The White House said Chu retained Obama's confidence, but Chu was widely expected to leave following Obama's re-election last fall.
In a letter to Energy Department employees, Chu said he was proud of his tenure and cited dozens of accomplishments, including doubling the production of renewable energy from wind and solar power. Installations of solar electric systems have nearly doubled in each of the last three years, he said, while fully 42 percent of new energy capacity in the U.S. last year was from wind — more than any other energy source.
"I came with dreams and am leaving with a set of accomplishments that we should all be proud of," he said.
One of his accomplishments was something that Chu rarely talked about, but was frequently cited by Obama: Chu's role in helping to plug the massive BP oil spill in the Gulf of Mexico. Chu and a team of engineers helped devised an interim solution before a replacement well permanently plugged the leak, which spewed more than 200 million gallons of oil in the worst offshore oil disaster in the country's history.
Chu came up with the solution "when nobody else could figure it out," Obama said Friday. "And that's typical of the incredible contributions that he's made to this country."
At Energy, Chu was most closely identified with his oversight of a massive, $35 billion loan guarantee program funded by the 2009 economic stimulus law. He also led efforts to develop a cutting-edge, alternative energy lab known as ARPA-E, or Advanced Research Projects Agency-Energy.
While tarnished by Solyndra, the loan program has had many successes, including huge solar projects in California and Arizona and wind farms in Oregon and Maine. The department also has boosted electric cars and nuclear power plants. Counting loans and guarantees to U.S. car makers and the nuclear industry, the program is supporting as many as 60,000 jobs and generating up to $40 billion in private investment, Chu said.
The ARPA-E project has led research in fields from electrofuels to batteries. "While it is too early to tell if we have home runs, there are a number of investments that have certainly rounded second base," Chu said in his farewell letter.
Chu also played a key role in the U.S. response to the Fukushima nuclear disaster in Japan, as well as an Obama administration decision to kill a planned nuclear waste dump at Nevada's Yucca Mountain.
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