Secretary Chu is a Nobel Prize-winning physicist who came into office with high hopes. He was selected to help the president pursue his green energy agenda and fight climate change. It turned out to be a rocky road. Some of the green companies that got big government loans, like Solyndra, ended up going bankrupt, and the president had to drop his plans to get Congress to adopt climate change legislation. Still Chu helped the country make progress in becoming more energy efficient.

Renee Montagne talks to Cheryl Martin, deputy director of the Energy Department's Advanced Research Projects Agency-Energy. Modeled after the Defense Department's research program, ARPA-E provides grants to researchers developing cutting edge energy technologies that are too early for private sector investment.

The Washington Post reported this week that Italy's effort to promote solar and wind power isn't so clean. A recent sting operation by the Italian government of the renewable energy sector resulted in the arrest of a dozen mafia figures.

Hydraulic fracturing gets the spotlight, but without another technology — horizontal drilling — natural gas drilling booms across the country would not be happening now.