Former U.S. President Bill Clinton and former Vice President Al Gore joined together in Washington Monday to urge the United States to reduce its dependence on foreign oil. Officials at the conference say the United States needs to distance itself from volatile prices and the countries that provide the bulk of oil imports.

Former Vice President Al Gore, who won a Nobel Peace Prize for his work on global warming, says the climate crisis, the economic crisis and national security challenges are exacerbated by our dependence on fossil fuels.

"The common thread running through all of them is our ridiculous over-dependence on dirty, dangerous, expensive, carbon-based fuels," he said. "Grab that thread and pull on it and all three of these crises begin to unravel.  And we hold in our hands the answer which is a generational one-off investment to switch from an energy infrastructure that's based on these carbon-based fuels to a new infrastructure that's based on fuels that are free forever."

Those resources include wind, sun and geothermal power, the go-to clean energy sources that President Barack Obama and congressional leaders hope can be used to power American homes and businesses.

But Energy Secretary Steven Chu says the United States still faces several challenges in trying to update the power grid to run off these natural sources.  

"We also have to remember that renewable resources like wind and solar are transient - they go up and down," he said.  "At the level of 2.8 percent, roughly what we are today, that's okay.  But imagine a world of 15, 25, 30 percent renewable [energy] going up and down. That's a bigger problem, a much bigger problem."

Chu says this is why it is necessary to build a long distance transmission system to carry wind power generated in Texas, for example, to places where no wind is blowing.  Chu says the country needs to look at large-scale power storage in order to fulfill these needs.  Chu says the United States will need to modernize its utility grid so energy can be distributed from multiple sources, including homes and businesses that may be able to generate their own power.

Congressional leaders, including the speaker of the U.S. House of Representatives Nancy Pelosi and Senate Majority Leader Harry Reid said money to modernize the country's power grid and other clean energy projects were included in the massive economic stimulus package signed by President Barack Obama last week.

Pelosi told the conference, which was organized by the Center for American Progress Action Fund, that another clean energy aspect to the new economic stimulus bill will be investment in the education of scientists.

"I would say there are four words that describe what we did there what we intend to do as we go forward: science, science, science, and science," she said.

Pelosi says increased funding for science and technology will ensure that the energy grid is built correctly, that so-called "green" jobs are created for future generations and that ultimately, it will lead to an improved environment.