Business-friendly, cost-competitive and ready to meet a significant portion of America's energy needs, renewable energy has gone mainstream. Wind power is the fastest growing form of electricity generation in the United States, expanding at an average annual rate of more than 20 percent. Solar energy employs more than 20,000 Americans in high-tech, high-paying jobs. And clean-burning biofuels made from plants show great promise as a replacement for gasoline -- ethanol producers already make 4 billion gallons of fuel a year, and new methods for making ethanol from farm wastes or energy crops could compete with oil on a very large scale in addition to providing extra income for farmers. By 2050, renewable energy and biofuels could meet a significant chunk of our energy needs. It Can Be Done: » Wind, Solar and Biomass Energy Today » Move Over, Gasoline: Here Come Biofuels » A Consumer's Guide to Buying Clean Energy Step 4: Return Carbon to the Ground.