At this point, not many people know how fuel cells work, and since there aren’t many moving parts — no cylinders, pistons, crankshafts, etc. — understanding the process seems like a chemistry test. But in a nutshell, here’s how it works:

In a fuel cell, electricity is produced from a reaction between hydrogen and air. First, hydrogen atoms are compressed and stored in high-pressure tanks, two of which are present in the Mirai, together holding about 11 pounds of hydrogen at 10,000 psi. The hydrogen atoms are sent through a platinum membrane that separates the electrons from the protons. Those electrons produce an electric current that powers an electric motor-generator capable of 151 hp and 247 lb-ft of torque. The newly liberated hydrogen protons are introduced to oxygen in the air on the other side of the membrane, which in turn creates water — about a half-cup per mile, says Toyota — which exits the tailpipe. And yes, it's drinkable.

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