"Trying to calm anxieties about soaring energy costs, President Bush is using his State of the Union address this week to focus on a package of energy of proposals aimed at bringing fuel-saving technologies out of the lab and into use. In Bush's vision, drivers will one day stop at hydrogen stations and fill their fuel-cell cars with the pollution-free fuel. Or they would power their engines with ethanol made from trash or corn. More Americans would run their lights at home on solar power.

"Bush noted to CBS that about 4.6 million cars on the road in the United States can run on ethanol. The fuel works in more than 30 models, including General Motor's Yukon, Chevrolet's Silverado and Ford's Taurus. However, almost all drivers of those vehicles outside the Corn Belt fill up with gasoline. Automakers and environmentalists are also excited about the prospect of fuel cells, which would run on hydrogen that would only emit water instead of gas fumes.

"But fuel cell vehicles are extremely expensive to produce and lack an infrastructure of fueling stations to make them viable. The government has said it hopes hydrogen fuel cell vehicles will be available in car showrooms by 2020.

"The threat posed by climate change may be greater than previously thought, and global warming is advancing at an unsustainable rate, a report by scientists published Monday says.