What it is
Alkaline is cheaper and uses no scarce catalysts, but it responds more slowly to changing power input. The choice between it and PEM is a direct trade between iridium and flexibility.
The material bill
Scale it up →Quantities are per MW of capacityindicative range
| Material | Low | High | Unit | Basis |
|---|---|---|---|---|
| Iron & Steel | 2,000 | 5,000 | kg | Stack, frames and vessels |
| Copper critical | 400.0 | 1,200 | kg | Power delivery |
| Nickel critical | 300.0 | 800.0 | kg | Electrodes and catalyst coatings |
| Potash critical | 100.0 | 400.0 | kg | Potassium hydroxide electrolyte |
Indicative range compiled from published technology studies and chemistry; verify against a manufacturer specification before use. Rows marked “trace” contain the material in quantities too small to state usefully as a mass — the constraint there is purity or supplier count, not tonnage.
The alternatives
Substitution is the most underrated force in materials. When a metal gets expensive or politically difficult, engineers design around it — and demand for a whole mine can evaporate.
HVDC Transmission Cable
High-voltage direct-current cable, the technology used to move power hundreds of kilometres with low loss.
PEM Electrolyser
Splits water using a polymer membrane, platinum and iridium — fast-responding but catalyst-hungry.
Pressurised Water Reactor
The most common reactor design: enriched uranium fuel in zirconium tubes, water as both coolant and moderator.
Three-Way Catalytic Converter
The ceramic honeycomb in an exhaust that converts three pollutants at once, coated in platinum-group metals.