Skeptics of alternative energy raise some valid concerns when they look across an array of wind turbines or a glittering spread of solar panels: what happens when the wind stops blowing and the sun stops shining? If renewables are dependent on weather conditions, doesn't that mean they stop generating energy when the climate doesn't favor them, leaving customers without power? Would a turn to renewable energy inevitably be accompanied by backup use of power plants using traditional methods of electricity generation like burning coal, to provide a backup in case of failure? The development of new technologies is often accompanied by skepticism, and naysayers can actually play an important role in pushing researchers to design the best systems possible. See full article.