidates Jon Ossoff and Rev. Raphael Warnock as the balance of power in the upper chamber -- and Biden's hopes to pass big-ticket legislation in the incoming administration -- hangs on two runoffs races in Georgia. As the first Democrat to win Georgia's presidential race since 1992, he kicked off the event by thanking supporters.

"Georgia, let me start with two simple words: Thank you," Biden said to honking horns at the drive-in rally.

"Your votes were counted and counted and counted again," Biden added with a smirk, referring to the fact that votes were counted three times in the state due to audits and recounts. "I am starting to feel like I won Georgia three times."

Biden went on to argue that Georgia "taught Donald Trump a lesson" in turning out the vote and should do the same for its Democratic contenders.

"In this election, Georgia wasn’t going to be bullied, Georgia wasn’t going to be silenced, Georgia certainly wasn’t going to stand by and let Donald Trump or the state of Texas or anyone else come in here and toss out your votes," Biden said.

"But you know, you know who did stand by? You know who did nothing while Trump, Texas and others were trying to wipe out every single one of the almost 5 million votes you had cast here in Georgia in November? Your two Republican senators, they stood by," Biden said. "You might want to remember that come Jan. 5."

"Maybe they think they represent Texas. Well, if you want to do the bidding of Texas, you should be running in Texas, not in Georgia," he added.

Calling out GOP Sens. Kelly Loeffler and David Purdue, Biden said Georgia's senators "fully embraced" nullifying five million Georgia votes -- while Ossoff and Warnock stand up for democracy, he said. Loeffler and Purdue had released a statement in support of the Texas case the Supreme Court has since refused to hear.

The State Department is receiving its first COVID-19 vaccines this week, according to an internal email from a senior official obtained by ABC News.

The “very limited number” of vaccines the department will receive will go to a small group of employees deemed mission critical or most at-risk, including front-line medical personnel and those serving in three countries with poor health care systems, Under Secretary of State for Management Brian Bulatao said in his email.

“While we would have preferred to vaccinate our entire Department workforce at once, we will have to do so incrementally based on vaccine availability,” Bulatao said, noting the agency is working with the Pentagon’s Operation Warp Speed and the Department of Health and Human Services on this.

Bulatao did not say how many vaccines the agency will get but identified five groups of employees who will begin receiving them: Front-line medical personnel, including the doctors and nurses serving in Washington, D.C., and at embassies overseas; employees at the agency’s 24/7 watch center; those working on “critical operations, maintenance, and custodial staff”; “mission-critical” diplomatic security staff in DC; and American personnel serving in Iraq, Afghanistan and Somalia, where “local conditions... can exacerbate the disease burden and the challenges of providing medical support services in these locations.”

It’s unclear whether that includes Secretary of State Mike Pompeo himself and his staff, although they likely fall under Bulatao’s “critical operations” category and his diplomatic security detail appear to make the list. Acting Defense Secretary Chris Miller was vaccinated on Monday, the only cabinet secretary to get one so far.

A State Department spokesperson declined to offer details of the agency’s plans, citing “operational sensitivity,” but added in a statement to ABC News that any vaccines obtained through Operation Warp Speed will “allow the Department to advance U.S. national security interests and ensure America’s essential diplomacy continues unimpeded.”

-ABC News' Conor Finnegan