PC World - Each year, the list of "green" gadgets gets longer, from solar-powered coasters or networked light bulbs. But some are a lot more useful than others. If you're looking for more than a novelty item, we've spotted ten devices that can save your company money by improving its energy efficiency. Some of them offer nifty, time-saving automation features and mobile apps too. Whether you're working from home or in a high-rise headquarters, these tools can put some energy dollars back in your pocket.