How can a solid oxide fuel cell and a steam turbine produce extra electricity together?
The proton exchange membrane is one of the most advanced fuel cell designs. Hydrogen gas under pressure is forced through a catalyst, typically made of platinum, on the anode (negative) side of the fuel cell. At this catalyst, electrons are stripped from the hydrogen atoms and carried by an external electric circuit to the cathode (positive) side. The positively charged hydrogen ions (protons) then pass through the proton exchange membrane to the catalyst on the cathode side, where they react with oxygen and the electrons from the electric circuit to form water vapour (H2O) and heat. The electric circuit is used to do work, such as power a motor.
A solid oxide fuel cell (SOFC) and a steam turbine can work together in a combined system to increase overall power generation efficiency, potentially reaching 60 percent.1
Because solid oxide fuel cells operate at very high temperatures—typically between 900 and 1,000 °C (1,600 to 1,800 °F)—they produce hot gas as a byproduct. In a configuration known as a bottoming steam cycle, this high-temperature exhaust is utilized to generate steam. This steam is then directed to run a turbine, allowing the system to extract additional power from the heat energy that would otherwise be wasted.1
This integrated approach is designed for central power-generation stations where the high operating temperatures can be managed efficiently.1