If you've ever seen a Toyota Prius or other electric car drive down the street, you've seen a fuel cell in action. In these cells, a fuel (such as liquid hydrogen) and an oxidant (like liquid oxygen) combine to form a chemical reaction that creates an electric current. These alternative energy sources are awesome because they decrease our need for precious natural resources (we're looking at you, gas). Fuel cell technicians, who report to engineers, may start by learning to build, test, install, and repair cells, but as they gain experience, they can take on higher-level duties like helping with the design process. Because the technology is so common, there are different kinds of places you could work: Companies that develop fuel cells or products that use them, government agencies, and universities are just a few examples. In the coming decades, our country is only going to become more reliant on alternative energy sources, so if you enter this field, you can take comfort knowing that your skills will be in mega-high demand for the foreseeable future.