IN SUMMARY
Hydrogen fuel cells convert hydrogen into electricity, producing only water and heat at the point of use, which makes them a promising technology for decarbonising transport, industry and stationary power. But hydrogen is an energy carrier, not a source, so a fuel cell's true environmental performance depends overwhelmingly on how its hydrogen is produced, alongside the impacts of the specialised materials in the cell itself. This guide, part of Minviro's "Path to Product" series, examines both proton exchange membrane fuel cells (PEMFCs) and solid oxide fuel cells (SOFCs), walking through their materials, manufacturing hotspots, the decisive role of hydrogen sourcing, and the tightening regulatory landscape, all through the lens of life cycle assessment.
Hydrogen sourcing dominates the footprint. Life cycle emissions vary by more than an order of magnitude depending on production pathway: grey hydrogen from steam methane reforming can exceed 90 g CO₂e/MJ, while renewable-powered electrolysis can fall below 20.
The two main fuel cell types suit different uses. PEMFCs run at 60–80°C and suit mobility like fuel cell vehicles; SOFCs run at 600–1000°C and suit stationary power, with higher efficiency but higher manufacturing impacts.
Materials concentrate the risk. PEMFCs depend on platinum (over 80% from South Africa and Russia) and PFSA membranes; SOFCs depend on yttrium, zirconium and lanthanum refined mainly in China, creating single-point-of-failure vulnerabilities.
How fuel cells work, and the two main types
A hydrogen fuel cell is an electrochemical device that converts hydrogen into electricity, producing only water and heat at the point of use. Hydrogen is split into protons and electrons at the anode; the protons cross a membrane or electrolyte while the electrons travel through an external circuit to generate electricity, recombining with oxygen at the cathode to form water. That zero-tailpipe-emission quality makes fuel cells promising for transport and stationary power, but because hydrogen is an energy carrier rather than a source, the technology carries thermodynamic inefficiencies across production, compression, storage, distribution and conversion. The two most commercially significant types differ sharply: PEMFCs operate at low temperatures (60–80°C) and suit mobility applications like fuel cell electric vehicles, forklifts and backup power, while SOFCs operate at high temperatures (600–1000°C) and suit stationary generation, industrial cogeneration and auxiliary power. Their different temperatures and requirements give them distinct material needs and life cycle profiles.
The materials behind each fuel cell type
PEMFCs and SOFCs rely on quite different materials. In a PEMFC, the heart is a proton-conducting membrane, typically a PFSA polymer like Nafion; platinum catalysts drive the reactions at both electrodes, making the technology reliant on platinum group metals even at reduced loadings; carbon-fibre gas diffusion layers manage reactant and water flow; and bipolar plates of graphite or coated stainless steel separate the cells. In an SOFC, yttria-stabilised zirconia (YSZ) is the dominant electrolyte, prized for oxygen-ion conductivity and stability at high temperature; nickel-based cermets (Ni-YSZ) typically form the anode, with lanthanum strontium manganite (LSM) or lanthanum strontium cobalt ferrite (LSCF) cathodes; and interconnects are ferritic stainless steels coated to limit chromium evaporation. These material differences are the root of each technology's distinct environmental and supply chain profile.