WASHINGTON (CBS SF) -- Energy Secretary Steven Chu, the Nobel Prize-winning former director of the Lawrence Berkeley National Laboratory, announced his resignation Friday, according to the U.S. Department of Energy.
In a letter to department employees Friday, Chu said that he had informed the president of his decision to leave a few days after the election, and noted that he and his wife are "eager to return to California.
"I would like to return to an academic life of teaching and research, but will still work to advance the missions that we have been working on together for the last four years," Chu said.
Chu's tenure was marked by controversy over his handling of federal loans to Solyndra, a Fremont solar panel manufacturer that went bankrupt in 2011. However, in the letter to employees Friday, he defended that loan, which was made as part of a 2009 federal stimulus package.
"Through the Recovery Act, the Department of Energy made grants and loans to more than 1,300 companies," Chu said in the letter. "While critics try hard to discredit the program, the truth is that only one percent of the companies we funded went bankrupt. That one percent has gotten more attention than the 99 percent that have not."
Chu, who was known as an outspoken advocate for scientific solutions to the problems of global warming before his appointment as energy secretary, noted that the production of renewable energy from wind and solar has doubled nationwide in the past four years.
In addition, installations of solar photovoltaic systems have nearly doubled in each of the past three years, he said.
U.S. Sen. Barbara Boxer praised Chu in a statement released Friday following the announcement of his resignation.
"Secretary Chu is a brilliant man who understands the importance of addressing the threat posed by climate change and has helped put America on a path toward energy independence and a clean energy future," Boxer said.
Chu was named director of the Berkeley lab on June 17, 2004, and assumed the post in August 2004.
He earned his doctorate from University of California at Berkeley and has taught at both UC Berkeley and Stanford University. He was awarded the Nobel Prize in physics with Claude Cohen-Tannoudji and William D. Phillips for developing methods to cool and trap atoms with laser light.
Chu was instrumental in bringing to the Bay Area the Joint BioEnergy Institute, a $135 million bio-energy research center funded by the Department of Energy and operated by a multi-institutional partnership under the leadership of Berkeley Lab.
Chu also played a major role in the creation of the Energy Biosciences Institute, which is funded by a $500 million grant from the petroleum company BP.
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