PLANTS absorb sunlight, produce energy, consume carbon dioxide and exhale oxygen. It is a perfect model for power generation, but copying Mother Nature is difficult. Although research into solar power has come a long way, sunset still poses a problem. Storing solar-made electricity in batteries can be expensive and inefficient. So to be really successful, the solar industry needs another way to keep power for use at night. Now researchers have found a chemical cocktail that might do the trick.