Alkaline fuel cells (AFC)

The alkaline fuel cell (AFC) is a piece of history: efficient, reliable, and famous for powering Apollo missions and the Space Shuttle. It's also a lesson in why purity matters.

How it works

AFCs use an alkaline electrolyte (typically potassium hydroxide) and run at low-to-moderate temperatures. They can be very efficient and don't necessarily require expensive precious-metal catalysts.

Strengths

High efficiency and a proven track record in demanding applications.
Lower catalyst cost potential than PEM.
Fast operation at modest temperatures.

The catch

AFCs are highly sensitive to carbon dioxide, which reacts with the electrolyte. They need very pure hydrogen and oxygen (or scrubbed air), which limited their everyday use — though renewed research is revisiting the design with improved materials.

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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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