Fuel Cells  A fuel cell is an electrochemical device that converts hydrogen, or other fuels, and oxygen into water, producing electricity and heat in the process. We are watching their advancement and look forward to combining their pollution-free properties with renewable solar energy. The operation of a fuel cell involves an electrochemical process that converts chemical energy into electrical energy, like a conventional battery. However, unlike a battery, a fuel cell is not a storage device. Fuel cells produce electricity continuously, as long as they are fed with fuel and an oxidant (oxygen). The process within a fuel cell may be thought of as the reverse of electrolysis, where water is split into hydrogen and oxygen using an electrical current. In a fuel cell, hydrogen and oxygen are introduced in the presence of catalysts, and electricity is produced. There are many applications for fuel cells: Power generation Road vehicles Consumer and professional electronics    There are also six main types of fuel cells: Phosphoric Acid Polymer electrolyte or proton exchange membrane Direct methanol Alkaline Molten Carbonate Solid oxide    The fuel cell that is probably closest to commercialization is the Proton Exchange Membrane (PEM). Its range of operation is in the milliwatts to the 100s of kilowatts, which makes it ideal for applications involving transportation, small-scale power generation and battery substitutes. Fuel cells are nearing the point where they will be cost competitive. How may we use them in the future? If the infrastructure to deliver hydrogen is better developed, the PEM fuel cell may be the source of power for our homes and business. These fuel cells can run on natural gas now, which, of course, is a non-renewable resource, one that has seen a lot of volatility on the energy markets. We'd prefer to wait on hydrogen-based fuel cells. Of course, our solar systems can produce hydrogen through a device called an electrolyzer. This might be useful in the near term for producing hydrogen for a modified automotive application. Your solar system could do double duty, producing both power for your home or business and a fuel for your fuel-cell car. For the pure production of electrical power for your home, however, the electrolyzer and fuel cell are not as cost-effective as using an inverter to convert sunlight to electrical power.