cost of fuel cells down, making development of PEMFC systems more realistic. However, there is significant debate as to whether hydrogen fuel cells will be a realistic technology for use in automobiles or other vehicles. (See hydrogen economy.) A large part of PEMFC production is for the Toyota Mirai. The US Department of Energy estimates a 2016 price at $53/kW if 500,000 units per year were made. See also Dynamic hydrogen electrode Gas diffusion electrode Glossary of fuel cell terms High Temperature Proton Exchange Membrane fuel cell Hydrogen sulfide sensor Power-to-weight ratio Reversible hydrogen electrode Timeline of hydrogen technologies References External links Gas diffusion layer and catalyst layer, 3D animation Fuel Cell elements, 3D animation Open Source PEM Fuel Cell Simulation Tool Fuel cells Proton ko:연료전지#고분자전해질 연료전지 (Polymer Electrolyte Membrane Fuel Cell, PEMFC)