Billionaire climate activist Tom Steyer will not run for office in 2018, but plans to funnel $30 million into congressional races as he attempts to flip Republican seats in Congress to the Democrats.

Steyer’s name had been floated as a Senate or gubernatorial candidate in California in 2018. The Democratic megadonor has other plans, announcing Monday in Washington, D.C., that he'll be targeting 24 Republican-held districts and swing seats Democrats are defending in 10 states.

Steyer burst onto the political scene in 2014 when he launched NextGen Climate, a group aimed at making climate change a wedge issue in elections. He again contributed to races and get-out-the-vote efforts in 2016 and 2017 elections.

“I’ve spent months wondering how I can make the biggest differential impact,” Steyer said. “I believe that the most important task for me, the task which I feel called to do, is organizing and mobilizing America’s voters.

“I’m not going to run for office in 2018,” Steyer added. “That’s not where I can make the biggest difference.”

The environmentalist has spent more than $100 million on races since 2016 and launched a national campaign pressuring lawmakers to impeach President Trump. On Monday, Steyer said his action group will be “redoubling” the impeachment campaign, including adding an “engagement” effort.

Steyer’s NextGen Rising will focus its efforts on registering and mobilizing millennials, the billionaire said. States targeted include Arizona, California, Florida, Iowa, Michigan and Wisconsin.

Steyer said his group will work with voters to push out House Republicans and “send the likes of Paul Ryan, Darrell Issa and Barbara Comstock home.”

The November midterms, Steyer said, will be about “radically different visions of America."

“We have to win,” he said. “We don’t just have to win, we have to run the table.”

NextGen will not have a litmus test on impeachment for Democrats in the races they are engaged in, Steyer said. The former hedge fund manager notably kept the door open for a potential 2020 run, declining to give specifics on his political future.

"We are all in through November 6, 2018,” Steyer said. “We really don’t have the ability to know what’s going to happen after that.”