Power Sources: Fuel Cells, Solar Cells and Batteries -- Who to Watch -- Recent Key Developments -- Sunlight Turns Water to Fuel -- Hydrogen Chip to Fuel Handhelds -- Hydrogen Storage Eased -- Metal Stores More Hydrogen -- Alcohol Powers Fuel Cell -- Munching Microbes Feed Fuel Cell -- Fuel Cell Aimed at Handhelds -- Alloy Lowers Fuel-Cell Cost -- Cheap Solar Power on Deck -- Material Soaks up the Sun -- Crystal Turns Heat to Light -- Chips Turn More Heat to Power -- Flexible Film Turns Heat to Power -- Circuit Gets More Power from Shakes -- On-Chip Battery Debuts -- Magnesium Batteries Show Mettle -- Metal Mix Boosts Batteries -- Nanotubes Pack Power -- Huge Lasers Could Spark Fusion -- Quantum Force Powers Microslide -- Quantum Effect Moves Machine -- Heat Engines Gain Quantum Afterburner -- Engine Fires up Electrical Devices -- Index.