President-elect Joe Biden will nominate onetime rival Pete Buttigieg to be his secretary of transportation and former Michigan governor Jennifer Granholm to be secretary of energy.

The move elevates Buttigieg to a key role in the incoming administration’s expected push to rebuild the nation’s infrastructure and economy and address climate change. Granholm, meanwhile, has been a strong voice for zero-emissions vehicles, arguing that the country must develop alternative energy technologies.

Biden also is tapping Gina McCarthy, who ran the Environmental Protection Agency under President Barack Obama and now leads a major advocacy group, to coordinate the new administration’s domestic climate agenda from a senior perch at the White House, according to three individuals familiar with the matter.

Buttigieg, a former mayor of South Bend, Ind., dropped out of the Democratic presidential race and endorsed Biden at a critical moment in March ahead of the Super Tuesday primaries. Shortly afterward, an emotional Biden compared the former intelligence officer for the Navy Reserve, who served a tour in Afghanistan, to his son Beau, who died of brain cancer at age 46.

“It’s the highest compliment I can give any man or woman,” Biden said then, citing Buttigieg’s “moral courage” and “backbone like a ramrod,” and predicting a long and bright future. “I promise you, you’re going to end up, over your lifetime, seeing a hell of a lot more of Pete than you are of me.”

In a statement Tuesday evening, Biden called Buttigieg “a patriot and a problem-solver who speaks to the best of who we are as a nation.” Buttigieg said in a Twitter message he was “honored” to be selected to serve in the role.

“This is a moment of tremendous opportunity — to create jobs, meet the climate challenge, and enhance equity for all,” he wrote.

Buttigieg, 38, built his presidential bid on calls for the leadership torch to be passed to a new generation, something Biden himself said was “absolutely essential.” Buttigieg was the first openly gay major-party candidate to win delegates in a bid for the White House, and his campaign was aided by the supportive presence of his husband, Chasten. He would be the first openly gay Cabinet member to be confirmed by the Senate.

The first Washington chapter of Buttigieg’s political story will be at a vast agency long viewed as a solid, if unflashy, perch that could provide an opportunity to make a lasting mark.

Biden’s promise to pursue vast investments in transportation and other infrastructure, while moving to sharply cut greenhouse gas emissions, will require a deft touch on questions involving technology, labor and partisanship on Capitol Hill.

Whether Buttigieg, a former Rhodes scholar and McKinsey and Co. consultant with a wonkish eye for policy but no real Washington experience, performs well against that and other challenges could play a significant role in the new president’s early successes or failures. His selection prompted a flurry of “Roads scholar” puns.

The transportation post also could give Buttigieg a chance to build ties with African American voters, a slice of the population that showed little enthusiasm for his presidential bid. He faced criticism over the shooting death of a Black man by a White police officer in South Bend, as well as questions over diversity on the city’s police force.

The top transportation job offers a chance to confront the nation’s history of building highways through disadvantaged urban neighborhoods, and what advocates say are the lasting social, economic and environmental consequences of doing so.

The transportation job will present a steep learning curve and rigorous test of his management skills. Buttigieg would oversee about 55,000 employees at the department, roughly half the population of South Bend. Some transportation experts have raised questions about Buttigieg’s lack of experience in the often-dense realm of federal transportation policy.

The sprawling department, with a budget of almost $90 billion, funds highways and transit systems, runs the air traffic control system, oversees the safety of civilian aircraft, and regulates a trucking industry that employs millions of people.

If Buttigieg is confirmed by the Senate, one of his most pressing tasks will be helping to rebuild the nation’s transportation networks, which have been battered by the coronavirus pandemic.

As passengers have stayed home and revenue has plummeted, airlines have laid off tens of thousands of employees, and major transit agencies are ailing. State transportation departments responsible for roads and bridges have projected shortfalls in the billions of dollars.

The Biden campaign has released ambitious plans to revamp the country’s transportation infrastructure — such as repairing aging bridges and highways — while reducing the impact of transportation on the environment by promoting electric vehicles, rail and transit ridership.

Getting a major infrastructure bill through Congress would be a critical early goal for Buttigieg and the administration, but one with major pitfalls.

Republicans did not pass major infrastructure legislation when they controlled the House and Senate early in President Trump’s term, instead prioritizing far-reaching corporate and other tax cuts.

