PEM fuel cells (PEMFC)

The proton-exchange membrane fuel cell (PEMFC, sometimes "polymer electrolyte membrane") is the type most people mean when they picture a hydrogen fuel cell — and the one powering most fuel-cell vehicles on the road today.

How it works

A thin polymer membrane sits between two electrodes. Hydrogen enters the anode, where a platinum catalyst splits it into protons and electrons. The membrane lets protons cross but blocks electrons, pushing them through the external circuit as electricity before they recombine with oxygen at the cathode to form water.

Why it's the workhorse

Low operating temperature (around 60–80 °C) — it starts quickly and handles stop-and-go demand.
Compact and lightweight — ideal for vehicles, forklifts, drones, and portable power.
Fast response to changing loads.

The trade-offs

PEMFCs need fairly pure hydrogen and a platinum catalyst, which adds cost and sensitivity to contaminants like carbon monoxide. They're brilliant for mobility, less suited to running on raw fossil gas the way high-temperature cells can.

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About the author — George Howell Ward is a long-time clean-energy advocate and early adopter, not a licensed engineer, energy professional, or scientist. He holds a B.S. in Civil Engineering from the University of California, Berkeley, and writes here as an enthusiast and technologist. These guides are educational, draw on legitimate science only, and avoid debunked claims. His interest goes back over a decade: he was an early hydrogen fuel-cell enthusiast who promoted the technology through hands-on demonstrations — including hydrogen fuel-cell model cars — and attended a multi-day fuel-cell seminar hosted by UC Irvine's National Fuel Cell Research Center. (Mentioning the Center is descriptive only — it does not imply the Center endorses George, this site, or its content.)

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