英語聽力：自然百科 Alternative Energy 可替代能源

When the wind picks up at the foot of the Rockies, there are those who believe they can hear the future. At the National Renewable Energy Laboratory, making alternative power sources competitive with fossil fuels has been a mission since the energy crisis of the 1970s. Scientists worked to create solar cells far more efficient than those currently available to homeowners. They believe the market for this technology is about to come of age. When it was installed, this was believed to be the largestresidential solar-electric system in the United States. The homeowner is actually selling electricity back to the power company. "I also feel good because I've always been committed about the environment and doing something and we have to start as individuals to do things."

But individuals can do only so much. Researchers here say, for renewable energy to really make a difference, it has to be on a large scale. There hasn't been any great sense of urgency for finding energy alternatives. For decades, low gas prices have kept Americans in their cars, usually alone. But a jumping gas prices often spotlights the search for something else to keep all those cars going.

What's in there now is a material that looks like straw or, it's actually the material that farmers just leave sitting on the ground after they go through when they harvest corn. We are trying to get farmers to collect this material so that we can run it through conversion technology to make new liquid fuels.

Since the energy crisis of the 70s, some farmers have been diverting part of their grain harvest to make a fuel called ethanol. But the emphasis now is on the stalks and stubble left on the ground after the harvest. "The cellulose attained here that actually is made up of sugars, is something that they can turn into ethanol on the same way that they're currently taking the corn grain that having it turned into fuel grade ethanol. "

The National Renewable Energy Lab has a plant that converts harvest leftovers and just about anything else into fuel. Proving that renewable energy technology is viable remains a struggle, at least in America. Wind turbines were pioneered in the United States, but countries in Europe use them to supply more meaningful amounts of power. With the current energy situation labeled a crisis, the urgency for finding reliable alternatives to fossil fuels may have arrived. And for renewable energy, the future may be now.