Depending on the outcome of two Senate races in Georgia, which will determine control of the chamber, Majority Leader Mitch McConnell (R-Ky.) could remain in a position to block the type of ambitious infrastructure spending that Biden, fellow Democrats and some Republicans argue is long overdue.

Biden has promised to repeal some Trump tax cuts to generate revenue to fund crucial infrastructure and other investments, but McConnell last year called that notion a “non-starter.”

Former Republican congressman Ray LaHood, who served as Obama’s first transportation secretary, praised Biden’s choice for transportation, saying Buttigieg knows what mayors and governors need and will work for a boss who has seen the importance of countering economic pain with tens of billions of dollars in stimulus spending.

“Let’s face it. There’s pent-up demand,” LaHood said. “Trump talked a good game, but he never did a damn thing on transportation infrastructure, and I believe Biden will.”

Sen. Amy Klobuchar (D-Minn.), a fellow Midwesterner and onetime rival who had a spell of mutual hostility with Buttigieg during the campaign but later teamed up with him to endorse Biden, said she and her husband were looking forward to welcoming Pete and Chasten to Washington. “I know you will bring both your big ideas & your local government experience to the job,” she tweeted of Buttigieg.

Civil liberties groups welcomed the move. Elliot Imse, vice president for communications at the Victory Institute, which works to advance LGBTQ public leaders, said Buttigieg’s selection “is a transformative moment for American politics, in that it shows that LGBTQ people can serve at the highest levels without concern of facing backlash simply because of their sexual orientation.”

During the primary campaign, Buttigieg outlined a transportation plan that is broadly in line with Biden’s proposals to focus on electric vehicles, transit and rehabilitating existing roads.

In February, Buttigieg said a major infrastructure proposal from Trump initially sounded like a good idea. But the plan ultimately relied on state and local leaders to put in most of the effort, “which is how it already works,” Buttigieg said at the time.

“We have an opportunity to do something different and take ‘infrastructure week’ back from being a punchline and actually make sure it is the template for a better future,” Buttigieg said. “In order to meet our climate goals, in order to meet our economic goals, we’ve got to do this.”

Even maintaining the status quo in federal transportation funding will be fraught for the new administration, given a deep shortfall in the Highway Trust Fund, which covers road and transit projects. The federal gas tax, a major source of its funds, has failed to keep up with inflation and national needs, leaving many states to raise fuel taxes on their own.

Presidents Ronald Reagan and Bill Clinton signed increases in the federal gas tax, and major business leaders have pushed in recent years to raise it again. The tax has been 18.4 cents per gallon since 1993, and attempts to increase it would face strong opposition.

Within the department, Buttigieg would have broad discretion to reset priorities, which under current Secretary Elaine Chao have revolved around efforts to cut regulations — including those affecting the environment — and attempts to privatize government functions, such as air traffic control.

Some major transportation projects, which were hobbled by Trump administration opposition, are likely to be freed up to move ahead more swiftly. For example, political leadership within the Transportation Department took pride in stymieing the Gateway Program, a set of major tunnel and bridge projects connecting New Jersey and New York.

Gateway is a priority of Senate Minority Leader Charles E. Schumer (D-N.Y.), with whom Trump sparred energetically despite their shared connection to New York. Gateway’s former interim executive director, John Porcari, went on to become a Biden infrastructure adviser.

Another high priority early in the new administration will be reaching a deal with automakers on emissions standards, giving Buttigieg a role in a critical climate issue. The National Highway Traffic Safety Administration, part of the Transportation Department, shares the job of setting those standards with the Environmental Protection Agency. Under Obama, they were pushed upward, only for the Trump administration to roll them back. But some auto companies endorsed California’s goal of adhering to more stringent limits, prompting a legal fight with the federal government.

Technology also is rapidly changing transportation, and NHTSA also plays a key role in the oversight of self-driving cars. As in many areas, the Trump administration took a hands-off approach to automated vehicles, giving manufacturers latitude to conduct tests. But safety advocacy organizations have urged the Biden administration to do more to set rules.

The Transportation Department includes the Federal Aviation Administration, whose reputation took a battering after the deadly crashes of two new Boeing 737 Max jets. The agency recently approved updates to the 737 Max’s flight control software, certifying the model as safe to fly again, but lawmakers are continuing to press for reforms.

Amy B Wang, Matt Viser, Juliet Eilperin and Samantha Schmidt contributed to this report.