Batteries and electrochemical capacitors

Electricity generated from renewable sources, such as solar and wind power, offers enormous potential for meeting future energy demands. But access to solar and wind energy is intermittent, whereas electricity must be reliably available for 24 hours a day: Even second-to-second fluctuations can cause major disruptions that cost tens of billions of dollars annually. Electrical energy storage devices will therefore be critical for effectively leveling the cyclic nature of renewable energy sources. (See the article by George Crabtree and Nathan Lewis, PHYSICS TODAY, March 2007, page 37.) They are also a key enabler in numerous areas of technological relevance ranging from transportation to consumer electronics. © 2008 American Institute of Physics.