Obama's energy secretary stepping down

US Energy Secretary Steven Chu, who has served under President Barack Obama since 2009, is stepping down, the White House said Friday.

Obama praised Chu for helping him "move America towards real energy independence," in a statement announcing Chu's departure.

"As a Nobel Prize winning scientist, Steve brought to the Energy Department a unique understanding of both the urgent challenge presented by climate change and the tremendous opportunity that clean energy represents for our economy," Obama noted.

Chu, who won a Nobel prize for physics, was chosen for the post soon after Obama won election in 2008.

"Over the past four years, we have doubled the use of renewable energy, dramatically reduced our dependence on foreign oil, and put our country on a path to win the global race for clean energy jobs," Obama said.

"We also expanded support for our brightest engineers and entrepreneurs as they pursue groundbreaking innovations that could transform our energy future," the president said.

Chu is the latest of Obama's cabinet to announce his departure, following in the footsteps of Secretary of State Hillary Clinton, Defense Secretary Leon Panetta, Treasury Secretary Timothy Geithner, Labor Secretary Hilda Solis, and Transportation Secretary Ray LaHood.