Countdowns

Power of the Future: 10 Ways to Run the 21st Century

Scientists are racing to perfect greener sources of energy to improve the environment and reduce dependence on oil and other fossil fuels. Some predict a hydrogen economy. Others say solar is the way to go. Wilder schemes involve sky-high wind turbines or antimatter engines. LiveScience explores the expectations, myths and realities of 10 top possibilities.

-- Ker Than, Special to LiveScience