In some races, certain endorsements matter much more than others, and Jared Polis bagged a big one early in the Democratic race for governor Wednesday.

Colorado Politics is the first to report that the International Brotherhood of Electrical Workers’ Colorado State Conference of Electrical Workers is backing the congressman from Boulder in the nine-candidate Democratic primary. Polis, in turn, cites the union’s role in his energy and infrastructure plans.

The high-profile union picked Polis over other such well-known Democrats as Lt. Gov. Donna Lynne, former state Sen. Mike Johnston, former state Treasurer Cary Kennedy and Denver businessman Noel Ginsburg.

While labor unions aren’t as politically potent as they used to, the endorsement remains coveted in Democratic circles.

On the other hand, it will continue to stir up Republican ire against Polis, which already includes his 2014 support for ballot initiatives to throttle fracking and the fact he’s one of the four millionaires most often credited with bringing the Democratic Party back to relevance in Colorado with his money and politically strategic activism.

Polis campaign boasted that the IBEW is one of Colorado’s oldest and largest labor unions in the state with about 7,000 licensed electricians, residential wiremen and utility workers.

“Jared Polis has held a strong record of supporting workers rights, energy independence, infrastructure investment and apprenticeship training in Congress and we are excited to support his campaign to lead our state into the future,” Jim Mantele, president of the IBEW Colorado State Conference of Electrical Workers, said in a statement. “Jared is committed to listening to working families and making sure that they have a strong voice in his future administration. IBEW supports Jared’s plans for our state and we will be mobilizing our members to help his campaign succeed.”

Polis’s campaign said his “bold” agenda supports working families, including all-day preschool and kindergarten, addressing transportation and other infrastructure needs and moving the state to use 100 percent renewable energy by 2040,

Polis sees the IBEW having a role in the energy and infrastructure discussions, his campaign said.

“I am deeply honored to have the support of IBEW in this campaign,” Polis said in a statement. “IBEW brings deep expertise to our cause on energy policy, infrastructure investment and workforce development through their excellent apprenticeship training programs. Organized labor is an important part of making economic growth work for everyone and I’m honored to be the candidate for governor of Colorado who working families proudly support. Our campaign welcomes IBEW to our team.”

Since 2013, the IBEW PAC has given almost $33,000 to Colorado candidates, all of the them Democrats, records from the Secretary of State’s Office show.

The Colorado State Conference of Electrical Workers is even more prolific in giving in races. In its last quarterly financial report, the organization’s small donor committee had $104,630 in its account. The committee spent more than $50,000 on state legislative races last November, records show.

Polis campaign said he won’t take PAC money.

(Editor’s note: This story was updated to include that Polis won’t accept money from political action committees.)