U.S. Department of Energy (DOE) Secretary Steven Chu has formally announced his resignation, following months of speculation.
In a letter to DOE employees, Chu recapped the department's numerous initiatives to further the U.S.' development of renewable energy, especially solar power, under his leadership.
PV installations have nearly doubled in each of the last three years, he noted. The SunShot Initiative, which aims to reduce the costs of utility-scale solar power, has progressed through several rounds over the years, focusing on everything from PV system permitting to cutting-edge module research.
SunShot's goal of making solar power cost-competitive by 2020 is now within reach, Chu said in his letter. "When we first discussed this goal, the industry did not take it seriously," he wrote. "Today, they tell me that our input challenged them to rethink their road maps and now agree that it is an achievable goal."
The private sector has similarly shifted its views of solar during Chu's tenure, as project deployment has boomed, costs have come down and bankability has increased. High-profile solar investors now include such names as Warren Buffett, Bank of America, Wells Fargo and Google, Chu pointed out.
Other solar-related highlights of Chu's term as DOE Secretary include building up the Advanced Research Projects Agency-Energy (ARPA-E), which focuses on early-stage technology research, and helping to launch the Clean Energy Ministerial, an international program intended to share best practices in renewable energy development.
However, during his tenure, Chu also became associated with the infamous bankrupt module manufacturer Solyndra, which had received a $535 million loan guarantee from the DOE.
During the extensive Congressional investigations that followed Solyndra's collapse, Chu and his colleagues from the DOE were forced to defend their decisions to lawmakers that believed the Solyndra loan was the result of inappropriate political influence. The hearings and independent investigation into the entire DOE loan guarantee portfolio received widespread mainstream media attention and turned Solyndra into a household name.
In his resignation letter, Chu stressed the overall success of the loan-guarantee program, indirectly referencing the Solyndra ordeal.
"While critics try hard to discredit the program, the truth is that only one percent of the companies we funded went bankrupt," he wrote. "That one percent has gotten more attention than the 99 percent that have not."
Overall, although the U.S. has made significant strides in clean energy deployment, much more work remains to be done - even if some investments and approaches do not pan out, Chu stressed in his letter.
"The test for America's policymakers will be whether they are willing to accept a few failures in exchange for many successes," he wrote. "America's entrepreneurs and innovators who are leaders in global clean energy race understand that not every risk can - or should - be avoided."
The Obama administration has yet to publicly name Chu's replacement. He plans to remain in his position through the end of the month, when the ARPA-E Summit takes place.
Chu's departure follows the resignation of two other cabinet members with roles in the renewable energy industry. Environmental Protection Agency Administrator Lisa Jackson and Department of the Interior Secretary Ken Salazar have also stepped down in recent months.