It will take the US years to get away from using fossil fuels, Department of Energy Secretary Steven Chu told CNBC Tuesday.
"It's a long road to achieve the goal," Chu said. "It will take many decades and you have to have something to replace them. We are working now on getting that done and getting alternative energy sources."
"We need a sustained push to reach clean energy technologies" said Chu. "We are on a path to doubling our wind and solar renewables by 2012. We are beginning to see some benefits."
As for nuclear energy, Chu said the US is working on a long term plan over several decades to develop safe nuclear technologies.
Just last month, the Energy department initiated an energy loan guarantee program, providing $8 billion in loan guarantees to break ground on the first new US nuclear plant in 30 years.
"We are doing this to get the nuclear industry going and hope the private sector picks up and runs with it," said Chu.
He also said the stimulus provided a down payment on reaching green energy efficiency.
As for oil, Chu said the recession has created a sufficient supply of oil now because of a reduction in demand. However, he said getting oil from non-traditional sources such as deep offshore drilling will cause the price of oil to go up.