With a possible Democratic primary challenge coming, the political action arm of the League of Conservation Voters announced Wednesday its endorsement of Hawaii Sen. Brian Schatz.

Schatz is running in the 2014 special election to fill the remaining two years of the late Sen. Daniel K. Inouye’s term, and he’s facing a possible challenge from Democratic Rep. Colleen Hanabusa. The endorsement means Schatz is now featured on LCV Action Fund’s bundling website, which helps raise money for candidates who support the group’s environmental causes.

“Brian Schatz is a lifelong environmentalist and a proven leader on climate change policy,” LCV Action Fund President Gene Karpinski said in a statement. “He has championed clean energy initiatives that have put Hawaii at the forefront of utilizing renewable energy and reducing dependence on petroleum. We will need his continued leadership in the U.S. Senate.”

On Dec. 26, Gov. Neil Abercrombie appointed Schatz to the Senate, then the lieutenant governor, instead of Hanabusa, whom Inouye had endorsed to replace him shortly before his death.

Hanabusa is now considering taking on either Schatz or Abercrombie, and she’s likely to decide in the next few weeks.